Common use of Installment Payment Dates Clause in Contracts

Installment Payment Dates. Each March 7, June 7, September 7 and December 7, commencing on September 7, 2015, with a final installment payment date of June 7, 2018. Payments on the Amortizing Notes: The Amortizing Notes will pay holders equal quarterly cash installments of $0.9375 per Amortizing Note (except for the September 7, 2015 installment payment, which will be $0.9063 per Amortizing Note), which in the aggregate will be equivalent to a 7.50% cash payment per year with respect to each $50 Stated Amount of Units. Each installment will constitute a payment of interest (at an annual rate of 1.50%) and a partial repayment of principal on the Amortizing Notes, allocated with respect to each Amortizing Note as set forth in the following amortization schedule: September 7, 2015 $ 0.8666 $ 0.0397 December 7, 2015 $ 0.8997 $ 0.0378 March 7, 2016 $ 0.9031 $ 0.0344 June 7, 2016 $ 0.9064 $ 0.0311 September 7, 2016 $ 0.9098 $ 0.0277 December 7, 2016 $ 0.9133 $ 0.0242 March 7, 2017 $ 0.9167 $ 0.0208 June 7, 2017 $ 0.9201 $ 0.0174 September 7, 2017 $ 0.9236 $ 0.0139 December 7, 2017 $ 0.9270 $ 0.0105 March 7, 2018 $ 0.9305 $ 0.0070 June 7, 2018 $ 0.9340 $ 0.0035 Indenture Indenture for Debt Securities with The Bank of New York Mellon Trust Company, N.A. dated September 19, 2006, as supplemented by that certain Third Supplemental Indenture dated as of June 10, 2015. Public Offering Price: $50 per Unit $400,000,000 in the aggregate (or $460,000,000 in the aggregate if the underwriters of the Units Offering exercise their over-allotment option in full). Underwriting Discount: $1.50 per Unit $12,000,000 in the aggregate (or $13,800,000 in the aggregate if the underwriters of the Units Offering exercise their over-allotment option in full). The underwriters of the Units Offering propose to offer the Units to dealers at the public offering price less a concession not in excess of $0.90 per Unit. Closing Date: June 10, 2015. Lock-Up Period and Securities 45 days; WGP Common Units, including securities convertible into, or exchangeable for WGP Common Units, or options, rights or warrants with respect to any WGP Common Units. Applicable Time: 4:45 p.m. Eastern Time, on the date of this Terms Agreement. Estimated Net Proceeds to Anadarko from the Units Offering: Estimated net proceeds from the sale of Units in the Units Offering, after deducting underwriting discounts and commissions and estimated offering expenses, will be approximately $387.1 million (or approximately $445.3 million if the underwriters of the Units Offering exercise their over-allotment option in full). Sole Book-Running Manager: ▇.▇. ▇▇▇▇▇▇ Securities LLC. Co-Managers: Barclays Capital Inc. Citigroup Global Markets Inc. Credit Suisse Securities (USA) LLC Deutsche Bank Securities Inc. ▇▇▇▇▇▇▇, Sachs & Co. ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. LLC RBC Capital Markets, LLC ▇▇▇▇▇ Fargo Securities, LLC Listing: Anadarko will apply to list the Units on the NYSE under the symbol “AEUA,” subject to satisfaction of its minimum listing standards with respect to the Units. If approved for listing, Anadarko expects trading on the NYSE to begin within 30 calendar days after the Units are first issued. Additional Information: ▇. ▇. ▇▇▇▇▇▇, the Chief Executive Officer and a director of Anadarko, is expected to purchase approximately $125,000 of WGP Common Units in connection with the WGP Common Unit Offering and approximately $125,000 stated amount of Units in connection with the Units Offering, in each case at the applicable public offering price. Other Relationships: Affiliates of each of ▇.▇. ▇▇▇▇▇▇ Securities LLC and ▇▇▇▇▇ Fargo Bank, N.A. are lenders under our senior secured revolving credit facility. CUSIP for the Units: 032511 404 ISIN for the Units: US0325114041 CUSIP for the Purchase Contracts: 032511 123 ISIN for the Purchase Contracts: US0325111237 CUSIP for the Amortizing Notes: 032511 503 ISIN for the Amortizing Notes: US0325115030 Anadarko will prepare a final term sheet relating to the Securities. For purposes of the Underwriting Agreement, the only information furnished to Anadarko by any Underwriter for use in the Prospectus consists of the following information in the Prospectus furnished on behalf of each Underwriter: The statements set forth in (i) the first and second sentences of the third paragraph and (ii) in the 12th and 13th under the caption “Underwriting” in the Prospectus, in each case only insofar as such statements relate to the amount of selling concessions and stabilization activities that may be undertaken by the Underwriters, constitute the only information furnished by or on behalf of the Underwriters, as such information is referred to in this Terms Agreement (including the Standard Provisions incorporated by reference herein). For purposes of the Underwriting Agreement, the only information furnished to the Partnership by any Underwriter for use in the Partnership Prospectus consists of the following information in the Partnership Prospectus furnished on behalf of each Underwriter: The statements set forth in eighth and ninth paragraphs under the caption “Plan of Distribution” in the Partnership Prospectus, insofar as such statements relate to stabilization activities that may be undertaken by the Underwriters, constitute the only information furnished by or on behalf of the Underwriters, as such information is referred to in this Terms Agreement (including the Standard Provisions incorporated by reference herein) Addresses for notice: ▇.