Cobalt International Energy, Inc. ("Cobalt") (NYSE:CIE) today announced that its previously announced 1-for-15 reverse stock split became effective at the close of regular NYSE trading hours on June 16, 2017. Cobalt's common stock will begin trading on a post-reverse stock split basis at the opening of the NYSE's regular trading hours on June 19, 2017. Cobalt effected the reverse stock split by filing an amendment to its second amended and restated certificate of incorporation with the Delaware Secretary of State. Cobalt's shares of common stock will continue to trade on the New York Stock Exchange ("NYSE") under the symbol "CIE" under the new CUSIP number 19075F 304. No fractional shares will be issued in connection with the reverse stock split. Any fractional shares resulting from the reverse stock split will be rounded up to the nearest whole share. Stockholders with certificated shares will receive a transmittal letter from the Company's transfer agent which will contain instructions on how to surrender certificates representing pre-split shares of common stock. Stockholders should not send in their old stock certificates until they receive the transmittal letter from the transfer agent. Stockholders with book-entry shares or who hold their shares in "street name" through a bank, broker, custodian or other nominee will not need to take any action. The transfer agent for Cobalt's common stock is Continental Stock Transfer & Trust Company. For questions relating to the transfer or mechanics of the reverse stock split, stockholders may contact Continental Stock Transfer & Trust Company, 1 State Street 30th Floor, New York, NY 10004-1561, or by phone at: (917) 262-2378. About Cobalt Cobalt International Energy, Inc. (NYSE:CIE) is an independent exploration and production company active in the deepwater U.S. Gulf of Mexico and offshore West Africa. Cobalt was formed in 2005 and is headquartered in Houston, Texas. Forward-Looking Statements This press release includes "forward-looking statements" within the meaning of the federal securities laws, including the safe harbor provisions of the Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 — that is, statements related to future, not past, events. Forward-looking statements are based on current expectations and include any statement that does not directly relate to a current or historical fact. In this context, forward-looking statements often address Cobalt's expected future business and financial performance, and often contain words such as "anticipate," "believe," "may," "will," "aim," "estimate," "continue," "intend," "could," "expect," "plan," and other similar words. These forward-looking statements involve certain risks and uncertainties that ultimately may not prove to be accurate. Actual results and future events could differ materially from those anticipated in such statements. For further discussion of risks and uncertainties, individuals should refer to Cobalt's SEC filings. Cobalt disclaims any obligation or undertaking, and does not intend, to update these forward-looking statements to reflect events or circumstances occurring after this press release, other than as required by law. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement.