Common use of Trust Clause in Contracts

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,588,746.85 Class B-5 B-6 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,588,746.85 Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-7 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-7 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class R Principal Balance as of the Cut-Off Date: $100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below, (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I and (iii) a pool of assets (“REMIC III”) consisting of interests in REMIC I and REMIC II. REMIC I, REMIC II and ▇▇▇▇▇ ▇▇▇ were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement, (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement and (iii) the REMIC III Available Distribution Amount for such Distribution Date, as specified in Section 4.05 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by2,907,000.00

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 11 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,228,000.00 Class B-5 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,228,000.00 Registered Owner Exhibit A CUSIP 93934F JN3 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 11 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,228,000.00 Class B-5 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,228,000.00 Registered Owner Exhibit A CUSIP 93934F JN3 Class B-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26March 28, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 2 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,034,000.00 Class B-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,034,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 29, 20052007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership The Agreement permits, but does not require, the Master Servicer, the Special Servicer or the Plurality Subordinate Certificateholder to purchase from the Trust all Mortgage Loans and any REO Properties (or, if specified in the Agreement with respect to any REO Property, the Trust's interests therein) remaining therein. The exercise of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, such right will effect early retirement of the Internal Revenue Code Certificates; however, such right to purchase is subject to the aggregate Stated Principal Balance of 1986the Mortgage Pool at the time of purchase being less than approximately 1.0% of the Initial Pool Balance. In addition, following the date on which the total principal balance of the Class A-1, Class A-2, Class A-3A, Class A-3B, Class A-SB, Class A-4, Class AM, Class ▇▇, ▇▇▇▇▇ ▇, ▇▇▇▇▇ ▇ ▇▇▇ ▇lass D Certificates is reduced to zero, any single Holder of each outstanding Class of Certificates (other than the Class Z, Class R-I and Class R-II Certificates) may, subject to such other conditions as amendedmay be set forth in the Agreement, exchange those Certificates for all Mortgage Loans and REO Properties (or, if specified in the Agreement with respect to any REO Property, the Trust's interests therein) remaining in the Trust Fund at the time of the exchange. The issue date Agreement permits, with certain exceptions therein provided, the amendment thereof, and the modification of the rights and obligations of the Depositor, the Master Servicer, the Special Servicer and the Trustee thereunder and the rights of the Certificateholders thereunder, at any time by the Master Servicer, the Special Servicer, the Trustee and the Fiscal Agent with the consent of the Holders of Certificates entitled to at least 66-2/3% of the Voting Rights. Any such consent by the Holder of this Certificate shall be conclusive and binding on such Holder and upon all future Holders of this Certificate and of any Certificate issued upon the transfer hereof or in exchange herefor or in lieu hereof whether or not notation of such consent is August 26, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENTmade upon this Certificate. The Class B-5 Certificates will be subordinate Agreement also permits the amendment thereof, in right certain circumstances, including any amendment necessary to maintain the status of payment to each of REMIC I and provide credit support to certain Classes of CertificatesREMIC II as a REMIC, as described in without the Pooling Agreement. WMALT Series 2005-7 Portion consent of the Class B-5 Principal Balance as Holders of any of the Cut-Off Date Evidenced Certificates. Unless the certificate of authentication hereon has been executed by the Authenticating Agent, by manual signature, this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1shall not be entitled to any benefit under the Agreement or be valid for any purpose. The registered Holder hereof, 2005 First Distribution Date: September 26by its acceptance hereof, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as agrees that it will look solely to the Trust (to the extent of its rights therein) for distributions hereunder. This Certificate shall be construed in accordance with the internal laws of the CutState of New York applicable to agreements made and to be performed in said State, without applying any conflicts of law principles of such state (other than the provisions of Section 5-Off Date: $2,379,000.00 Evidencing a beneficial interest 1401 of the New York General Obligations Law), and the obligations, rights and remedies of the Holder hereof shall be determined in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byaccordance with such laws.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26July 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 6 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,912,000.00 Class B-5 B-4 Certificate Interest Rate: Variable Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,912,000.00 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26October 27, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 9 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,333,773.50 Class B-5 B-6 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,333,773.50 Evidencing a beneficial interest Percentage Interest in certain distributions with respect to a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” certain rights specified in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedPooling Agreement. The issue date of this Certificate is August April 26, 20052007. