DT Midstream, Inc.

NOTE 1 —DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION

Description of the Business

DT Midstream is an owner, operator, and developer of an integrated portfolio of natural gas midstream assets. We provide multiple, integrated natural gas services to customers throughtwo segments: (i) Pipeline, which includes interstate pipelines, intrastate pipelines, storage systems, gathering lateral pipelines and compression and surface facilities, and (ii) Gathering, which includes gathering systems, related treatment plants, and compression and surface facilities. Our Pipeline segment also includes joint venture interests in equity method investees which own and operate interstate pipelines that connect to our wholly owned assets.

Our core assets strategically connect key demand centers in the Midwestern U.S., Eastern Canada and Northeastern U.S. regions to the premium production areas of the Marcellus/Utica natural gas formation in the Appalachian Basin, and connect key demand centers and LNG export terminals in the Gulf Coast region to premium production areas of the Haynesville natural gas formation.

Basis of Presentation

The Consolidated Financial Statements and Notes to Consolidated Financial Statements are prepared under GAAP.

These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from our estimates. We believe the assumptions underlying these financial statements are reasonable.

In our opinion, the accompanying unaudited Consolidated Financial Statements include all adjustments, consisting of normal recurring adjustments, necessary to present a fair statement of our financial position as of March 31, 2026, results of operations for the three months ended March 31, 2026 and 2025, statement of changes in stockholders' equity for the three months ended March 31, 2026 and 2025, and cash flows for the three months ended March 31, 2026 and 2025. The Consolidated Statement of Financial Position as of December 31, 2025 was derived from audited annual financial statements but does not include all disclosures required by GAAP. Financial results for this interim period are not necessarily indicative of results that may be expected for any other interim period or for the year ending December 31, 2026. The Consolidated Financial Statements should be read in conjunction with DT Midstream's Consolidated Financial Statements and Notes to Consolidated Financial Statements included in DT Midstream's 2025 Annual Report on Form 10-K.

Cash Management

Our sources of liquidity include cash generated from operations and available borrowings under our Revolving Credit Facility.

Principles of Consolidation

We consolidate all majority-owned subsidiaries and investments in entities in which we have a controlling influence. Non-controlled investments are accounted for using the equity method of accounting when we are able to significantly influence the operating policies of the investee. When we do not influence the operating policies of an investee, the equity investment is measured at fair value, if readily determinable, or if not readily determinable, at cost less impairment, if applicable. We eliminate all intercompany balances and transactions.

We evaluate whether an entity is a VIE whenever reconsideration events occur. We consolidate VIEs for which we are the primary beneficiary. When assessing the determination of the primary beneficiary, we consider all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. We perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.

We own an 85% interest in the Stonewall VIE and are the primary beneficiary, therefore Stonewall is consolidated. We own a 50% interest in the South Romeo VIE and are the primary beneficiary, therefore South Romeo is consolidated.

The following table summarizes the major line items in the Consolidated Statements of Financial Position for consolidated VIEs as of March 31, 2026 and December 31, 2025. All assets and liabilities of a consolidated VIE are included in the table when it has been determined that a consolidated VIE has either (1) assets that can be used only to settle obligations of the VIE or (2) liabilities for which creditors do not have recourse to the general credit of the primary beneficiary. The assets and liabilities of consolidated VIEs that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIEs' obligations have been excluded from the table below.

(a)Amounts shown are 100% of the consolidated VIEs' assets and liabilities.

Related Parties

Transactions between DT Midstream and our equity method investees have been presented as related party transactions in the accompanying Consolidated Financial Statements.

Equity Method Investments

Non-controlled investments are accounted for using the equity method of accounting when we are able to significantly influence the operating policies of the investee. Under the equity method of accounting, investments are recorded at historical cost as an asset and adjusted for capital contributions, dividends and distributions received, and our share of the investee's earnings or losses, which are recorded as earnings from equity method investees on the Consolidated Statements of Operations. Equity method investments and related activity are included in the Pipeline segment.

