UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

_____________________________________________

FORM 8-K

_____________________________________________

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of ~~the~~Report ~~Securities~~(Date ~~Exchange~~of ~~Act~~earliest ofevent ~~1934~~reported) August 25, 2025

~~Date of Report (Date of earliest event reported): August 11, 2025~~ _____________________________________________

MPLX LP

(Exact name of registrant as specified in its charter)

Delaware		001-35714		27-0005456
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

_____________________________________________

Delaware

001-35714

27-0005456

(State or other jurisdiction
of incorporation)

(Commission File Number)

(IRS Employer
Identification No.)

200 E. Hardin Street, Findlay, Ohio 45840

(Address of principal executive offices) (Zip code)

Registrant’s telephone number, including area code: (419) 422-2121

_____________________________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)


Securities registered pursuant to Section 12(b) of the Act:
Title of each class	Trading symbol(s)	Name of each exchange on which registered
Common Units Representing Limited Partnership Interests	MPLX	New York Stock Exchange

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading symbol(s) Name of each exchange on which registered Common Units Representing Limited Partnership Interests MPLX New York Stock Exchange


Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

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. ☐

~~Item~~☐ ~~8.01 Other Events.~~

~~MPLX~~Item LP5.02 ~~(the~~Departure ~~“Issuer”)~~of isDirectors ~~filing~~or ~~herewith~~Certain ~~the~~Officers; ~~following~~Election ~~exhibits~~of toDirectors; ~~its~~Appointment ~~Registration~~of ~~Statement~~Certain onOfficers; ~~Form~~Compensatory ~~S-3~~Arrangements ~~(Registration~~of ~~No. 333-271922):~~Certain Officers.

1.On ~~Underwriting~~August ~~Agreement~~25, ~~dated~~2025, asthe board of ~~August~~managers 7,of ~~2025,~~MPC byInvestment ~~and~~LLC, ~~among~~ the ~~Issuer,~~sole member of MPLX GP LLC, the general partner (the “General Partner”), of MPLX LP (the ~~Issuer~~“Partnership”), ~~and~~increased ~~each~~the size of Jthe board of directors of the General Partner (the “Board”) to eleven members and elected Ray N.P Walker, Jr. ~~Morgan~~to ~~Securities~~serve ~~LLC,~~on ~~Goldman~~the ~~Sachs~~Board &as ~~Co.~~a ~~LLC~~director, ~~BofA~~effective ~~Securities~~August 25, ~~Inc~~2025., ~~Mizuho~~Mr. ~~Securities~~Walker ~~USA~~is ~~LLC,~~expected TDto ~~Securities~~serve ~~(USA)~~on ~~LLC~~the audit committee and ~~Wells~~conflicts ~~Fargo~~committee ~~Securities,~~of ~~LLC~~the Board. As a non-management director, ~~acting~~Mr. Walker will receive compensation in the same manner as ~~representatives~~the Board’s other non-management directors. The terms of non-management director compensation were disclosed in the ~~several~~Partnership’s ~~underwriters~~Annual ~~named~~Report ~~therein;~~on Form 10-K for the year ended December 31, 2024, filed with the Securities and Exchange Commission on February 27, 2025.

2. Thirty-Second Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note);

3. Thirty-Third Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note);

4. Thirty-Fourth Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note);

5. Thirty-Fifth Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note); and

6. Opinion of Jones Day.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

ExhibitNumber		Description
1.1		Underwriting Agreement, dated as of August 7, 2025, by and among the Issuer, MPLX GP LLC, the general partner of the Issuer, and each of J.P. Morgan Securities LLC, Goldman Sachs & Co. LLC, BofA Securities, Inc., Mizuho Securities USA LLC, TD Securities (USA) LLC and Wells Fargo Securities, LLC, acting as representatives of the several underwriters named therein
4.1		Thirty-Second Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)
4.2		Thirty-Third Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)
4.3		Thirty-Fourth Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)
4.4		Thirty-Fifth Supplemental Indenture, dated as of August 11, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)
5.1		Opinion of Jones Day
23.1		Consent of Jones Day (included in Exhibit 5.1)
104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MPLX LP	~~MPLX LP~~
	By:	~~By:~~	~~MPLX GP LLC, its General Partner~~	MPLX GP LLC, its General Partner
Date: August 11, 2025		By:	/s/ Molly R. Benson
Date: August 25, 2025	By:			/s/ Molly R. Benson
			~~Name: Molly R. Benson~~	Name: Molly R. Benson
			~~Title: Chief Legal Officer and Corporate Secretary~~	Title: Chief Legal Officer and Corporate Secretary

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