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(h) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS PPP CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” certain rights specified in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedPooling Agreement. The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of 11 Percentage Interest evidenced by this Class PPP Certificate in the distributions to be made with respect to the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this CertificatePPP Certificates: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable 100.00% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Exhibit B CUSIP 93934F JK9 Class B-5 R Evidencing a Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-11 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. WMALT Series 2005-11 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.750%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: December 1, 2005 First Distribution Date: January 25, 2006 Last Scheduled Distribution Date: January 25, 2036 Class R Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial 100.00 Registered Owner Certificate No. ______ This Certificate does not represent an obligation of or interest in WaMu Asset Acceptance Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby WaMu Asset Acceptance Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below and (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I. REMIC I and REMIC II were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement and (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August April 26, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 3 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,352,626.17 Class B-5 B-6 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,352,626.17 Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-3 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-3 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: ________% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: April 1, 2005 First Distribution Date: May 25, 2005 Last Scheduled Distribution Date: May 25, 2035 Class R Principal Balance as of the Cut-Off Date: $100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below and (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I. REMIC I and REMIC II were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement and (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26November 29, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 10 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,389,616.23 Class B-5 B-6 Certificate Interest Rate: Variable Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,389,616.23 Evidencing a beneficial interest Percentage Interest in certain distributions with respect to a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 11 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,929,000.00 Class B-5 B-4 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,929,000.00 Registered Owner Exhibit A CUSIP 93934F JM5 Class B-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26November 29, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 10 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 4,437,800.00 Class B-5 B-4 Certificate Interest Rate: Variable Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 4,437,800.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26October 27, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 9 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,402,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,402,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 29, 20052007. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND “DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATEand any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAWANY TRANSFER, WILL NOT CONSTITUTE PLEDGE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OTHER USE HEREOF FOR VALUE OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OTHERWISE BY OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENTPERSON IS WRONGFUL inasmuch as the registered owner hereof, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUSTCede & Co., THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANYhas an interest herein. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e5.01(f) OF THE POOLING AGREEMENT. The Class NO TRANSFER OF THIS CLASS B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of CertificatesCERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED AN INVESTMENT LETTER IN THE FORM DESCRIBED IN SECTION 5.01(f) OF THE POOLING AGREEMENT. NOTWITHSTANDING THE FOREGOING PARAGRAPH, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class WITH RESPECT TO THE TRANSFER OF THIS CLASS B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, 2005 First Distribution Date: September 26(I) AN INVESTMENT LETTER, 2005 Last Scheduled Distribution Date: September 25AS DESCRIBED IN THE FOREGOING PARAGRAPH, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting ofSHALL NOT BE REQUIRED, among other things, conventional one- to four-family mortgage loans formed byAND (II) THE FOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26February 25, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 1 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,944,818.00 Class B-5 B-4 Certificate Interest Rate: Variable Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,944,818.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August April 26, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 3 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,161,000.00 Class B-5 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,161,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 11 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,929,000.00 Class B-5 B-4 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,929,000.00 Registered Owner Exhibit A CUSIP 93934F JM5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 30, 20052006. