RIGHTS AGREEMENT SIGMA-ALDRICH CORPORATION and COMPUTERSHARE INVESTOR SERVICES, LLC Rights Agent Dated as of August 8, 2000 INDEX

Exhibit 1

RIGHTS AGREEMENT

_____________________________

SIGMA-▇▇▇▇▇▇▇ CORPORATION

and

COMPUTERSHARE INVESTOR SERVICES, LLC

Rights Agent

_____________________________

Dated as of August 8, 2000

INDEX

	Page
Section 1. Certain Definitions	1
Section 2. Appointment of Rights Agent	4
Section 3. Issue of Right Certificates	5
Section 4. Form of Right Certificates	7
Section 5. Countersignature and Registration	8
Section 6. Transfer, Split Up, Combination and Exchange of Right Certificates; Mutilated, Destroyed, Lost or Stolen Right Certificates	8
Section 7. Exercise of Rights; Purchase Price; Expiration Date of Rights	9
Section 8. Cancellation and Destruction of Right Certificates	11
Section 9. Reservation and Registration of Shares of Common Stock	11
Section 10. Common Stock Record Date	12
Section 11. Adjustment of Purchase Price, Number of Shares or Number of Rights	13
Section 12. Certificate of Adjusted Purchase Price or Number of Shares	18
Section 13. Consolidation, Merge or Sale or Transfer of Assets or Earning Power	19
Section 14. Fractional Rights and Fractional Shares	21
Section 15. Rights of Action	22
Section 16. Agreement of Right Holders	22
Section 17. Right Certificate Holder Not Deemed a Stockholder	23
Section 18. Concerning the Rights Agent	23
Section 19. Merger or Consolidation or Change of Names of Rights Agent	24
Section 20. Duties of Rights Agent	24
Section 21. Change of Rights Agent	27
Section 22. Issuance of New Right Certificates	27
Section 23. Redemption and Termination	28
Section 24. Exchange	29
Section 25. Notice of Proposed Actions	30
Section 26. Notices	30
Section 27. Supplements and Amendments	31
Section 28. Successors	32
Section 29. Benefits of This Rights Agreement	32
Section 30. Severability	32
Section 31. Governing Law	32
Section 32. Counterparts	32
Section 33. Descriptive Headings	32

Exhibit A - Form of Right Certificate

Exhibit B - Summary of Common Stock Purchase Rights

RIGHTS AGREEMENT

This Rights Agreement, dated as of August 8, 2000 (the "Rights Agreement") is entered into between SIGMA-▇▇▇▇▇▇▇ CORPORATION, a Delaware corporation (the "Company"), and COMPUTERSHARE INVESTOR SERVICES, LLC, an Illinois limited liability company, as rights agent (the "Rights Agent").

W I T N E S S E T H

WHEREAS, on August 8, 2000 the Board of Directors of the Company authorized and declared a dividend distribution of one right (hereinafter referred to as a "Right") for each share of common stock, par value $1.00 per share, of the Company ("Common Stock") outstanding at the close of business on August 22, 2000 (the "Record Date") (other than shares of such Common Stock held in the Company's treasury on such date), and has authorized the issuance of one Right in respect of each share of Common Stock issued between the Record Date (whether originally issued or issued from the Company's treasury) and the Distribution Date (as such term is defined in Section 3 hereof), each Right representing the right to purchase one share of Common Stock, upon the terms and subject to the conditions hereinafter set forth (the "Rights"); and

WHEREAS, the Company desires to appoint the Rights Agent to act as provided herein, and the Rights Agent is willing to so act.

NOW, THEREFORE, in consideration of the premises and the mutual agreements herein set forth, the parties hereby agree as follows:

Section 1. Certain Definitions. For purposes of this Rights Agreement, the following terms have the meanings indicated:

(a) "Acquiring Person" shall mean any Person (as hereinafter defined) who or which, together with all Affiliates (as hereinafter defined) and Associates (as hereinafter defined) of such Person, without the Prior Written Approval of the Company (as hereinafter defined), shall be the Beneficial Owner (as hereinafter defined) of securities of the Company constituting 15% or more of the Voting Power (as hereinafter defined) of the Company or was such a Beneficial Owner at any time after the date hereof, whether or not such Person continues to be the Beneficial Owner of securities representing 15% or more of the Voting Power of the Company, but shall not include (i) the Company, any Subsidiary of the Company, any employee benefit plan or compensation arrangement of the Company or any Subsidiary of the Company, or any entity holding securities of the Company to the extent organized, appointed or established by the Company or any Subsidiary of the Company for or pursuant to the terms of any such employee benefit plan or compensation arrangement, or (ii) any Person who or which, together with all Affiliates and Associates of such Person, inadvertently may become the Beneficial Owner of securities of the Company representing 15% or more of the Voting Power of the Company or otherwise becomes such a Beneficial Owner without a plan or intention to acquire control of the Company, so long as such Person, individually or together with the Affiliates and Associates of such Person, promptly enters into, and delivers to the Company, an irrevocable commitment promptly to divest, and thereafter promptly divests (without exercising or retaining any power, including voting, with respect to such securities), sufficient securities of the Company so that such Person, together with all Affiliates and Associates of such Person, ceases to be the Beneficial Owner of 15% or more of the Voting Power of the Company. Notwithstanding the foregoing, no Person shall become an "Acquiring Person" as the result of an acquisition of voting securities of the Company by the Company which, by reducing the amount of such securities outstanding, increases the proportionate voting power of such securities beneficially owned by such Person to 15% or more of the Voting Power of the Company; provided, however, that if a Person becomes the Beneficial Owner of securities constituting 15% or more of the Voting Power of the Company by reason of purchases by the Company and shall, after such purchases by the Company, become the Beneficial Owner of any additional voting securities of the Company without the Prior Written Approval of the Company, then such Person shall be deemed to be an Acquiring Person.

(b) "Affiliate" and "Associate" shall have the respective meanings ascribed to such terms in Rule 12b-2 of the General Rules and Regulations under the Exchange Act (as defined below), as in effect on the date hereof.

(i) which such Person or any of such Person's Affiliates or Associates beneficially owns, directly or indirectly as determined pursuant to Rule 13d-3 of the General Rules and Regulations under the Exchange Act, as in effect on the date hereof;

(ii) which such Person or any of such Person's Affiliates or Associates has (A) the right to acquire (whether such right is exercisable immediately or only after the passage of time) pursuant to any agreement, arrangement or understanding (other than customary agreements with and between underwriters and selling group members with respect to a bona fide public offering of securities), or upon the exercise of conversion rights, exchange rights, rights (other than these Rights), warrants or options, or otherwise, provided, however, that a Person shall not be deemed the "Beneficial Owner" of securities tendered pursuant to a tender or exchange offer made by or on behalf of such Person or any of such Person's Affiliates or Associates until such tendered securities are accepted for payment or exchange; or (B) the right to vote pursuant to any agreement, arrangement or understanding, provided, however, that a Person shall not be deemed the "Beneficial Owner" of any security under this clause (B) if the agreement, arrangement or understanding to vote such security (1) arises solely from a revocable proxy or consent given in response to a public proxy or consent solicitation made pursuant to, and in accordance with, the applicable rules and regulations under the Exchange Act and (2) is not also then reportable by such person on Schedule 13D under the Exchange Act (or any comparable or successor report); or

(iii) which are beneficially owned, directly or indirectly, by any other Person with which such Person or any of such Person's Affiliates or Associates has any agreement, arrangement or understanding (other than customary agreements with and between underwriters and selling group members with respect to a bona fide public offering of securities) for the purpose of acquiring, holding, voting (except pursuant to a revocable proxy or consent as described in clause (B) of subparagraph (ii) of this paragraph (c)) or disposing of any securities of the Company.

Notwithstanding anything in this definition of Beneficial Ownership to the contrary, the phrase "then outstanding," when used with reference to a Person's Beneficial Ownership of securities of the Company, shall mean the number of such securities then issued and outstanding together with the number of such securities not then actually issued and outstanding which such Person would be deemed to own beneficially hereunder.

(d) "Board of Directors" shall mean the Board of Directors of the Company as constituted from time to time.

(e) "Business Day" shall mean any day other than a Saturday, Sunday, or a day on which banking institutions in the State of Missouri or Illinois are authorized or obligated by law or executive order to close.

(f) "Close of Business" on any given date shall mean 5:00 P.M., St. Louis, Missouri time, on such date; provided, however, that if such date is not a Business Day it shall mean 5:00 P.M., St. Louis, Missouri time, on the next succeeding Business Day.

(g) "Common Stock" shall have the meaning set forth in the Recitals of this Rights Agreement, except that "Common Stock" when used with reference to any Person other than the Company shall mean the capital stock with the greatest Voting Power of such Person or the equity securities or other equity interest having power to control or direct the management of such Person or, if such Person is a Subsidiary (as hereinafter defined) of another Person, of the Person which ultimately controls such first-mentioned Person and which has issued and outstanding such capital stock, equity securities or equity interests.

(h) "Company" shall have the meaning set forth in the Preamble of this Rights Agreement.

(i) "Distribution Date" shall have the meaning set forth in Section 3 hereof.

(j) "Exchange Act" shall mean the Securities Exchange Act of 1934, as amended.

(k) "Expiration Date" shall have the meaning set forth in Section 7(a) hereof.

(l) "Final Expiration Date" shall have the meaning set forth in Section 7(a) hereof.

(m) "Person" shall mean any individual, firm, corporation, partnership or other entity, and shall include any successor (by merger or otherwise) of any such entity.

(n) "Prior Written Approval of the Company" shall mean prior express written consent of the Company to the actions in question, executed on behalf of the Company by a duly authorized officer of the Company following express approval by action of at least a majority of the members of the Board of Directors then in office.

(o) "Purchase Price" shall have the meaning set forth in Section 4 hereof.

(p) "Record Date" shall have the meaning set forth in the Recitals of this Rights Agreement.

(q) "Redemption Price" shall have the meaning set forth in Section 23(a) hereof.

(r) "Right" shall have the meaning set forth in the Recitals of this Rights Agreement.

(s) "Rights Agent" shall have the meaning set forth in the Preamble of this Rights Agreement.

(t) "Securities Act" shall mean the Securities Act of 1933, as amended.

(u) "Section 11(b) Event" shall have the meaning set forth in Section 11(b) hereof.

(v) "Section 13 Event" shall mean an event described in clauses (x), (y) or (z) of Section 13(a) hereof.

(w) "Stock Acquisition Date" shall mean the earlier of (i) the first date of public announcement by a Person that an Acquiring Person has become an Acquiring Person, or (ii) the date on which the Company first has notice, direct or indirect, or otherwise determines that a Person has become an Acquiring Person.

(x) "Subsidiary" shall mean, with respect to any Person, any other Person of which securities or other ownership interests having ordinary Voting Power, in the absence of contingencies, to elect a majority of the board of directors (or other persons performing similar functions) of such other Person are at the time directly or indirectly owned by such Person or one or more of such Person's Subsidiaries, except that "Subsidiary" when used with reference to the Company shall mean any Person of which either a majority of the Voting Power of the voting equity securities or a majority of the equity interests is owned, directly or indirectly, by the Company.

(y) "Voting Power" shall mean the voting power of all securities of a Person then outstanding generally entitled to vote for the election of directors of the Person (or, where appropriate, for the election of persons performing similar functions).

Section 2. Appointment of Rights Agent. The Company hereby appoints the Rights Agent to act as agent for the Company and the holders of the Rights (who, in accordance with Section 3 hereof, shall prior to the Distribution Date also be the holders of the Common Stock) in accordance with the terms and conditions hereof, and the Rights Agent hereby accepts such appointment. The Company may from time to time appoint such Co-Rights Agents as it may deem necessary or desirable. In the event the Company appoints one or more Co-Rights Agents, the respective duties of the Rights Agents and any Co-Rights Agents shall be as the Company shall determine.

Section 3. Issue of Right Certificates.

(a) Until the earlier of (i) the Close of Business on the tenth Business Day after the Stock Acquisition Date or (ii) the Close of Business on the tenth Business Day (or such later date as may be determined by action of the Board of Directors but in no event later than the tenth Business Day after such time as any Person becomes an Acquiring Person) after the date that a tender or exchange offer by any Person (other than the Company, any Subsidiary of the Company, any employee benefit plan or compensation arrangement of the Company or of any Subsidiary of the Company, or any entity holding securities of the Company to the extent organized, appointed or established by the Company or any Subsidiary of the Company for or pursuant to the terms of any such employee benefit plan or compensation arrangement) is first published or sent or given within the meaning of Rule 14d-2(a) of the General Rules and Regulations under the Exchange Act, without the Prior Written Approval of the Company, which tender or exchange offer would result in any Person becoming the Beneficial Owner of Voting Power aggregating 15% or more of the outstanding Voting Power (including any such date which is after the date of this Rights Agreement and prior to the issuance of the Rights; the earlier of such dates being herein referred to as the "Distribution Date"), (y) the Rights will be evidenced (subject to the provisions of paragraph (b) of this Section 3) by the certificates for the Common Stock registered in the names of the holders of the Common Stock (which certificates for Common Stock shall be deemed also to be Right Certificates) and not by separate Right Certificates, as more fully set forth below, and (z) the Rights (and the right to receive certificates therefor) will be transferable only in connection with the transfer of the underlying shares of Common Stock, as more fully set forth below. As soon as practicable after the Company has notified the Rights Agent of the occurrence of the Distribution Date, the Company shall prepare and execute, and the Rights Agent shall countersign and send, at the expense of the Company, by first-class, insured, postage prepaid mail, to each record holder of the Common Stock as of the Close of Business on the Distribution Date, at the address of such holder shown on the records of the Company, a right certificate, in substantially the form of Exhibit B hereto (the "Right Certificate"), evidencing one Right for each share of Common Stock so held, subject to adjustment as provided herein. As of and after the Distribution Date, the Rights will be evidenced solely by such Right Certificates.

