Vanguard Portfolio Management (MPC) reports 5.35% ownership in Marathon Petroleum

Rhea-AI Filing Summary

Marathon Petroleum Corp reported that Vanguard Portfolio Management beneficially owns 15,765,266 shares of common stock, representing 5.35% of the class as reported on 03/31/2026. The filing states Vanguard exercises sole dispositive power over these shares and reports limited sole voting power of 93,153 shares. The disclosure notes ownership reflects holdings across Vanguard funds and managed accounts per SEC Release No. 34-39538.

Insights

Institutional Ownership Analyst

Vanguard disclosed a passive >5% stake in Marathon Petroleum (MPC).

Vanguard Portfolio Management reports beneficial ownership of 15,765,266 shares or 5.35% as of 03/31/2026, with dispositive control concentrated at the reporting business unit. Voting power shown is substantially smaller than dispositive power, consistent with diversified fund holdings.

This Schedule 13G indicates a passive investor position under the cited release; subsequent Form 13D would be required if ownership intent changes. Future SEC filings would show any material voting or disposition shifts.

Key Figures

Beneficial ownership: 15,765,266 shares Percent of class: 5.35% Sole voting power: 93,153 shares +3 more

6 metrics

Beneficial ownership 15,765,266 shares as of 03/31/2026

Percent of class 5.35% reported ownership percentage

Sole voting power 93,153 shares shares with sole power to vote

Sole dispositive power 15,765,266 shares shares with sole power to dispose

Reporting CUSIP 56585A102 Marathon Petroleum common stock identifier

Signature date 04/29/2026 Schedule 13G signed date

Key Terms

Schedule 13G, Beneficial ownership, Sole dispositive power, SEC Release No. 34-39538

4 terms

Schedule 13G regulatory

"reports beneficial ownership of 15,765,266 shares representing 5.35%"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

Beneficial ownership regulatory

"Amount beneficially owned: 15765266 (b) Percent of class: 5.35 %"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Sole dispositive power financial

"Sole power to dispose or to direct the disposition of: 15765266"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

SEC Release No. 34-39538 regulatory

"In accordance with SEC Release No. 34-39538 (January 12, 1998)"

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Marathon Petroleum Corp

(Name of Issuer)

Common Stock

(Title of Class of Securities)

56585A102

(CUSIP Number)

03/31/2026

(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): 56585A102

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 93,153.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 15,765,266.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

15,765,266.00

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)

5.35 %

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: Marathon Petroleum Corp
(b)	Address of issuer's principal executive offices: 539 South Main Street, Findlay, OH, 45840
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 Number(s): 56585A102
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: 15765266
(b)	Percent of class: 5.35 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 93153
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 15765266
	(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:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026

FAQ

What stake does Vanguard Portfolio Management report in Marathon Petroleum (MPC)?

Vanguard Portfolio Management reports beneficial ownership of 15,765,266 shares, representing 5.35% of Marathon Petroleum's common stock as of 03/31/2026. The filing attributes dispositive power to Vanguard and limited sole voting power of 93,153 shares.

Does this Schedule 13G filing indicate Vanguard controls Marathon Petroleum?

No. The filing shows Vanguard has dispositive power over the reported shares but this Schedule 13G classifies the position as passive. It does not assert control or activist intent; different disclosures would be required if intent or control changed.

What does 'sole dispositive power' mean in this filing for MPC?

Sole dispositive power means Vanguard Portfolio Management can decide when to buy or sell the reported 15,765,266 shares. The filing shows Vanguard holds that power while actual voting power is smaller at 93,153 shares.

When was the Vanguard 13G for MPC signed and who signed it?

The Schedule 13G was signed on 04/29/2026 by Ashley Grim, Head of Global Fund Administration. The ownership amount is reported as of 03/31/2026 within the filing text.