Diamondback Energy, Inc.

On August 13, 2025, Charles A. Meloy, a member of theboard of directors of the Company, adopted a Rule 10b5-1 trading agreement intended to satisfy Rule 10b5-1(c), as amended. The plan relates to the sale of up to 110,000 shares of our common stock between November 12, 2025, and May 8, 2026. The shares covered by this plan include shares of common stock currently held by Wolfrock Energy, L.L.C., a Texas limited liability company of which Mr. Meloy is the sole manager and has voting and dispositive power over the shares of common stock.

None of the Company’s other directors or officers adopted orterminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement during the Company’s fiscal quarter ended September 30, 2025.

On October 31, 2025, the Company’s board of directors approved certain amendments to our Fifth Amended and Restated Bylaws, effective immediately (as amended and restated, the “Sixth Amended and Restated Bylaws”). Among other things, the Sixth Amended and Restated Bylaws:

(i)clarify and enhance procedural mechanics and disclosure requirements relating to stockholders calling special meetings and stockholder director nominations and submissions of proposals, including requiring additional background information from proposed director nominees;

(ii)adopt a federal forum provision, selecting federal courts as the exclusive forum for claims under the Securities Act, unless the Company consents in writing to the selection of an alternative forum; and

(iii)make other technical, conforming, modernizing and clarifying amendments.

The foregoing summary does not purport to be complete and is qualified in its entirety by reference to the full text of the Sixth Amended and Restated Bylaws, a copy of which is filed as Exhibit 3.3 hereto.