(b) On the Record Date or as soon as practicable thereafter, the Company will send a copy of a Summary of Rights to Purchase Common Stock, in substantially the form of Exhibit A hereto (the "Summary of Rights"), by first-class, postage prepaid mail, to each record holder of the Common Stock as of the Close of Business on the Record Date, at the address of such holder shown on the records of the Company. With respect to certificates for the Common Stock outstanding as of the Record Date, until the Distribution Date (or the earlier redemption, expiration or termination of the Rights), the Rights will be evidenced by such certificates for the Common Stock registered in the names of the holders of the Common Stock and the registered holders of the Common Stock shall also be registered holders of the associated Rights. Until the Distribution Date (or the earlier redemption, expiration or termination of the Rights), the surrender for transfer of any of the certificates for the Common Stock outstanding in respect of which Rights have been issued shall also constitute the transfer of the Rights associated with the Common Stock represented by such certificate.

(c) Certificates for the Common Stock issued after the Record Date but prior to the earlier of the Distribution Date or the redemption, expiration or termination of the Rights shall be deemed also to be certificates for Rights and shall have impressed, printed or written on, or otherwise affixed to them a legend substantially to the following effect:

This certificate also evidences and entitles the holder hereof to certain Rights as set forth in a Rights Agreement (the "Rights Agreement") between Sigma-▇▇▇▇▇▇▇ Corporation (the "Company") and Computershare Investor Services, LLC, as Rights Agent, as it may from time to time be supplemented or amended, the terms of which are incorporated herein by reference and a copy of which is on file at the principal executive offices of the Company. Under certain circumstances, as set forth in the Rights Agreement, such Rights may expire or may be redeemed, exchanged or be evidenced by separate certificates and no longer be evidenced by this certificate. The Company will mail to the holder of this certificate a copy of the Rights Agreement without charge promptly after receipt of a written request therefor. Under certain circumstances, Rights issued to or held by Acquiring Persons or their Affiliates or Associates (as defined in the Rights Agreement) and any subsequent holder of such Rights may become null and void.

With respect to such certificates containing the foregoing legend, until the Distribution Date (or the earlier redemption, expiration or termination of the Rights), the Rights associated with the Common Stock represented by such certificates shall be evidenced by such certificates alone, and the surrender for transfer of any of such certificates shall also constitute the transfer of the Rights associated with the Common Stock represented by such certificates.

In the event that the Company purchases or acquires any Common Stock after the Record Date but prior to the Distribution Date, any Rights associated with such Common Stock shall be deemed canceled and retired so that the Company shall not be entitled to exercise any Rights associated with shares of Common Stock which are no longer outstanding.

Section 4. Form of Right Certificates.

(a) The Right Certificates (and the forms of election to purchase Common Stock and of assignment to be printed on the reverse thereof) shall be in substantially the same form as Exhibit A hereto and may have such marks of identification or designation and such legends, summaries or endorsements printed thereon as the Company may deem appropriate and as are not inconsistent with the provisions of this Rights Agreement, or as may be required to comply with any applicable law, rule or regulation or with any rule or regulation of any stock exchange on which the Rights may from time to time be listed, or to conform to customary usage. Subject to the provisions of Section 11 and Section 22 hereof, the Right Certificates, whenever issued, shall be dated as of the Record Date, and on their face shall entitle the holders thereof to purchase such number of shares of Common Stock as shall be set forth therein at the price per share as set forth therein (the "Purchase Price"), but the number and identity of such shares and the Purchase Price shall be and remain subject to adjustment as provided in Sections 11, 13 and 22 hereof.

(b) Any Right Certificate issued pursuant to Section 3(a) hereof that represents Rights beneficially owned by (i) an Acquiring Person or any Associate or Affiliate of an Acquiring Person, (ii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) which becomes a transferee after the Acquiring Person becomes such, or (iii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) which becomes a transferee prior to or concurrently with the Acquiring Person becoming such and which receives such Rights pursuant to either (A) a transfer (whether or not for consideration) from the Acquiring Person (or any such Associate or Affiliate) to holders of equity interests in such Acquiring Person (or such Associate or Affiliate) or to any Person with whom such Acquiring Person (or such Associate or Affiliate) has any continuing plan, agreement, arrangement or understanding regarding either the transferred Rights, shares of Company Common Stock or the Company or (B) a transfer which a majority of the Board of Directors has determined to be part of a plan, agreement, arrangement or understanding which has as a primary purpose or effect the avoidance of Section 7(e), and any Right Certificate issued pursuant to Section 6 hereof, Section 11 hereof or Section 22 hereof upon transfer, exchange, replacement or adjustment of any other Right Certificate referred to in this sentence, shall contain (to the extent feasible) the following legend:

The Rights represented by this Right Certificate are or were beneficially owned by a Person who was or became an Acquiring Person or an Affiliate or an Associate of an Acquiring Person. Accordingly, this Right Certificate and the Rights represented hereby are void in the circumstances specified in Section 7(e) of the Rights Agreement.

The failure to print the foregoing legend on any such Right Certificate or any defect therein shall not affect in any manner whatsoever the application or interpretation of the provisions of Section 7(e) hereof.

Section 5. Countersignature and Registration.

(a) The Right Certificates shall be executed on behalf of the Company by its Chairman of the Board, Chief Executive Officer and President, Chief Administrative Officer and Chief Financial Officer, or any Vice President, either manually or by facsimile signature, and shall have affixed thereto the Company's seal or a facsimile thereof which shall be attested by the Secretary or an Assistant Secretary of the Company, either manually or by facsimile signature. The Right Certificates shall be countersigned manually or by facsimile signature by the Rights Agent or the registrar or co-registrar for the Common Stock (the "Registrar") and shall not be valid for any purpose unless so countersigned. In case any officer of the Company whose manual or facsimile signature is affixed to the Right Certificates shall cease to be such officer of the Company before countersignature by the Rights Agent or the Registrar and issuance and delivery by the Company, such Right Certificates, nevertheless, may be countersigned by the Rights Agent or the Registrar, issued and delivered with the same force and effect as though the person who signed such Right Certificates had not ceased to be such officer of the Company. Any Right Certificate may be signed on behalf of the Company by any person who, at the actual date of the execution of such Right Certificate, shall be a proper officer of the Company to sign such Right Certificate, although at the date of the execution of this Rights Agreement any such person was not such an officer.

(b) Following the Distribution Date, the Rights Agent will keep or cause to be kept, at its stockholder services office or such other office designated for such purpose, books for registration and transfer of the Right Certificates issued hereunder. Such books shall show the names and addresses of the respective holders of the Right Certificates, the number of Rights evidenced on its face by each of the Right Certificates, the certificate number of each of the Right Certificates and the date of each of the Right Certificates.

Section 6. Transfer, Split Up, Combination and Exchange of Right Certificates; Mutilated, Destroyed, Lost or Stolen Right Certificates.

(a) Subject to the provisions of Section 14 hereof, at any time after the Close of Business on the Distribution Date, and at or prior to the Close of Business on the Expiration Date (as such term is defined in Section 7(a) hereof), any Right Certificate or Right Certificates may be transferred, split up, combined or exchanged for another Right Certificate or Right Certificates, entitling the registered holder to purchase a like number of shares of Common Stock as the Right Certificate or Right Certificates surrendered then entitled such holder to purchase. Any registered holder desiring to transfer, split up, combine or exchange any Right Certificate shall make such request in writing delivered to the Rights Agent, and shall surrender the Right Certificate or Right Certificates to be transferred, split up, combined or exchanged at the stockholder services office of the Rights Agent or such office designated for such purpose. Thereupon, the Rights Agent shall countersign and deliver to the person entitled thereto a Right Certificate or Right Certificates, as the case may be, as so requested. The Company may require payment of a sum sufficient to cover any tax or governmental charge that may be imposed in connection with any transfer, split up, combination or exchange of Right Certificates.

(b) Upon receipt by the Company and the Rights Agent of evidence reasonably satisfactory to them of the loss, theft, destruction or mutilation of a Right Certificate, and, in case of loss, theft or destruction, of indemnity or security reasonably satisfactory to them, and reimbursement to the Company and the Rights Agent of all reasonable expenses incidental thereto, and upon surrender to the Rights Agent and cancellation of the Right Certificate if mutilated, the Company will make and deliver a new Right Certificate of like tenor to the Rights Agent for countersignature and delivery to the registered owner in lieu of the Right Certificate so lost, stolen, destroyed or mutilated.

Section 7. Exercise of Rights; Purchase Price; Expiration Date of Rights.

(a) The registered holder of any Right Certificate may exercise the Rights evidenced thereby (except as otherwise provided herein) in whole or in part at any time after the Distribution Date upon surrender of the Right Certificate, with the form of election to purchase on the reverse side thereof duly executed, to the Rights Agent at the stockholder services office of the Rights Agent or such office designated for such purpose, together with payment of the Purchase Price for each share of Common Stock as to which the Rights are exercised, at or prior to the Close of Business on the Expiration Date. The "Expiration Date", as used in this Rights Agreement, shall be the earliest of (i) the Final Expiration Date (as defined below), (ii) the time at which the Rights are redeemed as provided in Section 23 hereof, or (iii) the time at which the Rights are exchanged as provided in Section 24 hereof. Provided that a Stock Acquisition Date has not occurred prior to such date, on the fourth anniversary of the date hereof, or as soon thereafter as is reasonably practicable, the Board of Directors shall consider whether to amend this Rights Agreement to cause the Final Expiration Date to be such earlier date as the Board of Directors shall determine. The "Final Expiration Date", as used in this Rights Agreement, shall be August 8, 2010, subject to amendment as provided in this Section 7(a) or in Section 27 hereof.

(b) The Purchase Price for each share of Common Stock pursuant to the exercise of a Right shall initially be $150.00, shall be subject to adjustment from time to time as provided in Sections 11 and 13 hereof and shall be payable in lawful money of the United States of America in accordance with paragraph (c) below.

(c) (i) Upon receipt of a Right Certificate, with the form of election to purchase duly executed, accompanied by payment of the Purchase Price for each share of Common Stock to be purchased and an amount equal to any applicable transfer tax required to be paid by the holder of the Rights pursuant hereto in accordance with Section 9 hereof by certified check, bank draft or money order payable to the order of the Company or the Rights Agent, the Rights Agent shall, subject to Section 20(k) hereof, thereupon promptly (A) requisition from any transfer agent of the shares of Common Stock (or make available, if the Rights Agent is the transfer agent) certificates for the number of shares of Common Stock to be purchased and the Company hereby irrevocably authorizes any such transfer agent to comply with all such requests, (B) promptly after receipt of such certificates, cause the same to be delivered to or upon the order of the registered holder of such Right Certificate, registered in such name or names as may be designated by such holder, (C) when appropriate, requisition from the Company the amount of cash to be paid in lieu of issuance of fractional shares in accordance with Section 14 hereof, (D) after receipt of any such cash, promptly deliver such cash to or upon the order of the registered holder of such Right Certificate, (E) when appropriate, requisition from the Company the amount of cash or securities issuable upon exercise of a Right pursuant to the provisions of Section 7(c)(ii), the adjustment provisions of Section 11 or the exchange provisions of Section 24, and (F) after receipt of any such cash or securities, promptly deliver such cash or securities to or upon the order of the registered holder of such Right Certificate.

(ii) In the event that there shall not be sufficient Treasury shares or authorized but unissued shares of Common Stock to permit the exercise in full of the Rights in accordance with the foregoing Section 7(c)(i), and the Rights become so exercisable, notwithstanding any other provision of this Rights Agreement, to the extent necessary and permitted by applicable law and any agreements in effect on the date hereof to which the Company is a party, each Right shall thereafter represent the right to receive, upon exercise thereof at the then current Purchase Price, multiplied by the then number of shares of Common Stock for which a Right is then exercisable (the "Exercise Shares") in accordance with the terms of this Rights Agreement, a number of shares, or units of shares, of (A) Common Stock, and (B) preferred stock (or other equity securities) of the Company, equal in the aggregate to the number of Exercise Shares where the Board of Directors shall have in good faith deemed such shares or units, other than the shares of Common Stock, to have at least the same value and voting rights as the Common Stock (a "common stock equivalent"); provided, however, if there are unavailable sufficient shares (or fractions of shares) of Common Stock and/or common stock equivalents, then the Company shall take all such action as may be necessary to authorize additional shares of Common Stock or common stock equivalents for issuance upon exercise of the Rights, including without limitation the calling of a meeting of stockholders; and provided, further, that if the Company is unable to cause sufficient shares of Common Stock and/or common stock equivalents to be available for issuance upon exercise in full of the Rights, then the Company, to the extent necessary and permitted by applicable law and any agreements or instruments in effect on the date thereof to which it is a party, shall make provision to pay an amount in cash equal to the amount, if any, by which the current market price of a share of Common Stock (determined as provided in Section 14(b) hereof) exceeds the then Purchase Price, in lieu of issuing each share of Common Stock and/or common stock equivalent which the Company is unable to issue. To the extent that the Company determines that some action needs to be taken pursuant to this Section 7(c)(ii), the Board of Directors by action of at least a majority of its members then in office may suspend the exercisability of the Rights for a period of up to sixty (60) days following the date on which the Distribution Event shall have occurred, in order to decide the appropriate form of distribution to be made pursuant to this Section 7(c)(ii) and to determine the value thereof. In the event of any such suspension, the Company shall issue a public announcement stating that the exercisability of the Rights has been temporarily suspended. The Board of Directors may, but shall not be required to, establish procedures to allocate the right to receive Common Stock and common stock equivalents upon exercise of the Rights among holders of Rights, which such allocation may be, but is not required to be, pro-rata.

(d) In case the registered holder of any Right Certificate shall exercise less than all the Rights evidenced thereby, a new Right Certificate evidencing Rights equivalent to the Rights remaining unexercised shall be issued by the Rights Agent to the registered holder of such Right Certificate or to such holder's duly authorized assigns, subject to the provisions of Section 14 hereof.

