Item 1.01 Entry into a Material Definitive Agreement.

As previously disclosed in the Current Report on Form 8-K filed by Cobalt International Energy, Inc. (the “ Company ”), on December 14, 2017, the Company and certain of its U.S. affiliates (together with the Company, the “ Debtors ”) filed voluntary petitions for relief under chapter 11 of the United States Bankruptcy Code in the United States Bankruptcy Court for the Southern District of Texas (the “ Bankruptcy Court ”). The Debtors’ chapter 11 cases are being jointly administered under the caption In re Cobalt International Energy, Inc., et al. , Case No. 17-36709 (together, the “ Chapter 11 Cases ”). Bankruptcy Court filings and other information related to the Chapter 11 Cases are available at a website administered by the notice and claims agent at www.kccllc.net/cobalt.

On December 19, 2017, Cobalt International Energy Angola Ltd., a wholly-owned subsidiary of the Company, and certain other subsidiaries of the Company named therein, executed an agreement (the “ Agreement ”) with the Angolan National Concessionaire Sociedade Nacional de Combustíveis de Angola — Empresa Pública and Sonangol Pesquisa e Produção, S.A. (collectively, “ Sonangol ”) to resolve all disputes and transition the Company’s interests in Blocks 20 and 21 offshore Angola (the “ Angola Assets ”) to Sonangol for $500 million. Pursuant to the Agreement, Sonangol is required to pay an initial non-refundable payment of $150 million on or before February 23, 2018 (the “ Initial Payment ”) and the final payment of $350 million on or before July 1, 2018 (the “ Final Payment ”). Within 48 hours of receipt of the Initial Payment, the Company is required under the Agreement to (i) notify the relevant International Chamber of Commerce (“ ICC ”) arbitral tribunal of the agreement between the Company and Sonangol to terminate the proceedings related to the joint interest receivable owed to the Company for operations on Block 21 offshore Angola (ICC Case No. 22782/TO) (the “ JOA Arbitration ”) and (ii) notify the relevant ICC arbitral tribunal of the agreement between the Company and Sonangol to extend the procedural timetable by an additional four months for the proceedings related to the purchase and sale agreement (the “ PSA Arbitration ”) for the sale by the Company to Sonangol of the Angola Assets (ICC Case No. 22781/TO).

The Agreement provides that all debts and obligations of Cobalt and Sonangol to each other are extinguished, except that Cobalt’s claims in the PSA Arbitration will not be extinguished until Cobalt’s receipt of the Final Payment by July 1, 2018. As such, the Company will retain the $250 million previously paid by Sonangol and Sonangol will no longer owe Cobalt the approximately $180 million joint interest receivable at issue in the JOA Arbitration. However, if the Initial Payment is not made by February 23, 2018, the Agreement will automatically be rescinded in all respects. The Agreement will be filed with, and is subject to the approval of, the Bankruptcy Court.

The foregoing summary of the Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Agreement attached as Exhibit 10.1 hereto.