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 20052006-7 1 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 5,840,000.00 Class B-5 B-4 Certificate Interest Rate: Variable Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 5,840,000.00 Registered Owner Exhibit A CUSIP 93934F KA 9 Class B-5 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 29, 20052007. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND “DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATEand any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAWANY TRANSFER, WILL NOT CONSTITUTE PLEDGE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OTHER USE HEREOF FOR VALUE OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OTHERWISE BY OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENTPERSON IS WRONGFUL inasmuch as the registered owner hereof, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUSTCede & Co., THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANYhas an interest herein. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e5.01(f) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of CertificatesNO TRANSFER OF THIS CLASS B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED AN INVESTMENT LETTER IN THE FORM DESCRIBED IN SECTION 5.01(f) OF THE POOLING AGREEMENT. NOTWITHSTANDING THE FOREGOING PARAGRAPH, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1WITH RESPECT TO THE TRANSFER OF THIS CLASS B-4 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, 2005 First Distribution Date: September 26(I) AN INVESTMENT LETTER, 2005 Last Scheduled Distribution Date: September 25AS DESCRIBED IN THE FOREGOING PARAGRAPH, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting ofSHALL NOT BE REQUIRED, among other things, conventional one- to four-family mortgage loans formed byAND (II) THE FOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 11 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,051,243.22 Class B-5 B-6 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,051,243.22 Registered Owner Evidencing a beneficial interest Percentage Interest in certain distributions with respect to a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26May 25, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 4 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 3,235,832.00 Class B-5 B-6 Certificate Interest Rate: :Variable Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 3,235,832.00 Exhibit B CUSIP 939336 7J 6 Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-4 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-4 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: ________% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: May 1, 2005 First Distribution Date: June 27, 2005 Last Scheduled Distribution Date: June 25, 2035 Class R Principal Balance as of the Cut-Off Date: $100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I and (iii) a pool of assets (“REMIC III”) consisting of interests in REMIC I and REMIC II. REMIC I, REMIC II and ▇▇▇▇▇ ▇▇▇ were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement, (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement and (iii) the REMIC III Available Distribution Amount for such Distribution Date, as specified in Section 4.05 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26January 29, 20052007. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND “DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATEand any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAWANY TRANSFER, WILL NOT CONSTITUTE PLEDGE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OTHER USE HEREOF FOR VALUE OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OTHERWISE BY OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENTPERSON IS WRONGFUL inasmuch as the registered owner hereof, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUSTCede & Co., THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENThas an interest herein. The Class B-5 1-A-9 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 20052007-7 1 Portion of the Class B-5 1-A-9 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,367,500.00 Class B-5 1-A-9 Certificate Interest Rate: Variable Cut-Off Date: August January 1, 2005 2007 First Distribution Date: September February 26, 2005 2007 Last Scheduled Distribution Date: September February 25, 2035 2037 Class B-5 1-A-9 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,367,500.00 Exhibit A CUSIP ▇▇▇▇▇▇▇▇▇ Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byby This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is a Subsequent Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 1-A-10 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $0.00 Class 1-A-10 Certificate Interest Rate: 5.500% Cut-Off Date: January 1, 2007 First Distribution Date: February 26, 2007 Last Scheduled Distribution Date: February 25, 2037 Class 1-A-10 Principal Balance as of the Cut-Off Date: $0.00 Maximum Initial Class 1-A-10 Principal Balance: $62,761,300.00 Exhibit A CUSIP ▇▇▇▇▇▇▇▇▇ Evidencing a beneficial interest in a trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is a Subsequent Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 1-A-11 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $0.00 Class 1-A-11 Certificate Interest Rate: 5.750% Cut-Off Date: January 1, 2007 First Distribution Date: February 26, 2007 Last Scheduled Distribution Date: February 25, 2037 Class 1-A-11 Principal Balance as of the Cut-Off Date: $0.00 Maximum Initial Class 1-A-11 Principal Balance: $62,761,300.00 Exhibit A CUSIP ▇▇▇▇▇▇▇▇▇ Evidencing a beneficial interest in a trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is a Subsequent Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 1-A-12 Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $0.00

