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 based on the nature of services it offers: Logistics and Storage (“L&S”), which relates primarily to crude oil, refined products, other hydrocarbon-based products and renewables; and Gathering and Processing (“G&P”), which relates primarily to natural gas and 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.

2. Summary of Principal Accounting Policies

Use of Estimates

The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods. Actual results could differ materially from those estimates. Estimates are subject to uncertainties due to the levels of subjectivity and judgment necessary to account for highly uncertain matters or the susceptibility of such matters to change and affect items such as valuing identified intangible assets; determining the fair value of derivative instruments; evaluating impairments of long-lived assets, goodwill and equity investments; establishing estimated useful lives for long-lived assets; acquisition accounting; estimating revenues, expense accruals and capital expenditures; valuing AROs; recognizing share-based compensation expense; and determining liabilities, if any, for environmental and legal contingencies.

Revenue Recognition

Revenue is measured based on consideration specified in a contract with a customer. MPLX recognizes revenue when it satisfies a performance obligation by transferring control over a product or providing services to a customer.

MPLX enters into a variety of contract types in order to generate Product sales and Service revenue. MPLX provides services under the following types of arrangements:

•Fee-based arrangements – Under fee-based arrangements, MPLX receives fees for the following services: gathering, processing and transportation of natural gas; transportation, fractionation, exchange and storage of NGLs; and transportation, terminalling, storage and distribution of crude oil, refined products, other hydrocarbon-based products, and renewables. The revenue MPLX earns from these arrangements is generally directly related to the volume of natural gas, NGLs, refined products or crude oil that is handled by or flows through MPLX’s systems and facilities and is not normally directly dependent on commodity prices. In certain cases, MPLX’s arrangements provide for minimum volume commitments. Fee-based arrangements are reported as Service revenue on the Consolidated Statements of Income. Revenue is recognized over time as services are performed. In certain instances when specifically stated in the contract terms, MPLX purchases product after fee-based services have been provided. Revenue from the sale of products purchased after services are provided is reported as Product sales on the Consolidated Statements of Income and recognized on a gross basis, as MPLX takes control of the product and is the principal in the transaction.

•Percent-of-proceeds arrangements – Under percent-of-proceeds arrangements, MPLX gathers and processes natural gas on behalf of producers; sells the resulting residue gas, condensate and NGLs at market prices; and remits to producers an agreed-upon percentage of the proceeds. In other cases, instead of remitting cash payments to the producer, MPLX delivers an agreed-upon percentage of the residue gas and NGLs to the producer (take-in-kind arrangements) and sells the volumes MPLX retains to third parties or related parties. Revenue is recognized on a net basis when MPLX acts as an agent and does not have control of the gross amount of gas and/or NGLs prior to it being sold. Percent-of-proceeds revenue is reported as Service revenue - product related on the Consolidated Statements of Income.

•Keep-whole arrangements – Under keep-whole arrangements, MPLX gathers natural gas from the producer, processes the natural gas and sells the resulting condensate and NGLs to third parties at market prices. Because the extraction of the condensate and NGLs from the natural gas during processing reduces the Btu content of the natural gas, MPLX must either purchase natural gas at market prices for return to producers or make cash payment to the producers equal to the value of the energy content of this natural gas. Certain keep-whole arrangements also have provisions that require MPLX to share a percentage of the keep-whole profits with the producers based on the oil to gas ratio or the NGL to gas ratio. Service revenue - product related is recorded based on the value of the NGLs received on the date the services are performed. Natural gas purchased to return to the producer and shared NGL profits are recorded as a reduction of Service revenue - product related on the Consolidated Statements of Income on the date the services are performed. Sales of NGLs under these arrangements are reported as Product sales on the Consolidated Statements of Income and are reported on a gross basis as MPLX is the principal in the arrangement and controls the product prior to sale. The sale of the NGLs may occur shortly after services are performed at the tailgate of the plant, or after a period of time as determined by MPLX.

•Purchase arrangements – Under purchase arrangements, MPLX purchases natural gas at either the wellhead or the tailgate of a plant. MPLX then gathers and delivers the natural gas to pipelines where MPLX may resell the natural gas. Wellhead purchase arrangements represent an arrangement with a supplier and are recorded in Purchased product costs. Often, MPLX earns fees for services performed prior to taking control of the product in these arrangements and Service revenue is recorded for these fees. Revenue generated from the sale of product obtained in tailgate purchase arrangements is reported as Product sales on the Consolidated Statements of Income and is recognized on a gross basis as MPLX purchases and takes control of the product prior to sale and is the principal in the transaction.

In many cases, MPLX provides services under contracts that contain a combination of more than one of the arrangements described above. When fees are charged (in addition to product received) under percent-of-proceeds arrangements, keep-whole arrangements or purchase arrangements, MPLX records such fees as Service revenue on the Consolidated Statements of Income. The terms of MPLX’s contracts vary based on gas quality conditions, the competitive environment when the contracts are signed, and customer requirements. Performance obligations are determined based on the specific terms of the arrangements, economics of the geographical regions, and the services offered and whether they are deemed distinct. MPLX allocates the consideration earned between the performance obligations based on the stand-alone selling price when multiple performance obligations are identified.

Revenue from MPLX’s service arrangements will generally be recognized over time as the performance obligation is satisfied as services are provided. MPLX has elected to use the output measure of progress to recognize revenue based on the units delivered, processed or transported. The transaction price may have fixed components related to minimum volume commitments and variable components, which are primarily dependent on volumes. Variable consideration will generally not be estimated at contract inception as the transaction price is specifically allocable to the services provided each period. In instances in which tiered pricing structures do not reflect our efforts to perform, MPLX will estimate variable consideration at contract inception. Product sales will be recognized at a point in time when control of the product transfers to the customer.

Minimum volume commitments may create contract liabilities if current period payments can be used for future services. Breakage is estimated and recognized into service revenue in instances where it is probable the customer will not use the credit in future periods.

Amounts billed to customers for shipping and handling, electricity, and other costs to perform services are included in the transaction price as a component of Revenues and other income on the Consolidated Statements of Income. Shipping and handling costs associated with product sales are included in Purchased product costs on the Consolidated Statements of Income.

Customers usually pay monthly based on the products purchased or services performed that month. Taxes collected from customers and remitted to the appropriate taxing authority are excluded from revenue.

Based on the terms of certain contracts, MPLX is considered to be the lessor under several implicit operating and sales-type lease arrangements in accordance with GAAP. Revenue and costs related to the portion of the revenue earned under these contracts considered to be implicit operating leases are recorded as Rental income and Rental cost of sales, respectively, on the Consolidated Statements of Income. Revenue related to the portion of the revenue earned under these contracts considered to be implicit sales-type lease arrangements is recorded as Sales-type lease revenue on the Consolidated Statements of Income, while related costs are recorded to Cost of revenues or Purchases - related parties.

Revenue and Expense Accruals

MPLX routinely makes accruals based on estimates for both revenues and expenses due to the timing of compiling billing information, receiving certain third-party information and reconciling MPLX’s records with those of third parties. The delayed information from third parties includes, among other things, actual volumes purchased, transported or sold, adjustments to inventory and invoices for purchases, actual natural gas and NGL deliveries, and other operating expenses. MPLX makes accruals to reflect estimates for these items based on its internal records and information from third parties. Estimated accruals are adjusted when actual information is received from third parties and MPLX’s internal records have been reconciled.

Other Taxes

Other taxes primarily include real estate taxes.

Cash and Cash Equivalents

Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid debt instruments with maturities of three months or less.

Receivables

Receivables primarily consist of customer accounts receivable, which are recorded at the invoiced amount and generally do not bear interest. Allowances for doubtful accounts are generally recorded when it becomes probable that the receivable will not be collected and are recorded to bad debt expense. We review the allowance quarterly with past-due balances over 150 days and other higher-risk amounts being reviewed individually for collectability. Balances that remain outstanding after reasonable collection efforts have been unsuccessful are written off through a charge to the valuation allowance and a credit to accounts receivable.

Leases

Contracts with a term greater than one year that convey the right to direct the use of and obtain substantially all of the economic benefit of an asset are accounted for as right of use (“ROU”) assets and lease liabilities.

Right of use asset and lease liability balances are recorded at the commencement date at present value of the fixed lease payments using a secured incremental borrowing rate with a maturity similar to the lease term because our leases do not provide implicit rates. We have elected to include both lease and non-lease components in the present value of the lease payments for all lessee asset classes with the exception of our marine and third-party contractor service and equipment leases. The lease component of the payment for the marine and equipment asset classes is determined using a relative standalone selling price. Operating lease expense is recognized on a straight-line basis over the lease term. See Note 20 for additional disclosures about our lease contracts.

