Material Event (Form 8-K)

Item 8.01 Other Events.

As previously announced, on November 2, 2025, Civitas Resources, Inc., a Delaware corporation ("Civitas" or the "Company"), SM Energy Company, a Delaware corporation ("SM Energy"), and Cars Merger Sub, Inc., a Delaware corporation and direct wholly owned subsidiary of SM Energy ("Merger Sub"), entered into an Agreement and Plan of Merger pursuant to which (i) Merger Sub will merge with and into Civitas, with Civitas surviving as a wholly owned subsidiary of SM Energy (the "First Company Merger"), and (ii) immediately following the First Company Merger, Civitas as the surviving corporation will merge with and into SM Energy, with SM Energy continuing as the surviving corporation (the "Second Company Merger" and, together with the First Company Merger, the "Mergers").

On December 5, 2025, SM Energy filed with the U.S. Securities and Exchange Commission (the "SEC") a Registration Statement on Form S-4 (Registration No. 333-291956) (the "Registration Statement"), which was declared effective by the SEC on December 19, 2025, and which included a joint proxy statement/prospectus of SM Energy and Civitas in connection with the Mergers (such joint proxy statement/prospectus as filed by Civitas on December 22, 2025, the "Joint Proxy Statement/Prospectus").

Litigation Related to the Mergers

Since the filing of the Joint Proxy Statement/Prospectus, as of the date hereof, two complaints have been filed by purported Civitas stockholders as individual actions against Civitas and the members of Civitas' Board of Directors in the Supreme Court of New York State. The complaints are captioned Johnson v. Civitas Resources, Inc. et al., No. 650089/2026 (N.Y. Sup.) (filed January 6, 2026) and Walsh v. Civitas Resources, Inc. et al., No. 650175/2026 (N.Y. Sup.) (filed January 8, 2026) (collectively, the "Stockholder Complaints"). The plaintiffs in the Stockholder Complaints allege that, among other things, the Joint Proxy Statement/Prospectus contains certain disclosure deficiencies and/or incomplete information regarding the Mergers, and assert claims for violations of New York law against Civitas and Civitas' Board of Directors. The plaintiffs in the Stockholder Complaints seek, among other relief, an order enjoining defendants and all persons acting in concert with them from proceeding with, consummating, or closing the Mergers and any vote on the Mergers, rescission or an award of rescissory damages in the event the Mergers are consummated, and costs and reasonable attorney and expert fees. As of the date hereof, Civitas also has, to its knowledge, received several demand letters from purported Civitas stockholders (the "Demand Letters" and, together with the Stockholder Complaints, the "Stockholder Actions") alleging that the Joint Proxy Statement/Prospectus contained disclosure deficiencies and/or incomplete information regarding the Mergers. It is possible that additional, similar complaints may be filed, or that additional, similar demand letters may be issued, regarding the Mergers. Absent new or different allegations that are material, Civitas will not necessarily disclose such additional complaints or demands.

Civitas and Civitas' directors deny that any further disclosure beyond that already contained in the Joint Proxy Statement/Prospectus is required under applicable law. However, in order to avoid the risk that the Stockholder Actions may delay or otherwise adversely affect the consummation of the Mergers, to avoid nuisance and minimize the distractions, uncertainties, and expense inherent in litigation, and without admitting any liability or wrongdoing, Civitas is voluntarily making certain disclosures below that supplement those contained in the Joint Proxy Statement/Prospectus. These disclosures, and disclosures of certain other matters, are provided in this Current Report on Form 8-K. Nothing in this Current Report on Form 8-K shall be deemed an admission of the legal necessity or materiality under applicable laws of any of the disclosures set forth herein. To the contrary, Civitas and Civitas' directors specifically deny all allegations in the Stockholder Actions and specifically deny that any additional disclosure was or is required.

SUPPLEMENT TO PROXY STATEMENT

The Company is supplementing the Joint Proxy Statement/Prospectus with certain additional information set forth below. These disclosures should be read in connection with the Joint Proxy Statement/Prospectus, which should be read in its entirety and is available on the SEC's website at https://www.sec.gov, along with the periodic reports and other information the Company files with the SEC. The supplemental disclosures contained herein will not affect the timing of special meetings of the Company's and SM Energy's stockholders, which are scheduled to be held on January 27, 2026, at 10:00 a.m. Mountain Time.