MPLX LP

17. Debt

MPLX’s outstanding borrowings consist of the following:

(1)See Note 21 for lease information.

The following table shows five years of scheduled debt payments, including payments on finance lease obligations, as of December 31, 2025:

Credit Agreement

MPLX Credit Agreement

MPLX’s credit agreement (the “MPLX Credit Agreement”) matures in July 2027 and, among other things, provides for a $2.0 billion unsecured revolving credit facility and letter of credit issuing capacity under the facility of up to $150 million. Letter of credit issuing capacity is included in, not in addition to, the $2.0 billion borrowing capacity. Borrowings under the MPLX Credit Agreement bear interest, at MPLX’s election, at either the Adjusted Term SOFR or the Alternate Base Rate, both as defined in the MPLX Credit Agreement, plus an applicable margin.

The borrowing capacity under the MPLX Credit Agreement may be increased by up to an additional $1.0 billion, subject to certain conditions, including the consent of lenders whose commitments would increase. In addition, the maturity date may be extended, for up totwo additionalone year periods, subject to, among other conditions, the approval of lenders holding the majority of the commitments then outstanding, provided that the commitments of any non-consenting lenders will terminate on the then-effective maturity date. MPLX is charged various fees and expenses in connection with the agreement, including administrative agent fees, commitment fees on the unused portion of the facility and fees with respect to issued and outstanding letters of credit. The applicable margins to the benchmark interest rates and certain fees fluctuate based on the credit ratings in effect from time to time on MPLX’s long-term debt.

The MPLX Credit Agreement contains certain representations and warranties, affirmative and restrictive covenants and events of default that MPLX considers to be usual and customary for an agreement of this type, including a financial covenant that requires MPLX to maintain a ratio of Consolidated Total Debt as of the end of each fiscal quarter to Consolidated EBITDA (both as defined in the MPLX Credit Agreement) for the prior four fiscal quarters of no greater than 5.0 to 1.0 (or 5.5 to 1.0 for up to two fiscal quarters following certain acquisitions). Consolidated EBITDA is subject to adjustments, including for certain acquisitions and dispositions completed and capital projects undertaken during the relevant period. Other covenants restrict MPLX and/or certain of its subsidiaries from incurring debt, creating liens on our assets and entering into transactions with affiliates. As of December 31, 2025, MPLX was in compliance with the covenants contained in the MPLX Credit Agreement.

Activity on the MPLX Credit Agreement during the year ended December 31, 2025 is summarized in the table below. There wereno revolver borrowings or repayments under the MPLX Credit Agreement during the year ended December 31, 2024.

Senior Notes

Interest on each series of MPLX LP and ANDX senior notes outstanding is payable semi-annually in arrears, according to the table below.

The following table summarizes debt issuances during the year ended December 31, 2025, all of which were issued in an underwritten public offering:

(1)On April 9, 2025, MPLX used $1.2 billion of the net proceeds from the issuance of senior notes in March 2025 to redeem all of (i) MPLX’s outstanding $1,189 million aggregate principal amount of 4.875 percent senior notes due June 2025 and (ii) MarkWest’s outstanding $11 million aggregate principal amount of 4.875 percent senior notes due June 2025. The remaining net proceeds from this offering were used for general partnership purposes.

(2)We used a portion of the net proceeds from this offering to fund the Northwind Midstream Acquisition, including the payment of related fees and expenses, and to increase cash and cash equivalents following the recently completed BANGL Acquisition and BANGL Debt Repayment. The remainder of the net proceeds from this offering were used for general partnership purposes.

On July 3, 2025, MPLX used cash on hand to extinguish approximately $656 million principal amount of debt outstanding, including interest, related to certain term and revolving loans assumed as part of the BANGL Acquisition. See Note 4 for additional information on the BANGL Acquisition.

On May 20, 2024, MPLX issued $1.65 billion aggregate principal amount of 5.50 percent senior notes due June 2034 (the “2034 Senior Notes”) in an underwritten public offering. The 2034 Senior Notes were offered at a price to the public of 98.778 percent of par, with interest payable semi-annually in arrears, commencing on December 1, 2024. On December 1, 2024, MPLX used $1,150 million of the net proceeds from the issuance of the 2034 Senior Notes to repay all of (i) MPLX’s outstanding $1,149 million aggregate principal amount of 4.875 percent senior notes due December 2024 and (ii) MarkWest’s outstanding $1 million aggregate principal amount of 4.875 percent senior notes due December 2024. On February 18, 2025, MPLX used the remaining net proceeds from the issuance of the 2034 Senior Notes to repay all of MPLX’s outstanding $500 million aggregate principal amount of 4.000 percent senior notes due February 2025.

Subordination of Senior Notes

The MPLX senior notes are direct, unsecured unsubordinated obligations of MPLX LP. As such, they rank equally in right of payment with all of MPLX LP’s other unsubordinated debt and are not guaranteed by any of MPLX LP’s subsidiaries. The MPLX notes are effectively junior to MPLX LP’s secured indebtedness, if any, to the extent of the value of the relevant collateral. The MPLX notes are not obligations of any of MPLX’s subsidiaries and are effectively subordinated to all indebtedness and other obligations of such subsidiaries. The MPLX notes may be redeemed, in whole or part, at any time at the option of MPLX at a redemption price specified in the indenture governing the applicable notes, plus accrued and unpaid interest to the redemption date. The indenture governing the MPLX senior notes does not limit the amount of debt that MPLX may issue under the indenture, nor the amount of other debt that MPLX or any of its subsidiaries may issue or guaranty.

The ANDX senior notes are non-recourse to MPLX and its subsidiaries other than ANDX, the general partner of ANDX and other subsidiaries, if any, of ANDX that are a co-issuer or guarantor of the ANDX senior notes.