SCHEDULE 13D/A 0001140361-24-041064 0002021141 XXXXXXXX LIVE 4 Common Stock, par value $0.01 per share 02/03/2026 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 97686727 0 97686727 97686727 34.1 PN Note to Row 13: Based upon 286,525,614 shares of Company Common Stock outstanding as of October 31, 2025, as disclosed by the Company in its Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on November 5, 2025. 0002021141 N Greth Lyndal a OO X1 0 97686727 0 97686727 97686727 34.1 IN Note to Row 13: Based upon 286,525,614 shares of Company Common Stock outstanding as of October 31, 2025, as disclosed by the Company in its Form 10-Q filed with the SEC on November 5, 2025. Common Stock, par value $0.01 per share Diamondback Energy, Inc. 500 WEST TEXAS AVE. SUITE 1200 MIDLAND TX 79701 This Amendment No. 4 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, and December 2, 2025 (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. 4 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 2(b) is hereby amended and restated in full. The principal business address of each Reporting Person is C/O SGF Capital LLC, 8111 Douglas Avenue, Suite 1200, Dallas, Texas 75225. Item 4 is hereby amended and supplemented to add the following: Pursuant to the Repurchase Agreement, on February 3, 2026, the Company agreed to repurchase 1,000,000 shares of Company Common Stock held by SGF FANG at the most recent NASDAQ closing price of $162.88 per share, and on February 4, 2026, the Company agreed to repurchase 1,000,000 shares of Company Common Stock held by SGF FANG at the most recent NASDAQ closing price of $168.99 per share. 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 02/05/2026 Greth Lyndal /s/ Kevin T. Keen 02/05/2026