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26October 27, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 9 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,669,000.00 Class B-5 B-4 Certificate Interest Rate: Variable Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,669,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26May 25, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 4 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 4,311,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 4,311,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August April 26, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 3 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 3,241,000.00 Class B-5 B-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August April 1, 2005 First Distribution Date: September 26May 25, 2005 Last Scheduled Distribution Date: September May 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 3,241,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August April 26, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 29, 20052007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 30, 20052006. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 20052006-7 1 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 4,672,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 4,672,000.00 Registered Owner Exhibit A CUSIP 93934F KB 7 Class B-6 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” certain rights specified in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedPooling Agreement. The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of 11 Percentage Interest evidenced by this Class PPP Certificate in the distributions to be made with respect to the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this CertificatePPP Certificates: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable 100.00% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Exhibit B CUSIP 93934F JK9 Evidencing a Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-11 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. WMALT Series 2005-11 Percentage Interest evidenced by this Class B-5 R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.750%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: December 1, 2005 First Distribution Date: January 25, 2006 Last Scheduled Distribution Date: January 25, 2036 Class R Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial 100.00 Registered Owner Certificate No. ______ This Certificate does not represent an obligation of or interest in WaMu Asset Acceptance Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby WaMu Asset Acceptance Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below and (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I. REMIC I and REMIC II were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement and (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” certain rights specified in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedPooling Agreement. The issue date of this Certificate is August 26January 29, 20052007. Interest is not payable with respect to this Certificate. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 C-PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(h) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS C-PPP CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26May 25, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 4 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 5,928,000.00 Class B-5 B-4 Certificate Interest Rate: Variable Cut-Off Date: August May 1, 2005 First Distribution Date: September 26June 27, 2005 Last Scheduled Distribution Date: September June 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 5,928,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26November 29, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 10 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 3,755,100.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 3,755,100.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-3 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-3 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 30, 20052006. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 20052006-7 1 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 3,504,659.14 Class B-5 B-6 Certificate Interest Rate: Variable Cut-Off Date: August January 1, 2005 2006 First Distribution Date: September 26February 27, 2005 2006 Last Scheduled Distribution Date: September February 25, 2035 2036 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 3,504,659.14 Registered Owner Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2006-1 Trust. This Certificate represents certain rights specified in the Pooling Agreement. The issue date of this Certificate is January 30, 2006. NO TRANSFER OF THIS CLASS PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. WMALT Series 2006-1 Percentage Interest evidenced by this Class PPP Certificate in the distributions to be made with respect to the Class PPP Certificates: 100.00% Cut-Off Date: January 1, 2006 First Distribution Date: February 27, 2006 Last Scheduled Distribution Date: February 25, 2036 Exhibit B CUSIP 93934F LL 4 Class R Evidencing a Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2006-1 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. WMALT Series 2006-1 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.750%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: January 1, 2006 First Distribution Date: February 27, 2006 Last Scheduled Distribution Date: February 25, 2036 Class R Principal Balance as of the Cut-Off Date: $100.00 Registered Owner Certificate No. ______ This Certificate does not represent an obligation of or interest in WaMu Asset Acceptance Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby WaMu Asset Acceptance Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below, (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I and (iii) a pool of assets (“REMIC III”) consisting of interests in REMIC I and REMIC II. REMIC I, REMIC II and ▇▇▇▇▇ ▇▇▇ were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement, (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement and (iii) the REMIC III Available Distribution Amount for such Distribution Date, as specified in Section 4.05 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26March 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 2 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,132,850.06 Class B-5 B-6 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,132,850.06 Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-2 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-2 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: ________% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: March 1, 2005 First Distribution Date: April 25, 2005 Last Scheduled Distribution Date: April 25, 2035 Class R Principal Balance as of the Cut-Off Date: $100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below and (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I. REMIC I and REMIC II were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement and (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26January 29, 20052007. