Business Combination Prospectus (Form 425)

Filed by: Civitas Resources, Inc.

Pursuant to Rule 425 under the

Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: Civitas Resources, Inc.

Commission File No.: 001-35371

The following communication was made available to certain stockholders of Civitas Resources, Inc. on January 13, 2026:

January 12, 2026

Dear Fellow Stockholder:

We previously sent you proxy materials for the important Special Meeting of Stockholders of Civitas Resources, Inc. to be held on January 27, 2026, in connection with the proposed merger with SM Energy.

Your Board of Directors unanimously recommends that you vote FOR the Merger and related proposals.

Your vote is very important. If you have not already done so, please vote TODAY via the Internet, by telephone, or by signing, dating, and returning the enclosed proxy card or voting instruction form in the envelope provided.

Thank you for your support.

Sincerely,

Wouter van Kempen
Interim Chief Executive Officer

Forward-Looking Statements

This communication contains "forward-looking statements" within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. All statements, other than statements of historical fact, included in this communication that address events or developments that SM Energy and Civitas expect, believe, or anticipate will or may occur in the future are forward-looking statements. The words "intend," "expect," and similar expressions are intended to identify forward-looking statements. Forward-looking statements in this communication include, but are not limited to, statements regarding the transactions (the "Transaction") contemplated by that certain Agreement and Plan of Merger, dated November 2, 2025 (the "Merger Agreement"), pro forma descriptions of the combined company and its operations, integration and transition plans, synergies, opportunities and anticipated future performance. There are a number of risks and uncertainties that could cause actual results to differ materially from the forward-looking statements included in this communication. These include the expected timing and likelihood of completion of the Transaction, the ability to successfully integrate the businesses, the occurrence of any event, change or other circumstances that could give rise to the termination of the Merger Agreement, the possibility that stockholders of SM Energy or Civitas may not approve the Transaction, the risk that the parties may not be able to satisfy the conditions to the Transaction in a timely manner or at all, risks related to disruption of management time from ongoing business operations due to the Transaction, the risk that any announcements relating to the Transaction could have adverse effects on the market price of SM Energy's common stock or Civitas' common stock, the risk that the Transaction and its announcement could have an adverse effect on the ability of SM Energy and Civitas to retain customers and retain and hire key personnel and maintain relationships with their suppliers and customers and on their operating results and businesses generally, the risk the pending Transaction could distract management of both entities and they will incur substantial costs, the risk that problems may arise in successfully integrating the businesses of the companies, which may result in the combined company not operating as effectively and efficiently as expected, the risk that the combined company may be unable to achieve synergies or it may take longer than expected to achieve those synergies and other important factors that could cause actual results to differ materially from those projected. All such factors are difficult to predict and are beyond SM Energy's or Civitas' control, including those detailed in SM Energy's annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K that are available on its website at sm-energy.com/investors and on the SEC's website at http://www.sec.gov, and those detailed in Civitas' annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K that are available on Civitas' website at ir.civitasresources.com/investor-relations and on the SEC's website at http://www.sec.gov. All forward-looking statements are based on assumptions that SM Energy and Civitas believe to be reasonable but that may not prove to be accurate. Such forward-looking statements are based on assumptions and analyses made by SM Energy and Civitas in light of their perceptions of current conditions, expected future developments, and other factors that SM Energy and Civitas believe are appropriate under the circumstances. These statements are subject to a number of known and unknown risks and uncertainties. Forward-looking statements are not guarantees of future performance and actual events may be materially different from those expressed or implied in the forward-looking statements. The forward-looking statements in this communication speak as of the date of this communication.

No Offer or Solicitation

This communication is for informational purposes only and is not intended to, and shall not, constitute an offer to buy or sell or the solicitation of an offer to buy or sell any securities, or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made, except by means of a prospectus meeting the requirements of Section 10 of the Securities Act.

Additional Information and Where to Find It

In connection with the proposed transaction, SM Energy has filed with the SEC a registration statement on Form S-4 (No. 333-291956) (the "Registration Statement") that includes a joint proxy statement of SM Energy and Civitas and a prospectus of SM Energy (the "Joint Proxy Statement/Prospectus"). Each of SM Energy and Civitas may also file other relevant documents with the SEC regarding the proposed transaction. This communication is not a substitute for the Joint Proxy Statement/Prospectus or Registration Statement or any other document that SM Energy or Civitas, as applicable, may file with the SEC in connection with the proposed transaction. The Registration Statement was declared effective on December 19, 2025, and SM Energy filed a prospectus on December 22, 2025 and Civitas filed a definitive proxy statement on December 22, 2025. SM Energy and Civitas commenced mailing of the definitive Joint Proxy Statement/Prospectus to their respective security holders on or about December 22, 2025. BEFORE MAKING ANY VOTING OR INVESTMENT DECISION, INVESTORS AND SECURITY HOLDERS OF SM ENERGY AND CIVITAS ARE URGED TO READ THE REGISTRATION STATEMENT, THE DEFINITIVE JOINT PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT MAY BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT SM ENERGY, CIVITAS, THE PROPOSED TRANSACTION AND RELATED MATTERS. Investors and security holders are able to obtain free copies of the Registration Statement and the definitive Joint Proxy Statement/Prospectus, as well as other filings containing important information about SM Energy, Civitas and the proposed transaction, once such documents are filed with the SEC through the website maintained by the SEC at https://www.sec.gov. Copies of the documents filed with the SEC by SM Energy are available free of charge on SM Energy's website at https://www.sm-energy.com/investors. Copies of the documents filed with the SEC by Civitas are available free of charge on Civitas' website at https://ir.civitasresources.com/investor-relations. The information included on, or accessible through, SM Energy's or Civitas' website is not incorporated by reference into this communication.

Participants in the Solicitation

SM Energy, Civitas and certain of their respective directors and executive officers may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information about the directors and executive officers of SM Energy, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in SM Energy's proxy statement for its 2025 Annual Meeting of Stockholders, which was filed with the SEC on April 7, 2025 (and which is available at https://www.sec.gov/Archives/edgar/data/893538/000089353825000032/sm-20250404.htm), a Form 8-K filed by SM Energy on September 8, 2025 (and which is available at https://www.sec.gov/Archives/edgar/data/893538/000089353825000116/sm-20250904.htm) and a Form 8-K filed by SM Energy on December 19, 2025 (and which is available at https://www.sec.gov/ix?doc=/Archives/edgar/data/893538/000089353825000167/sm-20251215.htm). Information about the directors and executive officers of Civitas, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in a Form 8-K filed by Civitas on August 6, 2025 (and which is available at https://www.sec.gov/Archives/edgar/data/1509589/000110465925074774/tm2522747d1_8k.htm), a Form 8-K filed by Civitas on May 7, 2025 (and which is available at https://www.sec.gov/Archives/edgar/data/1509589/000110465925045550/tm2514090d1_8k.htm), and Civitas' proxy statement for its 2025 Annual Meeting of Stockholders, which was filed with the SEC on April 21, 2025 (and which is available at https://www.sec.gov/Archives/edgar/data/1509589/000155837025005077/civi-20241231xdef14a.htm). Other information regarding the participants in the proxy solicitations and a description of their direct and indirect interests, by security holdings or otherwise, is contained in the definitive Joint Proxy Statement/Prospectus and other relevant materials to be filed with the SEC regarding the proposed transaction when such materials become available. Investors should read the definitive Joint Proxy Statement/Prospectus carefully before making any voting or investment decisions. You may obtain free copies of these documents from SM Energy and Civitas using the sources indicated above.