Our equity method investments are periodically evaluated for certain factors that may be indicative of other-than-temporary impairment. As of March 31, 2026 and December 31, 2025, our carrying amounts of investments in equity method investees exceeded our share of the underlying equity in the net assets of the investees by $316 million and $320 million, respectively. The difference will be amortized over the life of the underlying assets. As of both March 31, 2026 and December 31, 2025, our consolidated retained earnings balance did not have undistributed earnings from equity method investments. We use the cumulative earnings approach to classify proceeds received from equity method investees as dividends or distributions on the Consolidated Statements of Cash Flows.

Earnings from equity method investees include:

Equity method investees are described below:

The following table presents summarized financial information of our non-consolidated equity method investees. The amounts included below represent 100% of the results of continuing operations of such entities, including the portion owned by other parties.

Summarized income statement data is as follows:

NOTE 2 —SIGNIFICANT ACCOUNTING POLICIES

Cash and Cash Equivalents

Cash and cash equivalents include cash in banks and highly liquid money market investments with remaining maturities of three months or less, when purchased. Cash equivalents are stated at cost, which approximates fair value.

Financing Receivables

Financing receivables are primarily composed of trade accounts receivable and notes receivable, which are stated at net realizable value.

We regularly monitor the credit quality of our financing receivables by reviewing counterparty credit quality indicators and monitoring for triggering events, such as a credit rating downgrade or bankruptcy. We have three internal grades of credit quality, with internal grade 1 as the lowest risk and internal grade 3 as the highest risk. The related credit quality indicators and risk ratings utilized to develop the internal grades have been updated through March 31, 2026. As of March 31, 2026, the notes receivable — related party of $4 million, which originated prior to 2021, were classified as internal grade 1. There are no notes receivable on nonaccrual status andno past due financing receivables as of March 31, 2026.

For trade accounts receivable, the customer allowance for expected credit loss is calculated based on specific review of future collections based on receivable balances generally in excess of 30 days. Existing and future economic conditions, historical loss rates, customer trends and other relevant factors that may affect our ability to collect are also considered. Receivables are written off on a specific identification basis and determined based on the particular circumstances of the associated receivable. Uncollectible expense (recovery) waszero for each of the years ended March 31, 2026 and 2025.

Our collections on accounts receivable from customers are current, and no material rate of historical loss was noted, which resulted inno allowance for expected credit loss as of March 31, 2026 or December 31, 2025. Any balance would be shown as a deduction from the respective financing receivable's balance in the Consolidated Statements of Financial Position.

Property, Plant, and Equipment

Property is stated at cost and includes construction-related labor, materials, overhead and capitalized interest. Property for FERC-regulated entities includes debt and equity AFUDC. Debt AFUDC represents capitalized interest. Equity AFUDC represents the capitalization of the estimated average cost of equity during construction projects and is recorded as a credit to allowance for funds used during construction in our Consolidated Statements of Operations. Expenditures for maintenance and repairs are charged to expense when incurred. Property, plant and equipment is depreciated over its estimated useful life using the straight-line method.

Certain regulated properties are accounted for under ASC 980, which in some cases requires that the cost of regulated property retired or sold, plus removal costs, less salvage, be charged to accumulated depreciation. For regulated property, depreciation studies to assess the estimated useful lives of the asset are typically conducted as part of rate proceedings or tariff filings. Changes in economic lives, if applicable, are implemented prospectively as of the approved effective date. Our regulated properties are depreciated using the straight-line method based on composite depreciation rates applied to functional groups of properties with similar economic lives.

Intangible Assets

Intangible assets with finite useful lives are amortized on a straight-line basis over the periods benefited.

Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected undiscounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.

Goodwill

DT Midstream has goodwill resulting from business combinations. For each reporting unit with goodwill, we perform an impairment test annually or whenever events or circumstances indicate that the value of goodwill may be impaired.