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND “DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATEand any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAWANY TRANSFER, WILL NOT CONSTITUTE PLEDGE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OTHER USE HEREOF FOR VALUE OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OTHERWISE BY OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENTPERSON IS WRONGFUL inasmuch as the registered owner hereof, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUSTCede & Co., THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENThas an interest herein. The Class B-5 2-A-2 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 20052007-7 1 Portion of the Class B-5 2-A-2 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,474,000.00 Class B-5 2-A-2 Certificate Interest Rate: Variable 6.000% Cut-Off Date: August January 1, 2005 2007 First Distribution Date: September February 26, 2005 2007 Last Scheduled Distribution Date: September January 25, 2035 2022 Class B-5 2-A-2 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,474,000.00 Exhibit A CUSIP ▇▇▇▇▇▇▇▇▇ Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byby This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is a Subsequent Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 2-A-3 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $0.00 Class 2-A-3 Certificate Interest Rate: 5.500% Cut-Off Date: January 1, 2007 First Distribution Date: February 26, 2007 Last Scheduled Distribution Date: January 25, 2022 Class 2-A-3 Principal Balance as of the Cut-Off Date: $0.00 Maximum Initial Class 2-A-3 Principal Balance: $30,225,000.00 Exhibit A CUSIP ▇▇▇▇▇▇▇▇▇ Evidencing a beneficial interest in a trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is a Subsequent Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 2-A-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $0.00 Class 2-A-4 Certificate Interest Rate: 5.750% Cut-Off Date: January 1, 2007 First Distribution Date: February 26, 2007 Last Scheduled Distribution Date: January 25, 2022 Class 2-A-4 Principal Balance as of the Cut-Off Date: $0.00 Maximum Initial Class 2-A-4 Principal Balance: $30,225,000.00 Exhibit A CUSIP ▇▇▇▇▇▇▇▇▇ Evidencing a beneficial interest in a trust that owns a pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2007-1 Trust. This Certificate represents ownership of one or more “regular interests” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is January 29, 2007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. This Certificate is a Subsequent Exchangeable Certificate, as described in the Pooling Agreement. WMALT Series 2007-1 Portion of the Class 2-A-5 Notional Amount as of the Cut-Off Date Evidenced by this Certificate: $0.00

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26October 27, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 29, 20052007. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26February 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26March 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-4 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-4 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 2 Portion of the Class B-5 B-4 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,260,000.00 Class B-5 B-4 Certificate Interest Rate: Variable 5.500% Cut-Off Date: August March 1, 2005 First Distribution Date: September 26April 25, 2005 Last Scheduled Distribution Date: September April 25, 2035 Class B-5 B-4 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,260,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 30, 20052006. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26December 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 11 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,051,243.22 Class B-5 B-6 Certificate Interest Rate: Variable 5.750% Cut-Off Date: August December 1, 2005 First Distribution Date: September 26January 25, 2005 2006 Last Scheduled Distribution Date: September January 25, 2035 2036 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,051,243.22 Registered Owner CUSIP 93934F JP8 Evidencing a beneficial interest Percentage Interest in certain distributions with respect to a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedamended (the “Code”). The issue date of this Certificate is August 26January 29, 20052007. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND “DTC”), to the Trust or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATEand any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAWANY TRANSFER, WILL NOT CONSTITUTE PLEDGE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OTHER USE HEREOF FOR VALUE OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OTHERWISE BY OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENTPERSON IS WRONGFUL inasmuch as the registered owner hereof, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUSTCede & Co., THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANYhas an interest herein. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e5.01(f) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of CertificatesNO TRANSFER OF THIS CLASS B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED AN INVESTMENT LETTER IN THE FORM DESCRIBED IN SECTION 5.01(f) OF THE POOLING AGREEMENT. NOTWITHSTANDING THE FOREGOING PARAGRAPH, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1WITH RESPECT TO THE TRANSFER OF THIS CLASS B-6 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, 2005 First Distribution Date: September 26(I) AN INVESTMENT LETTER, 2005 Last Scheduled Distribution Date: September 25AS DESCRIBED IN THE FOREGOING PARAGRAPH, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting ofSHALL NOT BE REQUIRED, among other things, conventional one- to four-family mortgage loans formed byAND (II) THE FOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26July 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26July 28, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 6 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,673,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,673,000.00 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26February 25, 2005. NO TRANSFER OF THIS CLASS B-5 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 1 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 2,454,015.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 2,454,015.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed by

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26July 28, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 6 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,197,090.75 Class B-5 B-6 Certificate Interest Rate: Variable Cut-Off Date: August July 1, 2005 First Distribution Date: September 26August 25, 2005 Last Scheduled Distribution Date: September August 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,197,090.75 WASHINGTON MUTUAL MORTGAGE PASS-THROUGH CERTIFICATE Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-6 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-6 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: July 1, 2005 First Distribution Date: August 25, 2005 Last Scheduled Distribution Date: August 25, 2035 Class R Principal Balance as of the Cut-Off Date: $100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below, (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I and (iii) a pool of assets (“REMIC III”) consisting of interests in REMIC I and REMIC II. REMIC I, REMIC II and ▇▇▇▇▇ ▇▇▇ were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement, (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement and (iii) the REMIC III Available Distribution Amount for such Distribution Date, as specified in Section 4.05 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” certain rights specified in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedPooling Agreement. The issue date of this Certificate is August 26November 29, 2005. NO TRANSFER OF THIS CLASS B-5 PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of 10 Percentage Interest evidenced by this Class PPP Certificate in the distributions to be made with respect to the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this CertificatePPP Certificates: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable 100.00% Cut-Off Date: August November 1, 2005 First Distribution Date: September 26December 27, 2005 Last Scheduled Distribution Date: September December 25, 2010 Evidencing a Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-10 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-10 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.750%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: November 1, 2005 First Distribution Date: December 27, 2005 Last Scheduled Distribution Date: December 25, 2035 Class B-5 R Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial 100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below, (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I and (iii) a pool of assets (“REMIC III”) consisting of interests in REMIC I and REMIC II. REMIC I, REMIC II and ▇▇▇▇▇ ▇▇▇ were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement, (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement and (iii) the REMIC III Available Distribution Amount for such Distribution Date, as specified in Section 4.05 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26November 29, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26February 25, 2005. NO TRANSFER OF THIS CLASS B-5 B-6 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 B-6 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 1 Portion of the Class B-5 B-6 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 1,472,409.92 Class B-5 B-6 Certificate Interest Rate: Variable Cut-Off Date: August February 1, 2005 First Distribution Date: September 26March 25, 2005 Last Scheduled Distribution Date: September March 25, 2035 Class B-5 B-6 Principal Balance as of the Cut-Off Date: $2,379,000.00 1,472,409.92 Evidencing a beneficial Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-1 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-1 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: _____% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: February 1, 2005 First Distribution Date: March 25, 2005 Last Scheduled Distribution Date: March 25, Class R Principal Balance as of the Cut-Off Date: $100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below and (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I. REMIC I and REMIC II were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement and (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26March 28, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-2 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-2 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY:

