mplx-20251029

Delaware

001-35714

27-0005456

(State or other jurisdiction
of incorporation)

(Commission File Number)

(IRS Employer
Identification No.)

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))


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).


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 5.02			Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On October 29, 2025, the board of directors of MPLX GP LLC ("MPLX GP"), the general partner of MPLX LP (the “Partnership”), elected Maryann T. Mannen, President and Chief Executive Officer, and member of the board of directors of MPLX GP, as Chairman of the Board, effective as of January 1, 2026 (the “Effective Date”). Ms. Mannen will assume the role of Chairman of the Board in addition to her current responsibilities.

Ms. Mannen will succeed Michael J. Hennigan, who notified the Partnership on October 29, 2025 of his intention to retire as Executive Chairman and as a member of the board of directors of MPLX GP as of the Effective Date.

With the retirement of Mr. Hennigan, the size of the board of directors of MPLX GP will be decreased to 10 directors as of the Effective Date.

On November 4, 2025, the Partnership issued a press release announcing the changes reported above. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K.


Exhibit Number						Description


99.1						Press release issued by MPLX LP on November 4, 2025
104						Cover Page Interactive Data File (embedded within the Inline XBRL document)

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

	By:	MPLX GP LLC, its General Partner


Date: November 4, 2025	By:	/s/ Molly R. Benson
		Name: Molly R. Benson
		Title: Chief Legal Officer and Corporate Secretary


Item 8.01			Other Events.


Item 9.01			Financial Statements and Exhibits.