As a lessor under ASC 842, MPLX may be required to re-classify existing operating leases to sales-type leases upon modification and related reassessment of the leases. See Note 20 for further information regarding our ongoing evaluation of the impacts of lease reassessments as modifications occur. The net investment in sales-type leases with third parties is recorded within Receivables, net and Other noncurrent assets on the Consolidated Balance Sheets. The net investment in sales-type leases with related parties is recorded within Current assets - related parties and Noncurrent assets - related parties on the Consolidated Balance Sheets. These amounts are comprised of the present value of the sum of the future minimum lease payments representing the value of the lease receivable and the unguaranteed residual value of the leased assets. Management assesses the net investment in sales-type leases for recoverability quarterly.

Inventories

Inventories consist of materials and supplies to be used in operations, line fill and other NGLs. Cost for materials and supplies are determined primarily using the weighted-average cost method. Inventories are valued at the lower of cost or net realizable value.

Imbalances

Within our pipelines and storage assets, we experience volume gains and losses due to pressure and temperature changes, evaporation and variances in meter readings and other measurement methods. Until settled, positive imbalances are recorded as other current assets and negative imbalances are recorded as accounts payable. Positive and negative imbalances are settled in cash, settled by physical delivery of volumes from a different source, or tracked and settled in the future.

Investment in Unconsolidated Affiliates

Equity investments in which MPLX exercises significant influence but does not control and is not the primary beneficiary, are accounted for using the equity method and are reported in Equity method investments on the accompanying Consolidated Balance Sheets. This includes entities in which we hold majority ownership, but the minority shareholders have substantive participating rights. Differences in the basis of the investments and the separate net asset values of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets and liabilities, except for the excess related to goodwill.

Regular evaluation of these investments is appropriate to evaluate any potential need for impairment. MPLX uses evidence of a loss in value to identify if an investment has an other than a temporary decline. Impairments are recorded through Income from equity method investments.

Property, Plant and Equipment

Property, plant and equipment are recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets. Expenditures that extend the useful lives of assets are capitalized.

Long-lived assets used in operations are assessed for impairment whenever changes in facts and circumstances indicate that the carrying value of the assets may not be recoverable based on the expected undiscounted future cash flows of an asset group. For purposes of impairment evaluation, long-lived assets must be grouped at the lowest level for which independent cash flows can be identified, which is at least at the segment level and in some cases for similar assets in the same geographic region where cash flows can be separately identified. If the sum of the undiscounted future cash flows from the use of the asset group and its eventual disposition is less than the carrying value of an asset group, an impairment assessment is performed and the excess of the book value over the fair value is recorded as an impairment loss.

When items of property, plant and equipment are sold or otherwise disposed of, any gains or losses are reported on the Consolidated Statements of Income. Gains on the disposal of property, plant and equipment are recognized when they occur, which is generally at the time of closing. If a loss on disposal is expected, such losses are recognized when the assets are classified as held for sale.

Interest costs for the construction or development of long-lived assets are capitalized and amortized over the related asset’s estimated useful life.

Goodwill and Intangibles

Goodwill represents the excess of the purchase price over the estimated fair value of the net assets acquired in the acquisition of a business. Goodwill is not amortized, but rather is tested for impairment at the reporting unit level annually and when events or changes in circumstances indicate that the fair value of a reporting unit with goodwill has been reduced below carrying value. If we determine, based on a qualitative assessment, that it is not more likely than not that a reporting unit’s fair value is less than its carrying amount, no further impairment testing is required. If we do not perform a qualitative assessment or if that assessment indicates that further impairment testing is required, the fair value of each reporting unit is determined using an income and market approach which is compared to the carrying value of the reporting unit. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss would be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. The fair value under the income approach is calculated using the expected present value of future cash flows method. Significant assumptions used in the cash flow forecasts include future net operating margins, future volumes, discount rates, and future capital requirements. See Note 14 for further details.

Amortization of intangibles with definite lives is calculated using the straight-line method, which is reflective of the benefit pattern in which the estimated economic benefit is expected to be received over the estimated useful life of the intangible asset. Intangibles subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the intangible may not be recoverable. If the sum of the expected undiscounted future cash flows related to the asset is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset.

Environmental Costs

Environmental expenditures for additional equipment that mitigates or prevents future contamination or improves environmental safety or efficiency of the existing assets are capitalized. We recognize remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of a feasibility study or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed and determinable. If recoveries of remediation costs from third parties are probable, a receivable is recorded and is discounted when the estimated amount is reasonably fixed and determinable.

Asset Retirement Obligations

An ARO is a legal obligation associated with the retirement of tangible long-lived assets that generally result from the acquisition, construction, development or normal operation of the asset. The fair value of AROs is recognized in the period in which the obligations are incurred, if a reasonable estimate of fair value can be made, and added to the carrying amount of the associated asset. This additional carrying amount is then depreciated over the life of the asset. The liability is determined using a credit adjusted risk free interest rate and increases due to the passage of time based on the time value of money until the obligation is settled. AROs have not been recognized for certain assets because the fair value cannot be reasonably estimated since the settlement dates of the obligations are indeterminate. Such obligations will be recognized in the period when sufficient information becomes available to estimate a range of potential settlement dates. As of December 31, 2023 and 2022, MPLX’s asset retirement obligation was $39 million and $34 million, respectively, and is included on the balance sheet within Other long-term liabilities.

Derivative Instruments

MPLX may use commodity derivatives to economically hedge a portion of its exposure to commodity price risk. All derivative instruments (including derivatives embedded in other contracts) are recorded at fair value. MPLX discloses the fair value of all derivative instruments under the captions Other current assets, Other noncurrent assets, Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Certain commodity derivative positions are governed by master netting arrangements and are reflected on the consolidated balance sheets on a net basis by counterparty. We make a distinction between realized or unrealized gains and losses on derivatives. During the period when a derivative contract is outstanding, changes in the fair value of the derivative are recorded as an unrealized gain or loss. When a derivative contract matures or is settled, the previously recorded unrealized gain or loss is reversed, and the realized gain or loss of the contract is recorded. Changes in the fair value of derivative instruments are reported on the Consolidated Statements of Income in accounts related to the item whose value or cash flows are being managed. Derivative instruments are marked to market through Product sales and Purchased product costs on the Consolidated Statements of Income.

During the years ended December 31, 2023, 2022 and 2021, MPLX did not elect hedge accounting for any derivatives. MPLX has historically elected the normal purchases and normal sales designation for certain contracts related to the physical purchase of electric power and the sale of some commodities.

Fair Value Measurement

Financial assets and liabilities recorded at fair value in the Consolidated Balance Sheets are categorized based upon the fair value hierarchy established by GAAP, which classifies the inputs used to measure fair value into Level 1, Level 2 or Level 3. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The methods and assumptions utilized may produce a fair value that may not be realized in future periods upon settlement. Furthermore, while MPLX believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. For further discussion, see Note 15.

Equity-Based Compensation Arrangements

MPLX issues phantom units under the MPLX LP 2018 Incentive Compensation Plan. A phantom unit entitles the grantee a right to receive a common unit upon the issuance of the phantom unit. The fair value of phantom unit awards granted to employees and non-employee directors is based on the fair market value of MPLX LP common units on the date of grant. The fair value of the units awarded is amortized into earnings using a straight-line amortization schedule over the period of service corresponding with the vesting period. For phantom units that vest immediately and are not forfeitable, equity-based compensation expense is recognized at the time of grant.

MPLX previously issued performance units under the MPLX LP 2018 Incentive Compensation Plan. All the outstanding performance unit awards were settled as of February 1, 2023.

To satisfy common unit awards, MPLX may issue new common units, acquire common units in the open market or use common units already owned by the general partner.

Income Taxes

MPLX is not a taxable entity for United States federal income tax purposes or for the majority of the states that impose an income tax. Taxes on MPLX’s net income generally are borne by its partners through the allocation of taxable income. MPLX’s taxable income or loss, which may vary substantially from the net income or loss reported on the Consolidated Statements of Income, is includable in the federal income tax returns of each partner. MPLX and certain legal entities are, however, taxable entities under certain state jurisdictions.

MPLX accounts for income taxes under the asset and liability method. Deferred income taxes are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis, capital loss carryforwards and net operating loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of any tax rate change on deferred taxes is recognized as tax expense/(benefit) from continuing operations in the period that includes the enactment date of the tax rate change. Realizability of deferred tax assets is assessed and, if not more likely than not, a valuation allowance is recorded to reflect the deferred tax assets at net realizable value as determined by management. All deferred tax balances are classified as long-term in the accompanying Consolidated Balance Sheets. All changes in the tax bases of assets and liabilities are allocated among operations and items charged or credited directly to equity.

Distributions

In preparing the Consolidated Statements of Equity, net income attributable to MPLX LP is allocated to Series A and Series B preferred unitholders based on a fixed distribution schedule, as discussed in Notes 7 and 9, and subsequently allocated to the limited partner unitholders. Distributions, although earned, are not accrued as a liability until declared. The allocation of net income attributable to MPLX LP for purposes of calculating net income per limited partner unit is described below.

