Vanguard Portfolio Management (MGY) reports 8.39% Magnolia Oil & Gas ownership stake

Rhea-AI Filing Summary

Vanguard Portfolio Management LLC reports beneficial ownership of Magnolia Oil & Gas Corp common stock. Vanguard and certain affiliates beneficially own 15,517,234 shares, representing 8.39% of the class as of June 30, 2026.

Vanguard has sole voting power over 176,033 shares and sole dispositive power over 15,517,234 shares, with no shared voting or dispositive power. The position includes securities held by Vanguard funds and managed accounts over which Vanguard or specified affiliates exercise voting and/or dispositive authority. Vanguard indicates that various clients and funds have rights to dividends and sale proceeds, but no other single person has an interest in more than 5% of the class through these holdings.

Key Figures

Beneficial ownership: 15,517,234 shares Percent of class: 8.39% Sole voting power: 176,033 shares +3 more

6 metrics

Beneficial ownership 15,517,234 shares Common stock beneficially owned as reported by Vanguard Portfolio Management

Percent of class 8.39% Percentage of Magnolia Oil & Gas common stock class held by Vanguard

Sole voting power 176,033 shares Shares over which Vanguard has sole power to vote or direct the vote

Shared voting power 0 shares Shares over which Vanguard has shared power to vote

Sole dispositive power 15,517,234 shares Shares over which Vanguard has sole power to dispose or direct disposition

Shared dispositive power 0 shares Shares over which Vanguard has shared dispositive power

Key Terms

beneficially owned, dispositive power, sole power to vote, Investment Company Act of 1940, +1 more

5 terms

beneficially owned financial

"this reflects the securities beneficially owned, or deemed to be beneficially owned"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

dispositive power financial

"exercises dispositive power, in addition to securities held by clients"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

sole power to vote financial

"Number of shares as to which the person has (i) Sole power to vote"

Investment Company Act of 1940 regulatory

"investment companies registered under the Investment Company Act of 1940"

A U.S. federal law that sets the rulebook for pooled investment vehicles such as mutual funds, exchange-traded funds and similar money managers, requiring them to register with regulators, disclose holdings and fees, limit conflicts of interest, and follow governance standards. It matters to investors because these protections and transparency rules act like a referee and scoreboard, helping people compare funds, trust that managers follow fair practices, and spot hidden costs or risks.

percent of class financial

"Percent of class: 8.39 %"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 07/31/2026 - 11:23 AM Accepted by SEC EDGAR 07/31/2026 - 11:23 AM Learn about SEC filing dates

FAQ

How many Magnolia Oil & Gas (MGY) shares does Vanguard Portfolio Management report owning?

Vanguard Portfolio Management reports beneficial ownership of 15,517,234 shares of Magnolia Oil & Gas common stock. This total includes shares held by Vanguard funds and managed accounts over which Vanguard and certain affiliates exercise dispositive and, in some cases, voting power.

What percentage of Magnolia Oil & Gas (MGY) does Vanguard Portfolio Management hold?

Vanguard Portfolio Management reports holding 8.39% of the outstanding common stock of Magnolia Oil & Gas. This percentage is based on 15,517,234 shares deemed beneficially owned as of June 30, 2026, across Vanguard funds and managed accounts.

How much voting power does Vanguard have in Magnolia Oil & Gas (MGY)?

Vanguard reports sole voting power over 176,033 shares of Magnolia Oil & Gas and no shared voting power. It has broader dispositive power over 15,517,234 shares, but voting authority is more limited than its dispositive authority.

What dispositive power does Vanguard Portfolio Management have over Magnolia Oil & Gas (MGY) shares?

Vanguard reports sole dispositive power over 15,517,234 shares of Magnolia Oil & Gas and no shared dispositive power. This means Vanguard and specified affiliates can direct the sale or disposition of these shares on behalf of funds and clients.

Do other investors share in the Magnolia Oil & Gas (MGY) position reported by Vanguard?

Yes. Vanguard states that investment companies and other managed accounts have rights to dividends and sale proceeds from the reported shares. However, no single other person has an interest in more than 5% of the class through these holdings.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Magnolia Oil & Gas Corp

(Name of Issuer)

Common Stock

(Title of Class of Securities)

559663109

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 559663109

1

Names of Reporting Persons

Vanguard Portfolio Management

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 176,033.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 15,517,234.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

15,517,234.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.39 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Portfolio Management LLC, or business divisions of such subsidiaries whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Magnolia Oil & Gas Corp
(b)	Address of issuer's principal executive offices: 9 Greenway Plaza, Suite 1300, Houston, TX, 77046
Item 2.
(a)	Name of person filing: Vanguard Portfolio Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 559663109
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 15517234
(b)	Percent of class: 8.39 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 176033
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 15517234
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Vanguard Portfolio Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Vanguard Portfolio Management

Signature:	My Trieu-Gatt
Name/Title:	Authorized Signatory, Head of Global Fund Administration
Date:	07/31/2026