▇. ▇▇▇▇▇▇ Securities LLC ▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇ ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇ Subject to the terms and provisions of the above referenced Underwriting Agreement, which is incorporated herein in its entirety and made a part hereof to the same extent as if such terms and provisions had been set forth in full herein, Anadarko agrees to sell and each Underwriter severally agrees to purchase the number of Firm Securities set forth opposite its name. ▇.▇. ▇▇▇▇▇▇ Securities LLC 2,960,000 Barclays Capital Inc. 560,000 Citigroup Global Markets Inc. 560,000 Credit Suisse Securities (USA) LLC 560,000 Deutsche Bank Securities Inc. 560,000 ▇▇▇▇▇▇▇, Sachs & Co. 560,000 ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated 560,000 ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. LLC 560,000 RBC Capital Markets, LLC 560,000 ▇▇▇▇▇ Fargo Securities, LLC 560,000 Total 8,000,000 We represent that as Representative of the several Underwriters we are entitled to execute this Terms Agreement on behalf of the several Underwriters and otherwise to act as representative on their behalf. Anadarko shall be entitled to act and rely upon any request, consent, notice or agreement given by us as representative of the several Underwriters. [Signature page follows.] ▇.▇. ▇▇▇▇▇▇ SECURITIES LLC For itself and as Representative of the several Underwriters By: /s/ ▇▇▇ Oeljeschlager Name: ▇▇▇ Oeljeschlager Title: Executive Director Accepted: ANADARKO PETROLEUM CORPORATION By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇ Name: ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇ Title: Senior Vice President, Finance and Treasurer WESTERN GAS EQUITY HOLDINGS, LLC By: /s/ ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Name: ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Title: Senior Vice President, Chief Financial Officer and Treasurer WESTERN GAS EQUITY PARTNERS, LP By: Western Gas Equity Holdings, LLC By: /s/ ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Name: ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Title: Senior Vice President, Chief Financial Officer and Treasurer

Installment Payment Dates. Each March 7, June 7, September 7 and December 7, commencing on September 7, 2015, with a final installment payment date of June 7, 2018. Payments on the Amortizing Notes: The Amortizing Notes will pay holders equal quarterly cash installments of $0.9375 per Amortizing Note (except for the September 7, 2015 installment payment, which will be $0.9063 per Amortizing Note), which in the aggregate will be equivalent to a 7.50% cash payment per year with respect to each $50 Stated Amount of Units. Each installment will constitute a payment of interest (at an annual rate of 1.50%) and a partial repayment of principal on the Amortizing Notes, allocated with respect to each Amortizing Note as set forth in the following amortization schedule: September 7, 2015 $ 0.8666 $ 0.0397 December 7, 2015 $ 0.8997 $ 0.0378 March 7, 2016 $ 0.9031 $ 0.0344 June 7, 2016 $ 0.9064 $ 0.0311 September 7, 2016 $ 0.9098 $ 0.0277 December 7, 2016 $ 0.9133 $ 0.0242 March 7, 2017 $ 0.9167 $ 0.0208 June 7, 2017 $ 0.9201 $ 0.0174 September 7, 2017 $ 0.9236 $ 0.0139 December 7, 2017 $ 0.9270 $ 0.0105 March 7, 2018 $ 0.9305 $ 0.0070 June 7, 2018 $ 0.9340 $ 0.0035 Indenture Indenture for Debt Securities with The Bank of New York Mellon Trust Company, N.A. dated September 19, 2006, as supplemented by that certain Third Supplemental Indenture dated as of June 10, 2015. Public Offering Price: $50 per Unit $400,000,000 in the aggregate (or $460,000,000 in the aggregate if the underwriters of the Units Offering exercise their over-allotment option in full). Underwriting Discount: $1.50 per Unit $12,000,000 in the aggregate (or $13,800,000 in the aggregate if the underwriters of the Units Offering exercise their over-allotment option in full). The underwriters of the Units Offering propose to offer the Units to dealers at the public offering price less a concession not in excess of $0.90 per Unit. Closing Date: June 10, 2015. Lock-Up Period and Securities 45 days; WGP Common Units, including securities convertible into, or exchangeable for WGP Common Units, or options, rights or warrants with respect to any WGP Common Units. Applicable Time: 4:45 p.m. Eastern Time, on the date of this Terms Agreement. Estimated Net Proceeds to Anadarko from the Units Offering: Estimated net proceeds from the sale of Units in the Units Offering, after deducting underwriting discounts and commissions and estimated offering expenses, will be approximately $387.1 million (or approximately $445.3 million if the underwriters of the Units Offering exercise their over-allotment option in full). Sole Book-Running Manager: ▇.