MPLX LP

1. Description of the Business and Basis of Presentation

Description of the Business

MPLX LP is a diversified, large-cap master limited partnership formed by Marathon Petroleum Corporation that owns and operates midstream energy infrastructure and logistics assets, and provides fuels distribution services. References in this report to “MPLX LP,” “MPLX,” “the Partnership,” “we,” “ours,” “us,” or like terms refer to MPLX LP and its subsidiaries. References to our sponsor and customer, “MPC,” refer collectively to Marathon Petroleum Corporation and its subsidiaries, other than the Partnership. We are engaged in the gathering, transportation, storage and distribution of crude oil, refined products, other hydrocarbon-based products and renewables; the gathering, processing and transportation of natural gas; and the transportation, fractionation, storage and marketing of NGLs. MPLX’s principal executive office is located in Findlay, Ohio. MPLX was formed on March 27, 2012 as a Delaware limited partnership and completed its initial public offering on October 31, 2012.

MPLX’s business consists oftwo segments. In the fourth quarter of 2024, we renamed and modified the composition of our segments to better reflect the product-based value chains and growth strategy of MPLX’s operations. The primary changes were to rename the Logistics and Storage segment to the Crude Oil and Products Logistics segment and to rename the Gathering and Processing segment to the Natural Gas and NGL Services segment. In addition, we reclassified certain equity method investments serving natural gas and NGL customers from Crude Oil and Products Logistics to Natural Gas and NGL Services. The segment realignment is presented for the year ended December 31, 2024, with prior periods recast for comparability.

The Crude Oil and Products Logistics segment includes the gathering, transportation, storage and distribution of crude oil, refined products, other hydrocarbon-based products and renewables. The Natural Gas and NGL Services segment gathers, processes and transports natural gas; and transports, fractionates, stores and markets NGLs. See Note 10 for additional information regarding the operations and results of these segments.

Basis of Presentation

The accompanying consolidated financial statements of MPLX have been prepared in accordance with GAAP. The consolidated financial statements include all majority-owned and controlled subsidiaries. For non-wholly-owned consolidated subsidiaries, the interests owned by third parties have been recorded as Noncontrolling interests on the accompanying Consolidated Balance Sheets. Intercompany accounts and transactions have been eliminated. MPLX’s investments in which MPLX exercises significant influence but does not control and does not have a controlling financial interest are accounted for using the equity method. MPLX’s investments in VIEs, in which MPLX exercises significant influence but does not control and is not the primary beneficiary, are also accounted for using the equity method.

Certain prior period financial statement amounts have been reclassified to conform to current period presentation.