Magnolia Oil & Gas Corp

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-K

(Mark One)

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the year ended December 31, 2025

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from ___________ to ___________

Commission File Number:001-38083

Magnolia Oil & Gas Corp oration

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (713)842-9050

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes☐ No☒

The aggregate market value of the common stock held by non-affiliates of the registrant as of June 30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter, was approximately $4.1 billion based on the closing price on that day on the New York Stock Exchange.

As of February 9, 2026, there were 180,882,426 shares of Class A Common Stock, $0.0001 par value per share, and 5,523,479 shares of Class B Common Stock, $0.0001 par value per share, outstanding.

Documents Incorporated By Reference

Portions of the registrant’s definitive proxy statement for the 2026 Annual Meeting of Stockholders, to be filed no later than 120 days after the end of the fiscal year to which this Annual Report on Form 10-K relates, are incorporated by reference into Part III of this Annual Report on Form 10-K.

Table of Contents

GLOSSARY OF OIL AND NATURAL GAS TERMS

The following are abbreviations and definitions of certain terms used in this document, some of which are commonly used in the oil and gas industry:

“Bbl.” One stock tank barrel, of 42 U.S. gallons liquid volume, used herein in reference to crude oil, condensate, natural gas liquids, or water.

“Bbls/d.” Stock tank barrels per day.

“Bcf.” Billion cubic feet of natural gas.

“boe.” Barrels of oil equivalent. One boe is equal to one Bbl, six thousand cubic feet of natural gas, or 42 gallons of natural gas liquids. Based on approximate energy equivalency.

“boe/d.” Barrels of oil equivalent per day.

“British Thermal Unit or Btu.” The quantity of heat required to raise the temperature of a one-pound mass of water by one degree Fahrenheit.

“Completion.” The installation of permanent equipment for production of oil or natural gas, or, in the case of a dry well, the reporting to the appropriate authority that the well has been abandoned.

“DD&A.” Depletion, depreciation, and amortization.

“Developed acreage.” The number of acres that are allocated or assignable to productive wells or wells capable of production.

“Development well.” A well drilled within the proved area of an oil or natural gas reservoir to the depth of a stratigraphic horizon known to be productive.

“Dry well.” A well that is determined to be incapable of producing either oil or natural gas in sufficient quantities to justify completion as an oil and natural gas well.

“Exploratory well.” A well drilled to find a new field or to find a new reservoir in a field previously found to be productive of oil or natural gas in another reservoir.

“Extension well.” An extension well is a well drilled to extend the limits of a known reservoir.

“Field.” An area consisting of a single reservoir or multiple reservoirs all grouped on or related to the same individual geological structural feature and/or stratigraphic condition. There may be two or more reservoirs in a field that are separated vertically by intervening impervious, strata, or laterally by local geologic barriers, or by both. Reservoirs that are associated by being in overlapping or adjacent fields may be treated as a single or common operational field. The geological terms structural feature and stratigraphic condition are intended to identify localized geological features as opposed to the broader terms of basins, trends, provinces, plays, areas-of-interest, etc.

“Formation.” A layer of rock which has distinct characteristics that differs from nearby rock.

“Gross acres or gross wells.” Gross acres or gross wells are the total acres or wells in which all or part of the working interest is owned.

“Horizontal drilling.” A drilling technique used in certain formations where a well is drilled vertically to a certain depth and then drilled at an angle within a specified interval.

“MBbls.” One thousand barrels of crude oil, condensate or NGLs.

“Mboe/d.” Thousand barrels of oil equivalent per day.

“Mcf.” One thousand cubic feet of natural gas.

“Mcf/d.” Thousand cubic feet of natural gas per day.

“MMboe.” Million barrels of oil equivalent.

“MMBtu.” One million British thermal units.

“MMcf.” One million cubic feet of natural gas.