Operation and Maintenance

Operation and maintenance is primarily comprised of costs for labor and employee benefits, outside services, materials, compression, purchased natural gas, operating lease costs, office costs, and other operating and maintenance costs.

Depreciation and Amortization

Depreciation, depletion and amortization is related to property, plant and equipment and other intangible assets, net, used in our pipeline and gathering businesses.

Lessor Accounting

A lease exists when we have provided other parties with the right to control the use of identified property, plant or equipment, as conveyed through a contract, for a certain time period and consideration received. The right to control is deemed to occur when we have provided other parties with the right to obtain substantially all of the economic benefits of the identified assets and the right to direct the use of such assets. All of our leases are classified as operating leases. Lease income is recognized on a straight-line, ratable basis over the fixed, non-cancelable term of the relevant contract. Lease income is reported in Operating revenues in our Consolidated Statements of Operations.

Other Significant Accounting Policies

There have been no changes to the summary of other significant accounting policies previously identified in the Company's Annual Report on Form 10-K for the year ended December 31, 2025.

NOTE 3 —NEW ACCOUNTING PRONOUNCEMENTS

Recently Issued Pronouncements

In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The amendments require enhanced disclosures of specified costs and expenses included in significant expense captions in the income statement, including purchases of inventory, employee compensation, depreciation, amortization, and other key amounts. The FASB subsequently issued ASU No. 2025-01 in January 2025 to clarify the effective date of ASU No. 2024-03. The amendments are effective for annual reporting periods beginning after December 15, 2026 and interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of this standard's adoption on our Consolidated Financial Statements.

In September 2025, the FASB issued ASU No. 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. The amendments modernize the guidance by replacing the stage-based capitalization model with a “probable-to-complete” threshold, aligning impairment testing with the long-lived asset model under ASC 360, and requiring enhanced disclosures for significant internal-use software projects. The amendments are effective for annual reporting periods beginning after December 15, 2027, and interim reporting periods within those annual periods. Early adoption is permitted. The Company is currently evaluating the impact of this standard's adoption on our Consolidated Financial Statements.

In September 2025, the FASB issued ASU No. 2025-07, Derivatives and Hedging (Topic 815) and Revenue from Contracts with Customers (Topic 606): Derivatives Scope Refinements and Scope Clarification for Share-Based Noncash Consideration from a Customer in a Revenue Contract. The amendments provide a scope exception from derivative accounting for certain non-exchange traded contracts with underlyings based on operations or activities specific to one of the parties to the contract and clarify the application of revenue recognition guidance when entities receive share-based noncash consideration from customers in exchange for goods or services. The amendments are effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods within those annual reporting periods. Early adoption is permitted. The Company is currently evaluating the impact of this standard's adoption on our Consolidated Financial Statements, however, the adoption of this standard is not expected to have a significant impact on our Consolidated Financial Statements.

In December 2025, the FASB issued ASU No. 2025‑11, Interim Reporting (Topic 270): Narrow‑Scope Improvements. The amendments clarify the types of interim financial statements subject to ASC 270, reorganize interim disclosure requirements by consolidating cross‑Topic disclosures into a single framework, and introduce a disclosure principle requiring entities to describe material events occurring after the most recent annual reporting period. The amendments are effective for interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of this standard's adoption on our interim financial reporting and interim disclosures.

NOTE 4 —REVENUE

Disaggregation of Revenue

The following is a summary of revenues disaggregated by segment:

(a) Includes revenues outside the scope of ASC 606 primarily related to contracts accounted for as leases of $19 million and $21 million for the three months ended March 31, 2026 and 2025, respectively.

Nature of Services

We primarily provide two types of revenue services: firm service and interruptible service.