Net Income Per Limited Partner Unit

MPLX uses the two-class method when calculating the net income per unit applicable to limited partners, because there is more than one class of participating security. The classes of participating securities include common units, Series A and Series B preferred units and certain equity-based compensation awards.

Net income attributable to MPLX LP is allocated to the unitholders differently for preparation of the Consolidated Statements of Equity and the calculation of net income per limited partner unit. In preparing the Consolidated Statements of Equity, net income attributable to MPLX LP is allocated to Series A and Series B preferred unitholders based on a fixed distribution schedule and subsequently allocated to remaining unitholders in accordance with their respective ownership percentages. The allocation of net income attributable to MPLX LP for purposes of calculating net income per limited partner unit is described in Note 8.

In preparing net income per limited partner units, during periods in which a net loss attributable to MPLX is reported or periods in which the total distributions exceed the reported net income attributable to MPLX’s unitholders, the amount allocable to certain equity-based compensation awards is based on actual distributions to the equity-based compensation awards. Diluted earnings per unit is calculated by dividing net income attributable to MPLX’s common unitholders, after deducting amounts allocable to other participating securities, by the weighted average number of common units and potential common units outstanding during the period. Potential common units are excluded from the calculation of diluted earnings per unit during periods in which net income attributable to MPLX’s unitholders, after deducting amounts that are allocable to the outstanding equity-based compensation awards and preferred units, is a loss, as the impact would be anti-dilutive.

Business Combinations

We recognize and measure the assets acquired and liabilities assumed in a business combination based on their estimated fair values at the acquisition date. Any excess or deficit of the purchase consideration when compared to the fair value of the net tangible assets acquired, if any, is recorded as goodwill or gain from a bargain purchase. Depending on the nature of the transaction, management may engage an independent valuation specialist to assist with the determination of fair value of the assets acquired, liabilities assumed, noncontrolling interests, if any, and goodwill, based on recognized business valuation methodologies. An income, market or cost valuation method may be utilized to estimate the fair value of the assets acquired, liabilities assumed, and noncontrolling interests, if any, in a business combination. The income valuation method represents the present value of future cash flows over the life of the asset using: (i) discrete financial forecasts, which rely on management’s estimates of volumes, certain commodity prices, revenue and operating expenses; (ii) long-term growth rates; and (iii) appropriate discount rates. The market valuation method uses prices paid for a reasonably similar asset by other purchasers in the market, with adjustments relating to any differences between the assets. The cost valuation method is based on the replacement cost of a comparable asset at prices at the time of the acquisition reduced for depreciation of the asset. If the initial accounting for the business combination is incomplete by the end of the reporting period in which the acquisition occurs, an estimate will be recorded. Subsequent to the acquisition, and not later than one year from the acquisition date, MPLX will record any material adjustments to the initial estimate based on new information obtained that would have existed as of the acquisition date. An adjustment that arises from information obtained that did not exist as of the date of the acquisition will be recorded in the period of the adjustment. Acquisition-related costs are expensed as incurred in connection with each business combination.

Acquisitions in which the company or business being acquired by MPLX had an existing relationship with MPC may result in the transaction being considered a transfer between entities under common control. In these situations, MPLX records the assets acquired and liabilities assumed on its consolidated balance sheets at MPC’s historical carrying value. For the acquiring entity, transfers of businesses between entities under common control require prior periods to be retrospectively adjusted for those dates that the entity was under common control.

3. Accounting Standards

Recently Adopted

ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers

During 2023, we adopted ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers. The adoption of this accounting standard update did not have a material impact on our financial statements.

Not Yet Adopted

ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures

In November 2023, the FASB issued an ASU to update reportable segment disclosure requirements primarily by requiring enhanced disclosures about significant segment expenses. This ASU is effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. We are currently evaluating the impact this ASU will have on our disclosures.

ASU 2023-01, Leases (Topic 842): Common Control Arrangements

In March 2023, the FASB issued an ASU to amend certain provisions of ASC 842 that apply to arrangements between related parties under common control. The ASU amends the accounting for the amortization period of leasehold improvements in common-control leases for all entities and requires certain disclosures when the lease term is shorter than the useful life of the asset. This ASU is effective for fiscal years beginning after December 15, 2023, including interim periods within those fiscal years. Early adoption is permitted. We do not expect the application of this ASU to have a material impact on our consolidated financial statements or disclosures.

4. Acquisitions and Dispositions

Acquisition of 40 Percent Interest in MarkWest Torñado GP, L.L.C.

On December 15, 2023, MPLX used $303 million of cash on hand to purchase the remaining 40 percent interest in MarkWest Torñado GP, L.L.C. (“Torñado”) for approximately $270 million, including cash paid for working capital, and to extend the term of a gathering and processing agreement for approximately $33 million. As a result of this transaction, we now own 100 percent of Torñado and reflect it as a consolidated subsidiary within our consolidated financial results. It was previously accounted for as an equity method investment. Torñado provides natural gas gathering and processing related services in the Permian basin. Its assets include two gas processing plants, each with a capacity of 200 MMcf/d and approximately 142 miles of gathering pipeline. The results for this business are reported under our G&P segment.

At December 15, 2023, the carrying value of our 60 percent equity investment in Torñado was $311 million. Upon acquisition of the remaining 40 percent member interest, our existing equity investment was remeasured to fair value resulting in the recognition of a $92 million gain, which is presented in Other income on the Consolidated Statements of Income. The fair value of the previously-held equity method investment was primarily based on the price negotiated for the 40 percent interest in Torñado.

The acquisition was accounted for as a business combination requiring all of the Torñado assets and liabilities to be remeasured to fair value resulting in a consolidated fair value of net assets and liabilities of $673 million. The fair value of property, plant and equipment is based primarily on the cost approach. The fair value of the identifiable intangible assets, consisting of various customer contracts, was primarily based on the multi-period excess earnings method, which is an income approach. The following table reflects our determination of the fair value of the Torñado assets and liabilities (in millions):

Pro forma financial information assuming the 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.

Sale of Javelina

On February 12, 2021, MPLX completed the sale of its equity interests in MarkWest Javelina Company L.L.C., MarkWest Javelina Pipeline Company L.L.C., and MarkWest Gas Services L.L.C. (collectively, “Javelina”) pursuant to the terms of an Equity Purchase Agreement entered into with a third party on December 23, 2020. The agreement included adjustments for working capital as well as an earnout provision based on the performance of the assets. No gain or loss was recorded on the sale. The estimated value of the earnout provision was recorded as a contingent asset shown within Other noncurrent assets on the Consolidated Balance Sheets as of December 31, 2023 and 2022. Prior to the sale, Javelina was reported within the G&P segment.

5. Investments and Noncontrolling Interests

The following table presents MPLX’s equity method investments at the dates indicated:

(1)The investment in MarEn Bakken Company LLC includes our 9.19 percent indirect interest in a joint venture (“Dakota Access”) that owns and operates the Dakota Access Pipeline and Energy Transfer Crude Oil Pipeline projects (collectively referred to as the “Bakken Pipeline system”).

(2)Some investments included within Other have also been deemed to be VIEs.

(3)At December 31, 2022, we owned a 60 percent interest in Torñado. On December 15, 2023, we acquired the remaining 40 percent interest. As a result of acquiring the remaining interest, we obtained control of and now consolidate Torñado.

For those entities that have been deemed to be VIEs, neither MPLX nor any of its subsidiaries have been deemed to be the primary beneficiary due to voting rights on significant matters. While we have the ability to exercise influence through participation in the management committees which make all significant decisions, we have equal influence over each committee as a joint interest partner and all significant decisions require the consent of the other investors without regard to economic interest. As such, we have determined that these entities should not be consolidated and applied the equity method of accounting with respect to our investments in each entity.

Sherwood Midstream LLC (“Sherwood Midstream”) has been deemed the primary beneficiary of Sherwood Midstream Holdings LLC (“Sherwood Midstream Holdings”) due to its controlling financial interest through its authority to manage the joint venture. As a result, Sherwood Midstream consolidates Sherwood Midstream Holdings. Therefore, MPLX also reports its portion of

Sherwood Midstream Holdings’ net assets as a component of its investment in Sherwood Midstream. As of December 31, 2023, MPLX had a 24.55 percent indirect ownership interest in Sherwood Midstream Holdings through Sherwood Midstream.

MPLX’s maximum exposure to loss as a result of its involvement with equity method investments includes its equity investment, any additional capital contribution commitments and any operating expenses incurred by the subsidiary operator in excess of its compensation received for the performance of the operating services. MPLX did not provide any financial support to equity method investments that it was not contractually obligated to provide during the years ended December 31, 2023, 2022 and 2021. See Note 21 for information on our Guarantees related to indebtedness of equity method investees.

From time to time, changes in the design or nature of the activities of our equity method investments may require us to reconsider our conclusions on the entity’s status as a VIE and/or our status as the primary beneficiary. Such reconsideration could result in a change in the classification of the equity method investment. Summarized financial information for MPLX’s equity method investments for the years ended December 31, 2023, 2022 and 2021 is as follows:

Summarized balance sheet information for MPLX’s equity method investments as of December 31, 2023 and 2022 is as follows:

As of December 31, 2023 and 2022, the underlying net assets of MPLX’s investees in the G&P segment exceeded the carrying value of its equity method investments by approximately $45 million and $51 million, respectively. As of December 31, 2023 and 2022, the carrying value of MPLX’s equity method investments in the L&S segment exceeded the underlying net assets of its investees by $314 million and $320 million, respectively.

At both December 31, 2023 and 2022, the G&P basis difference related to goodwill was $31 million. At both December 31, 2023 and 2022, the L&S basis difference related to goodwill was $167 million.

6. Related Party Agreements and Transactions

MPLX engages in transactions with both MPC and certain of its equity method investments as part of its normal business; however, transactions with MPC make up the majority of MPLX’s related party transactions. Transactions with related parties are further described below.

MPLX has various long-term, fee-based commercial agreements with MPC. Under these agreements, MPLX provides transportation, gathering, terminal, fuels distribution, marketing, storage, management, operational and other services to MPC. MPC has committed to provide MPLX with minimum quarterly throughput volumes on crude oil and refined products and other fees for storage capacity; operating and management fees; and reimbursements for certain direct and indirect costs. MPC has also committed to provide a fixed fee for 100 percent of available capacity for boats, barges and third-party chartered equipment under the marine transportation service agreements. In addition, MPLX has obligations to MPC for services provided to MPLX by MPC under omnibus and employee services type agreements as well as various other agreements as discussed below.

The commercial agreements with MPC include:

•MPLX has a fuels distribution agreement with MPC under which MPC pays MPLX a tiered monthly volume-based fee for marketing and selling MPC’s products. This agreement is subject to a minimum quarterly volume and has an initial term of 10 years, subject to afive-year renewal period under terms to be renegotiated at that time.

•MPLX has various pipeline transportation agreements under which MPC pays MPLX fees for transporting crude and refined products on MPLX’s pipeline systems. These agreements are subject to minimum throughput volumes under which MPC will pay MPLX deficiency payments for any period in which they do not ship the minimum committed volume. Under certain agreements, deficiency payments can be applied as credits to future periods in which MPC ships volumes in excess of the minimum volume, subject to a limited period of time. These agreements are subject to various terms and renewal periods.

•MPLX has marine transportation agreements with initial terms offive tosix years under which MPC pays MPLX fees for providing marine transportation of crude oil, feedstock and refined petroleum products, and related services. These agreements are each subject toone remaining renewal period offive years.

•MPLX has numerous storage services agreements governing storage services at various types of facilities including terminals, pipeline tank farms, caverns and refineries, under which MPC pays MPLX per-barrel fees for providing storage services. Some of these agreements provide MPC with exclusive access to storage at certain locations, such as storage located at MPC’s refineries or storage in certain caverns. Under these agreements, MPC pays MPLX a per-barrel fee for such storage capacity, regardless of whether MPC fully utilizes the available capacity. These agreements are subject to various terms and renewal periods.

•MPLX has multiple terminal services agreements governing certain terminals under which MPC pays MPLX fees for terminal services. Under these agreements MPC pays MPLX agreed upon fees relating to MPC product receipts, deliveries and storage as well as any blending, additization, handling, transfers or other related charges. Many of these agreements are subject to minimum volume throughput commitments, or to various minimum commitments related to some or all terminal activities, under which MPC pays a deficiency payment for any period in which they do not meet the minimum commitment. Some of these agreements allow for deficiency payments to be applied as credits to a limited number of future periods with excess throughput volumes. These agreements are subject to various terms and renewal periods.

•MPLX has a keep-whole commodity agreement with MPC under which MPC pays us a processing fee for NGLs related to keep-whole agreements and we pay MPC a marketing fee in exchange for assuming the commodity risk. The pricing structure under this agreement provides for a base volume subject to a base rate and incremental volumes subject to variable rates, which are calculated with reference to certain of our costs incurred as processor of the volumes. The pricing for both the base and incremental volumes are subject to revision each year. This agreement is subject to automatic three-month renewal periods.

In many cases, agreements are location-based hybrid agreements, containing provisions relating to multiple of the types of agreements and services described above.

Operating Agreements

MPLX operates various pipelines owned by MPC under operating services agreements. Under these operating services agreements, MPLX receives an operating fee for operating the assets and is reimbursed for all direct and indirect costs associated with operating the assets. Most of these agreements are indexed for inflation. These agreements range fromone toten years in length and automatically renew unless terminated by either party.

Co-location Services Agreements

MPLX is party to co-location services agreements with MPC’s refineries, under which MPC provides management, operational and other services to MPLX. MPLX pays MPC monthly fixed fees and direct reimbursements for such services calculated as set forth in the agreements. These agreements have initial terms of 50 years.

Ground Lease Agreements

MPLX is party to ground lease agreements with certain of MPC’s refineries under which MPLX is the lessee of certain sections of property which contain facilities owned by MPLX and are within the premises of MPC’s refineries. MPLX pays MPC monthly fixed fees under these ground leases. These agreements are subject to various terms.

Marine Services Agreement with MPC

MPLX has an agreement with MPC under which it provides management services to assist MPC in the oversight and management of the marine business. MPLX receives fixed annual fees for providing the required services, which are subject to predetermined annual escalation rates. This agreement is subject to an initial term offive years and automatically renews forone additional five-year renewal period unless terminated by either party.

Omnibus Agreements

MPLX has omnibus agreements with MPC that address MPLX’s payment of fixed annual fees to MPC for the provision of executive management services by certain executive officers of the general partner and MPLX’s reimbursement of MPC for the provision of certain general and administrative services to it. They also provide for MPC’s indemnification to MPLX for certain matters, including environmental, title and tax matters, as well as our indemnification of MPC for certain matters under these agreements.

Employee Services Agreements

MPLX has various employee services agreements and secondment agreements with MPC under which MPLX reimburses MPC for employee benefit expenses, along with the provision of operational and management services in support of both our L&S and G&P segments’ operations.

Related Party Loan

MPLX is party to a loan agreement (the “MPC Loan Agreement”) with MPC. Under the terms of the MPC Loan Agreement, MPC extends loans to MPLX on a revolving basis as requested by MPLX and as agreed to by MPC. The borrowing capacity of the MPC Loan Agreement is $1.5 billion aggregate principal amount of all loans outstanding at any one time. The MPC Loan Agreement is scheduled to expire, and borrowings under the loan agreement are scheduled to mature and become due and payable, on July 31, 2024, provided that MPC may demand payment of all or any portion of the outstanding principal amount of the loan, together with all accrued and unpaid interest and other amounts (if any), at any time prior to maturity. Borrowings under the MPC Loan Agreement bear interest atone-month term SOFR adjusted upward by 0.10 percent plus 1.25 percent or such lower rate as would be applicable to such loans under the MPLX Credit Agreement as discussed in Note 17.

There was no activity on the MPC Loan Agreement for the year ended December 31, 2023. Activity on the MPC Loan Agreement for the years ended December 31, 2022 and 2021 was as follows:

Related Party Revenue

Related party sales to MPC primarily consist of crude oil and refined products pipeline services based on tariff or contracted rates; storage, terminal and fuels distribution services based on contracted rates; and marine transportation services. Related party sales to MPC also consist of revenue related to volume deficiency credits.

MPLX also has operating agreements with MPC under which it receives a fee for operating MPC’s retained pipeline assets and a fixed annual fee for providing oversight and management services required to run the marine business. MPLX also receives management fee revenue for engineering, construction and administrative services for operating certain of its equity method investments. Amounts earned under these agreements are classified as Other income-related parties in the Consolidated Statements of Income.

Certain product sales to MPC and other related parties net to zero within the consolidated financial statements as the transactions are recorded net due to the terms of the agreements under which such product was sold. For the years ended December 31, 2023, 2022 and 2021, these sales totaled $739 million, $1,002 million and $811 million, respectively.

Related Party Expenses

MPC charges MPLX for executive management services and certain general and administrative services provided to MPLX under the terms of our omnibus agreements (“Omnibus charges”) and for certain employee services provided to MPLX under employee services agreements (“ESA charges”). Omnibus charges and ESA charges are classified as Rental cost of sales - related parties, Purchases - related parties, or General and administrative expenses depending on the nature of the asset or activity with which the costs are associated.

In addition to these agreements, MPLX purchases products from MPC, makes payments to MPC in its capacity as general contractor to MPLX, and has certain rent and lease agreements with MPC.

For the years ended December 31, 2023, 2022 and 2021, General and administrative expenses incurred from MPC totaled $262 million, $235 million and $250 million, respectively.