“NGL” or “NGLs.” Natural gas liquids. Hydrocarbons found in natural gas which may be extracted as purity products such as ethane, propane, isobutane and normal butane, and natural gasoline.

“Net acres or net wells.” The sum of fractional working interests owned in gross acres or gross wells.

“NYMEX.” The New York Mercantile Exchange.

“Productive well.” An exploratory, development, or extension well that is not a dry well. Productive wells include producing wells and wells mechanically capable of production.

“Proved developed reserves.” Proved oil and natural gas reserves that can be expected to be recovered through existing wells with existing equipment and operating methods or in which the cost of the required equipment is relatively minor compared to the cost of a new well.

“Proved reserves.” Those quantities of oil and natural gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible—from a given date forward, from known reservoirs, and under existing economic conditions, operating methods, and government regulations—prior to the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. The project to extract the hydrocarbons must have commenced or the operator must be reasonably certain that it will commence the project within a reasonable time.

“Proved undeveloped reserves.” Proved oil and natural gas reserves that are expected to be recovered from new wells on undrilled acreage or from existing wells where a relatively major expenditure is required for recompletion. Reserves on undrilled acreage are limited to those directly offsetting development spacing areas that are reasonably certain of production when drilled, unless evidence using reliable technology exists that establishes reasonable certainty of economic producibility at greater distances. Undrilled locations can be classified as undeveloped reserves only if a plan has been adopted indicating that they are scheduled to be drilled within five years, unless the specific circumstances justify a longer time.

“Reservoir.” A porous and permeable underground formation containing a natural accumulation of producible oil and/or natural gas that is confined by impermeable rock or water barriers and is individual and separate from other reservoirs.

“Standardized measure.” Discounted future net cash flows estimated by applying the 12-month unweighted arithmetic average of the first-day-of-the-month price for the preceding 12 months to the estimated future production of year‑end proved reserves. Future cash inflows are reduced by estimated future production and development costs based on period‑end costs to determine pre‑tax cash inflows. Future income taxes, if applicable, are computed by applying the statutory tax rate to the excess of pre‑tax cash inflows over Magnolia’s tax basis in the oil and natural gas properties. Future net cash inflows after income taxes are discounted using a 10% annual discount rate.

“Undeveloped acreage.” Lease acreage on which wells have not been drilled or completed to a point that would permit the production of commercial quantities of oil, natural gas, and NGLs regardless of whether such acreage contains proved reserves.

“Unit.” The joining of all or substantially all interests in a reservoir or field, rather than a single tract, to provide for development and operation without regard to separate property interests. Also, the area covered by a unitization agreement.

“Working interest.” The right granted to the lessee of a property to explore for, to produce, and to own oil, natural gas, or other minerals. The working interest owners bear the exploration, development, and operating costs on either a cash, penalty, or carried basis.

“WTI.” West Texas Intermediate light sweet crude oil.

GLOSSARY OF CERTAIN TERMS AND CONVENTIONS USED HEREIN

The following are definitions of certain other terms and conventions that are used in this Annual Report on Form 10-K:

“The Company” or “Magnolia.”Magnolia Oil & Gas Corporation (either individually or together with its consolidated subsidiaries, as the context requires, including Magnolia Oil & Gas Holdings LLC, Magnolia LLC, Magnolia Intermediate, Magnolia Operating, and Magnolia Oil & Gas Finance Corp.).

“Magnolia Intermediate.” Magnolia Oil & Gas Intermediate LLC.

“Magnolia LLC.”Magnolia Oil & Gas Parent LLC.

“Magnolia LLC Units.”Units representing limited liability company interests in Magnolia LLC.

“Magnolia Operating.”Magnolia Oil & Gas Operating LLC.

“Highlander.” Highlander Oil & Gas Holdings LLC.

“EnerVest.”EnerVest, Ltd.

“Karnes County Assets.” Certain right, title, and interest in certain oil and natural gas assets located primarily in the Karnes County portion of the Eagle Ford Shale formation in South Texas.