Firm service revenue contracts provide for fixed revenue commitments regardless of actual volumes of natural gas that flow, which leads to more stable operating performance, revenues and cash flows and limits our exposure to natural gas price fluctuations. Firm service revenue contracts are typically long-term and structured using fixed demand charges or MVCs with fixed deficiency fee rates. Contracts structured using fixed demand charges contain a performance obligation of a stand-ready series of distinct services that are substantially the same with the same pattern of transfer to the customer, therefore revenue is recognized ratably over time. Contracts structured using MVCs with fixed deficiency fee rates require customers to transport or store a minimum volume of natural gas over a specified time period. If a customer fails to meet its MVCs for the specified time period, the contract consideration includes a fixed rate for the actual volumes gathered, transported or stored, and a deficiency fee for the shortfall between the MVCs and the actual volumes gathered, transported, or stored. If a customer exceeds its MVC for the specified time period, the contract consideration is based on fixed rates for the actual volumes gathered, transported, or stored. The contract consideration is allocated to each distinct monthly performance obligation, consistent with the allocation objective and based upon the level of effort required to satisfy the service obligation. Revenues are generally recognized over time based on the output measure of natural gas volumes gathered, transported, or stored, with the recognition of the deficiency fee revenue in the period when it is known the customer cannot make up the deficient volumes in the specified time period.

Interruptible service revenue contracts typically contain fixed rates, with total consideration dependent on actual natural gas volumes that flow. Interruptible service revenues are recognized over time based on the output measure of natural gas volumes gathered, transported, or stored. Certain of our contracts allow for the recovery of production-related operating expenses, which are offsetting in revenue and operating expense.

Contract Liabilities

The following is a summary of contract liability activity:

Contract liabilities generally represent amounts paid by or receivable from customers for which the associated performance obligation has not yet been satisfied. Contract liabilities associated with these services are recognized upon delivery of the service to the customer.

During the quarter ended March 31, 2026, we modified certain contracts with customers that extended the term of the agreement and the period over which the performance obligations are satisfied. This resulted in an extension of the period that deferred revenue associated with the contracts will be recognized.

The following table presents contract liability amounts as of March 31, 2026 that are expected to be recognized as revenue in future periods:

Transaction Price Allocated to the Remaining Performance Obligations

In accordance with optional exemptions available under ASC 606, we do not disclose the value of unsatisfied performance obligations for (1) contracts with an original expected length of one year or less, (2) with the exception of fixed consideration, contracts for which the amount of revenue recognized depends upon our invoices for actual volumes gathered, transported, or stored, and (3) contracts for which variable consideration relates entirely to an unsatisfied performance obligation.

Such contracts consist of various types of performance obligations, including providing midstream services. Contracts with variable volumes and/or variable pricing, including those with pricing provisions tied to a consumer price or other index, have also been excluded as the related contract consideration is variable at the contract inception. Contract lengths vary from cancellable to multi-year.

The following table presents revenue amounts related to fixed consideration associated with unsatisfied performance obligations as of March 31, 2026 that are expected to be recognized as revenue in future periods:

Costs to Obtain or Fulfill a Contract

We recognize an asset from the costs incurred to obtain a revenue contract only if we expect to recover those costs. In addition, the costs to fulfill a revenue contract are capitalized if the costs are specifically identifiable to a revenue contract, would result in enhancing resources that will be used in satisfying performance obligations in the future, and are expected to be recovered. These capitalized costs are amortized on a systematic basis consistent with the pattern of transfer of the services to which such costs relate.

As of March 31, 2026 and December 31, 2025, we had capitalized costs to obtain or fulfill a contract of $16 million and $17 million, respectively, which are included in other current assets and other noncurrent assets in the accompanying Consolidated Statements of Financial Position. During the three months ended March 31, 2026, and 2025 we recognized less than $1 million of amortization expense related to such capitalized costs.

NOTE 5 —GOODWILL

We have goodwill that resulted from business combinations. The carrying value of goodwill is evaluated for impairment on an annual basis or whenever events or circumstances indicate that the value of goodwill may be impaired. We performed our prior year annual impairment test as of October 1, 2025 and determined that the estimated fair value of each reporting unit exceeded its carrying value, and no impairment existed. No additions, impairments or other changes occurred during the three months ended March 31, 2026.