(e) Notwithstanding anything in this Rights Agreement to the contrary, upon the first occurrence of a Section 11(b) Event or a Section 13 Event, any Rights beneficially owned by (i) an Acquiring Person or an Associate or Affiliate of an Acquiring Person, (ii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) which becomes a transferee after the Acquiring Person becomes such, or (iii) a transferee of an Acquiring Person (or of any such Associate or Affiliate) which becomes a transferee prior to or concurrently with the Acquiring Person becoming such and which receives such Rights pursuant to either (A) a transfer (whether or not for consideration) from the Acquiring Person (or any such Associate or Affiliate) to holders of equity interests in such Acquiring Person (or any such Associate or Affiliate) or to any Person with whom such Acquiring Person (or such Associate or Affiliate) has any continuing agreement, arrangement or understanding regarding the transferred Rights, shares of Company Common Stock or the Company or (B) a transfer which a majority of the Board of Directors has determined to be part of a plan, agreement, arrangement or understanding which has as a primary purpose or effect the avoidance of this Section 7(e), shall be null and void without any further action, and no holder of such Rights shall have any rights whatsoever with respect to such Rights, whether under any provision of this Agreement or otherwise. The Company shall use all reasonable efforts to ensure that the provisions of this Section 7(e) and Section 4(b) are complied with, but shall have no liability to any holder of Rights or any other Person as a result of its failure to make any determination under this Section 7(e) or Section 4(b) with respect to an Acquiring Person or its Affiliates, Associates or transferees hereunder.

(f) Notwithstanding anything in this Rights Agreement to the contrary, neither the Rights Agent nor the Company shall be obligated to undertake any action with respect to a registered holder upon the occurrence of any purported exercise as set forth in this Section 7 unless the certificate contained in the appropriate form of election to purchase set forth on the reverse side of the Right Certificate surrendered for such exercise shall have been properly completed and duly executed by the registered holder thereof and the Company shall have been provided with such additional evidence of the identity of the Beneficial Owner (or former Beneficial Owner) or Affiliates or Associates thereof as the Company shall reasonably request.

Section 8. Cancellation and Destruction of Right Certificates. All Right Certificates surrendered for the purpose of exercise, transfer, split up, combination or exchange shall, if surrendered to the Company or to any of its agents, be delivered to the Rights Agent for cancellation or in canceled form, or, if surrendered to the Rights Agent, shall be canceled by it, and no Right Certificates shall be issued in lieu thereof except as expressly permitted by any of the provisions of this Rights Agreement. The Company shall deliver to the Rights Agent for cancellation and retirement, and the Rights Agent shall so cancel and retire, any other Right Certificate purchased or acquired by the Company otherwise than upon the exercise thereof. The Rights Agent shall deliver a certificate of cancellation to the Company in connection with all Rights Certificates so canceled and retired by the Rights Agent and shall maintain any such canceled Rights Certificates in accordance with Rules 17Ad-6(c) and 17Ad-7 of the General Rules and Regulations under the Exchange Act or their successor provisions.

Section 9. Reservation and Registration of Shares of Common Stock.

(a) Prior to a Distribution Date, the Company may, but shall not be required to, reserve and keep available out of its authorized and unissued shares of Common Stock or its authorized and issued shares of Common Stock held in its treasury, the number of shares of Common Stock that will be sufficient to permit the exercise in full of all outstanding Rights. After the occurrence of a Distribution Date, Section 11(b) Event or a Section 13 Event, the Company shall take all such action as may be necessary to allow it so to reserve and keep available a sufficient number of shares of Common Stock and/or other securities which may be required to permit the exercise in full of the Rights pursuant to this Rights Agreement, including without limitation seeking approval from the Company's stockholders of an increase in the number of authorized shares of Common Stock and/or other securities.

(b) The Company covenants and agrees that it will take all such action as may be necessary to ensure that all shares of Common Stock and/or other securities delivered upon exercise of Rights shall, at the time of delivery of the certificates for such shares or other securities (subject to payment of the Purchase Price), be duly and validly authorized and issued and fully paid and nonassessable shares or securities.

(c) The Company shall use its best efforts to (i) file, as soon as practicable following the first occurrence of an event which would establish the Distribution Date, a registration statement under the Securities Act, with respect to the securities purchasable upon exercise of the Rights on an appropriate form, (ii) cause such registration statement to become effective as soon as practicable after such filing, and (iii) cause such registration statement to remain effective (with a prospectus at all times meeting the requirements of the Securities Act) until the Expiration Date. The Company will also take such action as may be appropriate under the "blue sky laws" of the various states.

(d) The Company further covenants and agrees that it will pay when due and payable any and all federal and state taxes and charges which may be payable in respect of the issuance or delivery of the Right Certificates or of any shares of Common Stock and/or other securities upon the exercise of Rights. The Company shall not, however, be required to pay any transfer tax which may be payable in respect of any transfer involved in the transfer or delivery of Right Certificates or the issuance or delivery of certificates for Common Stock and/or other securities in a name other than that of the registered holder of the Right Certificate evidencing Rights surrendered for exercise, nor shall the Company be required to issue or deliver any certificates for shares of Common Stock and/or other securities upon the exercise of any Rights until any such tax shall have been paid (any such tax being payable by the holder of such Right Certificate at the time of surrender) or until it has been established to the Company's satisfaction that no such tax is due.

Section 10. Common Stock Record Date. Each Person (other than the Company) in whose name any certificate for shares of Common Stock (or other securities) is issued upon the exercise of Rights shall for all purposes be deemed to have become the holder of record of the Common Stock (or other securities) represented thereby on, and such certificate shall be dated, the date upon which the Right Certificate evidencing such Rights was duly surrendered and payment of the Purchase Price (and any applicable transfer taxes) was made; provided, however, that if the date of such surrender and payment is a date upon which the Common Stock (or other securities) transfer books of the Company are closed, such person shall be deemed to have become the record holder of such shares on, and such certificate shall be dated, the next succeeding Business Day on which the Common Stock (or other securities) transfer books of the Company are open. Prior to the exercise of the Rights evidenced thereby, the holder of a Right Certificate shall not be entitled to any rights of a stockholder of the Company with respect to shares for which the Rights shall be exercisable, including, without limitation, the right to vote, to receive dividends or other distributions or to exercise any preemptive rights, and shall not be entitled to receive any notice of any proceedings of the Company, except as provided herein.

Section 11. Adjustment of Purchase Price, Number of Shares or Number of Rights. The Purchase Price, the number and identity of shares covered by each Right and the number of Rights outstanding are subject to adjustment from time to time as provided in this Section 11.

(a) In the event the Company shall at any time after the date of this Rights Agreement (i) declare a dividend on the Common Stock payable in shares of Common Stock, (ii) subdivide the outstanding Common Stock, (iii) combine the outstanding Common Stock into a smaller number of shares or (iv) issue any shares of its capital stock in a reclassification of the Common Stock (including any such reclassification in connection with a consolidation or merger in which the Company is the continuing or surviving corporation), except as otherwise provided in this Section 11, the Purchase Price in effect at the time of the record date for such dividend or the time of the effective date of such subdivision, combination or reclassification, and the number and kind of shares of capital stock, including Common Stock, issuable upon exercise of a Right, shall be proportionately adjusted so that the holder of any Right exercised after such time, upon payment of the aggregate consideration such holder would have had to pay to exercise such Right prior to such time, shall be entitled to receive the aggregate number and kind of shares of capital stock, including Common Stock, which, if such Right had been exercised immediately prior to such date and at a time when the Common Stock transfer books of the Company were open, such holder would have owned upon such exercise and been entitled to receive by virtue of such dividend, subdivision, combination or reclassification.

(b) In the event any Person becomes an Acquiring Person ("Section 11(b) Event"), then proper provision shall be made so that each holder of a Right, subject to Section 7(e) and Section 24 hereof and except as provided below, shall after the later of the occurrence of such event and the effective date of an appropriate registration statement pursuant to Section 9 hereof, have a right to receive, upon exercise thereof at the then current Purchase Price, multiplied by the then number of shares of Common Stock for which a Right is then exercisable, in accordance with the terms of this Rights Agreement, such number of shares of Common Stock of the Company as shall equal the result obtained by (y) multiplying the then current Purchase Price by the then number of shares of Common Stock for which a Right is then exercisable and dividing that product by (z) 50% of the current market price per one share of Common Stock (determined pursuant to Section 11(f) hereof on the date of the occurrence of the Section 11(b) Event) (such number of shares being referred to as the "number of Adjustment Shares").

(c) In the event that there shall not be sufficient Treasury shares or authorized but unissued shares of Common Stock to permit the exercise in full of the Rights in accordance with the foregoing Section 11(b), and the Rights become so exercisable, notwithstanding any other provision of this Rights Agreement, to the extent necessary and permitted by applicable law and any agreements in effect on the date hereof to which the Company is a party, each Right shall thereafter represent the right to receive, upon exercise thereof at the then current Purchase Price, multiplied by the then number of shares of Common Stock for which a Right is then exercisable in accordance with the terms of this Rights Agreement, a number of shares, or units of shares, of (y) Common Stock, and (z) preferred stock (or other equity securities) of the Company, equal in the aggregate to the number of Adjustment Shares where the Board of Directors shall have in good faith deemed such shares or units, other than the shares of Common Stock, to have at least the same value and voting rights as the Common Stock (a "common stock equivalent"); provided, however, if there are unavailable sufficient shares (or fractions of shares) of Common Stock and/or common stock equivalents, then the Company shall take all such action as may be necessary to authorize additional shares of Common Stock or common stock equivalents for issuance upon exercise of the Rights, including without limitation the calling of a meeting of stockholders; and provided, further, that if the Company is unable to cause sufficient shares of Common Stock and/or common stock equivalents to be available for issuance upon exercise in full of the Rights, then the Company, to the extent necessary and permitted by applicable law and any agreements or instruments in effect on the date thereof to which it is a party, shall make provision to pay an amount in cash equal to twice the Purchase Price (as adjusted pursuant to this Section 11), in lieu of issuing shares of Common Stock and/or common stock equivalents. To the extent that the Company determines that some action needs to be taken pursuant to this Section 11(c), the Board of Directors by action of at least a majority of its members then in office may suspend the exercisability of the Rights for a period of up to sixty (60) days following the date on which the Section 11(b) Event shall have occurred, in order to decide the appropriate form of distribution to be made pursuant to this Section 11(c) and to determine the value thereof. In the event of any such suspension, the Company shall issue a public announcement stating that the exercisability of the Rights has been temporarily suspended. The Board of Directors may, but shall not be required to, establish procedures to allocate the right to receive Common Stock and common stock equivalents upon exercise of the Rights among holders of Rights, which such allocation may be, but is not required to be, pro-rata.

(d) If the Company shall fix a record date for the issuance of rights or warrants to all holders of Common Stock entitling them (for a period expiring within 90 calendar days after such record date) to subscribe for or purchase Common Stock (or securities having the same or more favorable rights, privileges and preferences as the Common Stock ("equivalent common stock")) or securities convertible into Common Stock or equivalent common stock, at a price per share of Common Stock or per share of equivalent common stock or having a conversion or exercise price per share, as the case may be, less than the current market price (as defined in Section 11(f) hereof) per share of Common Stock on such record date, the Purchase Price to be in effect after such record date shall be determined by multiplying the Purchase Price in effect immediately prior to such date by a fraction, the numerator of which shall be the number of shares of Common Stock outstanding on such record date plus the number of shares of Common Stock which the aggregate offering price of the total number of shares of Common Stock or equivalent common stock to be offered (and/or the aggregate initial conversion price of the convertible securities so to be offered) would purchase at such current market price, and the denominator of which shall be the number of shares of Common Stock outstanding on such record date plus the number of additional shares of Common Stock and/or equivalent common stock to be offered for subscription or purchase (or into which the convertible securities so to be offered are initially convertible). In case such subscription price may be paid in a consideration, part or all of which shall be in a form other than cash, the value of such consideration shall be as determined in good faith by a majority of the Board of Directors, whose determination shall be described in a statement filed with the Rights Agent. Shares of Common Stock owned by or held for the account of the Company shall not be deemed outstanding for the purpose of any such computation. Such adjustment shall be made successively whenever such a record date is fixed; and in the event that such rights or warrants are not so issued, the Purchase Price shall be adjusted to be the Purchase Price which would then be in effect if such record date had not been fixed.

(e) If the Company shall fix a record date for the making of a distribution to all holders of Common Stock (including any such distribution made in connection with a consolidation or merger in which the Company is the continuing or surviving corporation) of evidences of indebtedness, cash (other than a regular periodic cash dividend out of earnings or retained earnings of the Company), assets (other than a dividend payable in Common Stock, but including any dividend payable in stock other than Common Stock) or convertible securities, subscription rights or warrants (excluding those referred to in Section 11(d) hereof), the Purchase Price to be in effect after such record date shall be determined by multiplying the Purchase Price in effect immediately prior to such record date by a fraction, the numerator of which shall be the current market price for one share of Common Stock (as defined in Section 11(f) hereof) on such record date less the fair market value (as determined in good faith by a majority of the Board of Directors, whose determination shall be described in a statement filed with the Rights Agent) of the portion of the assets or evidences of indebtedness so to be distributed or of such convertible securities, subscription rights or warrants applicable to one share of Common Stock, and the denominator of which shall be such current market price for one share of Common Stock. Such adjustments shall be made successively whenever such a record date is fixed; and in the event that such distribution is not so made, the Purchase Price shall again be adjusted to be the Purchase Price which would then be in effect if such record date had not been fixed.

