MPLX LP

During the quarter ended December 31, 2025, no director or officer (as defined in Rule 16a-1(f) promulgated under the Exchange Act) of MPLX adopted orterminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement” (as each term is defined in Item 408 of Regulation S-K).

Marathon Petroleum Termination Allowance Plan

Marathon Petroleum Company LP (“MPC LP”), an affiliate of MPC, sponsors and maintains the Marathon Petroleum Termination Allowance Plan (the “TAP Plan”), which is intended to provide eligible employees of MPC LP and its affiliates with certain severance (a “termination allowance”) and other benefits in connection with certain involuntary terminations of employment. On February 25, 2026, MPC’s Board of Directors approved changes to the termination allowance formula applicable to certain employees of MPC, including those employees who are MPLX’s named executive officers.

All employees must meet certain requirements to be eligible for a termination allowance and other benefits under the TAP Plan. The amount of the termination allowance for an eligible employee who is a Senior Leader (as defined in the TAP Plan to include MPLX’s named executive officers) is the sum of his or her: (a) annual base salary rate as in effect on the date preceding his or her termination date and (b) target award amount pursuant to MPC’s Annual Cash Bonus Program. The amount of the termination allowance for the Chief Executive Officer is two times the sum of his or her: (a) annual base salary rate as in effect on the date preceding his or her termination date and (b) target award amount pursuant to MPC’s Annual Cash Bonus Program.

MPLX does not directly employ any of the personnel responsible for managing and operating MPLX’s business, including MPLX’s named executive officers. Instead, MPLX pays MPC a fixed amount to provide the necessary personnel, all of whom are employed by MPC and its affiliates.

The foregoing description of the TAP Plan is qualified in its entirety by reference to the full text of the TAP Plan, a copy of which is attached as Exhibit 10.57 to this Annual Report on Form 10-K and incorporated herein by reference.