Trust. This Certificate represents ownership of a “regular interest” certain rights specified in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amendedPooling Agreement. The issue date of this Certificate is August 26October 27, 2005. NO TRANSFER OF THIS CLASS B-5 PPP CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of 9 Percentage Interest evidenced by this Class PPP Certificate in the distributions to be made with respect to the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this CertificatePPP Certificates: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable 100.00% Cut-Off Date: August October 1, 2005 First Distribution Date: September 26November 25, 2005 Last Scheduled Distribution Date: September November 25, 2010 Evidencing a Percentage Interest in certain distributions with respect to a pool of conventional one- to four-family mortgage loans formed by ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES A TRANSFER AFFIDAVIT TO THE COMPANY AND THE TRUSTEE THAT (1) SUCH TRANSFEREE IS NOT EITHER (A) THE UNITED STATES, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR INSTRUMENTALITY OF ANY OF THE FOREGOING, (B) ANY ORGANIZATION (OTHER THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) WHICH IS EXEMPT FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (C) ANY ORGANIZATION DESCRIBED IN SECTION 1381(a)(2)(C) OF THE CODE (ANY SUCH PERSON DESCRIBED IN THE FOREGOING CLAUSES (A), (B), OR (C) BEING HEREINAFTER REFERRED TO AS A “DISQUALIFIED ORGANIZATION”), OR (D) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (2) NO PURPOSE OF SUCH TRANSFER IS TO ENABLE THE TRANSFER TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX. SUCH AFFIDAVIT SHALL INCLUDE CERTAIN REPRESENTATIONS AS TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR OTHER DISPOSITION OF THIS CLASS R CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS ON THIS CERTIFICATE. EACH HOLDER OF A CLASS R CERTIFICATE BY ACCEPTANCE OF THIS CERTIFICATE SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS PARAGRAPH. IN THE CASE OF ANY CLASS R CERTIFICATE PRESENTED FOR REGISTRATION IN THE NAME OF ANY PERSON, THE TRUSTEE SHALL REQUIRE (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF A CLASS R CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED (“ERISA”), OR SECTION 4975 OF THE CODE AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. This Certificate is issued by Washington Mutual Mortgage Pass-Through Certificates WMALT Series 2005-9 Trust. Solely for U.S. federal income tax purposes, this Certificate represents “residual interests” in “real estate mortgage investment conduits,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. Series 2005-9 Percentage Interest evidenced by this Class R Certificate in the distributions to be made with respect to the Class R Certificates: __________% Class R Certificate Interest Rate: 5.500%. Additionally the Class R Certificates are entitled to Excess Liquidation Proceeds and the Residual Distribution Amount as defined in the Pooling Agreement. Cut-Off Date: October 1, 2005 First Distribution Date: November 25, 2005 Last Scheduled Distribution Date: November 25, 2035 Class B-5 R Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial 100.00 This Certificate does not represent an obligation of or interest in Washington Mutual Mortgage Securities Corp. or any of its affiliates. Neither this Certificate nor the underlying Mortgage Loans are guaranteed by any agency or instrumentality of the United States. This certifies that the above-named Registered Owner is the registered owner of certain interests in (i) a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets (“REMIC I”) consisting of, among other things, conventional one- to four-family mortgage loans (the “Mortgage Loans”), formed byby Washington Mutual Mortgage Securities Corp. (the “Company”), which term includes any successor entity under the Pooling Agreement referred to below, (ii) a pool of assets (“REMIC II”) consisting of interests in REMIC I and (iii) a pool of assets (“REMIC III”) consisting of interests in REMIC I and REMIC II. REMIC I, REMIC II and ▇▇▇▇▇ ▇▇▇ were created pursuant to a Pooling and Servicing Agreement, dated as of the Cut-Off Date stated above (the “Pooling Agreement”), among the Company, the Servicer, LaSalle Bank National Association, as Trustee (the “Trustee”), and Christiana Bank & Trust Company, as Delaware Trustee, a summary of certain of the pertinent provisions of which is set forth hereafter. To the extent not defined herein, the capitalized terms used herein have the meanings assigned in the Pooling Agreement. Nothing herein shall be deemed inconsistent with such meanings, and in the event of any conflict between the Pooling Agreement and the terms of this Certificate, the Pooling Agreement shall control. This Certificate is issued under and is subject to the terms, provisions and conditions of the Pooling Agreement, to which Pooling Agreement the Holder of this Certificate, by virtue of the acceptance hereof, assents and by which such Holder is bound. Distributions will be made, pursuant to the Pooling Agreement, on the 25th day of each month or, if such 25th day is not a Business Day, the Business Day immediately following (the “Distribution Date”), commencing on the first Distribution Date specified above, to the Person in whose name this Certificate is registered at the close of business on the last day (or if such last day is not a Business Day, the Business Day immediately preceding such last day) of the month immediately preceding the month of such distribution (the “Record Date”), to the extent of such Certificateholder's Percentage Interest represented by this Certificate in the portions (if any) then distributable on the Certificates of this Class of (i) the REMIC I Available Distribution Amount for such Distribution Date, as specified in Section 4.01 of the Pooling Agreement, (ii) the REMIC II Available Distribution Amount for such Distribution Date, as specified in Section 4.04 of the Pooling Agreement and (iii) the REMIC III Available Distribution Amount for such Distribution Date, as specified in Section 4.05 of the Pooling Agreement. Distributions on this Certificate will be made by the Trustee by wire transfer or check mailed to the address of the Person entitled thereto, as such name and address shall appear on the Certificate Register. Notwithstanding the above, the final distribution on this Certificate will be made after due notice by the Trustee of the pendency of such distribution and only upon presentation and surrender of this Certificate to the Certificate Registrar. Reference is hereby made to the further provisions of this Certificate set forth below, which further provisions shall for all purposes have the same effect as if set forth at this place. Unless the certificate of authentication hereon has been executed by or on behalf of the Trustee, by manual signature, this Certificate shall not be entitled to any benefit under the Pooling Agreement or be valid for any purpose.

