MPLXの適時開示・その他

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 Report (Date of earliest event reported) October 29, 2025

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MPLX LP

(Exact name of registrant as specified in its charter)

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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))


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 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.


Item 8.01			Other Events.

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.


Item 9.01			Financial Statements and Exhibits.

(d) Exhibits.


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)

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

	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

EX-99.1 2 mplxex991mplxchairman.htm EX-99.1 Document

Exhibit 99.1

MPLX Elects Maryann T. Mannen as Chairman of the Board

FINDLAY, Ohio, Nov. 4, 2025 - MPLX LP (NYSE: MPLX) today announced that the board of directors of the general partner of MPLX has elected Maryann T. Mannen, president and chief executive officer and member of the board, as chairman of the board, effective Jan. 1, 2026. Mannen will assume the role of chairman of the board in addition to her current responsibilities. Mannen will succeed Michael J. Hennigan, who has elected to retire as executive chairman and as a member of the board of directors of the general partner of MPLX, also effective Jan. 1, 2026. Chris Helms will continue to serve as the independent lead director of the board.

“On behalf of the entire board of directors, we extend our congratulations to Maryann as our new leader and our gratitude to Mike for his dedication to the partnership,” said Mr. Helms.

Mr. Hennigan has led the general partner of MPLX as chairman of the board of directors since April 2020, as CEO from November 2019 to August 2024, and as President from June 2017 to August 2024. Ms. Mannen has served as CEO since August 2024 and as a member of the board of directors since February 2021.

Also announced today and effective Jan. 1, 2026, Mr. Hennigan will retire as executive chairman of MPC, with Ms. Mannen to succeed him as chairman and continuing to lead MPC as its president and CEO.

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About MPLX LP

MPLX is a diversified, large-cap master limited partnership that owns and operates midstream energy infrastructure and logistics assets and provides fuels distribution services. MPLX's assets include a network of crude oil and refined product pipelines; an inland marine business; light-product terminals; storage caverns; refinery tanks, docks, loading racks, and associated piping; and crude and light-product marine terminals. The company also owns crude oil and natural gas gathering systems and pipelines as well as natural gas and NGL processing and fractionation facilities in key U.S. supply basins. More information is available at www.MPLX.com.

Investor Relations Contact: (419) 421-2071

Kristina Kazarian, Vice President Finance and Investor Relations

Brian Worthington, Senior Director, Investor Relations

Isaac Feeney, Director, Investor Relations

Evan Heminger, Analyst, Investor Relations

Media Contact: (419) 421-3577

Jamal Kheiry, Communications Manager