(f) For the purpose of any computation hereunder, the "current market price" of any security (a "Security" for purposes of this Section 11(f)) on any date shall be deemed to be the average of the daily closing prices per share of such Security for the 30 consecutive Trading Days (as hereinafter defined) immediately prior to but not including such date; provided, however, that in the event that the current market price per share of such Security is determined during a period following the announcement by the issuer of such Security of (A) a dividend or distribution on such Security payable in shares of such Security or securities convertible into shares of such Security or (B) any subdivision, combination or reclassification of such Security, and prior to the expiration of 30 Trading Days after but not including the ex-dividend date for such dividend or distribution or the record date for such subdivision, combination or reclassification, then, and in each such case, the "current market price" shall be appropriately adjusted to reflect the current market price per share equivalent of such Security. The closing price for each day shall be the last sale price, regular way, or, in case no such sale takes place on such day, the average of the closing bid and asked prices, regular way, in either case as reported in the principal consolidated transaction reporting system with respect to securities listed or admitted to trading on the New York Stock Exchange or, if the Security is not listed or admitted to trading on the New York Stock Exchange, as reported in the principal consolidated transaction reporting system with respect to securities listed or admitted to trading on the principal national securities exchange on which the Security is listed or admitted to trading or, if the Security is not listed or admitted to trading on any national securities exchange, as reported by the National Association of Securities Dealers, Inc. Automated Quotation System ("Nasdaq") National Market, or if the Security is not listed or admitted to trading on any national securities exchange or included in the Nasdaq National Market, the average of the high bid and low asked prices in the over-the-counter market, as reported by Nasdaq or such other system then in use, or, if on any such date the Security is not quoted by any such organization, the average of the closing bid and asked prices as furnished by a professional market maker making a market in the Security selected by a majority of the Board of Directors. If on any such date no market maker is making a market in the Security, the fair value of such Security on such date as determined in good faith by a majority of the Board of Directors shall be used. The term "Trading Day" shall mean a day on which the principal national securities exchange on which the Security is listed or admitted to trading is open for the transaction of business or, if the Security is not listed or admitted to trading on any national securities exchange a day on which the Nasdaq National Market is open for the transaction of business or, if the Security is not listed or admitted to trading on any national securities exchange or included in the Nasdaq National Market, a Business Day. If the Security is not publicly held or not so listed or traded, "current market price" shall mean the fair value as determined in good faith by a majority of the Board of Directors, whose determination shall be described in a statement filed with the Rights Agent.

(g) No adjustment in the Purchase Price shall be required unless such adjustment would require an increase or decrease of at least 1% in the Purchase Price; provided, however, that any adjustments which by reason of this Section 11(g) are not required to be made shall be carried forward and taken into account in any subsequent adjustment. All calculations under this Section 11 shall be made to the nearest cent or to the nearest ten-thousandth of a share, as the case may be. Notwithstanding the first sentence of this Section 11(g), any adjustment required by this Section 11 shall be made no later than the earlier of (i) three years from the date of the transaction which mandates such adjustment or (ii) the Expiration Date.

(h) In the event that at any time, as a result of an adjustment made pursuant to Section 11(a) or (b) hereof, the holder of any Right shall be entitled to receive upon exercise of such Right any shares of capital stock of the Company other than shares of Common Stock, thereafter the number of such other shares so receivable upon exercise of any Right shall be subject to adjustment from time to time in a manner and on terms as nearly equivalent as practicable to the provisions with respect to the shares contained in Section 11 hereof, inclusive, and the provisions of Sections 7, 9, 10, 13 and 14 hereof with respect to the shares of Common Stock shall apply on like terms to any such other shares.

(i) All Rights originally issued by the Company subsequent to any adjustment made to the Purchase Price hereunder shall evidence the right to purchase, at the adjusted Purchase Price, the number of shares of Common Stock or other capital stock of the Company purchasable from time to time hereunder upon exercise of the Rights, all subject to further adjustment of the Purchase Price.

(j) Unless the Company shall have exercised its election as provided in Section 11(k) hereof, upon each adjustment of the Purchase Price as a result of the calculations made in Section 11(d) and (e) hereof, each Right outstanding immediately prior to the making of such adjustment shall thereafter evidence the right to purchase, at the adjusted Purchase Price, that number of shares of Common Stock (calculated to the nearest one ten-thousandth) obtained by (i) multiplying (A) the number of shares of Common Stock covered by a Right immediately prior to the adjustment by (B) the Purchase Price in effect immediately prior to such adjustment of the Purchase Price and (ii) dividing the product so obtained by the Purchase Price in effect immediately after such adjustment of the Purchase Price.

(k) The Company may elect on or after the date of any adjustment of the Purchase Price to adjust the number of Rights, in substitution for any adjustment in the number of shares of Common Stock purchasable upon the exercise of a Right. Each of the Rights outstanding after such adjustment of the number of Rights shall be exercisable for the number of shares of Common Stock for which such Right was exercisable immediately prior to such adjustment. Each Right held of record prior to such adjustment of the number of Rights shall become that number of Rights (calculated to the nearest ten-thousandth) obtained by dividing the Purchase Price in effect immediately prior to adjustment of the Purchase Price by the Purchase Price in effect immediately after adjustment of the Purchase Price. The Company shall make a public announcement of its election to adjust the number of Rights, indicating the record date for the adjustment, and, if known at the time, the amount of the adjustment to be made. This record date may be the date on which the Purchase Price is adjusted or any day thereafter, but, if the Right Certificates have been issued, shall be at least 10 days later than the date of the public announcement. If Right Certificates have been issued, upon each adjustment of the number of Rights pursuant to this Section 11(k), the Company shall, as promptly as practicable, cause to be distributed to holders of record of Right Certificates on such record date Right Certificates evidencing, subject to Section 14 hereof, the additional Rights to which such holders shall be entitled as a result of such adjustment, or, at the option of the Company, shall cause to be distributed to such holders of record in substitution and replacement for the Right Certificates held by such holders prior to the date of adjustment, and upon surrender thereof, if required by the Company, new Right Certificates evidencing all the Rights to which such holders shall be entitled after such adjustment. Right Certificates so to be distributed shall be issued, executed and countersigned in the manner provided for herein (and may bear, at the option of the Company, the adjusted Purchase Price) and shall be registered in the names of the holders of record of Right Certificates on the record date specified in the public announcement.

(l) Irrespective of any adjustment or change in the Purchase Price or the number of shares of Common Stock issuable upon the exercise of the Rights, the Right Certificates theretofore and thereafter issued may continue to express the Purchase Price and the number of shares which were expressed in the initial Right Certificates issued hereunder.

(m) Before taking any action that would cause an adjustment reducing the Purchase Price below the then par value, if any, of the shares of Common Stock or other securities, issuable upon exercise of the Rights, the Company shall take any corporate action which may, in the opinion of its counsel, be necessary in order that the Company may validly and legally issue fully paid and nonassessable shares of such Common Stock or other securities at such adjusted Purchase Price. If upon any exercise of the Rights, a holder is to receive a combination of Common Stock and common stock equivalents, a portion of the consideration paid upon such exercise, equal to at least the then par value of a share of Common Stock of the Company, shall be allocated as the payment for each share of Common Stock of the Company so received.

(n) In any case in which this Section 11 shall require that an adjustment in the Purchase Price be made effective as of a record date for a specified event, the Company may elect to defer until the occurrence of such event the issuing to the holder of any Right exercised after such record date the shares of Common Stock and other capital stock or securities of the Company, if any, issuable upon such exercise over and above the shares of Common Stock and other capital stock or securities of the Company, if any, issuable upon such exercise on the basis of the Purchase Price in effect prior to such adjustment; provided, however, that the Company shall deliver to such holder a due ▇▇▇▇ or other appropriate instrument evidencing such holder's right to receive such additional shares upon the occurrence of the event requiring such adjustment.

(o) Anything in this Section 11 to the contrary notwithstanding, the Company shall be entitled to make such reductions in the Purchase Price, in addition to those adjustments expressly required by this Section 11, as and to the extent that in their good faith judgment a majority of the Board of Directors shall determine to be advisable in order that any (i) consolidation or subdivision of the Common Stock, (ii) issuance wholly for cash of any Common Stock at less than the then current market price, (iii) issuance wholly for cash of Common Stock or securities which by their terms are convertible into or exchangeable for Common Stock, (iv) stock dividends or (v) issuance of rights, options or warrants referred to hereinabove in this Section 11, hereafter made by the Company to the holders of its Common Stock, shall not be taxable to such stockholders.

(p) The Company covenants and agrees that it shall not, at any time after the Distribution Date and so long as the Rights have not been redeemed pursuant to Section 23 hereof or exchanged pursuant to Section 24 hereof, (i) consolidate with, (ii) merge with or into, or (iii) sell or transfer, in one or more transactions, assets or earning power aggregating more than 50% of the assets or earning power of the Company and its Subsidiaries (taken as a whole) to, any other Person, if at the time of or immediately after such consolidation, merger or sale there are any rights, warrants or other instruments or securities outstanding or agreements in effect which would substantially diminish or otherwise eliminate the benefits intended to be afforded by the Rights.

(q) The Company covenants and agrees that, after the Stock Acquisition Date, it will not, except as permitted by Sections 23 and 24 hereof, take any action the purpose or effect of which is to diminish substantially or otherwise eliminate the benefits intended to be afforded by the Rights.

Section 12. Certificate of Adjusted Purchase Price or Number of Shares. Whenever an adjustment is made as provided in Sections 11 or 13 hereof, the Company shall (a) promptly prepare a certificate setting forth such adjustment, and a brief statement of the facts accounting for such adjustment, (b) promptly file with the Rights Agent and with each transfer agent for the Common Stock a copy of such certificate and (c) include a brief summary thereof in a mailing to each holder of a Right Certificate in accordance with Section 26 hereof, or prior to the Distribution Date, disclose a brief summary in a filing under the Exchange Act. The Rights Agent shall be fully protected in relying on any such certificate and on any adjustments therein contained and shall not be obligated or responsible for calculating any adjustment nor shall it be deemed to have knowledge of such adjustment unless and until it shall have received such certificate.

Section 13. Consolidation, Merger or Sale or Transfer of Assets or Earning Power.

(a) In the event that, directly or indirectly, at any time after a Person has become an Acquiring Person, (x) the Company shall consolidate with, or merge with and into, any other Person, (y) any Person shall consolidate with or merge with and into the Company, and the Company shall be the continuing or surviving corporation of such merger and, in connection with such merger, all or part of the Common Stock shall be changed into or exchanged for stock or other securities of any other Person (or the Company) or cash or any other property, or (z) the Company shall sell, or otherwise transfer (or one or more of its Subsidiaries shall sell or otherwise transfer), in one or more transactions, assets or earning power aggregating 50% or more of the assets or earning power of the Company and its Subsidiaries (taken as a whole) to any other Person other than to the Company or one or more of its wholly-owned Subsidiaries, then, and in each such case, proper provision shall be made so that (i) each holder of a Right, subject to Section 7(e) hereof, shall thereafter have the right to receive, upon the exercise thereof at the then current Purchase Price multiplied by the then number of shares of Common Stock for which a Right is then exercisable (or if a Section 11(b) Event has occurred prior to the first occurrence of a Section 13 Event, multiplying the number of such shares for which a Right was exercisable immediately prior to the first occurrence of a Section 11(b) Event by the Purchase Price in effect immediately prior to such first occurrence) in accordance with the terms of this Rights Agreement, such number of shares of freely tradable Common Stock of the Principal Party (as hereinafter defined), free and clear of liens, rights of call or first refusal, encumbrances or other adverse claims, as shall be equal to the result obtained by (A) multiplying the then current Purchase Price by the number of shares of Common Stock for which a Right is then exercisable (or if a Section 11(b) Event has occurred prior to the first occurrence of a Section 13 Event, multiplying the number of such shares for which a Right was exercisable immediately prior to the first occurrence of a Section 11(b) Event by the Purchase Price in effect immediately prior to such first occurrence), and dividing that product by (B) 50% of the current market price per share of the Common Stock of such Principal Party (determined in the manner described in Section 11(f) hereof) on the date of consummation of such consolidation, merger, sale or transfer; (ii) the Principal Party shall thereafter be liable for, and shall assume, by virtue of such consolidation, merger, sale or transfer, all the obligations and duties of the Company pursuant to this Rights Agreement; (iii) the term "Company" shall thereafter be deemed to refer to such Principal Party, it being specifically intended that the provisions of Section 11 hereof, except for the provisions of 11(b), shall apply to such Principal Party; and (iv) such Principal Party shall take such steps (including, but not limited to, the authorization and reservation of a sufficient number of shares of its Common Stock to permit exercise of all outstanding Rights in accordance with this Section 13(a)) in connection with such consummation as may be necessary to assure that the provisions hereof shall thereafter be applicable, as nearly as reasonably may be, in relation to the shares of its Common Stock thereafter deliverable upon the exercise of the Rights.

(b) "Principal Party" shall mean:

(i) in the case of any transaction described in clause (x) or (y) of the first sentence of Section 13(a) hereof, the Person that is the issuer of any securities into which shares of Common Stock of the Company are converted in such merger or consolidation, and if no securities are so issued, the Person, including the Company, that is the other party to the merger or consolidation; and

(ii) in the case of any transaction described in clause (z) of the first sentence of Section 13(a) hereof, the Person that is the party receiving the greatest portion of the assets or earning power transferred pursuant to such transaction or transactions; provided, however, that in any case described in clause (i) or (ii) in this Section 13(b), (x) if the Common Stock of such Person is not at such time and has not been continuously over the preceding 12-month period registered under Section 12 of the Exchange Act, and such Person is a direct or indirect Subsidiary or Affiliate of another Person, "Principal Party" shall refer to such other Person; (y) in case such Person is a Subsidiary, directly or indirectly, or Affiliate of more than one Person, the Common Stocks of all of which are and have been so registered, "Principal Party" shall refer to whichever of such Persons is the issuer of the Common Stock having the greatest aggregate market value, and (z) in case such Person is, or is owned directly or indirectly by, a partnership or joint venture formed by two or more Persons that are not owned, directly or indirectly, by the same Person, the rules set forth in (x) and (y) above shall apply to each of the chains of ownership having an interest in such joint venture as if such party were a "Subsidiary" of both or all of such joint venturers and the Principal Parties in each such chain shall bear the obligations set forth in this Section 13 in the same ratio as their direct or indirect interests in such Person bear to the total of such interests.

