MPLX LP

3. Acquisitions and Other Transactions

Northwind Midstream Acquisition

On August 29, 2025, MPLX completed the acquisition of 100 percent of Northwind Delaware Holdings LLC (“Northwind Midstream”) for $2.4 billion in cash (the “Northwind Midstream Acquisition”). Northwind Midstream provides sour gas gathering and treating services in Lea County, New Mexico, which enhances MPLX’s Permian natural gas and NGL value chain. The

Northwind Midstream Acquisition was financed with the net proceeds from MPLX's $4.5 billion senior notes issued in August 2025.

Northwind Midstream consists of over 200,000 dedicated acres, more than 200 miles of gathering pipelines, two in-service acid gas injection wells at 20 MMcf/d and a third permitted well that will bring its total capacity to 37 MMcf/d. At the time of acquisition, the system had 150 MMcf/d of sour gas treating capacity, with in-process expansion projects expected to increase capacity to over 400 MMcf/d by the second half of 2026. The system is supported by minimum volume commitments by regional producers.

The Northwind Midstream Acquisition was accounted for as a business combination requiring all Northwind Midstream assets and liabilities to be remeasured to fair value. The fair value of property, plant and equipment was based primarily on the cost approach. The fair value of the identifiable intangible assets was primarily based on the multi-period excess earnings method, which is an income approach. The intangible assets acquired are related to various commercial contracts with a weighted average amortization period of 15 years. The following table reflects our preliminary allocation of the $2.4 billion purchase price to the Northwind Midstream assets and liabilities:

The allocation is subject to revision, as certain data necessary to complete the purchase price allocation is not yet available, including, but not limited to, the final valuation of property, plant and equipment and intangible assets acquired, which may impact the amount of goodwill recognized. The final valuation will be completed no later than one year from the acquisition date. The results for the acquired business are reported within our Natural Gas and NGL Services segment.

The purchase price allocation resulted in the recognition of $356 million in goodwill by our Natural Gas and NGL Services segment, all of which is deductible for tax purposes. Goodwill represents the accelerated growth opportunities in the Permian using Northwind Midstream's asset base, which is complementary and adjacent to MPLX's existing Delaware basin natural gas system and offers optionality to direct volumes through our integrated system.

Pro forma financial information assuming the Northwind Midstream Acquisition had occurred as of the beginning of the calendar year prior to the year of the acquisition, as well as the revenues and earnings generated during the period since the acquisition date, were not material for disclosure purposes.

Announced Divestiture of Rockies Operations

On August 26, 2025, MPLX entered into a definitive agreement to divest its Rockies gathering and processing operations (the “Rockies”) to a subsidiary of Harvest Midstream (“Harvest”) for $1.0 billion in cash, subject to customary purchase price adjustments.

The assets and liabilities to be sold as part of this transaction are shown on the Consolidated Balance Sheet as Assets held for sale and Liabilities held for sale, respectively, as of September 30, 2025. Upon classification as held for sale, depreciation and amortization of the assets ceased. Since the sale of these assets does not represent a strategic shift that has or will have a material effect on our operations or financial results, the planned divestiture is not considered to be a discontinued operation. The Rockies operations are currently reported within the Natural Gas and NGL Services segment.

The transaction is expected to close in the fourth quarter of 2025, subject to customary closing conditions, and is expected to result in an estimated gain in excess of $150 million upon closing.

The following table presents the carrying value of assets and liabilities as presented within assets and liabilities held for sale on our Consolidated Balance Sheets as of September 30, 2025:

BANGL, LLC Acquisitions

BANGL, LLC (“BANGL”) owns and operates an NGL pipeline system that connects production in the Delaware and Midland basins to key demand centers along the Gulf Coast. On July 31, 2024, MPLX exercised its right of first offer under the BANGL joint venture agreement to purchase an additional 20 percent ownership interest in BANGL for $210 million in cash, which increased total ownership interest to 45 percent (the “2024 BANGL Transaction”). The purchase price of the additional 20 percent ownership interest in BANGL exceeded our portion of the underlying net assets of the joint venture by approximately $156 million. Following the 2024 BANGL Transaction, our investment in BANGL continued to be accounted for as an equity method investment.

On July 1, 2025, MPLX purchased the remaining 55 percent interest in BANGL for $703 million in cash, plus an earnout provision of up to $275 million based on targeted EBITDA growth from 2026 to 2029 (the “BANGL Acquisition”). We recorded a liability for these contingent payments in the third quarter of 2025. See Note 10 for additional details on the inputs used to measure the fair value of these contingent payments. 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 (the “BANGL Debt Repayment”).

Upon acquisition of the remaining 55 percent interest in BANGL, our existing equity investment was remeasured to fair value resulting in the recognition of a $484 million gain, which is included in Gain on equity method investments within the accompanying Consolidated Statements of Income. The fair value of the previously held equity method investment was estimated using an income approach, with significant valuation inputs including forecasted cash flows and discount rates ranging from 11 to 12 percent. As a result of the BANGL Acquisition, we now own 100 percent of BANGL and its results are reflected in our Natural Gas and NGL Services segment within our consolidated financial results.