The following is a summary of the carrying value of goodwill by reporting unit:

While we believe the estimates and assumptions in the estimated fair value are reasonable, the actual results may differ from projections. To the extent projected results or cash flows are revised downward, the reporting unit may be required to write down all or a portion of its goodwill, which would adversely impact our earnings.

NOTE 6 —EARNINGS PER SHARE AND DIVIDENDS

Basic earnings per share is calculated by dividing Net Income attributable to DT Midstream by the weighted-average number of common shares outstanding during the period. Diluted earnings per share reflect the dilution that would occur if any potentially dilutive instruments were exercised or converted into common shares, using the treasury stock method. Restricted stock units and performance share awards, including dividend equivalents on those grants, are potentially dilutive and, if dilutive, are included in the determination of weighted-average shares outstanding. Restricted stock units and performance share awards do not receive cash dividends, as such, these awards are not considered participating securities.

The following is a reconciliation of basic and diluted earnings per share:

We declared the following cash dividends:

NOTE 7 —INCOME TAXES

Effective Tax Rates

We record income taxes during the interim period using an estimated annual effective tax rate and recognize specific events discretely as they occur.

The interim period effective tax rate of DT Midstream was 21% for the three months ended March 31, 2026 and 24% for the three months ended March 31, 2025.

The current period interim effective tax rate did not differ materially from the federal statutory rate of 21% due to the effect of state income taxes being offset by the discrete tax benefit related to stock-based compensation recognized during the quarter. The difference between the prior period interim effective tax rate and the federal statutory rate was primarily driven by state income taxes.

NOTE 8 —FAIR VALUE

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable inputs. We make certain assumptions we believe that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. We believe we use valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.

Significant Accounting Policy – Fair Value

A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. We classify fair value balances based on the fair value hierarchy defined as follows:

•Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access as of the reporting date.

•Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the assets or liabilities or indirectly observable through corroboration with observable market data.

•Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.

Fair Value of Financial Instruments

The following table presents the carrying amount and fair value of financial instruments:

(a)Cash equivalents are stated at cost, which approximates fair value.

(b)Long‑term related party notes receivable were reclassified to short‑term during the three months ended March 31, 2026 due to contractual maturity occurring within the next twelve months.

(c)Carrying value represents principal of $3.4 billion, net of unamortized debt discounts and issuance costs.

NOTE 9 —DEBT

Long-Term Debt

The following is a summary of long-term debt:

(a) Interest payable semi-annually in arrears each June 15 and December 15.

(b) Interest payable semi-annually in arrears each April 15 and October 15.

Short-Term Credit Arrangements and Borrowings

The following table presents the availability under the Revolving Credit Facility:

(a) This amount includes $16 million of letters of credit issued to third-party creditors on behalf of Millennium to support its outstanding debt obligations.

Borrowings under the Revolving Credit Facility, if any, are used for general corporate purposes, acquisitions, and letter of credit issuances to support our operations and liquidity. Revolving Credit Facility issuance and amendment costs, net of amortization, of $5 million and $6 million as of March 31, 2026 and December 31, 2025, respectively, are included in other noncurrent assets in our Consolidated Statements of Financial Position and are being amortized over the remaining term of the Revolving Credit Facility.

The Credit Agreement covering the Revolving Credit Facility includes a financial covenant requiring us to maintain a maximum consolidated net leverage ratio. The maximum consolidated net leverage ratio is set at 5 to 1 (except, that the Company may elect to temporarily step up the maximum consolidated net leverage ratio to 5.5 to 1 for a period of up to three fiscal quarters after the consummation of an acquisition or investment involving consideration exceeding $50 million). The consolidated net leverage ratio means the ratio of net debt determined in accordance with GAAP to annual consolidated EBITDA, as defined in the Credit Agreement. The Credit Agreement definition of annual consolidated EBITDA excludes EBITDA from equity method investees, but includes dividends and distributions from equity method investees. As of March 31, 2026, the consolidated net leverage ratio was 2.7 to 1 and we were in compliance with the financial covenant.

