Cash Equivalents. Cash equivalents are highly liquid investments purchased with an original maturity of three months or less. In all periods prior to the Separation Date, the cash and cash equivalents held by ParentCo at the corporate level were not attributed to the Arconic Corporation Businesses. Only cash amounts specifically attributable to the Arconic Corporation Businesses were reported on the Company’s Consolidated Financial Statements.

Properties, Plants, and Equipment. Properties, plants, and equipment are recorded at cost. Also, interest related to the construction of qualifying assets is capitalized as part of the construction costs. Depreciation is recorded on the straight-line method at rates based on the estimated useful lives of the assets. The following table details the weighted-average useful lives of structures and machinery and equipment by reporting segment (numbers in years):

Properties, plants, and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of such assets may not be recoverable. Recoverability of assets is determined by comparing the estimated undiscounted net cash flows of the related operations (asset group) to the carrying value of the associated assets. An impairment loss would be recognized when the carrying value of the assets exceeds the estimated undiscounted net cash flows of the asset group. The amount of the impairment loss to be recorded is calculated as the excess of the carrying value of the assets over their fair value, with fair value determined using the best information available, which generally is a discounted cash flow (DCF) model. In certain circumstances, Arconic may use the services of a third-party to assist with other valuation techniques. The determination of what constitutes an asset group, the associated estimated undiscounted net cash flows, and the estimated useful lives of the assets also require significant judgments.

Goodwill. Goodwill is not amortized; it is reviewed for impairment annually (in the fourth quarter) or more frequently if indicators of impairment exist or if a decision is made to sell, exit, or realign a business. A significant amount of judgment is involved in determining if an indicator of impairment has occurred. Such indicators may include, among others, deterioration in general economic conditions, negative developments in equity and credit markets, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows, or a trend of negative or declining cash flows over multiple periods. The fair value that could be realized in an actual transaction may differ from that used to evaluate goodwill for impairment.

Goodwill is allocated among and evaluated for impairment at the reporting unit level, which is defined as an operating segment or one level below an operating segment. Arconic has three reporting units, the Rolled Products segment, the Building and Construction Systems segment, and the Extrusions segment (full impairment of goodwill in 2021 – see below). At the time of the Company’s annual 2022 review of goodwill for impairment, the carrying value of goodwill for Rolled Products and Building and Construction Systems was $232 and $67, respectively.

In reviewing goodwill for impairment, an entity has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not (greater than 50%) that the estimated fair value of a reporting unit is less than its carrying amount. If an entity elects to perform a qualitative assessment and determines that an impairment is more likely than not, the entity is then required to perform a quantitative impairment test (described below), otherwise no further analysis is required. An entity also may elect not to perform the qualitative assessment and, instead, proceed directly to the quantitative impairment test. The ultimate outcome of the goodwill impairment review for a reporting unit should be the same whether an entity chooses to perform the qualitative assessment or proceeds directly to the quantitative impairment test.

Arconic determines annually, based on facts and circumstances, which of its reporting units will be subject to the qualitative assessment. For those reporting units where a qualitative assessment is either not performed or for which the conclusion is that an impairment is more likely than not, a quantitative impairment test will be performed. The Company’s policy is that a quantitative impairment test be performed for each reporting unit at least once during every three-year period.

Under the qualitative assessment, various events and circumstances (or factors) that would affect the estimated fair value of a reporting unit are identified (similar to impairment indicators above). These factors are then classified by the type of impact they would have on the estimated fair value using positive, neutral, and adverse categories based on current business conditions. Additionally, an assessment of the level of impact that a particular factor would have on the estimated fair value is determined using high, medium, and low weighting. Furthermore, management considers the results of the most recent quantitative impairment test completed for a reporting unit and compares the weighted average cost of capital (WACC) between the current and prior years for each reporting unit.