(c) The Company shall not consummate any such consolidation, merger, sale or transfer unless the Principal Party shall have a sufficient number of shares of its authorized Common Stock which have not been issued or reserved for issuance to permit the exercise in full of the Rights in accordance with this Section 13 and unless prior thereto the Company and each Principal Party and each other Person who may become a Principal Party as a result of such consolidation, merger, sale or transfer shall have executed and delivered to the Rights Agent a supplemental agreement providing for the terms set forth in paragraphs (a) and (b) of this Section 13 and further providing that, as soon as practicable after the date of any consolidation, merger, sale or transfer of assets mentioned in paragraph (a) of this Section 13, the Principal Party will:

(i) prepare and file a registration statement under the Securities Act with respect to the Rights and the securities purchasable upon exercise of the Rights on an appropriate form, will use its best efforts to cause such registration statement to become effective as soon as practicable after such filing and will use its best efforts to cause such registration statement to remain effective (with a prospectus at all times meeting the requirements of the Securities Act) until the Expiration Date;

(ii) use its best efforts to qualify or register the Rights and the securities purchasable upon exercise of the Rights under the "blue sky laws" of such jurisdictions as may be necessary or appropriate; and

(iii) deliver to holders of the Rights historical financial statements for the Principal Party and each of its Affiliates which comply in all respects with the requirements for registration on Form 10 under the Exchange Act.

The provisions of this Section 13 shall similarly apply to successive mergers or consolidations or sales or other transfers. In the event that a Section 13 Event shall occur at any time after the occurrence of a Section 11(b) Event, the Rights which have not theretofore been exercised shall thereafter also become exercisable in the manner described in Section 13(a) hereof.

Section 14. Fractional Rights and Fractional Shares.

(a) The Company shall not be required to issue fractions of Rights or to distribute Right Certificates which evidence fractional Rights. In lieu of such fractional Rights, there shall be paid to the registered holders of the Right Certificates with regard to which such fractional Rights would otherwise be issuable, an amount in cash equal to the same fraction of the current market value of a whole Right. For the purposes of this Section 14(a), the current market value of a whole Right shall be the closing price of the Rights for the Trading Day immediately prior to the date on which such fractional Rights would have been otherwise issuable. The closing price for any day shall be the last sale price, regular way, or, in case no such sale takes place on such day, the average of the closing bid and asked prices, regular way, in either case as reported in the principal consolidated transaction reporting system with respect to securities listed or admitted to trading on the New York Stock Exchange or, if the Rights are not listed or admitted to trading on the New York Stock Exchange, as reported in the principal consolidated transaction reporting system with respect to securities listed or admitted to trading on the principal national securities exchange on which the Rights are listed or admitted to trading or, if the Rights are not listed or admitted to trading on any national securities exchange, as reported by the Nasdaq National Market or, if the Rights are not listed or admitted to trading on any national securities exchange or included in the Nasdaq National Market, the last quoted price, or, if not so quoted, the average of the high bid and low asked prices in the over-the-counter market, as reported by Nasdaq or such other system then in use or, if on any such date the Rights are not quoted by any such organization, the average of the closing bid and asked prices as furnished by a professional market maker making a market in the Rights selected by a majority of the Board of Directors. If on any such date no such market maker is making a market in the Rights, the fair value of the Rights on such date as determined in good faith by a majority of the Board of Directors shall be used.

(b) The Company shall not be required to issue fractions of shares of Common Stock upon exercise of the Rights or to distribute certificates which evidence fractional shares of Common Stock. In lieu of fractional shares of Common Stock, the Company may pay to the registered holders of Right Certificates at the time such Right Certificates are exercised as herein provided, an amount in cash equal to the same fraction of the current market value of a share of Common Stock. For purposes of this Section 14(b), the current market value of a share of Common Stock shall be the closing price of a share of Common Stock (as determined pursuant to Section 11(f) hereof) for the Trading Day immediately prior to the date of such exercise.

(c) Following the occurrence of one of the transactions or events specified in Section 11 hereof giving rise to the right to receive common stock equivalents (other than Common Stock) or other securities upon the exercise of a Right, the Company shall not be required to issue fractions of shares or units of such common stock equivalents or other securities upon exercise of the Rights or to distribute certificates which evidence fractional shares of such common stock equivalents or other securities. In lieu of fractional shares or units of such common stock equivalents or other securities, the Company may pay to the registered holders of Right Certificates at the time such Rights are exercised as herein provided an amount in cash equal to the same fraction of the current market value of a share or unit of such common stock equivalent or other securities. For purposes of this Section 14(c), the current market value shall be determined in the manner set forth in Section 11(f) hereof for the Trading Day immediately prior to the date of such exercise and, if such common stock equivalent is not traded, each such common stock equivalent shall have the value of a share of Common Stock.

(d) Except as otherwise expressly provided in this Section 14, the holder of a Right by the acceptance of the Right expressly waives such holder's right to receive any fractional Rights or any fractional share upon exercise of Rights.

Section 15. Rights of Action. All rights of action in respect of this Rights Agreement, except for rights of action given to the Rights Agent under Section 18 or Section 20 hereof, are vested in the respective registered holders of the Right Certificates (and, prior to the Distribution Date, the registered holders of Common Stock); and any registered holder of any Right Certificate (or, prior to the Distribution Date, of the Common Stock), without the consent of the Rights Agent or of the holder of any other Right Certificate (or, prior to the Distribution Date, of the Common Stock), may, in such holder's own behalf and for such holder's own benefit, enforce, and may institute and maintain any suit, action or proceeding against the Company to enforce, or otherwise act in respect of, such holder's right to exercise the Rights evidenced by such Right Certificate in the manner provided in such Right Certificate and in this Rights Agreement. Without limiting the foregoing or any remedies available to the holders of Rights, it is specifically acknowledged that the holders of Rights would not have an adequate remedy at law for any breach of this Rights Agreement and will be entitled to specific performance of the obligations under, and injunctive relief against actual or threatened violations of, the obligations of any Person subject to this Rights Agreement. Holders of Rights shall be entitled to recover the reasonable costs and expenses, including attorneys' fees, incurred by them in any action to enforce the provisions of this Rights Agreement.

Section 16. Agreement of Right Holders. Every holder of a Right by accepting the same consents and agrees with the Company and the Rights Agent and with every other holder of a Right that:

(a) prior to the Distribution Date, the Rights will be transferable only in connection with the transfer of Common Stock;

(b) after the Distribution Date, the Right Certificates are transferable only on the registry books of the Rights Agent if surrendered at the stockholder services office of the Rights Agent or such office designated for such purpose, duly endorsed or accompanied by a proper instrument of transfer; and

(c) the Company and the Rights Agent may deem and treat the Person in whose name the Right Certificate (or, prior to the Distribution Date, the associated Common Stock Certificate) is registered as the absolute owner of such Right Certificate and of the Rights evidenced thereby (notwithstanding any notations of ownership or writing on the Right Certificate or the associated Common Stock certificate made by anyone other than the Company or the Rights Agent) for all purposes whatsoever, and neither the Company nor the Rights Agent shall be affected by any notice to the contrary.

(d) Notwithstanding anything in this Agreement to the contrary, neither the Company nor the Rights Agent shall have any liability to any holder of a Right or other Person as a result of its inability to perform any of its obligations under this Agreement by reason of any preliminary or permanent injunction or other order, decree or ruling issued by a court or by a governmental, regulatory or administrative agency or commission, or any statute, rule, regulation or executive order promulgated or enacted by any governmental authority prohibiting or otherwise restraining performance of the obligation; provided, however, the Company must use its best efforts to have any order, decree or ruling lifted or otherwise overturned.

Section 17. Right Certificate Holder Not Deemed a Stockholder. No holder, as such, of any Right Certificate shall be entitled to vote, receive dividends or be deemed for any purpose the holder of Common Stock or any other securities of the Company which may at any time be issuable on the exercise of the Rights represented thereby, nor shall anything contained herein or in any Right Certificate be construed to confer upon the holder of any Right Certificate, as such, any of the rights of a stockholder of the Company or any right to vote for the election of directors or upon any matter submitted to stockholders at any meeting thereof, or to give or withhold consent to any corporate action, or to receive notice of meetings or other actions affecting stockholders (except as provided in Section 25 hereof), or to receive dividends or subscription rights, or otherwise, until the Right or Rights evidenced by such Right Certificate shall have been exercised in accordance with the provisions hereof.

Section 18. Concerning the Rights Agent.

(a) The Company agrees to pay to the Rights Agent reasonable compensation for all services rendered by it hereunder and, from time to time, on demand of the Rights Agent, its reasonable expenses and counsel fees and other disbursements incurred in the administration and execution of this Rights Agreement and the exercise and performance of its duties hereunder. The Company also agrees to indemnify the Rights Agent for, and to hold it harmless against, any loss, liability, or expense, incurred without negligence, bad faith or willful misconduct on the part of the Rights Agent, for anything done or omitted by the Rights Agent in connection with the acceptance and administration of this Rights Agreement, including the costs and expenses of defending against any claim of liability. The costs and expenses of enforcing this right of indemnification shall also be paid by the Company. The indemnification provided for hereunder shall survive the expiration of the Rights, the resignation or removal of the Rights Agent and termination of this Agreement.

(b) The Rights Agent may conclusively rely upon and shall be protected and shall incur no liability for or in respect of any action taken, suffered or omitted by it in connection with its administration of this Rights Agreement in reliance upon any Right Certificate or certificate for Common Stock or for other securities of the Company, instrument of assignment or transfer, power of attorney, endorsement, affidavit, letter, notice, direction, consent, certificate, statement, or other paper or document believed by it to be genuine and to be signed, executed and, where necessary, verified or acknowledged, by the proper Person or Persons.

(c) Notwithstanding anything in this Rights Agreement to the contrary, in no event shall the Rights Agent be liable for special, indirect or consequential loss or damage of any kind whatsoever (including but not limited to lost profits), even if the Rights Agent has been advised of the likelihood of such loss or damage and regardless of the form of the action.

Section 19. Merger or Consolidation or Change of Name of Rights Agent.

(a) Any Person into which the Rights Agent or any successor Rights Agent may be merged or with which it may be consolidated, or any Person resulting from any merger or consolidation to which the Rights Agent or any successor Rights Agent shall be a party, or any Person succeeding to the corporate trust powers or business or the stock transfer business of the Rights Agent or any successor Rights Agent, shall be the successor to the Rights Agent under this Rights Agreement without the execution or filing of any paper or any further act on the part of any of the parties hereto, provided that such Person would be eligible for appointment as a successor Rights Agent under the provisions of Section 21 hereof. In case at the time such successor Rights Agent shall succeed to the agency created by this Rights Agreement, any of the Right Certificates shall have been countersigned but not delivered, any such successor Rights Agent may adopt the countersignature of the predecessor Rights Agent and deliver such Right Certificates so countersigned; and in case at that time any of the Right Certificates shall not have been countersigned, any successor Rights Agent may countersign such Right Certificates either in the name of the predecessor Rights Agent or in the name of the successor Rights Agent; and in all such cases such Right Certificates shall have the full force provided in the Right Certificates and in this Rights Agreement.

(b) In case at any time the name of the Rights Agent shall be changed and at such time any of the Right Certificates shall have been countersigned but not delivered, the Rights Agent may adopt the countersignature under its prior name and deliver Right Certificates so countersigned; and in case at that time any of the Right Certificates shall not have been countersigned, the Rights Agent may countersign such Right Certificates either in its prior name or in its changed name; and in all such cases such Right Certificates shall have the full force provided in the Right Certificates and in this Rights Agreement.

Section 20. Duties of Rights Agent. The Rights Agent undertakes the duties and obligations imposed by this Rights Agreement upon the following terms and conditions by all of which the Company and the holders of Right Certificates, by their acceptance thereof, shall be bound and no implied duties or obligations shall be read into this Rights Agreement against the Rights Agent:

(a) Before the Rights Agent acts or refrains from acting, the Rights Agent may consult with legal counsel (who may be legal counsel for the Company), and the opinion of such counsel shall be full and complete authorization and protection to the Rights Agent as to any action taken or omitted by it in good faith and in accordance with such opinion.

(b) Whenever in the performance of its duties under this Rights Agreement the Rights Agent shall deem it necessary or desirable that any fact or matter be proved or established by the Company prior to taking or suffering any action hereunder, such fact or matter (unless other evidence in respect thereof be herein specifically prescribed) may be deemed to be conclusively proved and established by a certificate signed by the Chairman of the Board, Chief Executive Officer and President, Chief Administrative Officer and Chief Financial Officer, or any Vice President and by the Treasurer or any Assistant Treasurer or the Secretary or any Assistant Secretary of the Company and delivered to the Rights Agent; and such certificate shall be full authorization to the Rights Agent for any action taken or suffered in good faith by it under the provisions of this Rights Agreement in reliance upon such certificate.

(d) The Rights Agent shall not be liable for or by reason of any of the statements of fact or recitals contained in this Rights Agreement or in the Right Certificates (except its countersignature thereof) or be required to verify the same, but all such statements and recitals are and shall be deemed to have been made by the Company only.

(e) The Rights Agent shall not be under any responsibility in respect of the validity of this Rights Agreement or the execution and delivery hereof (except the due execution hereof by the Rights Agent) or in respect of the validity or execution of any Right Certificate (except its countersignature thereof); nor shall it be responsible for any breach by the Company of any covenant or condition contained in this Rights Agreement or in any Right Certificate; nor shall it be responsible for any adjustment required under the provisions of Sections 11 or 13 hereof or responsible for the manner, method or amount of any such adjustment or the ascertaining of the existence of facts that would require any such adjustment (except with respect to the exercise of Rights evidenced by Right Certificates after actual notice to the Rights Agent of any such adjustment); nor shall it by any act hereunder be deemed to make any representation or warranty as to the authorization or reservation of any shares of Common Stock or other securities to be issued pursuant to this Rights Agreement or any Right Certificate or as to whether any shares of Common Stock or other securities will, when issued, be validly authorized and issued, fully paid and nonassessable.