Some charges incurred under the omnibus and employee service agreements are related to engineering services and are associated with assets under construction. These charges are added to Property, plant and equipment, net on the Consolidated Balance Sheets. For 2023, 2022 and 2021, these charges totaled $94 million, $70 million and $55 million, respectively.

Related Party Assets and Liabilities

Assets and liabilities with related parties appearing in the Consolidated Balance Sheets are detailed in the table below. This table identifies the various components of related party assets and liabilities, including those associated with leases (see Note 20 for additional information) and deferred revenue on minimum volume commitments. If MPC fails to meet its minimum committed volumes, MPC will pay MPLX a deficiency payment based on the terms of the agreement. The deficiency amounts received under these agreements (excluding payments received under agreements classified as sales-type leases) are recorded as Current liabilities - related parties. In many cases, MPC may then apply the amount of any such deficiency payments as a credit for volumes in excess of its minimum volume commitment in future periods under the terms of the applicable agreements. MPLX recognizes related party revenues for the deficiency payments when credits are used for volumes in excess of minimum quarterly volume commitments, where it is probable the customer will not use the credit in future periods or upon the expiration of the credits. The use or expiration of the credits is a decrease in Current liabilities - related parties. Deficiency payments under agreements that have been classified as sales-type leases are recorded as a reduction against the corresponding lease receivable. In addition, capital projects MPLX undertakes at the request of MPC are reimbursed in cash and recognized as revenue over the remaining term of the applicable agreements or in some cases, as a contribution from MPC.

(1) There wereno borrowings outstanding on the MPC Loan Agreement as of December 31, 2023 or December 31, 2022.

Other Related Party Transactions

From time to time, MPLX may also sell to or purchase from related parties, assets and inventory at the lesser of average unit cost or net realizable value.

7. Equity

Units Outstanding

MPLX had 1,003,498,875 common units outstanding as of December 31, 2023. Of that number,647,415,452 were owned by MPC. The table below summarizes the changes in the number of units outstanding for the years ended December 31, 2021, 2022, and 2023:

Unit Repurchase Program

On November 2, 2020, MPLX announced the board authorization of a unit repurchase program for the repurchase of up to $1 billion of MPLX’s outstanding common units held by the public, which was exhausted during the fourth quarter of 2022. On August 2, 2022, we announced the board authorization for the repurchase of up to an additional $1 billion of MPLX common units held by the public. This unit repurchase authorization has 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 discontinued at any time. The table below summarizes the repurchases made under the unit repurchase program for the years ended December 31, 2023, 2022 and 2021:

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

As of December 31, 2023, we had $846 million available under our remaining unit repurchase authorization.

Series A Redeemable Preferred Unit Conversions

Since 2020, certain Series A preferred unitholders have exercised their rights to convert their Series A preferred units into approximately 2.4 million common units as discussed in Note 9.

Redemption of the Series B Preferred Units

On February 15, 2023, MPLX exercised its right to redeem all 600,000 units of 6.875 percent Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series B preferred units”). MPLX paid unitholders the Series B preferred unit redemption price of $1,000 per unit.

Distributions on the Series B preferred units were payable semi-annually in arrears on the 15th day, or the first business day thereafter, of February and August of each year up to and including February 15, 2023. In accordance with these terms, MPLX made a final cash distribution of $21 million to Series B preferred unitholders on February 15, 2023, in conjunction with the redemption.

The changes in the Series B preferred unit balance during 2023, 2022 and 2021 are included in the Consolidated Statements of Equity within Series B preferred units.

Cash Distributions

Total distributions for the years ended December 31, 2023, 2022 and 2021 are summarized in the table below. The 2021 period includes a supplemental distribution amount of $0.575 per common unit (the “Supplemental Distribution Amount”) related to the distribution declared for the third quarter of 2021, which was paid during the fourth quarter of 2021.

The allocation of total quarterly cash distributions to limited, and preferred unitholders is as follows for the years ended December 31, 2023, 2022 and 2021. The Partnership Agreement sets forth the calculation to be used to determine the amount and priority of cash distributions that the common unitholders and preferred unitholders will receive. MPLX’s distributions are declared subsequent to quarter end; therefore, the following table represents total cash distributions applicable to the period in which the distributions were earned.

(1)2021 period includes the Supplemental Distribution Amount.

(2)2023 period includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to the redemption.

On January 24, 2024, MPLX declared a quarterly cash distribution, based on the results of the fourth quarter of 2023, totaling $853 million, or $0.8500 per common unit. This rate was also received by Series A preferred unitholders. These distributions were paid on February 14, 2024 to unitholders of record on February 5, 2024.

8. Net Income/(Loss) Per Limited Partner Unit

Net income/(loss) per unit applicable to common limited partner units is computed by dividing net income/(loss) attributable to MPLX LP less income/(loss) allocated to participating securities by the weighted average number of common units outstanding. Classes of participating securities include common units, equity-based compensation awards, Series A preferred units and Series B preferred units.

In 2023, 2022 and 2021, MPLX had dilutive potential common units consisting of certain equity-based compensation awards. Anti-dilutive potential common units omitted from the diluted earnings per unit calculation for the years ended December 31, 2023, 2022 and 2021 were less than 1 million.

(1)The year ended December 31, 2022 includes a $509 million gain on a lease reclassification. See Note 20 for additional information.

(2)The year ended December 31, 2021 includes the Supplemental Distribution Amount.

(1)Includes a $509 million gain on a lease reclassification. See Note 20 for additional information.

(1) Includes the Supplemental Distribution Amount.

9. Series A Preferred Units

Private Placement of Preferred Units

On May 13, 2016, MPLX completed the private placement of approximately 30.8 million 6.5 percent Series A Convertible preferred units for a cash purchase price of $32.50 per unit. The aggregate net proceeds of approximately $984 million from the sale of the Series A preferred units were used for capital expenditures, repayment of debt and general business purposes.

Preferred Unit Distribution Rights

The Series A preferred units rank senior to all common units and pari passu with all Series B preferred units with respect to distributions and rights upon liquidation. The holders of the Series A preferred units are entitled to receive, when and if declared by the board, a quarterly distribution equal to the greater of $0.528125 per unit or the amount of distributions they would have received on an as converted basis, including any supplemental distributions made to common unitholders. On January 24, 2024, MPLX declared a quarterly cash distribution of $0.8500 per common unit for the fourth quarter of 2023. Holders of the Series A preferred units received the common unit rate in lieu of the lower $0.528125 base amount.

The holders may convert their Series A preferred units into common units at any time, in full or in part, subject to minimum conversion amounts and conditions. After the fourth anniversary of the issuance date, MPLX may convert the Series A preferred units into common units at any time, in whole or in part, subject to certain minimum conversion amounts and conditions, if the closing price of MPLX common units is greater than $48.75 for the 20-day trading period immediately preceding the conversion notice date. The conversion rate for the Series A preferred units shall be the quotient of (a) the sum of (i) $32.50, plus (ii) any unpaid cash distributions on the applicable preferred unit, divided by (b) $32.50, subject to adjustment for unit distributions, unit splits and similar transactions. The holders of the Series A preferred units are entitled to vote on an as-converted basis with the common unitholders and have certain other class voting rights with respect to any amendment to the MPLX partnership agreement that would adversely affect any rights, preferences or privileges of the preferred units. In addition, upon certain events involving a change of control, the holders of preferred units may elect, among other potential elections, to convert their Series A preferred units to common units at the then applicable change of control conversion rate.

Preferred Units Outstanding

During the years ended December 31, 2023 and December 31, 2021, certain Series A preferred unitholders exercised their rights to convert their Series A preferred units into 2,281,831 common units and 93,108 common units, respectively. Approximately 27.2 million Series A preferred units remain outstanding as of December 31, 2023.

Financial Statement Presentation

The Series A preferred units are considered redeemable securities under GAAP due to the existence of redemption provisions upon a deemed liquidation event, which is outside MPLX’s control. Therefore, they are presented as temporary equity in the mezzanine section of the Consolidated Balance Sheets. The Series A preferred units have been recorded at their issuance date fair value, net of issuance costs. Income allocations increase the carrying value and declared distributions decrease the carrying value of the Series A preferred units. As the Series A preferred units are not currently redeemable and not probable of becoming redeemable, adjustment to the initial carrying amount is not necessary and would only be required if it becomes probable that the Series A preferred units would become redeemable.

For a summary of changes in the redeemable preferred balance for the years ended December 31, 2023, 2022 and 2021, see the Consolidated Statements of Equity.

10. Segment Information

MPLX’s chief operating decision maker (“CODM”) is the chief executive officer of its general partner. The CODM reviews MPLX’s discrete financial information, makes operating decisions, assesses financial performance and allocates resources on a type of service basis. MPLX hastwo reportable segments: L&S and G&P. Each of these segments is organized and managed based upon the nature of the products and services it offers.