During the 2022 annual review of goodwill for impairment, management performed the qualitative assessment for the Building and Construction Systems reporting unit. Management concluded it was not more likely than not that the estimated fair value of this reporting unit was less than the carrying value. As such, no further analysis was required. Management last proceeded directly to the quantitative impairment test for the Building and Construction Systems reporting unit in 2021. At that time, the estimated fair value of this reporting unit was substantially in excess of its carrying value, resulting in no impairment.

Under the quantitative impairment test, the evaluation of the recoverability of goodwill involves comparing the current fair value of each reporting unit to its carrying value, including goodwill. Arconic uses a DCF model to estimate the current fair value of its reporting units when testing for impairment, as management believes forecasted cash flows are the best indicator of such fair value. Several significant assumptions and estimates are involved in the application of the DCF model to forecast operating cash flows, including sales growth (volumes and pricing), production costs, capital spending, working capital levels, and discount rate. Certain of these assumptions may vary significantly among the reporting units. Cash flow forecasts are generally based on approved business unit five-year operating plans and a terminal value. The WACC rate for the individual reporting units is estimated by management with the assistance of valuation experts. In the event the estimated fair value of a reporting unit per the DCF model is less than the carrying value, the Company would recognize an impairment charge equal to the excess of the reporting unit’s carrying value over its fair value without exceeding the total amount of goodwill applicable to that reporting unit.

The respective annual review of goodwill for impairment in 2021 and 2020 indicated that goodwill was not impaired for any of Arconic’s reporting units, except for the Extrusions segment (see below), and there were no triggering events since that time that necessitated an interim quantitative impairment test for any of the Company’s reporting units. That said, in light of the

In 2021, the estimated fair value of the Extrusions reporting unit was lower than the associated carrying value by an amount greater than the carrying value of the Extrusions reporting unit’s goodwill. Accordingly, the Company recorded an impairment charge of $65 in the fourth quarter of 2021. As a result, there is no goodwill remaining for the Extrusions reporting unit.

The impairment of the Extrusion reporting unit’s goodwill resulted from a combination of market-based factors, including continued delays in aerospace market improvement, the expectation that significant cost inflation will extend beyond 2021 resulting in increasingly limited ability for management to drive margin expansion, and a longer than previously anticipated shift in product mix to lower margin industrial products to replace most of the lost aerospace volume. Further, current market factors also resulted in a 150-basis point increase in the WACC compared to the fourth quarter of 2020. Accordingly, given these factors, the estimated fair value of the Extrusions reporting unit was less than the carrying value resulting in a full impairment of its goodwill.

Leases. Arconic determines whether a contract contains a lease at inception. The Company leases certain land and buildings, plant equipment, vehicles, and computer equipment, which have been classified as operating leases. Certain real estate leases include one or more options to renew; the exercise of lease renewal options is at Arconic’s discretion. The Company includes renewal option periods in the lease term when it is determined that the options are reasonably certain to be exercised. Certain of Arconic’s real estate lease agreements include rental payments that either have fixed contractual increases over time or adjust periodically for inflation. Also, certain of the Company’s lease agreements include variable lease payments. The variable portion of payments is not included in the initial measurement of the right-of-use asset or lease liability due to the uncertainty of the payment amount and is recorded as lease cost in the period incurred.

Operating lease right-of-use assets and lease liabilities with an initial term greater than 12 months are recorded on the balance sheet at the present value of the future minimum lease payments over the lease term calculated at the lease commencement date and are recognized as lease expense on a straight-line basis over the lease term. Arconic uses an incremental collateralized borrowing rate based on the information available at the lease commencement date in determining the present value of future payments, as most of the Company’s leases do not provide an implicit rate. The operating lease right-of-use assets also include any lease prepayments made and are reduced by lease incentives and accrued exit costs.