(f) The Company agrees that it will perform, execute, acknowledge and deliver or cause to be performed, executed, acknowledged and delivered all such further and other acts, instruments and assurances as may reasonably be required by the Rights Agent for the carrying out or performing by the Rights Agent of the provisions of this Rights Agreement.

(g) The Rights Agent is hereby authorized and directed to accept instructions with respect to the performance of its duties hereunder from the Chairman of the Board, Chief Executive Officer and President, Chief Administrative Officer and Chief Financial Officer, any Vice President, the Secretary, any Assistant Secretary, the Treasurer or any Assistant Treasurer of the Company, and to apply to such officers for advice or instructions in connection with its duties, and it shall not be liable for any action taken or suffered to be taken by it in good faith in accordance with instructions of any such officer or for any delay in acting while waiting for those instructions. Any application by the Rights Agent for written instructions from the Company may, at the option of the Rights Agent, set forth in writing any action proposed to be taken or omitted by the Rights Agent under this Rights Agreement and the date on or after which such action shall be taken or such omission shall be effective. The Rights Agent shall not be liable for any action taken by, or omission of, the Rights Agent in accordance with a proposal included in any such application on or after the date specified in such application (which date shall not be less than ten Business Days after the date any such officer of the Company actually receives such application, unless any such officer shall have consented in writing to an earlier date) unless, prior to taking any such action (or the effective date in the case of an omission), the Rights Agent shall have received written instructions in response to such application subject to the proposed action or omission and/or specifying the action to have taken or omitted.

(h) The Rights Agent and any stockholder, director, affiliate officer, employee, agent or representative of the Rights Agent may buy, sell or deal in any of the Rights or other securities of the Company or become pecuniarily interested in any transaction in which the Company may be interested, or contract with or lend money to the Company or otherwise act as fully and freely as though it were not the Rights Agent under this Rights Agreement. Nothing herein shall preclude the Rights Agent from acting in any other capacity for the Company or for any other Person.

(i) The Rights Agent may execute and exercise any of the rights or powers hereby vested in it or perform any duty hereunder either itself or by or through its attorneys or agents, and the Rights Agent shall not be answerable or accountable for any act, default, neglect or misconduct of any such attorneys or agents or for any loss to the Company resulting from any such act, default, neglect or misconduct, provided that reasonable care was exercised in the selection and continued employment thereof.

(j) No provision of this Rights Agreement shall require the Rights Agent to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its duties hereunder or in the exercise of its rights if there shall be reasonable grounds for believing that repayment of such funds or adequate indemnification against such risk or liability is not reasonably assured to it.

(k) If, with respect to any Rights Certificate surrendered to the Rights Agent for exercise or transfer, the certificate attached to the form of assignment or form of election to purchase, as the case may be, has either not been completed or indicates an affirmative response to clause 1, clause 2 and/or, in the case of the certificate attached to the form of election to purchase, clause 3 thereof, the Rights Agent shall not take any further action with respect to such requested exercise of transfer without first consulting with the Company.

(l) The Rights Agent shall not be required to take notice or be deemed to have any notice of any fact, event or determination (including, without limitation, any dates or events defined in this Agreement or the designation of any Person as an Acquiring Person, Affiliate or Associate) under this Agreement unless and until the Rights Agent shall be specifically notified in writing by the Company of such fact, event or determination.

Section 21. Change of Rights Agent. The Rights Agent or any successor Rights Agent may resign and be discharged from its duties under this Rights Agreement upon 30 days notice in writing mailed to the Company and to each transfer agent of the Common Stock by registered or certified mail, and, at the expense of the Company, to the holders of the Right Certificates by first-class mail. The Company may remove the Rights Agent or any successor Rights Agent upon 30 days notice in writing, mailed to the Rights Agent or successor Rights Agent, as the case may be, and to each transfer agent of the Common Stock by registered or certified mail, and to the holders of the Right Certificates by first-class mail or, prior to the Distribution Date, through any filing made by the Company pursuant to the Exchange Act. If the Rights Agent shall resign or be removed or shall otherwise become incapable of acting, the Company shall appoint a successor to the Rights Agent. If the Company shall fail to make such appointment within a period of 30 days after such removal or after it has been notified in writing of such resignation or incapacity by the resigning or incapacitated Rights Agent or by the holder of a Right Certificate (which holder shall, with such notice, submit such holder's Right Certificate for inspection by the Company), then the registered holder of any Right Certificate or such resigning, removed or incapacitated Rights Agent, may apply to any court of competent jurisdiction for the appointment of a new Rights Agent. Any successor Rights Agent, whether appointed by the Company or by such a court, shall be (a) a corporation or other entity organized and doing business under the laws of the United States or of any state, in good standing, having an office in the States of New York, Illinois or Missouri, which is authorized under such laws to exercise corporate trust or stock transfer powers and is subject to supervision or examination by federal or state authority, or (b) an affiliate of a corporation or other entity described in clause (a) of this sentence. After appointment, the successor Rights Agent shall be vested with the same powers, rights, duties and responsibilities as if it had been originally named as Rights Agent without further act or deed; but the predecessor Rights Agent shall deliver and transfer to the successor Rights Agent any property at the time held by it hereunder, and execute and deliver any further assurance, conveyance, act or deed necessary for the purpose. Not later than the effective date of any such appointment the Company shall file notice thereof in writing with the predecessor Rights Agent and each transfer agent of the Common Stock, and mail a notice thereof in writing to the registered holders of the Right Certificates or, prior to the Distribution Date, through any filing made by the Company pursuant to the Exchange Act. Failure to give any notice provided for this Section 21, however, or any defect therein, shall not affect the legality or validity of the resignation or removal of the Rights Agent or the appointment of the successor Rights Agent, as the case may be.

Section 22. Issuance of New Right Certificates.

(a) Notwithstanding any of the provisions of this Rights Agreement or of the Rights to the contrary, the Company may, at its option, issue new Right Certificates evidencing Rights in such form as may be approved by a majority of the Board of Directors then in office to reflect any adjustment or change in the Purchase Price and the number or kind or class of shares of stock or other securities or property purchasable under the Right Certificates made in accordance with the provisions of this Rights Agreement.

(b) In addition, in connection with the issuance or sale of Common Stock following the Distribution Date and prior to the redemption, exchange or expiration of the Rights, the Company (i) shall with respect to shares of Common Stock so issued or sold pursuant to the exercise of stock options or under any employee benefit plan or arrangement, or upon the exercise, conversion or exchange of securities hereinafter issued by the Company, and (ii) may, in any other case, if deemed necessary or appropriate by the Board of Directors, issue Right Certificates representing the appropriate number of Rights in connection with such issuance or sale; provided, however, that (x) no such Right Certificates shall be issued if, and to the extent that, the Company shall be advised by counsel that such issuance would create a significant risk of material adverse tax consequences to the Company or the Person to whom such Right Certificates would be issued, and (y) no Right Certificate shall be issued if, and to the extent that, appropriate adjustment shall otherwise have been made in lieu of the issuance thereof.

Section 23. Redemption and Termination.

(a) A majority of the Board of Directors then in office may, at its option, at any time prior to the earlier of (i) the Close of Business on the tenth Business Day following the Stock Acquisition Date or (ii) the Close of Business on the Final Expiration Date, elect to redeem all but not less than all of the then outstanding Rights at a redemption price of $0.01 per Right, as appropriately adjusted to reflect any stock split, stock dividend or similar transaction occurring after the date hereof (such redemption price being hereinafter referred to as the "Redemption Price"). Notwithstanding anything contained in this Rights Agreement to the contrary, the Rights shall not be exercisable after the first occurrence of a Section 11(b) Event until such time as the Company's right of redemption hereunder has expired. The redemption of the Rights by the Board of Directors may be made effective at such time, on such basis and with such conditions as the Board of Directors in its sole discretion may establish.

(b) Immediately upon the action of a majority of the Board of Directors then in office electing to redeem the Rights, evidence of which shall be promptly filed with the Rights Agent, or, when appropriate, immediately upon the time or satisfaction of such conditions as the Board of Directors may have established, and without any further action and without any notice, the right to exercise the Rights will terminate and the only right thereafter of the holders of Rights shall be to receive the Redemption Price. The Company shall promptly give public disclosure of any such redemption; provided, however, that the failure to give, or any defect in, any such disclosure shall not affect the validity of such redemption. Within 10 days after the action of the Board of Directors ordering the redemption of the Rights, the Company shall give notice of such redemption to the holders of the then outstanding Rights by mailing such notice to all such holders at their last addresses as they appear upon the registry books of the Rights Agent or, prior to the Distribution Date, on the registry books of the Transfer Agent for the Common Stock. Any notice which is mailed in the manner herein provided shall be deemed given, whether or not the holder receives the notice. Each such notice of redemption will state the method by which the payment of the Redemption Price will be made.

(c) Neither the Company nor any of its Affiliates or Associates may redeem, acquire or purchase for value any Rights at any time in any manner other than that specifically set forth in this Section 23 or Section 24 hereof and other than in connection with the purchase of Common Stock prior to the Distribution Date.

Section 24. Exchange.

(a) The Board of Directors may, at its option, at any time after any Person becomes an Acquiring Person, exchange all or part of the then outstanding and exercisable Rights (which shall not include Rights that have become null and void pursuant to the provisions of Section 7(e) hereof) for Common Stock at an exchange ratio of one share of Common Stock per Right, appropriately adjusted to reflect adjustments in the number of Rights pursuant to Section 11 of this Rights Agreement (such exchange ratio being hereinafter referred to as the "Exchange Ratio"). Notwithstanding the foregoing, the Board of Directors shall not be empowered to effect such exchange at any time after any Person (other than the Company, any Subsidiary of the Company, any employee benefit plan or compensation arrangement of the Company or any such Subsidiary, or any entity holding securities of the Company to the extent organized, appointed or established by the Company or any such Subsidiary for or pursuant to the terms of any such employee benefit plan or compensation arrangement), together with all Affiliates and Associates of such Person, becomes the Beneficial Owner of 50% or more of the Voting Power of the Company.

(b) Immediately upon the action of the Board of Directors ordering the exchange of any Rights pursuant to paragraph (a) of this Section 24 and without any further action and without any notice, the right to exercise such Rights shall terminate and the only rights thereafter of holders of such Rights shall be to receive that number of shares of Common Stock equal to the number of such Rights held by such holder multiplied by the Exchange Ratio. The Company promptly shall give public notice of any such exchange; provided, however, that the failure to give, or any defect in, such notice shall not affect the validity of such exchange. The Company promptly shall mail a notice of any such exchange to all of the holders of such Rights at their last addresses as they appear upon the registry books of the Rights Agent. Any notice which is mailed in the manner herein provided shall be deemed given, whether or not the holder receives the notice. Each such notice of exchange will state the method by which the exchange of Common Stock for Rights will be effected and, in the event of any partial exchange, the number of Rights which will be exchanged. Any partial exchange shall be effected pro rata based on the number of Rights (other than Rights which have become void pursuant to the provisions of Section 7(e) hereof) held by each holder of Rights.

(c) In the event that there shall not be sufficient shares of Common Stock issued but not outstanding or authorized but unissued to permit any exchange of Rights as contemplated in accordance with this Section 24, the Company shall take all such action as may be necessary to authorize additional shares of Common Stock for issuance upon exchange of the Rights, including without limitation seeking approval from the Company's stockholders of an increase in the number of authorized shares of Common Stock.

(d) The Company shall not be required to issue fractions of Common Stock or to distribute certificates which evidence fractional shares of Common Stock. In lieu of such fractional shares of Common Stock, the Company shall pay to the registered holders of the Right Certificates with regard to which such fractional shares of Common Stock would otherwise be issuable an amount in cash equal to the same fraction of the current market value of a whole share of Common Stock. For the purposes of this paragraph (d), the current market value of a whole share of Common Stock shall be the current market price of a share of Common Stock (as determined pursuant to the second sentence of Section 11(f) hereof) for the Trading Day immediately prior to the date of exchange pursuant to this Section 24.

Section 25. Notice of Proposed Actions.

(a) In case the Company shall propose at any time after the Distribution Date (a) to pay any dividend payable in stock of any class to the holders of the Common Stock or to make any other distribution to the holders of the Common Stock (other than a regular periodic cash dividend out of earnings or retained earnings of the Company), (b) to offer to the holders of the Common Stock rights or warrants to subscribe for or to purchase any additional shares of Common Stock or shares of stock of any other class or any other securities, rights or options, (c) to effect any reclassification of the Common Stock (other than a reclassification involving only the subdivision of outstanding shares of Common Stock), (d) to effect any consolidation or merger into or with, or to effect any sale or other transfer (or to permit one or more of its Subsidiaries to effect any sales or other transfer), in one or more transactions, of 50% or more of the assets or earning power of the Company and its Subsidiaries (taken as a whole) to, any other Person, (e) to effect the liquidation, dissolution or winding up of the Company, or (f) to declare or pay any dividend on the Common Stock payable in Common Stock or to effect a subdivision, combination or consolidation of the Common Stock (by reclassification or otherwise than by payment of dividends in Common Stock), then, in each such case, the Company shall give to each holder of a Right and the Rights Agent, in accordance with Section 26 hereof, a notice of such proposed action, which shall specify the record date for the purposes of such stock dividend, distribution of rights or warrants, or the date on which such reclassification, consolidation, merger, sale, transfer, liquidation, dissolution, or winding up is to take place and the date of participation therein by the holders of the Common Stock, if any such date is to be fixed. Such notice shall be so given in the case of any action covered by clauses (a) or (b) above at least ten days prior to the record date for determining holders of the Common Stock for purposes of such action, and in the case of any such other action, at least ten days prior to the date of the taking of such proposed action or the date of participation therein by the holders of Common Stock, whichever shall be the earlier. The failure to give notice required by this Section 25 or any defect therein shall not affect the legality or validity of the action taken by the Company or the vote upon any such action.

(b) In case a Section 11(b) Event shall occur, then the Company shall as soon as practicable thereafter give to each holder of a Right Certificate, in accordance with Section 26 hereof, a notice of the occurrence of such event, which shall specify the event and the consequences of the event to holders of Rights under Section 11(b) hereof.

Section 26. Notices. Notices or demands authorized by this Rights Agreement to be given or made by the Rights Agent or by the holder of any Right Certificate to or on the Company shall be sufficiently given or made if sent by first-class mail, postage prepaid, addressed (until another address is filed in writing with the Rights Agent) as follows:

Sigma-▇▇▇▇▇▇▇ Corporation

▇▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇. ▇▇▇▇▇, ▇▇▇▇▇▇▇▇ ▇▇▇▇▇

Attention: Chief Administrative Officer

Subject to the provisions of Section 21 hereof, any notice or demand authorized by this Rights Agreement to be given or made by the Company or by the holder of any Right Certificate to or on the Rights Agent shall be sufficiently given or made if received by the Rights Agent by registered or certified mail, postage prepaid and return receipt requested, addressed (until another address is filed in writing with the Company) as follows:

Computershare Investor Services, LLC, as Rights Agent

▇ ▇▇▇▇▇ ▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇ ▇▇▇▇▇

▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ ▇▇▇▇▇

Attention: ▇▇▇▇▇▇ ▇▇▇▇▇▇

Notices or demands authorized by this Rights Agreement to be given or made by the Company or the Rights Agent to the holder of any Right Certificate shall be sufficiently given or made if sent by first-class mail, postage prepaid, addressed to such holder at the address of such holder as shown on the registry books of the Company.

Section 27. Supplements and Amendments. The Company may from time to time supplement or amend this Rights Agreement without the approval of any holders of Right Certificates in order (a) to cure any ambiguity, (b) to correct or supplement any provision contained herein which may be defective or inconsistent with any other provisions herein, (c) to shorten or lengthen any time period hereunder (including without limitation to extend or, pursuant to the last sentence of Section 7(a) of this Rights Agreement or otherwise, to accelerate or defer the Final Expiration Date), (d) to increase or decrease the Purchase Price, or (e) to change or supplement the provisions hereunder in any manner which the Company may deem necessary or desirable; provided, however, that from and after such time as any Person becomes an Acquiring Person, this Rights Agreement shall not be amended in any manner which would adversely affect the interests of the holders of Rights; provided further that this Rights Agreement may not be supplemented or amended to lengthen pursuant to clause (c) of this sentence, (A) the time period relating to when the Rights may be redeemed at such time as the Rights are not then redeemable, or (B) any other time period unless such lengthening is for the purpose of protecting, enhancing or clarifying the rights of, and/or the benefits to, the holders of the Rights; provided further that the Company shall have the right to make unilaterally any changes necessary to facilitate the appointment of a successor Rights Agent, which such changes shall be set forth in a writing by the Company or by the Company and such successor Rights Agent. Without limiting the foregoing, the Company may at any time prior to such time as any Person becomes an Acquiring Person amend this Rights Agreement to lower the thresholds set forth in Sections 1(a) and 3(a) hereof from 15% to not less than the greater of (i) any percentage greater than the largest percentage of the Voting Power of the Company then known by the Company to be beneficially owned by any Person (other than the Company, any Subsidiary of the Company, or any employee benefit plan or compensation arrangement of the Company or any Subsidiary of the Company, and any entity holding securities of the Company to the extent organized, appointed or established by the Company or any such Subsidiary for or pursuant to the terms of any such employee benefit plan or compensation arrangement) together with all Affiliates and Associates of such Person and (ii) 10%. Upon the delivery of a certificate from an appropriate officer of the Company which states that the proposed supplement or amendment is in compliance with the terms of this Section 27, the Rights Agent shall execute such supplement or amendment. Notwithstanding anything in this Rights Agreement to the contrary, no supplement or amendment that changes the rights and duties of the Rights Agent under this Agreement will be effective against the Rights Agent without the execution of such supplement or amendment by the Rights Agent.

Section 28. Successors. All the covenants and provisions of this Rights Agreement by or for the benefit of the Company or the Rights Agent shall bind and inure to the benefit of their respective successors and assigns hereunder.

Section 29. Benefits of This Rights Agreement. Nothing in this Rights Agreement shall be construed to give to any Person other than the Company, the Rights Agent and the registered holders of the Right Certificates (and, prior to the Distribution Date, the Common Stock) any legal or equitable right, remedy or claim under this Rights Agreement; but this Rights Agreement shall be for the sole and exclusive benefit of the Company, the Rights Agent and the registered holders of the Right Certificates (and, prior to the Distribution Date, the Common Stock).

Section 30. Severability. If any term, provision, covenant or restriction of this Rights Agreement is held by a court of competent jurisdiction or other authority to be invalid, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions of this Rights Agreement shall remain in full force and effect and shall in no way be affected, impaired or invalidated. It is the intent of the parties hereto to enforce the remainder of the terms, provisions, covenants and restrictions of this Rights Agreement to the maximum extent permitted by law.

Section 31. Governing Law. This Rights Agreement and each Right Certificate issued hereunder shall be deemed to be a contract made under the laws of the State of Delaware and for all purposes shall be governed by and construed in accordance with the laws of such State applicable to contracts to be made and performed entirely within such State.

Section 32. Counterparts. This Rights Agreement may be executed in any number of counterparts and each of such counterparts shall for all purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument.

Section 33. Descriptive Headings. Descriptive headings of the several Sections of this Rights Agreement are inserted for convenience only and shall not control or affect the meaning or construction of any of the provisions hereof.

IN WITNESS WHEREOF, the parties hereto have caused this Rights Agreement to be duly executed, all as of the day and year first above written.

Attest:

SIGMA-▇▇▇▇▇▇▇ CORPORATION

By /c/ ▇▇▇▇▇ ▇. ▇▇▇▇▇▇

Name: ▇▇▇▇▇ ▇. ▇▇▇▇▇▇

Title: Director Treasury Operations

By /c/ ▇▇▇▇▇▇▇ ▇▇▇▇▇

Name: ▇▇▇▇▇▇▇ ▇▇▇▇▇

Title: Chief Administrative Officer and

Chief Financial Officer

Attest:

COMPUTERSHARE INVESTOR SERVICES, LLC, as Rights Agent

By /c/ ▇▇▇▇▇▇ ▇▇▇▇▇▇

Name: ▇▇▇▇▇▇ ▇▇▇▇▇▇

Title: Account Manager

By /c/ ▇▇▇ ▇▇▇▇▇▇▇

Name: ▇▇▇ ▇▇▇▇▇▇▇

Title: Vice President

Exhibit A

[Form of Right Certificate]

Certificate No. R-___________

____ Rights

NOT EXERCISABLE AFTER THE EXPIRATION DATE. AT THE OPTION OF THE COMPANY, THE RIGHTS ARE SUBJECT TO REDEMPTION AT $0.01 PER RIGHT OR EXCHANGE FOR COMMON STOCK, UNDER THE CIRCUMSTANCES AND ON THE TERMS SET FORTH IN THE RIGHTS AGREEMENT. UNDER CERTAIN CIRCUMSTANCES, RIGHTS BENEFICIALLY OWNED BY AN ACQUIRING PERSON OR AN ASSOCIATE OR AFFILIATE OF AN ACQUIRING PERSON AND ANY SUBSEQUENT HOLDER OF SUCH RIGHTS MAY BECOME NULL AND VOID. [THE RIGHTS REPRESENTED BY THIS RIGHT CERTIFICATE WERE ISSUED TO A PERSON WHO WAS AN ACQUIRING PERSON OR AN AFFILIATE OR AN ASSOCIATE OF AN ACQUIRING PERSON. THIS RIGHT CERTIFICATE AND THE RIGHTS REPRESENTED HEREBY ARE VOID IN THE CIRCUMSTANCES SPECIFIED IN SECTION 7(e) OF THE RIGHTS AGREEMENT.]*

Right Certificate

SIGMA-▇▇▇▇▇▇▇ CORPORATION

This certifies that , or registered assigns, is the registered owner of the number of Rights set forth above, each of which entitles the owner thereof, subject to the terms, provisions and conditions of the Rights Agreement dated as of August 8, 2000 (the "Rights Agreement") between Sigma-▇▇▇▇▇▇▇ Corporation, a Delaware corporation (the "Company"), and Computershare Investor Services, LLC, an Illinois limited liability company, as rights agent (the "Rights Agent"), to purchase from the Company at any time after the Distribution Date (as such term is defined in the Rights Agreement) and prior to 5:00 p.m. St. Louis, Missouri time on the Expiration Date, as that term is defined in the Rights Agreement, at the stockholder services office (or such office designated for such purpose) of the Rights Agent, or its successor as Rights Agent, one share of the Common Stock, par value $1.00 per share ("Common Stock"), of the Company, at a purchase price of $150.00 per share (the "Purchase Price") upon presentation and surrender of this Right Certificate with the Form of Election to Purchase duly executed. The number of Rights evidenced by this Right Certificate (and the number of shares which may be purchased upon exercise of each Right) and the Purchase Price set forth above, are the number and Purchase Price as of _________, _____based on the shares of Common Stock of the Company as constituted at such date.

The Purchase Price and the number of shares of Common Stock which may be purchased upon the exercise of each of the Rights evidenced by this Right Certificate are subject to modification and adjustment upon the happening of certain events as provided in the Rights Agreement.

This Right Certificate is subject to all of the terms, provisions and conditions of the Rights Agreement, which terms, provisions and conditions are hereby incorporated herein by reference and made a part hereof and to which Rights Agreement reference is hereby made for a full description of the rights, limitations of rights, obligations, duties and immunities hereunder of the Rights Agent, the Company and the holders of the Right Certificates. Copies of the Rights Agreement are on file at the Company and the above-mentioned office of the Rights Agent and are also available upon written request to the Company.

This Right Certificate, with or without other Right Certificates, upon surrender at the stockholder services office (or such office designated for such purpose) of the Rights Agent, may be exchanged for another Right Certificate or Right Certificates of like tenor and date evidencing Rights entitling the holder to purchase a like aggregate number of shares of Common Stock as the Rights evidenced by the Right Certificate or Right Certificates surrendered shall have entitled such holder to purchase. If this Right Certificate shall be exercised in part, the holder shall be entitled to receive, upon surrender hereof, another Right Certificate or Right Certificates for the number of whole Rights not exercised.

Subject to the provisions of the Rights Agreement, the Rights evidenced by this Certificate may be redeemed by the Company at its option at a redemption price of $0.01 per Right on or prior to the tenth Business Day following the Stock Acquisition Date (each as defined in the Rights Agreement). In addition, subject to the provisions of the Rights Agreement, each Right evidenced by this Certificate may be exchanged by the Company at its option for one share of Common Stock following the Stock Acquisition Date and prior to the time an Acquiring Person, as that term is defined in the Rights Agreement, owns 50% or more of the Voting Power, as that term is defined in the Rights Agreement, of the Company.

No fractional shares of Common Stock will be issued upon the exercise of any Rights evidenced hereby. In lieu of fractions of a share, a cash payment will be made, as provided in the Rights Agreement.

No holder of this Right Certificate shall be entitled to vote or receive dividends or be deemed for any purpose the holder of shares of Common Stock or of any other securities of the Company which may at any time be issuable on the exercise hereof, nor shall anything contained in the Rights Agreement or herein be construed to confer upon the holder hereof, as such, any of the rights of a stockholder of the Company or any right to vote for the election of directors or upon any matter submitted to stockholders at any meeting thereof, or to give or withhold consent to any corporate action, or to receive notice of meetings or other actions affecting stockholders (except as provided in the Rights Agreement), or to receive dividends or subscription rights, or otherwise, until the Rights evidenced by this Right Certificate shall have been exercised as provided in the Rights Agreement.

This Right Certificate shall not be valid or obligatory for any purpose until it shall have been countersigned by the Rights Agent.

WITNESS the facsimile signature of the proper officers of the Company and its corporate seal. Dated as of __________, _____.

Attest:

SIGMA-▇▇▇▇▇▇▇ CORPORATION

By_______________________

Name:____________________

Title:_____________________

By_______________________

Name:____________________

Title:_____________________

Countersigned:

COMPUTERSHARE INVESTOR SERVICES, LLC, as Rights Agent

By:________________________

Authorized signature

[Form of Reverse Side of Right Certificate]

FORM OF ASSIGNMENT

(To be executed by the registered holder if such

holder desires to transfer the Right Certificate.)

FOR VALUE RECEIVED

hereby sells, assigns and transfers unto

(Please print name and address of transferee)

this Right Certificate, together with all right, title and interest therein, and does hereby irrevocably constitute and appoint _____________ Attorney to transfer the within Right Certificate on the books of the within-named Company, with full power of substitution.

Dated:__________________

Signature

(Signature must conform in all respects to name of holder as specified on the face of this Right Certificate)

Signature Guaranteed:

Signatures must be guaranteed by a member or a participant in the Securities Transfer Agent Medallion Program, the New York Stock Exchange Medallion Signature Program or the Stock Exchange Medallion Program.

CERTIFICATE

The undersigned hereby certifies by checking the appropriate boxes that:

(1) this Right Certificate [ ] is [ ] is not being sold, assigned and transferred by or on behalf of a Person who is or was an Acquiring Person or an Affiliate or Associate of any such Acquiring Person (as such terms are defined pursuant to the Rights Agreement);

(2) after due inquiry and to the best knowledge of the undersigned, it [ ] did [ ] did not acquire the Rights evidenced by this Right Certificate from any Person who is, was or subsequently became an Acquiring Person or an Affiliate or Associate of an Acquiring Person.

