Filed by: Cabot Oil & Gas Corporation

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: Cimarex Energy Co.

Commission File No. for Registration Statement
on Form S-4 filed by Cabot Oil & Gas Corporation: 333-257534

As previously disclosed, on June 14, 2021, notification and report forms under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”) were filed by each of Cabot Oil & Gas Corporation (“Cabot”) and Cimarex Energy Co. (“Cimarex”) with the Federal Trade Commission and the Department of Justice with respect to the proposed merger between Cimarex and a subsidiary of Cabot (the “merger”). The waiting period with respect to the merger expired at 11:59 p.m. Eastern Time on July 14, 2021. Accordingly, the condition to the merger relating to the expiration or termination of any waiting period under the HSR Act has been satisfied. Completion of the merger remains subject to other customary conditions, including the requisite approvals by the stockholders of each of Cabot and Cimarex.

Cautionary Statement Regarding Forward-Looking Statements

This communication contains certain forward-looking statements within the meaning of federal securities laws. Words such as “anticipates,” “believes,” “expects,” “intends,” “plans,” “outlook,” “will,” “should,” “may” and similar expressions may be used to identify forward-looking statements. Forward-looking statements are not statements of historical fact and reflect Cabot’s and Cimarex’s current views about future events. Such forward-looking statements include, but are not limited to, statements about the benefits of the proposed merger involving Cabot and Cimarex, including future financial and operating results; Cabot’s and Cimarex’s plans, objectives, expectations and intentions; the expected timing and likelihood of completion of the transaction; the expected timing and amount of any future dividend; and other statements that are not historical facts, including estimates of oil and natural gas reserves and resources, estimates of future production, assumptions regarding future oil and natural gas pricing, planned drilling activity, future results of operations, projected cash flow and liquidity, the achievement of synergies, business strategy and other plans and objectives for future operations. No assurances can be given that the forward-looking statements contained in this communication will occur as projected and actual results may differ materially from those projected. Forward-looking statements are based on current expectations, estimates and assumptions that involve a number of risks and uncertainties that could cause actual results to differ materially from those projected. These risks and uncertainties include, without limitation, the ability to obtain the requisite Cabot and Cimarex stockholder approvals; the risk that an event, change or other circumstances could give rise to the termination of the proposed merger; the risk that a condition to closing of the merger may not be satisfied on a timely basis or at all; the length of time necessary to close the proposed transaction, which may be longer than anticipated for various reasons; the risk that the businesses will not be integrated successfully; the risk that the cost savings and any other synergies from the transaction may not be fully realized or may take longer to realize than expected; the risk that any announcement relating to the proposed transaction could have adverse effects on the market price of Cabot’s common stock or Cimarex’s common stock; the risk of litigation related to the proposed transaction; the effect of future regulatory or legislative actions on the companies or the industry in which they operate, including the risk of new restrictions with respect to well spacing, hydraulic fracturing, natural gas flaring or other oil and natural gas development activities; the risk that the credit ratings of the combined business may be different from what the companies expect; disruption from the transaction making it more difficult to maintain relationships with customers, employees or suppliers; the diversion of management time on merger-related issues; the volatility in commodity prices for crude oil and natural gas; the continuing effects of the COVID-19 pandemic and the impact thereof on Cabot’s and Cimarex’s businesses, financial condition and results of operations; actions by, or disputes among or between, the Organization of Petroleum Exporting Countries and other producer countries; the presence or recoverability of estimated reserves; the ability to replace reserves; environmental risks; drilling and operating risks; exploration and development risks; competition; the ability of management to execute its plans to meet its goals; and other risks inherent in Cabot’s and Cimarex’s businesses. In addition, the declaration and payment of any future dividends, whether regular base quarterly dividends, variable dividends or special dividends following completion of the proposed transaction, will depend on the combined business’ financial results, cash requirements, future prospects and other factors deemed relevant by the board of directors of Cabot (as then constituted). These risks, as well as other risks related to the proposed transaction, are described in the registration statement on Form S-4 and preliminary joint proxy statement/prospectus that was filed with the Securities and Exchange Commission (“SEC”) and the definitive joint proxy statement/prospectus if and when it becomes available in connection with the proposed transaction. While the list of factors presented here is, and the list of factors to be presented in the registration statement on Form S-4 are, considered representative, no such list should be considered to be a complete statement of all potential risks and uncertainties. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual outcomes may vary materially from those indicated. For additional information about other factors that could cause actual results to differ materially from those described in the forward-looking statements, please refer to: (1) Cabot’s annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, which are available on Cabot’s website at www.cabotog.com/investor-relations and on the SEC’s website at http://www.sec.gov; and (2) Cimarex’s annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, which are available on its website at www.cimarex.com/investor-relations and on the SEC’s website at http://www.sec.gov.

