MPLX LP

6. Equity

The changes in the number of common units during the nine months ended September 30, 2025 are summarized below:

Unit Repurchase Program

On August 5, 2025, we announced a board authorization for the repurchase of $1.0 billion of MPLX common units held by the public in addition to the $1.0 billion common unit repurchase authorization announced on August 2, 2022. These unit repurchase authorizations have no expiration date. We may utilize various methods to effect the repurchases, which could include open market repurchases, negotiated block transactions, accelerated unit repurchases, tender offers or open market solicitations for units, some of which may be effected through Rule 10b5-1 plans. The timing and amount of future repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be suspended, discontinued or restarted at any time.

Total unit repurchases were as follows for the respective periods:

(1)Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.

As of September 30, 2025, we had $1.2 billion remaining under the unit repurchase authorizations.

Series A Redeemable Preferred Unit Conversions

On February 11, 2025, MPLX exercised its right to convert the remaining 6 million outstanding Series A preferred units into common units in accordance with the conversion provision outlined in our Sixth Amended and Restated Agreement of Limited Partnership.

Distributions

On October 28, 2025, MPLX declared a cash distribution for the third quarter of 2025, totaling $1,095 million, or $1.0765 per common unit. This distribution will be paid on November 14, 2025 to common unitholders of record on November 7, 2025.

Quarterly distributions for 2025 and 2024 are summarized below:

The allocation of total quarterly cash distributions to common and preferred unitholders is as follows for the three and nine months ended September 30, 2025 and September 30, 2024. Distributions are not accrued until declared. MPLX’s distributions are declared for the prior quarter subsequent to the quarter end; therefore, the following table represents total cash distributions applicable to the period for which the distributions relate as opposed to the quarter in which they were declared and paid.