Environmental Matters. Expenditures for current operations are expensed or capitalized, as appropriate. Expenditures relating to existing conditions caused by past operations, which will not contribute to future revenues, are expensed. Liabilities are recorded when remediation costs are probable and can be reasonably estimated. The liability may include costs such as site investigations, consultant fees, feasibility studies, outside contractors, and monitoring expenses. Estimates are generally not reduced by potential claims for recovery, which are recognized when probable and as agreements are reached with third parties. The estimates may also include costs related to other potentially responsible parties to the extent that Arconic has reason to believe such parties will not fully pay their proportionate share. The liability is continuously reviewed and adjusted to reflect current remediation progress, prospective estimates of required activity, and other factors that may be relevant, including changes in technology or regulations. The portion of the liability associated with post-remediation operations, maintenance, and monitoring activities are discounted using a risk-free-rate.

Litigation Matters. For asserted claims and assessments, liabilities are recorded when an unfavorable outcome of a matter is deemed to be probable and the loss is reasonably estimable. Management determines the likelihood of an unfavorable outcome based on many factors such as, among others, the nature of the matter, available defenses and case strategy, progress of the matter, views and opinions of legal counsel and other advisors, applicability and success of appeals processes, and the outcome of similar historical matters. Once an unfavorable outcome is deemed probable, management weighs the probability of

estimated losses, and the most reasonable loss estimate is recorded. If an unfavorable outcome of a matter is deemed to be reasonably possible, the matter is disclosed and no liability is recorded. With respect to unasserted claims or assessments, management must first determine the probability an assertion will be made is likely; then a determination as to the likelihood of an unfavorable outcome and the ability to reasonably estimate the potential loss is made. Legal matters are reviewed on a continuous basis to determine if there has been a change in management’s judgment regarding the likelihood of an unfavorable outcome or the estimate of a potential loss.

Revenue Recognition. The Company’s contracts with customers are generally comprised of acknowledged purchase orders incorporating Arconic’s standard terms and conditions, or for larger customers, may also generally include terms under negotiated multi-year agreements. These customer contracts typically consist of the manufacture of products, which represent single performance obligations that are satisfied upon transfer of control of the product to the customer. The Company produces aluminum sheet and plate; extruded and machined parts; integrated aluminum architectural systems; and architectural extrusions. Transfer of control is assessed based on alternative use of the products produced and Arconic’s enforceable right to payment for performance to date under the contract terms. Transfer of control and revenue recognition generally occur upon shipment or delivery of the product, which is when title, ownership, and risk of loss pass to the customer and is based on the applicable shipping terms. The shipping terms vary across all businesses and depend on the product, the country of origin, and the type of transportation (truck, train, or vessel).

In certain circumstances, the Company receives advanced payments from its customers for product to be delivered in future periods. These advanced payments are recorded as deferred revenue until the product is delivered and title and risk of loss have passed to the customer in accordance with the terms of the contract. Deferred revenue is reported in Other current liabilities and Other noncurrent liabilities on the Consolidated Balance Sheet.

Pension and Other Postretirement Benefits. In all periods prior to January 1, 2020 (see below), certain employees attributable to the Arconic Corporation Businesses participated in defined benefit pension and other postretirement benefit plans sponsored by ParentCo (the “Shared Plans”), which also included participants attributable to non-Arconic Corporation Businesses. Arconic accounted for the portion of the Shared Plans related to its employees as multiemployer benefit plans. Accordingly, the Company did not record an asset or liability to recognize any portion of the funded status of the Shared Plans. However, the related expense recorded by Arconic was based primarily on pensionable compensation and estimated interest costs related to participants attributable to the Arconic Corporation Businesses.

In all periods prior to the Separation Date, certain other ParentCo plans that were entirely attributable to employees of the Arconic Corporation Businesses (“Direct Plans”) were accounted for as defined benefit pension and other postretirement benefit plans. Accordingly, the funded or unfunded position of each Direct Plan was recorded in the Consolidated Balance Sheet. Actuarial gains and losses that have not yet been recognized in earnings were recorded in accumulated other comprehensive income, net of taxes, until they were amortized as a component of net periodic benefit cost. The determination of benefit obligations and recognition of expenses related to the Direct Plans is dependent on various assumptions, including, among others, discount rates, long-term expected rates of return on plan assets, and future compensation increases. ParentCo’s management developed each assumption using relevant company experience in conjunction with market-related data for each individual location in which such plans exist.