•L&S – gathers, transports, stores and distributes crude oil, refined products, other hydrocarbon-based products and renewables. Also includes the operation of refining logistics, fuels distribution and inland marine businesses, terminals, rail facilities and storage caverns.

•G&P – gathers, processes and transports natural gas; and transports, fractionates, stores and markets NGLs.

Our CODM evaluates the performance of our segments using Segment Adjusted EBITDA. Amounts included in net income and excluded from Segment Adjusted EBITDA include: (i) depreciation and amortization; (ii) interest and other financial costs; (iii) income/(loss) from equity method investments; (iv) distributions and adjustments related to equity method investments; (v) gain on sales-type leases and equity method investments; (vi) impairment expense; (vii) noncontrolling interests; and (viii) other adjustments as applicable. These items are either: (i) believed to be non-recurring in nature; (ii) not believed to be allocable or controlled by the segment; or (iii) are not tied to the operational performance of the segment. Assets by segment are not a measure used to assess the performance of the Partnership by our CODM and thus are not reported in our disclosures.

The tables below present information about revenues and other income, Segment Adjusted EBITDA, capital expenditures and investments in unconsolidated affiliates for our reportable segments:

(1)Within the total segment revenues and other income amounts presented above, third party revenues for the L&S segment were $776 million, $644 million and $503 million for the years ended December 31, 2023, 2022 and 2021, respectively. Third party revenues for the G&P segment were $4,827 million, $5,678 million and $4,463 million for the years ended December 31, 2023, 2022 and 2021, respectively.

(2)See below for the reconciliation from Segment Adjusted EBITDA to Net income.

(3)Includes a $92 million gain on remeasurement of our existing equity investment in Torñado in conjunction with the purchase of the remaining joint venture interest in 2023. Includes a $509 million gain on a lease reclassification for the year ended December 31, 2022. See Note 20 in the Consolidated Financial Statements for additional information.

The table below provides a reconciliation between Net income and Segment Adjusted EBITDA.

(1)Depreciation and amortization attributable to L&S was $530 million, $515 million and $546 million for the years ended December 31, 2023, 2022 and 2021, respectively. Depreciation and amortization attributable to G&P was $683 million, $715 million and $741 million for the years ended December 31, 2023, 2022 and 2021, respectively.

(2)In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $16 million of incident response costs, net of insurance recoveries, during the year ended December 31, 2023.

(3)Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.

11. Major Customers and Concentration of Credit Risk

The table below shows, by segment, the percentage of total revenues and other income with MPC which is our most significant customer and our largest concentration of credit risk.

(1)The percent calculations for the year ended December 31, 2023 exclude a $92 million gain associated with the remeasurement of its existing equity investment in Torñado. The percent calculations for the year ended December 31, 2022 exclude a $509 million gain on a lease reclassification.

Revenue from the sale of products purchased after services are provided is reported as Product sales on the Consolidated Statements of Income and recognized on a gross basis, as MPLX takes control of the product and is the principal in the transaction. For the year ended December 31, 2023, revenues with one customer primarily related to these NGL transactions accounted for approximately 10 percent of our total revenues and other income for the year ended December 31, 2023.

MPLX has a concentration of trade receivables due from customers in the same industry: MPC, integrated oil companies, natural gas exploration and production companies, independent refining companies and other pipeline companies. These concentrations of customers may impact MPLX’s overall exposure to credit risk as they may be similarly affected by changes in economic, regulatory and other factors. MPLX manages its exposure to credit risk through credit analysis, credit limit approvals and monitoring procedures; and for certain transactions, it may request letters of credit, prepayments or guarantees.

12. Inventories

Inventories consist of the following:

13. Property, Plant and Equipment

Property, plant and equipment with associated accumulated depreciation is shown below:

We capitalize interest as part of the cost of major projects during the construction period. Capitalized interest totaled $15 million, $9 million and $14 million as of the years ended December 31, 2023, 2022 and 2021, respectively.

In the second quarter of 2021, we recognized impairment expense of $42 million within our G&P segment related to our continued emphasis on portfolio optimization with the divestiture of several non-core assets and the closure of other non-core assets.

14. Goodwill and Intangibles

Goodwill

MPLX annually evaluates goodwill for impairment as of November 30, as well as whenever events or changes in circumstances indicate it is more likely than not that the fair value of a reporting unit with goodwill is less than its carrying amount.

Our reporting units are one level below our operating segments and are determined based on the way in which segment management operates and reviews each operating segment. We have five reporting units, three of which have goodwill allocated to them. For the annual impairment assessment as of November 30, 2023, management performed only a qualitative assessment for two reporting units as we determined it was more likely than not that the fair values of the reporting units exceeded their carrying values. The fair value of the crude gathering reporting unit for which a quantitative assessment was performed was determined based on applying both a discounted cash flow, or income approach, as well as a market approach which resulted in the fair value of the reporting unit exceeding its carrying value by greater than 10 percent. The significant assumptions used to develop the estimate of the fair value under the discounted cash flow method included management’s best estimates of the discount rate of 10.2 percent as well as estimates of future cash flows, which are impacted primarily by producer customers’ development plans, which impact future volumes and capital requirements. Fair value determinations require considerable judgment and are sensitive to changes in underlying assumptions and factors. As a result, there can be no assurance that the estimates and assumptions made for purposes of the annual goodwill impairment test will prove to be an accurate prediction of the future. The fair value measurements for the individual reporting units represent Level 3 measurements. Total goodwill at December 31, 2023 was $7,645 million andno impairment was recorded as a result of our November 30, 2023 annual goodwill impairment analysis.

The changes in carrying amount of goodwill were as follows for the periods presented:

Intangible Assets

MPLX’s intangible assets are comprised of customer contracts and relationships. Gross intangible assets with accumulated amortization as of December 31, 2023 and 2022 is shown below:

(1)Amortization expense attributable to the L&S segment for both years ended December 31, 2023 and 2022 was $36 million. Amortization expense attributable to the G&P segment for the years ended December 31, 2023 and 2022 was $92 million and $90 million, respectively.

Estimated future amortization expense related to the intangible assets at December 31, 2023 is as follows:

15. Fair Value Measurements

Fair Values – Recurring

The following table presents the impact on the Consolidated Balance Sheets of MPLX’s financial instruments carried at fair value on a recurring basis as of December 31, 2023 and 2022 by fair value hierarchy level.

Level 2 instruments include over-the-counter fixed swaps to mitigate the price risk from our sales of propane. The swap valuations are based on observable inputs in the form of forward prices based on Mont Belvieu propane forward spot prices and contain no significant unobservable inputs. All of our Level 2 instruments were settled during 2023. There were no positions outstanding as of December 31, 2023.

Level 3 instruments relate to an embedded derivative liability for a natural gas purchase commitment embedded in a keep-whole processing agreement. The fair value calculation for these Level 3 instruments used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.61 to $1.44 per gallon with a weighted average of $0.76 per gallon and (2) a 100 percent probability of renewal for thefive-year renewal term of the gas purchase commitment and related keep-whole processing agreement. Increases or decreases in the fractionation spread result in an increase or decrease in the fair value of the embedded derivative liability, respectively.

Changes in Level 3 Fair Value Measurements

The following table is a reconciliation of the net beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy.

(1)(Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs on the Consolidated Statements of Income.

Fair Values – Non-recurring

Non-recurring fair value measurements and disclosures in 2023 relate primarily to the acquisition of the remaining interest in Torñado as discussed in Note 4.

Non-recurring fair value measurements and disclosures in 2022 and 2021 relate primarily to MPLX’s sales-type leases as discussed in Note 20. The net investment in sales-type leases is recorded at the estimated fair value of the underlying leased assets at contract modification date. The leased assets were valued using a cost method valuation approach which utilizes Level 3 inputs.

Fair Values – Reported

We believe the carrying value of our other financial instruments, including cash and cash equivalents, receivables, receivables from related parties, lease receivables, lease receivables from related parties, accounts payable, and payables to related parties, approximate fair value. MPLX’s fair value assessment incorporates a variety of considerations, including the duration of the instruments, MPC’s investment-grade credit rating and the historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk. The recorded value of the amounts outstanding under the bank revolving credit facility, if any, approximates fair value due to the variable interest rate that approximates current market rates. Derivative instruments are recorded at fair value, based on available market information (see Note 16).

The fair value of MPLX’s debt is estimated based on prices from recent trade activity and is categorized in Level 3 of the fair value hierarchy. The following table summarizes the fair value and carrying value of our third-party debt, excluding finance leases and unamortized debt issuance costs:

(1)Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties on the Consolidated Balance Sheets.

16. Derivative Financial Instruments

During the year ended December 31, 2023, MPLX entered into commodity contracts that were executed to manage price risk during 2023. All of those positions were settled during 2023, with the associated gains included in the table below. As of December 31, 2023, MPLX hadno outstanding commodity contracts beyond the embedded derivative discussed below.

