SCHEDULE 13D/A 0001578109 XXXXXXXX LIVE 3 Common Stock, par value $0.01 per share 03/11/2026 false 0001922446 25520W107 Diversified Energy Co

1600 Corporate Drive Birmingham AL 35242

EIG Asset Management, LLC 202-600-3300 Krisy Lee, Chief Compliance Officer, 600 New Hampshire Ave NW, Suite 1200 Washington DC 20037 0001636951 N EIG Redwood Co-Investment, L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0002069543 N EIG Energy XV Blocker Agent (Redwood), LLC OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 OO 0002069539 N EIG Holdings Carry Splitter (Redwood), L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0002069540 N EIG Energy Fund XV, L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0002069541 N EIG Energy Fund XV-A, L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0001578109 N EIG Energy Fund XVI, L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0001591998 N EIG Energy Fund XVI-E, L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0002069542 N EIG Energy Fund XVI Holdings Splitter (FourPoint), L.P. OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 PN 0002070688 N EIG Energy Fund XV Blocker Series C (FourPoint) LLC OO N DE 0.00 0.00 0.00 0.00 0.00 N 0.00 OO Common Stock, par value $0.01 per share Diversified Energy Co 1600 Corporate Drive Birmingham AL 35242 This Amendment No. 3 (this "Amendment") amends and supplements the statement on Schedule 13D originally filed with the SEC by the Reporting Persons on May 29, 2025 (the "Original Schedule 13D") as amended by Amendment No. 1 filed on September 22, 2025 ("Amendment No. 1"), and Amendment No. 2 filed on January 12, 2026 ("Amendment No. 2", together with the Original Schedule 13D and Amendment No. 1, the "Schedule 13D"). Capitalized terms used but not defined in this Amendment shall have the meanings ascribed to such terms in the Schedule 13D. Except as specifically provided herein, this Amendment does not modify any of the information previously reported in the Schedule 13D. Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following at the end thereof: Underwriting Agreement On March 9, 2026, in connection with a registered block trade of Common Stock (the "Underwritten Block Trade"), the Issuer, the Reporting Persons, and Citigroup Global Markets Inc. (the "Underwriter") entered into an underwriting agreement (the "Underwriting Agreement") pursuant to which the Reporting Persons agreed to sell to the Underwriter, and the Underwriter agreed to purchase from the Reporting Persons, subject to and upon the terms and conditions set forth therein, 7,501,585 shares of Common Stock at a price of $14.311 per share. The Reporting Persons completed the Underwritten Block Trade on March 11, 2026. References to and descriptions of the Underwriting Agreement set forth above in this Item 4 do not purport to be complete and are qualified in their entirety by reference to the full text of the Underwriting Agreement, which has been filed as an exhibit hereto and incorporated by reference herein. The information set forth in lines 11 and 13 of each of the cover pages hereto is incorporated by reference into this Item 5. The information (i) set forth or incorporated by reference in Item 4 of this Amendment and (ii) set forth on lines 7 through 10 of each of the cover pages hereto is incorporated by reference into this Item 5. In connection with the Underwritten Block Trade, the Reporting Persons sold 7,501,585 shares of Common Stock. The Reporting Persons have not otherwise effected any transactions in Common Stock within the prior 60 days. Except as otherwise described in this Amendment, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, securities covered by this Amendment. As a result of the Underwritten Block Trade reported in this Amendment, the Reporting Persons ceased to be the beneficial owners of more than five percent of the Common Stock as of March 11, 2026 and are no longer subject to the reporting requirements of Rule 13d-1(a) of the Exchange Act. The information set forth or incorporated by reference in Item 4 of this Amendment is incorporated by reference into this Item 6. Item 7 of the Schedule 13D is hereby amended and supplemented by the addition at the end thereof: 5. Underwriting Agreement, dated March 9, 2026, by and among Diversified Energy Company, certain affiliates of EIG Global Energy Partners, listed on Schedule I thereto, and Citigroup Global Markets Inc., as Underwriter (incorporated by reference to Exhibit 1.1 to the Issuer's Current Report on Form 8-K filed with the SEC on March 12, 2026). EIG Redwood Co-Investment, L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy XV Blocker Agent (Redwood), LLC /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Holdings Carry Splitter (Redwood), L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy Fund XV, L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy Fund XV-A, L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy Fund XVI, L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy Fund XVI-E, L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy Fund XVI Holdings Splitter (FourPoint), L.P. /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026 EIG Energy Fund XV Blocker Series C (FourPoint) LLC /s/ Kristin Kelly 03/13/2026 /s/ Kamyar Daneshvar 03/13/2026