NOTE 10 —COMMITMENTS AND CONTINGENCIES

From time to time, we are subject to legal, administrative and environmental proceedings before various courts, arbitration panels and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits and pending judicial matters. We cannot predict the final disposition of such proceedings. We regularly review legal matters and record provisions for claims that we can estimate and are considered probable of loss. The amount or range of reasonably possible losses is not anticipated to, either individually or in the aggregate, materially adversely affect our business, financial condition and results of operations.

Guarantees

In certain limited circumstances, we enter into contractual guarantees. We may guarantee another entity's obligation in the event it fails to perform and may provide guarantees in certain indemnification agreements. We did not have any guarantees of other parties' obligations as of March 31, 2026.

Surety Bonds

In certain limited circumstances, we enter into contracts that require us to obtain external surety bonds to secure our payment and performance. We agree to indemnify the issuers of these surety bonds for amounts, if any, paid by them under these agreements. In the event that any surety bonds are called for non-performance, we would be obligated to reimburse the issuer of the surety bond. The maximum potential indemnification under our surety bond agreements as of March 31, 2026 is $11 million.

Vector Line of Credit

We are the lender under a revolving term credit facility to Vector, the borrower, in the amount of CAD $70 million. The credit facility was executed in response to the passage of Canadian regulations requiring oil and gas pipelines to demonstrate their financial ability to respond to a catastrophic event and exists for the sole purpose of satisfying these regulations. Vector may only draw upon the facility if the funds are required to respond to a catastrophic event. The maximum potential payout as of March 31, 2026 is USD $50 million. The funding of a loan under the terms of the revolving term credit facility is considered remote.

Clean Fuels Gathering Contingent Payments

A gas supply agreement at Clean Fuels Gathering requires contingent payments from DT Midstream of up to $34 million upon the completion of certain milestones, including cumulative production and income tax credits, and variable payments under a sharing mechanism. One milestone was achieved in 2024 related to verification of gas production volumes and $10 million was paid and recorded as a prepaid asset. No additional milestones have been achieved as of March 31, 2026. The remaining unamortized prepaid asset is $1 million and $7 million in current and long-term other assets, respectively, in DT Midstream's Consolidated Statements of Financial Position as of March 31, 2026.

Contingent Liability

In order to comply with certain state environmental regulations, we have an obligation to restore pipeline right-of-way slope failures that may arise in the ordinary course of business in the Utica and Marcellus formations. We completed evaluations of all locations, which were prioritized based on the severity and proximity of the slope failures, and used updated cost information to assess the adequacy of the estimate for the contingent liability accrual. As of March 31, 2026 and December 31, 2025, we had accrued contingent liabilities of$2 million and $2 million, respectively, for future slope restoration expenditures. The accrual is included in other current liabilities and other liabilities in the Consolidated Statements of Financial Position. While restoration is ongoing, we believe the accrued amounts are sufficient to cover estimated future expenditures.

Stonewall Litigation

On November 27, 2024, Antero Resources Corporation ("Antero") filed a lawsuit against Stonewall regarding the application of certain rate provisions under the Agreement between the parties dated June 20, 2014. On December 12, 2025, the Third Division of the Business Court of Texas issued an Order granting Antero’s Motion for Summary Judgment related to one aspect of the dispute. On January 12-16, 2026, trial was held on the remaining issues. On April 2, 2026, an Order was issued related to the application of the aforementioned rate provisions resulting in no damages awarded to Antero. Both parties have the right to appeal this order and to seek attorney’s fees, which the Court can award on a discretionary basis under Texas’s Declaratory Judgment Act.

Stonewall intends to continue to defend against Antero’s claim. The Company deems the probability of loss to be remote at this time, and we have not recorded a contingent liability.