Forward-looking statements are based on the estimates and opinions of management at the time the statements are made. Except to the extent required by applicable law, neither Cabot nor Cimarex undertakes any obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise. Readers are cautioned not to place undue reliance on these forward-looking statements that speak only as of the date hereof.

No Offer or Solicitation

This communication 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 U.S. Securities Act of 1933, as amended.

Additional Information about the Merger and Where to Find It

In connection with the proposed transaction, Cabot filed with the SEC a registration statement on Form S-4 on June 29, 2021, that includes a preliminary joint proxy statement of Cabot and Cimarex and that also constitutes a preliminary prospectus of Cabot. If and when the registration statement becomes effective and the joint proxy statement/prospectus is in definitive form, such joint proxy statement/prospectus will be sent to the stockholders of Cabot and Cimarex. Each of Cabot and Cimarex also intends to file other relevant documents with the SEC regarding the proposed transaction, including the definitive joint proxy statement/prospectus. The information in the preliminary joint proxy statement/prospectus is not complete and may be changed. This communication is not a substitute for the preliminary joint proxy statement/prospectus or registration statement or any other document that Cabot or Cimarex may file with the SEC. The definitive joint proxy statement/prospectus (if and when available) will be mailed to stockholders of Cabot and Cimarex. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT, THE PRELIMINARY JOINT PROXY STATEMENT/PROSPECTUS, THE DEFINITIVE JOINT PROXY STATEMENT/PROSPECTUS IF AND WHEN IT BECOMES AVAILABLE AND ANY OTHER RELEVANT DOCUMENTS THAT MAY BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT CABOT, CIMAREX AND THE PROPOSED TRANSACTION. Investors and security holders are able to obtain free copies of the registration statement and preliminary joint proxy statement/prospectus and all other documents containing important information about Cabot, Cimarex and the proposed transaction, once such documents are filed with the SEC, including the definitive joint proxy statement/prospectus if and when it becomes available, through the website maintained by the SEC at http://www.sec.gov. Copies of the documents filed with the SEC by Cabot may be obtained free of charge on Cabot’s website at www.cabotog.com/investor-relations or by contacting Matt Kerin by email at matt.kerin@cabotog.com or by phone at 281-589-4642. Copies of the documents filed with the SEC by Cimarex may be obtained free of charge on Cimarex’s website at www.cimarex.com/investor-relations.

Participants in the Solicitation

Cabot, Cimarex 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 Cabot, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in Cabot’s proxy statement for its 2021 Annual Meeting of Stockholders, which was filed with the SEC on March 12, 2021, and Cabot’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, which was filed with the SEC on February 26, 2021. Information about the directors and executive officers of Cimarex, including a description of their direct or indirect interests, by security holdings or otherwise, is set forth in Cimarex’s proxy statement for its 2021 Annual Meeting of Stockholders, which was filed with the SEC on March 26, 2021, and Cimarex’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020, which was filed with the SEC on February 23, 2021. Investors may obtain additional information regarding the interests of those persons and other persons who may be deemed participants in the proposed transaction by reading the preliminary joint proxy statement/prospectus, including any amendments thereto, as well as the definitive joint proxy statement/prospectus if and when it becomes available and other relevant materials to be filed with the SEC regarding the proposed transaction when such materials become available. Investors should read the preliminary joint proxy statement/prospectus, and the definitive joint proxy statement/prospectus if and when it becomes available, carefully before making any voting or investment decisions. You may obtain free copies of these documents from Cabot or Cimarex using the sources indicated above.