“Giddings Assets.”Certain right, title, and interest in certain oil and natural gas assets located primarily in the Giddings area of the Austin Chalk formation.

“Business Combination.”The acquisition, which closed on July 31, 2018, of the Karnes County Assets; the Giddings Assets; and a 35% membership interest in Ironwood Eagle Ford Midstream, LLC.

“Class A Common Stock.”Magnolia’s Class A Common Stock, par value $0.0001 per share.

“Class B Common Stock.”Magnolia’s Class B Common Stock, par value $0.0001 per share.

“Issuers.”Magnolia Operating and Magnolia Oil & Gas Finance Corp., a wholly owned subsidiary of Magnolia Operating, as it relates to the 2026 Senior Notes and the 2032 Senior Notes.

“Magnolia LLC Unit Holders.”EnerVest Energy Institutional Fund XIV-A, L.P., a Delaware limited partnership, EnerVest Energy Institutional Fund XIV-WIC, L.P., a Delaware limited partnership, EnerVest Energy Institutional Fund XIV-2A, L.P., a Delaware limited partnership, EnerVest Energy Institutional Fund XIV-3A, L.P., a Delaware limited partnership, and EnerVest Energy Institutional Fund XIV-C-AIV, L.P., a Delaware limited partnership.

“RBL Facility.”Senior secured reserve-based revolving credit facility, as amended November 13, 2024.

“2026 Senior Notes.” 6.0% Senior Notes due 2026.

“2032 Senior Notes.” 6.875% Senior Notes due 2032.

“OPEC.” The Organization of the Petroleum Exporting Countries.

FORWARD-LOOKING STATEMENTS

This report includes “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements of historical facts included or incorporated by reference in this report, including, without limitation, statements regarding the Company’s future financial position, business strategy, budgets, projected revenues, projected costs, and plans and objectives of management for future operations, are forward-looking statements. Such forward-looking statements are based on the beliefs of management, as well as assumptions made by, and information currently available to, the Company’s management. In addition, forward-looking statements generally can be identified by the use of forward-looking terminology such as “may,” “will,” “could,” “expect,” “intend,” “project,” “estimate,” “anticipate,” “plan,” “believe,” or “continue” or similar terminology. Although Magnolia believes that the expectations reflected in such forward-looking statements are reasonable, the Company can give no assurance that such expectations will prove to have been correct. Important factors that could cause actual results to differ materially from the Company’s expectations include, but are not limited to:

•legislative, regulatory, or policy changes, including those following the change in presidential administrations;

•the market prices of oil, natural gas, NGLs, and other products or services;

•the supply and demand for oil, natural gas, NGLs, and other products or services, including impacts of actions taken by OPEC and other state-controlled oil companies;

•production and reserve levels;

•the timing and extent of the Company’s success in discovering, developing, producing and estimating reserves;

•geopolitical and business conditions in key regions of the world;

•drilling risks;

•economic and competitive conditions;

•the availability of capital resources;

•capital expenditures and other contractual obligations;

•weather conditions;

•inflation rates;

•the availability of goods and services;

•cybersecurity threats, including increased use of artificial intelligence technologies;

•the occurrence of property acquisitions or divestitures;

•the integration of acquisitions;

•the securities or capital markets and related risks such as general credit, liquidity, market, and interest-rate risks; and

•other factors disclosed in this Annual Report on Form 10-K, including under Items 1 and 2—Business and Properties, Item 1A—Risk Factors, Item 7—Management’s Discussion and Analysis of Financial Condition and Results of Operations, and Item 7A—Quantitative and Qualitative Disclosures About Market Risk.

All subsequent written and oral forward-looking statements attributable to the Company, or persons acting on its behalf, are expressly qualified in their entirety by the cautionary statements above. Except as required by law, Magnolia assumes no duty to update or revise its forward-looking statements based on changes in internal estimates or expectations or otherwise.

Part I