Trust. This Certificate represents ownership of a “regular interest” in a “real estate mortgage investment conduit,” as those terms are defined in Sections 860G and 860D, respectively, of the Internal Revenue Code of 1986, as amended. The issue date of this Certificate is August 26May 25, 2005. Unless this Certificate is presented by an authorized representative of The Depository Trust Company, a New York corporation (“DTC”), to the Company or its agent for registration of transfer, exchange, or payment, and any Certificate issued is registered in the name of Cede & Co. or such other name as is requested by an authorized representative of DTC (and any payment is made to Cede & Co. or to such other entity as is requested by an authorized representative of DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner hereof, Cede & Co., has an interest herein. NO TRANSFER OF THIS CLASS B-5 B-1 CERTIFICATE WILL BE MADE UNLESS THE TRUSTEE HAS RECEIVED (I) AN OFFICER’S CERTIFICATE IN THE FORM DESCRIBED IN SECTION 5.01(d5.01(g) OF THE POOLING AGREEMENT AND (II) IF SO INDICATED IN SUCH OFFICER’S CERTIFICATE, AN OPINION OF COUNSEL ACCEPTABLE TO AND IN FORM AND SUBSTANCE SATISFACTORY TO THE TRUSTEE AND THE COMPANY TO THE EFFECT THAT THE PURCHASE AND HOLDING OF THIS CERTIFICATE ARE PERMISSIBLE UNDER APPLICABLE LAW, WILL NOT CONSTITUTE OR RESULT IN A NON-EXEMPT PROHIBITED TRANSACTION UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE, AND WILL NOT SUBJECT THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY TO ANY OBLIGATION OR LIABILITY (INCLUDING OBLIGATIONS OR LIABILITIES UNDER SECTION 406 OF ERISA OR SECTION 4975 OF THE CODE) IN ADDITION TO THOSE UNDERTAKEN IN THE POOLING AGREEMENT, WHICH OPINION OF COUNSEL SHALL NOT BE AN EXPENSE OF THE TRUST, THE TRUSTEE, THE DELAWARE TRUSTEE, THE SERVICER OR THE COMPANY. NOTWITHSTANDING THE SECURITIES REPRESENTED BY FOREGOING PARAGRAPH, WITH RESPECT TO THE TRANSFER OF THIS CLASS B-1 CERTIFICATE TO DTC OR ANY OTHER CLEARING AGENCY OR ANY SUBSEQUENT TRANSFER OF ANY INTEREST IN THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER FOR SO LONG AS THIS CERTIFICATE IS HELD BY DTC OR ANY OTHER CLEARING AGENCY, (I) AN OFFICER’S CERTIFICATE (AND, IF APPLICABLE, A BENEFIT PLAN OPINION), AS DESCRIBED IN THE SECURITIES ACT OF 1933. THESE SECURITIES MAY FOREGOING PARAGRAPH, SHALL NOT BE OFFEREDREQUIRED, SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN AND (II) THE ABSENCE OF REGISTRATION OR THE AVAILABILITY OF AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933 AND EXCEPT IN ACCORDANCE WITH SECTION 5.01(e) OF THE POOLING AGREEMENT. The Class B-5 Certificates will be subordinate in right of payment to and provide credit support to certain Classes of Certificates, as described in the Pooling Agreement. WMALT Series 2005-7 Portion of the Class B-5 Principal Balance as of the Cut-Off Date Evidenced by this Certificate: $2,379,000.00 Class B-5 Certificate Interest Rate: Variable Cut-Off Date: August 1, 2005 First Distribution Date: September 26, 2005 Last Scheduled Distribution Date: September 25, 2035 Class B-5 Principal Balance as of the Cut-Off Date: $2,379,000.00 Evidencing a beneficial interest in a pool of assets consisting of beneficial interests in another pool of assets consisting of beneficial interests in another pool of assets consisting of, among other things, conventional one- to four-family mortgage loans formed byFOLLOWING CONDITIONS SHALL APPLY: