WILLIAMS COMPANIES INC

Preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions. The nature of these estimates and assumptions is material due to the subjectivity and judgment necessary, or the susceptibility of such matters to change, and the impact of these on the financial condition or results of operations.

Williams’ Pension and Postretirement Obligations

Williams has pension and other postretirement benefit plans that require the use of assumptions and estimates to determine the benefit obligations and costs. These estimates and assumptions involve significant judgment and actual results will likely be different than anticipated. Estimates and assumptions utilized include the expected long-term rates of return on plan assets, discount rates, cash balance interest crediting rate, and employee demographics, including retirement age and mortality. These assumptions are reviewed annually and adjustments are made as needed. The assumptions utilized to compute the benefit obligations and costs are shown in Note 7 – Employee Benefit Plans.

The following table presents the estimated increase (decrease) in net periodic benefit cost and obligations resulting from a one-percentage-point change in the specific assumption.

Williams’ expected long-term rates of return on plan assets, as determined at the beginning of each fiscal year, are based on historical returns, forward-looking capital market expectations of at least 10 years from Williams’ third-party independent investment advisor, as well as the investment strategy and relative weightings of the asset classes within the investment portfolio. Williams’ expected long-term rate of return on plan assets used for Williams’ pension plans was 5.31 percent in 2024. The 2024 actual return on plan assets for Williams’ pension plans was approximately 8.0 percent. The 10-year average rate of return on pension plan assets through December 2024 was approximately 6.6 percent. The expected rates of return on plan assets are long-term in nature and are not significantly impacted by short-term market performance.

The discount rates for Williams’ pension and other postretirement benefit plans are determined separately based on an approach specific to Williams’ plans, which considers a yield curve of high-quality corporate bonds and the duration of the expected benefit cash flows of each plan.

The cash balance interest crediting rate assumption represents the average long-term rate by which the pension plans’ cash balance accounts are expected to grow. Interest on the cash balance accounts is based on the 30-year U.S. Treasury securities rate.

Regulatory Accounting

Transco and NWP are regulated by the FERC. Accounting Standards Codification (ASC) Topic 980, “Regulated Operations,” (ASC 980) provides that certain costs that would otherwise be charged to expense should be deferred as regulatory assets, based on the expected recovery from customers in future rates. Likewise, certain actual or anticipated credits that would otherwise reduce expense should be deferred as regulatory liabilities, based on the expected return to customers in future rates. Management’s expected recovery of deferred costs and return of deferred credits generally results from specific decisions by regulators granting such ratemaking treatment. Transco and NWP record certain incurred costs and obligations as regulatory assets or liabilities if, based on regulatory orders or other available evidence, it is probable that the costs or obligations will be included in amounts allowable for recovery or refunded in future rates.

Accounting for businesses that are regulated and apply the provisions of ASC 980 can differ from the accounting requirements for non-regulated businesses. Transactions that are recorded differently as a result of regulatory accounting requirements include the capitalization of an equity return component on regulated capital projects, capitalization of other project costs, retirements of general plant assets, levelized cost of service, employee-related benefits, environmental costs, negative salvage, asset retirement obligations (ARO) and other costs and taxes included in, or expected to be included in, future rates. As rate-regulated entities, Transco’s and NWP’s management has determined that it is appropriate to apply the accounting prescribed by ASC 980 and, accordingly, the accompanying financial statements include the effects of the types of transactions described above that result from regulatory accounting requirements. Management’s assessment of the probability of recovery or pass through of regulatory assets and liabilities requires judgment and interpretation of laws and regulatory commission orders. If, for any reason, either Transco or NWP ceases to meet the criteria for application of regulatory accounting treatment for all or part of our operations, the regulatory assets and liabilities related to those portions ceasing to meet such criteria would be eliminated from the Balance Sheet and included in the Statement of Net Income for the period in which the discontinuance of regulatory accounting treatment occurs and can be estimated, unless otherwise required to be recorded under other provisions of U.S. generally accepted accounting principles.

The aggregate amount of regulatory assets reflected on Transco’s and NWP’s Balance Sheets at December 31, 2024, is $394 million and $55 million, respectively. The aggregate amount of regulatory liabilities reflected on Transco’s and NWP’s Balance Sheets at December 31, 2024, is $1.0 billion and $253 million, respectively. A summary of regulatory assets and liabilities is included in Note 10 – Regulatory Assets and Liabilities.