MPLX (MPLX) COO awarded 5,986 units; tax withholdings follow

Rhea-AI Filing Summary

MPLX LP executive vice president and COO Gregory Scott Floerke received a grant of 5,986 common units of limited partner interests on March 1, 2026 at a stated price of $59.22 per unit. On March 2, 2026, three tax-withholding dispositions totaling 995, 1,100 and 797 units reduced his directly owned units to 95,337.

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

OMB APPROVAL

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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^*

Floerke Gregory Scott

(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)
	Exec. VP and COO

3. Date of Earliest Transaction (Month/Day/Year)
03/01/2026

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)	03/01/2026		A		5,986	A	$0	98,229	D
Common Units (Limited Partner Interests)	03/02/2026		F		995	D	$59.22	97,234	D
Common Units (Limited Partner Interests)	03/02/2026		F		1,100	D	$59.22	96,134	D
Common Units (Limited Partner Interests)	03/02/2026		F		797	D	$59.22	95,337	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 Executive Vice President and Chief Operating Officer 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/ Molly R. Benson, Attorney-in-Fact for Gregory S. Floerke	03/03/2026
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transactions did MPLX EVP and COO Gregory Scott Floerke report?

Gregory Scott Floerke reported receiving a grant of 5,986 MPLX common units, then three tax-withholding dispositions of 995, 1,100 and 797 units. All transactions involved common units of limited partner interests and were reported as direct ownership changes.

Was the MPLX Form 4 transaction a market purchase or sale of units?

The Form 4 shows no open-market buys or sells. It reports a grant of 5,986 MPLX common units and three code F transactions classified as tax-withholding dispositions to cover exercise price or tax liabilities, not discretionary market trading.

How many MPLX units does Gregory Scott Floerke own after these transactions?

After the reported grant and subsequent tax-withholding dispositions, Gregory Scott Floerke’s direct ownership stands at 95,337 MPLX common units of limited partner interests, according to the share balances disclosed following the final March 2, 2026 transaction.

What is the reported price per MPLX unit in Gregory Floerke’s Form 4?

The filing lists a transaction price of $59.22 per MPLX common unit for the reported grant and related tax-withholding dispositions. This price is used to value the non-derivative common unit transactions disclosed for March 1–2, 2026.

What do code F transactions mean in the MPLX Form 4 for Gregory Floerke?

Code F transactions in this Form 4 are described as payments of exercise price or tax liability by delivering securities. For Gregory Floerke, three such code F entries reflect tax-withholding dispositions of MPLX common units rather than ordinary market sales.