Embedded Derivative - MPLX has a natural gas purchase commitment embedded in a keep-whole processing agreement with a producer customer in the Southern Appalachian region expiring in December 2027. The customer has the unilateral option to extend the agreement forone five-year term through December 2032. For accounting purposes, the natural gas purchase commitment and the term extending option have been aggregated into a single compound embedded derivative. The probability of the customer exercising its option is determined based on assumptions about the customer’s potential business strategy decision points that may exist at the time they would elect whether to renew the contract. The changes in fair value of this compound embedded derivative are based on the difference between the contractual and index pricing, the probability of the producer customer exercising its option to extend, and the estimated favorability of these contracts compared to current market conditions. The changes in fair value are recorded in earnings through Purchased product costs in the Consolidated Statements of Income. For further information regarding the fair value measurement of derivative instruments, see Note 15. See Note 2 for a discussion of derivatives MPLX may use and the reasons for them. As of both December 31, 2023 and 2022, the estimated fair value of this contract was a liability of $61 million.

As of December 31, 2023 and 2022, there were no derivative assets or liabilities that were offset on the Consolidated Balance Sheets.

The impact of MPLX’s derivative contracts not designated as hedging instruments and the location of gains and losses recognized in the Consolidated Statements of Income is summarized below:

17. Debt

MPLX’s outstanding borrowings at December 31, 2023 and 2022 consisted of the following:

(1)See Note 20 for lease information.

The following table shows five years of scheduled debt payments, including payments on finance lease obligations, as of December 31, 2023:

Credit Agreements

MPLX Credit Agreement

MPLX’s credit agreement (the “MPLX Credit Agreement”) matures July 7, 2027 and, among other things, provides for a $2 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 billion borrowing capacity. The financial covenants of the MPLX Credit Agreement are substantially the same as those contained in the previous credit agreement. Borrowings under the new 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, 2023, MPLX was in compliance with the covenants contained in the MPLX Credit Agreement.

Activity on the MPLX Credit Agreement was as follows:

Senior Notes

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

On February 9, 2023, MPLX issued $1.6 billion aggregate principal amount of notes, consisting of $1.1 billion principal amount of 5.00 percent senior notes due 2033 (the “2033 Senior Notes”) and $500 million principal amount of 5.65 percent senior notes due 2053 (the “2053 Senior Notes”). The 2033 Senior Notes were offered at a price to the public of 99.170 percent of par with interest payable semi-annually in arrears, commencing on September 1, 2023. The 2053 Senior Notes were offered at a price to the public of 99.536 percent of par with interest payable semi-annually in arrears, commencing on September 1, 2023.

On February 15, 2023, MPLX used $600 million of the net proceeds from the offering of the 2033 Senior Notes and 2053 Senior Notes described above to redeem all of the outstanding Series B preferred units. On March 13, 2023, MPLX used the remaining proceeds from the offering, and cash on hand, to redeem all of MPLX’s and MarkWest’s $1.0 billion aggregate principal amount of 4.50 percent senior notes due July 2023, at par, plus accrued and unpaid interest. The redemption resulted in a loss of $9 million due to the immediate expense recognition of unamortized debt discount and issuance costs, which is included on the Consolidated Statements of Income as Other financial costs, net.

On March 14, 2022, MPLX issued $1.5 billion aggregate principal amount of 4.950 percent senior notes in a public offering due March 2052 (the “2052 Senior Notes”). The 2052 Senior Notes were offered at a price to the public of 98.982 percent of par with interest payable semi-annually in arrears, commencing on September 14, 2022. The net proceeds were used to repay amounts outstanding under the MPC Intercompany Loan Agreement and the MPLX Credit Agreement as well as for general partnership purposes.

On August 11, 2022, MPLX issued $1.0 billion aggregate principal amount of 4.950 percent senior notes due September 2032 (the “2032 Senior Notes”) in an underwritten public offering. The 2032 Senior Notes were offered at a price to the public of 99.433 percent of par with interest payable semi-annually in arrears, commencing on March 1, 2023. The net proceeds were used to redeem all of the 3.500 percent senior notes due December 2022 and all of the 3.375 percent senior notes due March 2023, as discussed below.

On August 25, 2022, MPLX redeemed all of the $500 million 3.500 percent senior notes due December 2022, $14 million of which was issued by Andeavor Logistics LP, at 100.101 percent of the aggregate principal amount, plus accrued and unpaid interest to, but not including the redemption date. On September 15, 2022, MPLX redeemed all of the $500 million 3.375 percent senior notes due March 2023 at 100 percent of the aggregate principal amount. The impact of these debt extinguishments was not material to the Consolidated Statements of Income.

On January 15, 2021, MPLX redeemed all of the $750 million outstanding aggregate principal amount of 5.250 percent senior notes, due January 15, 2025, including approximately $42 million aggregate principal amount of senior notes issued by ANDX, at a price equal to 102.625 percent of the principal amount. The payment of $20 million related to the note premium, offset by the immediate expense recognition of $12 million of unamortized debt premium and issuance costs, resulted in a loss on extinguishment of debt of $8 million that is included on the Consolidated Statements of Income as Other financial costs, net.

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

18. Revenue

Disaggregation of Revenue

The following tables represent a disaggregation of revenue for each reportable segment for the years ended December 31, 2023, 2022 and 2021:

(1)Non-ASC 606 Revenue includes rental income, sales-type lease revenue, income from equity method investments, and other income.

Contract Balances

Our receivables are primarily associated with customer contracts. Payment terms vary by product or service type; however, the period between invoicing and payment is not significant. Included within the receivables are balances related to commodity sales on behalf of our producer customers, for which we remit the net sales price back to the producer customers upon completion of the sale.

Under certain of our contracts, we recognize revenues in excess of billings which we present as contract assets. Contract assets typically relate to deficiency payments related to minimum volume commitments and aid in construction agreements where the revenue recognized and MPLX’s rights to consideration for work completed exceeds the amount billed to the customer. Contract assets are included in Other current assets and Other noncurrent assets on the Consolidated Balance Sheets.

Under certain of our contracts, we receive payments in advance of satisfying our performance obligations, which are recorded as contract liabilities. Contract liabilities, which we present as Deferred revenue and Long-term deferred revenue, typically relate to advance payments for aid in construction agreements and deferred customer credits associated with makeup rights and minimum volume commitments. Related to minimum volume commitments, breakage is estimated and recognized into service revenue in instances where it is probable the customer will not use the credit in future periods. We classify contract liabilities as current or long-term based on the timing of when we expect to recognize revenue.

The tables below reflect the changes in ASC 606 contract balances for the years ended December 31, 2023 and 2022:

(1)No significant revenue was recognized related to past performance obligations in the current periods.

Remaining Performance Obligations

The table below includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied) as of December 31, 2023. The amounts presented below are generally limited to fixed consideration from contracts with customers that contain minimum volume commitments.

A significant portion of our future contracted revenue is excluded from the amounts presented below in accordance with ASC 606. Variable consideration that is constrained or not required to be estimated as it reflects our efforts to perform is excluded from this disclosure. Additionally, we do not disclose information on the future performance obligations for any contract with an original expected duration of one year or less, or that are terminable by our customer with little or no termination penalties. Potential future performance obligations related to renewals that have not yet been exercised or are not certain of exercise are excluded from the amounts presented below. Revenues classified as Rental income and Sales-type lease revenue are also excluded from this table.

As of December 31, 2023, unsatisfied performance obligations included in the Consolidated Balance Sheets are $479 million and will be recognized as revenue as the obligations are satisfied, which is expected to occur over the next 20 years. A portion of this amount is not disclosed in the table above as it is deemed variable consideration due to volume variability.

19. Supplemental Cash Flow Information

(1)Represents the book value of MPLX’s equity method investment in Torñado prior to MPLX buying out the remaining interest in this entity. See Note 4 for additional information.

The Consolidated Statements of Cash Flows exclude changes to the Consolidated Balance Sheets that did not affect cash. The following is a reconciliation of additions to property, plant and equipment to total capital expenditure:

20. Leases

Lessee

We lease a wide variety of facilities and equipment under leases from third parties, including land and building space, office and field equipment, storage facilities and transportation equipment, while our related party leases primarily relate to ground leases associated with our refining logistics assets. Our remaining lease terms range from less thanone year to 95 years. Some long-term leases include renewal options ranging fromone to 50 years and, in certain leases, also include purchase options. Renewal options and termination options were not included in the measurement of ROU assets and lease liabilities since it was determined they were not reasonably certain to be exercised.

The components of lease cost were as follows:

Supplemental balance sheet data related to leases were as follows:

As of December 31, 2023, maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows:

Lessor

Certain fee-based transportation and storage services agreements with MPC and third parties and certain fee-based natural gas transportation and processing agreements with third parties are accounted for as operating leases under ASC 842. The transportation and storage agreements have remaining terms ranging from less thanone year tonine years with renewal options ranging fromone year tofive years, with some agreements having multiple renewal options. The primary terms of the natural gas transportation and processing agreements expire between 2026 and 2036, however, these contracts either have renewal options or will continue thereafter on a year-to-year basis until terminated by either party.