The following table summarizes the purchase price consideration in connection with the BANGL Acquisition:

The BANGL Acquisition was accounted for as a business combination requiring all BANGL assets and liabilities to be remeasured to fair value. The fair value of property, plant and equipment was determined using a combination of both the cost and income approach. The fair value of the identifiable intangible assets was primarily based on the multi-period excess earnings method, which is an income approach. The intangible asset acquired is related to a customer relationship with an amortization period of 11 years. The following table reflects our preliminary determination of the fair value of the BANGL assets and liabilities:

The allocation is subject to revision, as certain data necessary to complete the purchase price allocation is not yet available, including, but not limited to, the final valuation of property, plant and equipment and intangible assets acquired, which may impact the amount of goodwill recognized. The final valuation will be completed no later than one year from the acquisition date.

The purchase price allocation resulted in the recognition of $731 million in goodwill by our Natural Gas and NGL Services segment,55 percent of which is deductible for tax purposes. Goodwill represents the advancement of our wellhead-to-water strategy by securing full ownership of a strategically located NGL transport asset which further integrates our midstream infrastructure connecting the Permian and Gulf Coast regions.

Pro forma financial information assuming the BANGL Acquisition had occurred as of the beginning of the calendar year prior to the year of the acquisition, as well as the revenues and earnings generated during the period since the acquisition date, were not material for disclosure purposes.

Matterhorn Express Pipeline Acquisition

On June 16, 2025, MPLX purchased an additional five percent ownership interest in the joint venture that owns and operates the Matterhorn Express pipeline for $151 million, bringing our total interest to 10 percent. The pipeline is designed to transport natural gas from the Permian basin to the Katy area near Houston. The purchase price of the additional five percent ownership interest in the joint venture exceeded the amount of the claim to the underlying net assets of the joint venture by approximately $124 million, with $63 million of this difference attributed to property, plant and equipment and $61 million attributed to customer-related intangibles. The amounts attributed to property, plant and equipment and customer-related intangibles will be amortized to net income over the remaining useful lives of the assets and the weighted average remaining term of the customer contracts, respectively. Our investment in the joint venture that owns and operates the Matterhorn Express pipeline continues to be accounted for as an equity method investment within our Natural Gas and NGL Services segment.

Whiptail Midstream Acquisition

On March 11, 2025, MPLX acquired gathering businesses from Whiptail Midstream, LLC for $237 million in cash. These San Juan basin assets consist primarily of crude and natural gas gathering systems in the Four Corners region, and enhance our strategic relationship with MPC. The acquisition was accounted for as a business combination, which requires all the identifiable assets acquired and liabilities assumed to be remeasured to fair value at the date of acquisition. The preliminary determination of the fair value includes $172 million of property, plant and equipment, $41 million of intangibles and $24 million of net working capital. The allocation is subject to revision, as certain data necessary to complete the purchase price allocation is not yet available, including, but not limited to, the final valuation of assets acquired and liabilities assumed. The final valuation will be completed no later than one year from the acquisition date. The results for the acquired business are allocated between our two segments based on the product-based value chain the underlying assets support.

Whistler Joint Venture Transaction

On May 29, 2024, MPLX and its joint venture partner contributed their respective membership interests in Whistler Pipeline, LLC to a newly formed joint venture, WPC Parent, LLC, and issued a 19 percent voting interest in WPC Parent, LLC to an affiliate of Enbridge Inc. in exchange for the contribution of cash and the Rio Bravo Pipeline project (collectively, the “Whistler Joint Venture Transaction”). As a result of the transaction, MPLX’s voting interest in the joint venture was reduced from 37.5 percent to 30.4 percent. MPLX recognized a gain of $151 million and received a cash distribution of $134 million, recorded as a return of capital, related to the dilution of the ownership interest. The gain is included in Income from equity method investments on the accompanying Consolidated Statements of Income and the return of capital is included in Investments - redemptions, repayments, return of capital and sales proceeds within the investing section of the accompanying Consolidated Statements of Cash Flows.

Utica Midstream Acquisition

On March 22, 2024, MPLX used $625 million of cash to purchase additional ownership interests in existing joint ventures and gathering assets (the “Utica Midstream Acquisition”), which will enhance our position in the Utica basin. Prior to the acquisition, we owned an indirect interest in Ohio Gathering Company L.L.C. (“OGC”) and a direct interest in Ohio Condensate Company L.L.C. (“OCC”). After giving effect to the acquisition, MPLX owns a combined direct and indirect 73 percent interest in OGC and a 100 percent interest in OCC. In addition, MPLX acquired a 100 percent interest in a dry gas gathering system in the Utica basin, including 53 miles of gathering pipeline and three dehydration units with a combined capacity of approximately 620 MMcf/d. OGC continues to be accounted for as an equity method investment, as MPLX did not obtain control of OGC as a result of the transaction. The acquisition date fair value of our investment in OGC exceeded our portion of the underlying net assets of the joint venture by approximately $75 million. This basis difference is being amortized into net income over the remaining estimated useful lives of the underlying net assets. OCC was previously accounted for as an equity method investment, and it is now reflected as a consolidated subsidiary within our consolidated financial results. The results for the acquired business are reported within our Natural Gas and NGL Services segment.

The Utica Midstream Acquisition was accounted for as a business combination requiring all the acquired assets and liabilities to be remeasured to fair value resulting in a consolidated fair value of net assets and liabilities of $625 million. The fair value includes $507 million related to acquired interests in the joint ventures and the remaining balance related to other acquired assets and liabilities. The revaluation of MPLX’s existing 62 percent equity method investment in OCC resulted in a $20 million gain, which is included in Gain on equity method investments within the accompanying Consolidated Statements of Income. The fair value of equity method investments was based on a discounted cash flow model.