Sec Form 4 Filing - EnerVest, Ltd. @ Magnolia Oil & Gas Corp - 2021-10-07

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person EnerVest, Ltd. 2. Issuer Name and Ticker or Trading Symbol Magnolia Oil & Gas Corp [ MGY] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1001 FANNIN STREET, SUITE 800, 3. Date of Earliest Transaction (MM/DD/YY) 10/07/2021 (Street) HOUSTON, TX77002 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 10/07/2021 C 3,622,962 ( 4 ) A 23,735,406 ( 2 ) ( 3 ) ( 5 ) ( 9 ) ( 10 ) D Class A Common Stock 10/07/2021 S 5,000,000 ( 13 ) D $ 18.5 ( 7 ) 18,735,406 ( 2 ) ( 3 ) ( 9 ) ( 10 ) ( 12 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Class B Common Stock ( 1 ) ( 4 ) 10/07/2021 C 3,622,962 ( 4 ) ( 1 ) ( 8 ) Class A Common Stock 3,622,962 ( 4 ) $ 0 ( 1 ) 49,292,476 ( 2 ) ( 3 ) ( 6 ) ( 9 ) ( 10 ) ( 11 ) D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other EnerVest, Ltd. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X X EnerVest Management GP, L.C. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Energy Institutional Fund XIV-A, L.P. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Energy Institutional Fund XIV-2A, L.P. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Energy Institutional Fund XIV-3A, L.P. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Energy Institutional Fund XIV-WIC, L.P. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Energy Institutional Fund XIV-C-AIV, L.P. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Energy Institutional Fund XIV-C, L.P. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X EnerVest Investment Services, L.L.C. C/O ENERVEST LTD. 1001 FANNIN STREET, SUITE 800 HOUSTON, TX77002 X Signatures /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd. 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C. 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd., the sole member of EVFA GP XIV, LLC, the Managing General Partner of EnerVest Energy Institutional Fund XIV-A, L.P. 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd., the sole member of EVFA XIV-2A, LLC, the Managing General Partner of EnerVest Energy Institutional Fund XIV-2A, L.P 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd., the sole member of EVFA XIV-3A, LLC, the Managing General Partner of EnerVest Energy Institutional Fund XIV-3A, L.P. 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd., the sole member of EnerVest Holding XIV, LLC, the General Partner of EnerVest Energy Institutional Fund XIV-WIC, L.P. 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd., the sole member of EVFC GP XIV, LLC, the Managing General Partner of EnerVest Energy Institutional Fund XIV-C, L.P. 10/12/2021 Signature of Reporting Person Date /s/ Jud Walker, President & Chief Executive Officer, EnerVest Management GP, L.C., the General Partner of EnerVest, Ltd., the sole member of EVFC GP XIV, LLC, the Managing General Partner of EnerVest Energy Institutional Fund XIV-C-AIV, L.P. 10/12/2021 Signature of Reporting Person Date /s/ Travis W. Hancock, Senior Vice President & Chief Financial Officer, EnerVest Operating, L.L.C., the General Partner of EnerVest Holding, L.P., the sole member of EnerVest Investment Services, L.L.C. 10/12/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares of the Issuer's Class B Common Stock ("Class B Common Stock"), when combined with an equal number of units ("Units") of MagnoliaOil & Gas Parent LLC, a Delaware limited liability company of which the Issuer is the managing member, are exchangeable from time to time at theoption of the holders thereof for shares of the Issuer's Class A Common Stock ("Class A Common Stock") on a one-for-one basis (or, at the Issuer'soption, for cash). ( 2 )EnerVest Management GP, L.C. ("EVM GP") is the general partner of EnerVest, Ltd. ("EnerVest"), which is the sole member, with sole controlover the actions of, each of, EVFA GP XIV, LLC, EVFA XIV-2A, LLC and EVFA XIV-3A, LLC, the managing general partners, respectively, ofEnerVest