X0202 SCHEDULE 13D/A 0001140361-24-041064 0002021141 XXXXXXXX LIVE 6 Common Stock, par value $0.01 per share 06/04/2026 0001539838 25278X109 Diamondback Energy, Inc.

500 WEST TEXAS AVE. SUITE 1200 MIDLAND TX 79701

Hillary H. Holmes (346) 718-6600 Gibson, Dunn & Crutcher LLP 811 Main Street, Suite 3000 Houston TX 77002 Y SGF FANG Holdings, LP a OO DE 0 74036722 0 74036722 74036722 26.3 PN Note to Row 13: Based upon 281,313,297 shares of Company Common Stock outstanding as of May 1, 2026, as disclosed by the Company in its Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on May 6, 2026. 0002021141 N Greth Lyndal a OO X1 0 74036722 0 74036722 74036722 26.3 IN Note to Row 13: Based upon 281,313,297 shares of Company Common Stock outstanding as of May 1, 2026, as disclosed by the Company in its Form 10-Q filed with the SEC on May 6, 2026. Common Stock, par value $0.01 per share Diamondback Energy, Inc. 500 WEST TEXAS AVE. SUITE 1200 MIDLAND TX 79701 This Amendment No. 6 amends and supplements the statement on Schedule 13D originally filed with the SEC on September 13, 2024, as amended on September 24, 2024, August 15, 2025, December 2, 2025, February 5, 2026, and March 16, 2026 (the "Schedule 13D"), by the Reporting Persons with respect to shares of Company Common Stock. Unless otherwise defined herein, capitalized terms used in this Amendment No. 6 shall have the meanings ascribed to them in the Schedule 13D. Unless amended or supplemented below, the information in the Schedule 13D remains unchanged. Item 4 is hereby amended and supplemented to add the following: On June 4, 2026, SGF FANG sold an aggregate of 10,000,000 shares of Common Stock at a price of $204.25 per share pursuant to Rule 144 under the Securities Act of 1933, as amended (the "June 4, 2026 Sale"). In connection with the June 4, 2026 Sale, SGF FANG is subject to a lock-up period from June 4, 2026 through the date 30 days after June 4, 2026, during which SGF FANG may not sell any shares of Common Stock without the mutual agreement of SGF FANG and J.P. Morgan Securities LLC. Item 5(a) is hereby amended and restated in full. The information contained on the cover pages and Item 2 to this Schedule 13D is incorporated herein by reference. Item 5(b) is hereby amended and restated in full. The information contained on the cover pages and Item 2 to this Schedule 13D is incorporated herein by reference. Item 5(c) is hereby amended and supplemented to add the information set forth in Item 4 of this Schedule 13D. Item 6 is hereby amended and supplemented to add the information set forth in Item 4 of this Schedule 13D. SGF FANG Holdings, LP /s/ Kevin T. Keen 06/05/2026 Greth Lyndal /s/ Kevin T. Keen 06/05/2026