▇. ▇▇▇▇▇▇ Securities LLC. Co-Managers: Barclays Capital Inc. Citigroup Global Markets Inc. Credit Suisse Securities (USA) LLC Deutsche Bank Securities Inc. ▇▇▇▇▇▇▇, Sachs & Co. ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. LLC RBC Capital Markets, LLC ▇▇▇▇▇ Fargo Securities, LLC Listing: Anadarko will apply to list the Units on the NYSE under the symbol “AEUA,” subject to satisfaction of its minimum listing standards with respect to the Units. If approved for listing, Anadarko expects trading on the NYSE to begin within 30 calendar days after the Units are first issued. Additional Information: ▇. ▇. ▇▇▇▇▇▇, the Chief Executive Officer and a director of Anadarko, is expected to purchase approximately $125,000 of WGP Common Units in connection with the WGP Common Unit Offering and approximately $125,000 stated amount of Units in connection with the Units Offering, in each case at the applicable public offering price. Other Relationships: Affiliates of each of ▇.▇. ▇▇▇▇▇▇ Securities LLC and ▇▇▇▇▇ Fargo Bank, N.A. are lenders under our senior secured revolving credit facility. CUSIP for the Units: 032511 404 ISIN for the Units: US0325114041 CUSIP for the Purchase Contracts: 032511 123 ISIN for the Purchase Contracts: US0325111237 CUSIP for the Amortizing Notes: 032511 503 ISIN for the Amortizing Notes: US0325115030 Anadarko will prepare a final term sheet relating to the Securities. For purposes of the Underwriting Agreement, the only information furnished to Anadarko by any Underwriter for use in the Prospectus consists of the following information in the Prospectus furnished on behalf of each Underwriter: The statements set forth in (i) the first and second sentences of the third paragraph and (ii) in the 12th and 13th under the caption “Underwriting” in the Prospectus, in each case only insofar as such statements relate to the amount of selling concessions and stabilization activities that may be undertaken by the Underwriters, constitute the only information furnished by or on behalf of the Underwriters, as such information is referred to in this Terms Agreement (including the Standard Provisions incorporated by reference herein). For purposes of the Underwriting Agreement, the only information furnished to the Partnership by any Underwriter for use in the Partnership Prospectus consists of the following information in the Partnership Prospectus furnished on behalf of each Underwriter: The statements set forth in eighth and ninth paragraphs under the caption “Plan of Distribution” in the Partnership Prospectus, insofar as such statements relate to stabilization activities that may be undertaken by the Underwriters, constitute the only information furnished by or on behalf of the Underwriters, as such information is referred to in this Terms Agreement (including the Standard Provisions incorporated by reference herein) Addresses for notice: ▇.▇. ▇▇▇▇▇▇ Securities LLC ▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇ ▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇ ▇▇▇▇▇ Subject to the terms and provisions of the above referenced Underwriting Agreement, which is incorporated herein in its entirety and made a part hereof to the same extent as if such terms and provisions had been set forth in full herein, Anadarko agrees to sell and each Underwriter severally agrees to purchase the number of Firm Securities set forth opposite its name. ▇.▇. ▇▇▇▇▇▇ Securities LLC 2,960,000 Barclays Capital Inc. 560,000 Citigroup Global Markets Inc. 560,000 Credit Suisse Securities (USA) LLC 560,000 Deutsche Bank Securities Inc. 560,000 ▇▇▇▇▇▇▇, Sachs & Co. 560,000 ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated 560,000 ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. LLC 560,000 RBC Capital Markets, LLC 560,000 ▇▇▇▇▇ Fargo Securities, LLC 560,000 Total 8,000,000 We represent that as Representative of the several Underwriters we are entitled to execute this Terms Agreement on behalf of the several Underwriters and otherwise to act as representative on their behalf. Anadarko shall be entitled to act and rely upon any request, consent, notice or agreement given by us as representative of the several Underwriters. [Signature page follows.] ▇.▇. ▇▇▇▇▇▇ SECURITIES LLC For itself and as Representative of the several Underwriters By: /s/ ▇▇▇ Oeljeschlager Name: ▇▇▇ Oeljeschlager Title: Executive Director [Signature Page to Terms Agreement] Accepted: ANADARKO PETROLEUM CORPORATION By: /s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇ Name: ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇ Title: Senior Vice President, Finance and Treasurer WESTERN GAS EQUITY HOLDINGS, LLC By: /s/ ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Name: ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Title: Senior Vice President, Chief Financial Officer and Treasurer WESTERN GAS EQUITY PARTNERS, LP By: Western Gas Equity Holdings, LLC By: /s/ ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Name: ▇▇▇▇▇▇▇▇ ▇. ▇▇▇▇ Title: Senior Vice President, Chief Financial Officer and TreasurerTreasurer [Signature Page to Terms Agreement]