APC Anadarko Petroleum Corporation

On September 12, 2016, Anadarko Petroleum Corporation (the “ Company ”) entered into an Underwriting Agreement (the “ Underwriting Agreement ”) with J.P. Morgan Securities LLC, relating to the public offering of 35,250,000 shares of the Company’s common stock, $0.10 par value (the “ Common Stock ”). On September 13, 2016, the Underwriter exercised in full its option to purchase 5,287,500 additional shares, bringing the total offering to 40,537,500 shares of Common Stock (the “ Shares ”). The Company expects the net proceeds from the offering to be approximately $2,157.3 million, after deducting estimated fees and expenses. The Company intends to use the net proceeds from the offering to fund the net purchase price for the acquisition of certain interests in oil and gas properties located in the deepwater Gulf of Mexico, and the remaining net proceeds will be used for general corporate purposes. If the acquisition is not consummated, all of the net proceeds will be used for general corporate purposes.

The offering was made pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-213104), which became effective upon filing with the Securities and Exchange Commission on August 12, 2016. A legal opinion relating to the validity of the Shares is filed herewith as Exhibit 5.1.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company, indemnification obligations of the Company and the underwriter, including for liabilities under the Securities Act of 1933, as amended, other obligations of the parties and termination provisions. The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Underwriting Agreement, which is filed as Exhibit 1.1 hereto and incorporated by reference herein.

Relationships

The underwriter and certain of its affiliates have provided from time to time, and may provide in the future, investment and commercial banking and financial advisory services to us and our affiliates in the ordinary course of business, for which they have received and may continue to receive customary fees and commissions.