During the third quarter of 2022, the approved expansion of a gathering and compression system triggered the first assessment of the related third-party agreement under ASC 842. Additionally, during the years ended December 31, 2022 and 2021, we executed amendments to certain related party storage, transportation and terminal service agreements between MPLX and MPC to provide for reimbursements for projects, changes to minimum volume commitments or to extend the term of the agreement. The changes required the embedded leases within these agreements to be reassessed under ASC 842. As a result of these lease assessments, certain leases were reclassified from an operating lease to a sales-type lease. Accordingly, the underlying property, plant and equipment, net, and associated deferred revenue, if any, were derecognized and the present value of the future lease payments and the unguaranteed residual value of the assets were recorded as a net investment in sales-type lease during the respective periods.

Lease revenues included on the Consolidated Statements of Income during 2023, 2022 and 2021 were as follows:

MPLX did not elect to use the practical expedient to combine lease and non-lease components for lessor arrangements. The tables below represent the portion of the contract allocated to the lease component based on relative standalone selling price. We elected the practical expedient to carry forward historical classification conclusions until a modification of an existing agreement occurs. Once a modification occurs, the amended agreement is required to be assessed under ASC 842, to determine whether a reclassification of the lease is required.

The following presents the consolidated financial statement impact of related-party and third-party sales-type leases, on commencement or modification date. These transactions, including any related gains recognized in the Consolidated Statements of Income, were non-cash transactions. There were no amounts to report for the year ended December 31, 2023.

(1)The amount recognized on commencement date was recorded as a Contribution from MPC in the Consolidated Statements of Equity given the underlying agreements are between entities under common control.

(2)The amount recognized on commencement date was recorded as a gain in Other income in the Consolidated Statements of Income.

The following is a schedule of minimum future rental payments on the non-cancellable operating leases as of December 31, 2023:

Annual minimum undiscounted lease payment receipts under our sales-type leases were as follows as of December 31, 2023:

(1)This amount does not include the unguaranteed residual assets.

(2)The related-party balance is presented in Current assets - related parties and the third-party balance is presented in Receivables, net in the Consolidated Balance Sheets.

(3)The related-party balance is presented in Noncurrent assets - related parties and the third-party balance is presented in Other noncurrent assets in the Consolidated Balance Sheets.

The following schedule summarizes MPLX’s investment in assets held under operating lease by major classes as of December 31, 2023 and 2022:

Capital expenditures related to assets subject to sales-type lease arrangements were $85 million, $72 million and $48 million for the years ended December 31, 2023, 2022 and 2021, respectively. These amounts are reflected as Additions to property, plant and equipment in the Consolidated Statements of Cash Flows.

21. Commitments and Contingencies

MPLX is the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Some of these matters are discussed below. For matters for which MPLX has not recorded a liability, MPLX is unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material.

Environmental Matters

MPLX is subject to federal, state and local laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites. Penalties may be imposed for non-compliance.

At December 31, 2023 and 2022, accrued liabilities for remediation totaled $19 million and $17 million, respectively. It is not presently possible to estimate the ultimate amount of all remediation costs that might be incurred or the penalties, if any, that may be imposed.

MPLX is involved in environmental enforcement matters arising in the ordinary course of business. While the outcome and impact to MPLX cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on its consolidated results of operations, financial position or cash flows.

Other Legal Proceedings

In July 2020, Tesoro High Plains Pipeline Company, LLC (“THPP”), a subsidiary of MPLX, received a Notification of Trespass Determination from the Bureau of Indian Affairs (“BIA”) relating to a portion of the Tesoro High Plains Pipeline that crosses the Fort Berthold Reservation in North Dakota. The notification demanded the immediate cessation of pipeline operations and assessed trespass damages of approximately $187 million. After subsequent appeal proceedings and in compliance with a new order issued by the BIA, in December 2020, THPP paid approximately $4 million in assessed trespass damages and ceased use of the portion of the pipeline that crosses the property at issue. In March 2021, the BIA issued an order purporting to vacate the BIA's prior orders related to THPP’s alleged trespass and direct the Regional Director of the BIA to reconsider the issue of THPP’s alleged trespass and issue a new order. In April 2021, THPP filed a lawsuit in the District of North Dakota against the United States of America, the U.S. Department of the Interior and the BIA (collectively, the “U.S. Government Parties”) challenging the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. On February 8, 2022, the U.S. Government Parties filed their answer and counterclaims to THPP’s suit claiming THPP is in continued trespass with respect to the pipeline and seeking disgorgement of pipeline profits from June 1, 2013 to present, removal of the pipeline and remediation. On November 8, 2023, the Court granted THPP’s motion to sever and stay the U.S. Government Parties’ counterclaims. The case will proceed on the merits of THPP’s challenge to the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. THPP continues not to operate that portion of the pipeline that crosses the property at issue.

MPLX is also a party to a number of other lawsuits and other proceedings arising in the ordinary course of business. While the ultimate outcome and impact to MPLX cannot be predicted with certainty, management believes the resolution of these other lawsuits and proceedings will not, individually or collectively, have a material adverse effect on its consolidated financial position, results of operations or cash flows.

Guarantees

Over the years, MPLX has sold various assets in the normal course of its business. Certain of the related agreements contain performance and general guarantees, including guarantees regarding inaccuracies in representations, warranties, covenants and agreements, and environmental and general indemnifications that require MPLX to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications are part of the normal course of selling assets. MPLX is typically not able to calculate the maximum potential amount of future payments that could be made under such contractual provisions because of the variability inherent in the guarantees and indemnities. Most often, the nature of the guarantees and indemnities is such that there is no appropriate method for quantifying the exposure because the underlying triggering event has little or no past experience upon which a reasonable prediction of the outcome can be based.

We hold a 9.19 percent indirect interest in Dakota Access, which owns and operates the Bakken Pipeline system. In 2020, the U.S. District Court for the District of Columbia (the “D.D.C.”) ordered the United States Army Corps of Engineers (“Army Corps”), which granted permits and an easement for the Bakken Pipeline system, to prepare an environmental impact statement (“EIS”) relating to an easement under Lake Oahe in North Dakota. The D.D.C. later vacated the easement. The Army Corps issued a draft EIS in September 2023 detailing various options for the easement, including denying the easement, approving the easement with additional measures, rerouting the easement, or approving the easement with no changes. The Army Corps has not selected a preferred alternative, but will make a decision in its final review, after considering input from the public and other agencies. The pipeline remains operational while the Army Corps finalizes its decision which is expected to be issued by the end of 2024.

We have entered into a Contingent Equity Contribution Agreement whereby MPLX LP, along with the other joint venture owners in the Bakken Pipeline system, has agreed to make equity contributions to the joint venture upon certain events occurring to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. The senior notes were issued to repay amounts owed by the pipeline companies to fund the cost of construction of the Bakken Pipeline system.

If the vacation of the easement results in a temporary shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of funds required to pay interest accruing on the notes and any portion of the principal that matures while the pipeline is shutdown. MPLX also expects to contribute its 9.19 percent pro rata share of any costs to remediate any deficiencies to reinstate the easement and/or return the pipeline into operation. If the vacation of the easement results in a permanent shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of the cost to redeem the bonds (including the one percent redemption premium required pursuant to the indenture governing the notes) and any accrued and unpaid interest. As of December 31, 2023, our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement were approximately $170 million.

Contractual Commitments and Contingencies

At December 31, 2023, MPLX’s contractual commitments to acquire property, plant and equipment totaled $136 million. In addition, from time to time and in the ordinary course of business, MPLX and its affiliates provide guarantees of MPLX’s subsidiaries payment and performance obligations in the G&P segment. Certain natural gas processing and gathering arrangements require MPLX to construct new natural gas processing plants, natural gas gathering pipelines and NGL pipelines and contain certain fees and charges if specified construction milestones are not achieved for reasons other than force majeure. In certain cases, certain producers may have the right to cancel the processing arrangements if there are significant delays that are not due to force majeure. As of December 31, 2023, management does not believe there are any indications that MPLX will not be able to meet the construction milestones, that force majeure does not apply or that such fees and charges will otherwise be triggered.

Other Contractual Obligations

MPLX executed various third-party transportation, terminalling, and gathering and processing agreements that obligate us to minimum volume, throughput or payment commitments over the remaining terms, which range from less thanone year toeight years. After the minimum volume commitments are met in these agreements, MPLX pays additional amounts based on throughput. These agreements may include escalation clauses based on various inflationary indices; however, those potential increases have not been incorporated in minimum fees due under these agreements presented below. The minimum future payments under these agreements as of December 31, 2023 are as follows: