Crude Oil ( ) Brent Crude ( ) Natural Gas ( ) S&P 500 ( ) PHLX Oil ( )

Diamondback Energy, Inc. (FANG) (“Diamondback” or the “Company”) announced today the pricing of an underwritten public offering of 4,000,000 shares of its common stock. The 4,000,000 share offering represents a 1,000,000 share upsize to the originally proposed 3,000,000 share offering. The underwriter intends to offer the shares from time to time for sale in one or more transactions on the NASDAQ Global Select Market, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or at negotiated prices. The total gross proceeds of the offering (before underwriter’s discounts and commissions and estimated offering expenses) will be approximately $297 million. The underwriter has an option to purchase up to an additional 600,000 shares of common stock from Diamondback.

Diamondback intends to use the net proceeds from this offering to fund a portion of the purchase price for its previously announced pending acquisitions of additional acreage in the Midland Basin, primarily in northwestern Howard County, in the Permian Basin (the “Pending Acquisitions”). To the extent one or more of the Pending Acquisitions is not consummated, or one or more of the purchase prices is reduced because Diamondback acquires less than all of the oil and natural gas assets subject to the applicable purchase agreement, Diamondback intends to use any remaining net proceeds to repay borrowings under its revolving credit facility, fund a portion of its exploration and development activities and for general corporate purposes, which may include leasehold interest and property acquisitions and working capital.

The offering is expected to close on May 13, 2015, subject to customary closing conditions.

Credit Suisse Securities (USA) LLC is acting as sole book-running manager for the offering. Copies of the preliminary prospectus supplement for the offering may be obtained on the website of the Securities and Exchange Commission, www.sec.gov or by contacting Credit Suisse Securities (USA) LLC, Prospectus Department (1-800-221-1037), at One Madison Avenue, New York, New York 10010.

The common stock will be issued and sold pursuant to an effective automatic shelf registration statement on Form S-3 previously filed with the Securities and Exchange Commission.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such state or jurisdiction. This offering may only be made by means of a prospectus supplement and related base prospectus.

About Diamondback Energy, Inc.

Diamondback is an independent oil and natural gas company headquartered in Midland, Texas focused on the acquisition, development, exploration and exploitation of unconventional, onshore oil and natural gas reserves in the Permian Basin in West Texas. Diamondback’s activities are primarily focused on the horizontal exploitation of multiple intervals within the Wolfcamp, Spraberry, Clearfork and Cline formations.