Dated:_________________ __________________________________

Signature

(Signature must conform in all respects to name of holder as specified on the face of this Right Certificate)

FORM OF ELECTION TO PURCHASE

(To be executed if holder desires to

exercise the Right Certificate.)

To Sigma-▇▇▇▇▇▇▇ Corporation:

The undersigned hereby irrevocably elects to exercise Rights represented by this Right Certificate to purchase the shares of Common Stock issuable upon the exercise of such Rights and requests that certificates for such shares be issued in the name of:

Name:____________________

Address:__________________

___________________

Social security

or taxpayer identification

number:__________________

If such number of Rights shall not be all the Rights evidenced by this Right Certificate, a new Right Certificate for the balance remaining of such Rights shall be registered in the name of and delivered to:

Name:____________________

Address:__________________

___________________

Social security

or taxpayer identification

number:__________________

Dated:__________________

Signature

(Signature must conform in all respects to name of holder as specified on the face of this Right Certificate)

Signature Guaranteed:

CERTIFICATE

The undersigned hereby certifies by checking the appropriate boxes that:

(1) the Rights evidenced by this Right Certificate [ ] are [ ] are not being exercised by or on behalf of a Person who is or was an Acquiring Person or an Affiliate or Associate of any such Acquiring Person (as such terms are defined pursuant to the Rights Agreement);

(2) this Rights Certificate [ ] is [ ] is not being sold, assigned and transferred by or on behalf of a Person who is or was an Acquiring Person or an Affiliate or Associate of any such Acquiring Person (as such terms are defined pursuant to the Rights Agreement);

(3) after due inquiry and to the best knowledge of the undersigned, it [ ] did [ ] did not acquire the Rights evidenced by this Right Certificate from any Person who is, was or became an Acquiring Person or an Affiliate or Associate of an Acquiring Person.

Dated:_______________

Signature

(Signature must conform in all respects to name of holder as specified on the face of this Right Certificate)

NOTICE

The signature in the foregoing Forms of Assignment and Election must conform to the name as written upon the face of this Right Certificate in every particular, without alteration or enlargement or any change whatsoever.

In the event the certification set forth above in the form of Assignment or the form of Election to Purchase, as the case may be, is not completed, the Company and the Rights Agent will deem the beneficial owner of the Rights evidenced by this Right Certificate to be an Acquiring Person or an Affiliate or Associate thereof (as defined in the Rights Agreement) and such Assignment or Election to Purchase will not be honored as described in Section 7(e) of the Rights Agreement.

Exhibit B

SIGMA-▇▇▇▇▇▇▇ CORPORATION

Summary of Common Stock

Purchase Rights

On August 8, 2000, the Board of Directors of Sigma-▇▇▇▇▇▇▇ Corporation (the "Company") declared a dividend of one common share purchase right (a "Right") for each outstanding share of Common Stock, par value $1.00 per share, of the Company (the "Common Stock"). The dividend distribution is payable on August 22, 2000 (the "Record Date") to the stockholders of record as of the close of business on that date. Each Right entitles the registered holder to purchase from the Company one share of Common Stock at a price of $150.00 per share (the "Purchase Price"), subject to adjustment. The description and terms of the Rights are set forth in a Rights Agreement dated as of August 8, 2000, as the same may be amended from time to time (the "Rights Agreement"), between the Company and Computershare Investor Services, LLC, as Rights Agent (the "Rights Agent").

Until the earlier to occur of (i) the close of business on the tenth business day following the date of public announcement or the date on which the Company first has notice or determines that a person or group of affiliated or associated persons (other than the Company, any subsidiary of the Company or any employee benefit plan of the Company) (an "Acquiring Person") has acquired, or obtained the right to acquire, 15% or more of the outstanding shares of voting stock of the Company without the prior express written consent of the Company executed on behalf of the Company by a duly authorized officer of the Company following express approval by action of at least a majority of the members of the Board of Directors then in office (the "Stock Acquisition Date") or (ii) the close of business on the tenth business day (or such later date as may be determined by action of the Board of Directors but not later than the Stock Acquisition Date) following the commencement of a tender offer or exchange offer, without the prior written consent of the Company, by a person (other than the Company, any subsidiary of the Company or any employee benefit plan of the Company) which, upon consummation, would result in such party's control of 15% or more of the Company's voting stock (the earlier of the dates in clause (i) or (ii) above being called the "Distribution Date"), the Rights will be evidenced, with respect to any of the Common Stock certificates outstanding as of the Record Date, by such Common Stock certificates.

The Rights Agreement provides that, until the Distribution Date (or earlier redemption or expiration of the Rights), the Rights will be transferred with and only with the Company's Common Stock. Until the Distribution Date (or earlier redemption, exchange or expiration of the Rights), new Common Stock certificates issued after the Record Date upon transfer or new issuances of Common Stock will contain a notation incorporating the Rights Agreement by reference. Until the Distribution Date (or earlier redemption, exchange or expiration of the Rights), the surrender for transfer of any certificates for shares of Common Stock outstanding as of the Record Date, even without such notation or a copy of this Summary of Rights, will also constitute the transfer of the Rights associated with the Common Stock represented by such certificate. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights ("Right Certificates") will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and such separate certificates alone will then evidence the Rights.

The Rights are not exercisable until the Distribution Date. The Rights Agreement requires the Board of Directors to review the Rights after they have been outstanding for four years, provided they have not then become exercisable, to determine whether they should be terminated or left in effect. The Rights will expire, if not previously exercised or if the Rights Agreement has not been terminated following such review, on August 8, 2010 (the "Final Expiration Date"), unless the Final Expiration Date is extended or unless the Rights are earlier redeemed or exchanged by the Company.

The Purchase Price payable, and the number of shares of Common Stock or other securities or property issuable, upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of the Common Stock, (ii) upon the issuance of Common Stock or rights to subscribe for shares of Common Stock, or securities convertible into Common Stock with a conversion price of less than the then-current market price of the Common Stock or (iii) upon the distribution to holders of Common Stock of securities (other than those described in (ii) above), evidences of indebtedness or assets (excluding regular periodic cash dividends or dividends out of earnings or retained earnings).

If any person or group (other than the Company, any subsidiary of the Company, any employee benefit plan of the Company) acquires 15% or more of the Company's outstanding voting stock without the prior written consent of the Board of Directors, each Right, except those held by such persons, would entitle each holder of a Right to acquire such number of shares of the Company's Common Stock as shall equal the result obtained by multiplying the then current Purchase Price by the number of shares of Common Stock for which a Right is then exercisable and dividing that product by 50% of the then current per-share market price of Company Common Stock.

If any person or group (other than the Company, any subsidiary of the Company, or any employee benefit plan of the Company) acquires more than 15% but less than 50% of the outstanding Company Common Stock without prior written consent of the Board of Directors, each Right, except those held by such persons, may be exchanged by the Board of Directors for one share of Company Common Stock.

If the Company were acquired in a merger or other business combination transaction where the Company is not the surviving corporation or where Company Common Stock is exchanged or changed or 50% or more of the Company's assets or earnings power is sold in one or several transactions without the prior written consent of the Board of Directors, each Right would entitle the holders thereof (except for the Acquiring Person) to receive such number of shares of the acquiring company's common stock as shall be equal to the result obtained by multiplying the then current Purchase Price by the number of shares of Common Stock for which a Right is then exercisable and dividing that product by 50% of the then current market price per share of the common stock of the acquiring company on the date of such merger or other business combination transaction.

With certain exceptions, no adjustment in the Purchase Price will be required until cumulative adjustments require an adjustment of at least 1% in such Purchase Price. No fractional shares of Common Stock will be issued. In lieu of fractional shares, an adjustment in cash will be made based on the market price of the Common Stock on the last trading day prior to the date of exercise.

At any time prior to the tenth Business Day following the time an Acquiring Person becomes such, the Board of Directors of the Company may redeem the Rights in whole, but not in part, at a price of $0.01 per Right (the "Redemption Price"). The redemption of the Rights may be made effective at such time, on such basis and with such conditions as the Board of Directors in its sole discretion may establish. Immediately upon any redemption of the Rights, the right to exercise the Rights will terminate and the only right of the holders of Rights will be to receive the Redemption Price.

The terms of the Rights may be amended by the Board of Directors of the Company without the consent of the holders of the Rights, including, but not limited to, an amendment to lower certain thresholds described above to not less than the greater of (i) any percentage greater than the largest percentage of the voting power of all securities of the Company then known to the Company to be beneficially owned by any person or group of affiliated or associated persons (other than an excepted person) and (ii) 10%, except that from and after such time as any person or group of affiliated or associated persons becomes an Acquiring Person no such amendment may adversely affect the interests of the holders of the Rights.

Until a Right is exercised, the holder thereof, as such, will have no rights as a stockholder of the Company, including, without limitation, the right to vote or to receive dividends.

A copy of the Rights Agreement has been filed with the Securities and Exchange Commission as an Exhibit to a Registration Statement on Form 8-A. A copy of the Rights Agreement is available free of charge from the Company. This summary description of the Rights does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement, as the same may be amended from time to time, which is hereby incorporated herein by reference.

Exhibit 2

[Sigma-▇▇▇▇▇▇▇ Corporation Letterhead]

August 22, 2000

To Our Stockholders:

On August 8, 2000, your Board of Directors adopted a Stockholder Rights Plan designed to provide our Stockholders with assurance that they will benefit from the long term prospects and increases in value of the Company. The Board of Directors declared a dividend distribution of one Common Stock Purchase Right for each outstanding share of the Company's common stock to holders of record as of the close of business on August 22, 2000.

Each Right will entitle you, under certain conditions, to purchase one share of common stock. Although you are the owner of the Right as of August 22, 2000, under the terms of the Plan no certificate evidencing the Right will be issued to you at this time. At the present time, the summary description referred to in the immediately succeeding paragraph of this letter, and a legend appearing on the backs of common stock certificates issued after August 22, 2000, are the only evidence you will receive or require with respect to your ownership of the Rights.

This letter describes the Board's reasons for issuing the Rights. In addition, we are enclosing a Summary description which outlines the principal features of the new Plan, and we urge you to read it carefully.

Over 2,000 U.S. and Canadian publicly-held companies currently have similar plans. The Board considers the Plan to be an appropriate means to protect your equity investment in the Company and the full value of that investment.

The Plan is designed to protect Stockholders against abusive takeover tactics. We believe that such tactics can unfairly deprive Stockholders of their opportunity to profit from the long term potential of the Company, and can pressure Stockholders to act hastily by threatening to squeeze them out of their investments at less than fair value.

The Board was aware when it approved the Rights Plan that some people have advanced arguments that such plans deter legitimate acquisition proposals. The Board carefully considered those views and concluded that such arguments are speculative and unconvincing and certainly do not justify leaving Stockholders with less effective protection against unfair treatment by an acquirer who, after all, would be seeking to further its own interests, and not yours. The Rights Agreement requires the Board to review the Rights after they have been outstanding for four years to determine whether they should be terminated or left in effect.

It must be emphasized that the Stockholder Rights Plan is not intended to prevent a tender offer or other acquisition proposal for the Company which is fair and equitable to all Stockholders. The Rights should not affect any prospective offeror who is willing to negotiate with your Board of Directors and to make an offer for all of the Company's stock at a full and fair price. Furthermore, the Plan will not in any way prevent an individual Stockholder from exercising his or her right to vote for a change in the management or operation of the Company.

The distribution of the Rights is not taxable to you or to the Company and does not in any way weaken the financial strength of the Company or interfere with its business plans. If the Rights should become exercisable, Stockholders, depending upon the particular circumstances then applicable, may realize taxable income at that time. The Rights are not dilutive and will not affect reported earnings per share, nor will the Rights affect the manner in which you may presently buy or sell the Company's shares.

A copy of the Rights Agreement has been filed with the Securities and Exchange Commission and is available free of charge from either the Company or the Rights Agent, Computershare Investors Services, LLC.

In conclusion, your Board believes that the Stockholder Rights Plan represents a sound and reasonable means of providing Stockholders with protection against takeovers that do not provide fair value. Your Board and management are enthusiastic about the potential for your Company and are committed to serving the best interests of its Stockholders. Accordingly, we take great satisfaction in providing these new Rights to you in order to preserve for you the long-term value of your investment in the Company.

Sincerely,

/c/ ▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇

Chairman of the Board

SIGMA-▇▇▇▇▇▇▇ CORPORATION

Summary of Common Stock

Purchase Rights

The Rights Agreement provides that, until the Distribution Date (or earlier redemption or expiration of the Rights), the Rights will be transferred with and only with the Companys Common Stock. Until the Distribution Date (or earlier redemption, exchange or expiration of the Rights), new Common Stock certificates issued after the Record Date upon transfer or new issuances of Common Stock will contain a notation incorporating the Rights Agreement by reference. Until the Distribution Date (or earlier redemption, exchange or expiration of the Rights), the surrender for transfer of any certificates for shares of Common Stock outstanding as of the Record Date, even without such notation or a copy of this Summary of Rights, will also constitute the transfer of the Rights associated with the Common Stock represented by such certificate. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights ("Right Certificates") will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and such separate certificates alone will then evidence the Rights.

If any person or group (other than the Company, any subsidiary of the Company, any employee benefit plan of the Company) acquires 15% or more of the Companys outstanding voting stock without the prior written consent of the Board of Directors, each Right, except those held by such persons, would entitle each holder of a Right to acquire such number of shares of the Company's Common Stock as shall equal the result obtained by multiplying the then current Purchase Price by the number of shares of Common Stock for which a Right is then exercisable and dividing that product by 50% of the then current per-share market price of Company Common Stock.

Until a Right is exercised, the holder thereof, as such, will have no rights as a stockholder of the Company, including, without limitation, the right to vote or to receive dividends.

RIGHTS AGREEMENT SIGMA-ALDRICH CORPORATION and COMPUTERSHARE INVESTOR SERVICES, LLC Rights Agent Dated as of August 8, 2000 INDEX

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