NOTE 11 —SEGMENT AND RELATED INFORMATION

We set strategic goals, allocate resources, and evaluate performance based on the followingtwo segments: Pipeline and Gathering.

The Pipeline segment owns and operates interstate and intrastate natural gas pipelines, storage systems, and natural gas gathering lateral pipelines. The Pipeline segment also has interests in equity method investees that own and operate interstate natural gas pipelines. The segment is engaged in the transportation and storage of natural gas for intermediate and end user customers.

The Gathering segment owns and operates gas gathering systems. The segment is engaged in collecting natural gas from points at or near customers’ wells for delivery to plants for treating, to gathering pipelines for further gathering, or to pipelines for transportation, as well as associated ancillary services.

Inter-segment billing for goods and services exchanged between segments is based upon contracted prices of the provider.

Financial data for our business segments follows:

NOTE 12 —REGULATORY MATTERS

Significant Accounting Policy – Regulation

Guardian, Midwestern and Viking are subject to rate regulation and accounting requirements of FERC. The regulated operations of each of these subsidiaries have rates that are (i) established by independent, third-party regulators, (ii) set at levels that will recover our costs when considering the demand and competition for our services and (iii) charged to and collectible from our customers. Accordingly, we follow the accounting for regulated operations as defined in ASC 980 for these pipelines, which results in differences in the application of GAAP between our regulated and non-regulated businesses. During the rate-making process, FERC sets the framework for what we can charge to and collect from our customers for our services and establish the manner that our costs are accounted for, including allowing us to defer recognition of certain costs and permitting cost recovery through rates over time as opposed to expensing such costs as incurred. Examples include costs for fuel and losses, contributions in aid of construction, charges for depreciation, gains or losses on disposition of assets and deferral of tax benefits related to changes in tax rates.

Regulatory Assets and Liabilities

Under ASC 980, our regulated operations are required to record regulatory assets and liabilities for certain transactions that would have been treated as revenue or expense in non-regulated businesses. Future regulatory changes could result in changes in the amounts of regulatory assets and liabilities or the discontinuance of this accounting treatment for regulatory assets and liabilities and may require the write-off of the portion of any regulatory asset or liability that is no longer probable of recovery through regulated rates. Actions by regulatory authorities could also have an effect on the amounts we charge to and collect from our customers. Any difference in the amounts recoverable or deferred is recorded as income or expense at the time of regulatory action.

Continued applicability of regulatory accounting treatment requires that rates be designed to recover specific costs of providing regulated services and be charged to and collected from customers. We believe that currently available facts support the continued use of regulatory accounting and that all regulatory assets and liabilities are recoverable or refundable in the current regulatory environment. Regulatory assets are included in Other Assets–Other on our Consolidated Statements of Financial Position.

Rate Case Settlements

The FERC approval dates for the most recent FERC rate proceedings for Guardian, Midwestern and Viking were February 15, 2023, May 3, 2022 and July 31, 2024, respectively. As of March 31, 2026, there were no open FERC rate proceedings for these pipelines. The most recent approved rate proceeding for Guardian included a max tariff rate reduction of approximately 13% which was effective April 1, 2025, and an additional 5% reduction effective April 1, 2026.

NOTE 13 —SUBSEQUENT EVENTS

Dividend Declaration

On April 30, 2026, we announced that our Board of Directors declared a quarterly dividend of $0.88 per share of common stock. The dividend is payable to our stockholders of record as of June 15, 2026 and is expected to be paid on July 15, 2026.

Guardian Term Loan

On April 30, 2026, Guardian entered into an unsecured term loan credit agreement pursuant to which it borrowed $150 million. The term loan matures on April 30, 2033 and bears interest at a variable rate equal to SOFR plus 1.95%. Total debt issuance costs related to the term loan are expected to be approximately $1 million. The credit agreement contains customary covenants, including a maximum leverage ratio of 4.5 to 1.