Energy Institutional Fund XIV-A, L.P. ("EV XIV-A"), EnerVest Energy Institutional Fund XIV-2A, L.P. ("EV XIV-2A") and EnerVestEnergy Institutional Fund XIV-3A, L.P. ("EV XIV-3A"). EnerVest is also the sole member, with sole control over the actions of, each of, EnerVestHolding XIV, LLC, the general partner of EnerVest Energy Institutional Fund XIV-WIC, L.P. ("EV XIV-WIC"), EVFC GP XIV, LLC, the managinggeneral partner of EnerVest Energy Institutional Fund XIV-C-AIV, L.P. ("EV XIV-C-AIV"), and EVFC GP XIV, LLC, the managing general partnerof EnerVest Energy Institutional Fund XIV-C, L.P. ("EV XIV-C"). ( 3 )EnerVest Investment Services, L.L.C. ("EIS, LLC") is the investment advisor for EV XIV-A, EV XIV-2A, EV XIV-3A, EV XIV-WIC, EV XIVC-AIV and EV XIV-C (such six entities together, the "Record Holders" and each, a "Record Holder"). ( 4 )Represents: (i) 2,397,825 shares of Class B Common Stock held by EV XIV-A converted to the same number of shares of Class A Common Stock;(ii) 25,049 shares of Class B Common Stock held by EV XIV-WIC converted to the same number of shares of Class A Common Stock; (iii) 458,868shares of Class B Common Stock held by EV XIV-2A converted to the same number of shares of Class A Common Stock; (iv) 473,369 shares of ClassB Common Stock held by EV XIV-3A converted to the same number of shares of Class A Common Stock; and (v) 267,851 shares of Class B CommonStock held by EV XIV-C-AIV converted to the same number of shares of Class A Common Stock (collectively, the "October 2021 ConversionShares"). ( 5 )Represents the October 2021 Conversion Shares and 20,112,444 shares of Class A Common Stock held by EV XIV-C. ( 6 )Represents shares of Class B Common Stock held as follows: (i) 32,623,791 shares of Class B Common Stock held by EV XIV-A; (ii) 340,804shares of Class B Common Stock held by EV XIV-WIC; (iii) 6,243,160 shares of Class B Common Stock held by EV XIV-2A; (iv) 6,440,457 sharesof Class B Common Stock held by EV XIV-3A; and (v) 3,644,264 shares of Class B Common Stock held by EV XIV-C-AIV. ( 7 )This amount represents the purchase price in the 10b5-1 Trade (as defined below). ( 8 )Not applicable. ( 9 )Each Record Holder and each of EVM GP, EnerVest, EVFA GP XIV, LLC, EVFA XIV-2A, LLC, EVFA XIV-3A, LLC, EnerVest Holding XIV, LLC, EVFC GP XIV, LLC, and EIS, LLC (collectively, the "Non-Fund Entities") directly (whether through ownership or position) or indirectly through one or more intermediaries, may be deemed for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, to be the indirect beneficial owner of some or all of the Equity Interests (as defined below) owned by the Record Holders and, therefore, a "ten percent holder" hereunder. ( 10 )Each Record Holder and each Non-Fund Entity disclaims beneficial ownership of the Equity Interests reported herein, except to the extent of its pecuniary interest therein, and, with respect to each of the Record Holders, except to the extent of its respective direct ownership reported herein, and this report shall not be deemed an admission that the Reporting Persons are the beneficial owners of such securities for purposes of Section 16 or for any other purposes. ( 11 )Represents the aggregate number of shares of Class B Common Stock owned by EV XIV-A, EV XIV-2A, EV XIV-3A, EV XIV-WIC, and EV XIV-C-AIV. (EV XIV-C's shares of Class A Common Stock, together with the shares of Class B Common Stock and Units held by EV XIV-A, EV XIV-2A, EV XIV-3A, EV XIV-WIC, and EV XIV-C-AIV, are collectively referred to herein as the "Equity Interests.") ( 12 )EV XIV-C owns of record 18,735,406 shares of Class A Common Stock. ( 13 )Represents shares of Class A Common Stock sold in a transaction pursuant to the 10b5-1 Sale Plan Agreements (the "Plans") entered into by the Record Holders on September 30, 2021 (the "10b5-1 Trade"). All sales contemplated by the Plans have been completed, and there are no securities available under the Plans remaining to be sold.

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