MPLX LP (MPLX) legal officer reports disposition of 306 units

Rhea-AI Filing Summary

MPLX LP reporting person Molly R. Benson disclosed a transaction involving 306 common units (limited partner interests) on 12/12/2025 at a price of $54.85 per unit. After this disposition, she beneficially owns 40,163 common units directly. Benson is the Chief Legal Officer and Corporate Secretary of MPLX GP LLC, the general partner whose directors and executive officers manage MPLX LP.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Benson Molly R

(Last) (First) (Middle)

C/O MPLX LP

200 E. HARDIN STREET

(Street)

FINDLAY OH 45840

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
MPLX LP [ MPLX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Legal Ofc & Corp Sec

3. Date of Earliest Transaction (Month/Day/Year)
12/12/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Units (Limited Partner Interests)	12/12/2025		F		306	D	$54.85	40,163	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

The Reporting Person is the Chief Legal Officer and Corporate Secretary of MPLX GP LLC, the general partner of the Issuer. The Issuer is managed by the directors and executive officers of MPLX GP LLC.

	/s/ Shane T. Pfleiderer, Attorney-in-Fact for Molly R. Benson	12/16/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

Who is the reporting person in the MPLX (MPLX) Form 4 filing?

The reporting person is Molly R. Benson, who serves as Chief Legal Officer and Corporate Secretary of MPLX GP LLC, the general partner of MPLX LP.

What transaction did Molly R. Benson report for MPLX LP common units?

She reported a disposition of 306 MPLX LP common units (limited partner interests) at a price of $54.85 per unit on 12/12/2025.

How many MPLX LP units does Molly R. Benson own after the reported transaction?

Following the reported transaction, Molly R. Benson beneficially owns 40,163 MPLX LP common units, held in direct ownership.

What is Molly R. Benson’s relationship to MPLX LP?

She is the Chief Legal Officer and Corporate Secretary of MPLX GP LLC, which is the general partner of MPLX LP. The issuer is managed by the directors and executive officers of MPLX GP LLC.

Is this MPLX LP Form 4 filed by one reporting person or multiple persons?

The document indicates that the Form is filed by one reporting person, not by a group.

What type of security is involved in this MPLX LP Form 4 transaction?

The transaction involves Common Units (Limited Partner Interests) of MPLX LP.