In preparation for the Separation, effective January 1, 2020, certain of the Shared Plans were separated into standalone plans for both Arconic (“New Direct Plans”) and ParentCo (see Note H). Additionally, effective April 1, 2020, portions of the other remaining Shared Plans were assumed by Arconic (“Additional New Direct Plans”) (see Note H). Accordingly, beginning on the respective effective dates, the New Direct Plans and the Additional New Direct Plans are accounted for as defined benefit pension and other postretirement plans. Additionally, the Direct Plans continue to be accounted for as defined benefit pension and other postretirement plans.

Stock-Based Compensation. In all periods prior to the Separation Date, eligible employees attributable to the Arconic Corporation Businesses participated in ParentCo’s stock-based compensation plan. The compensation expense recorded by the Company included the expense associated with these employees, as well as the expense associated with an allocation of stock-based compensation expense for ParentCo’s corporate employees (see Cost Allocations in Note A). Beginning on the Separation Date, Arconic recorded stock-based compensation expense for all of the Company's employees eligible to participate in Arconic’s stock-based compensation plan. The following describes the manner in which stock-based compensation expense was initially determined for both Arconic and ParentCo.

Compensation expense for employee equity grants is recognized using the non-substantive vesting period approach, in which the expense is recognized ratably over the requisite service period based on the grant date fair value. The fair value of stock options is estimated on the date of grant using a lattice-pricing model. The fair value of performance stock units containing a market condition is valued using a Monte Carlo valuation model. Determining the fair value at the grant date

Income Taxes. The provision for income taxes is determined using the asset and liability approach of accounting for income taxes. Under this approach, the provision for income taxes represents income taxes paid or payable (or received or receivable) for the current year plus the change in deferred taxes during the year. Deferred taxes represent the future tax consequences expected to occur when the reported amounts of assets and liabilities are recovered or paid, and result from differences between the financial and tax bases of Arconic’s assets and liabilities and are adjusted for changes in tax rates and tax laws when enacted.

In all periods prior to the Separation Date, the Arconic Corporation Businesses were included in the income tax filings of ParentCo. The provision for income taxes was determined in the same manner described above, but on a separate return methodology as if the Company was a standalone taxpayer filing hypothetical income tax returns where applicable. Any additional accrued tax liability or refund arising as a result of this approach was assumed to be immediately settled with ParentCo as a component of Parent Company net investment. Deferred taxes were also determined in the same manner described above and were reported in the Consolidated Balance Sheet for net operating losses, credits or other attributes to the extent that such attributes were expected to transfer to Arconic upon the Separation. Any difference from attributes generated in a hypothetical return on a separate return basis was adjusted as a component of Parent Company net investment.

Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not (greater than 50%) that a tax benefit will not be realized. In evaluating the need for a valuation allowance, management considers all potential sources of taxable income, including income available in carryback periods, future reversals of taxable temporary differences, projections of taxable income, and income from tax planning strategies, as well as all available positive and negative evidence. Positive evidence includes factors such as a history of profitable operations, projections of future profitability within the carryforward period, including from tax planning strategies, and the Company’s experience with similar operations. Existing favorable contracts and the ability to sell products into established markets are additional positive evidence. Negative evidence includes items such as cumulative losses, projections of future losses, or carryforward periods that are not long enough to allow for the utilization of a deferred tax asset based on existing projections of income. Deferred tax assets for which no valuation allowance is recorded may not be realized upon changes in facts and circumstances, resulting in a future charge to establish a valuation allowance. Existing valuation allowances are re-examined under the same standards of positive and negative evidence. If it is determined that it is more likely than not that a deferred tax asset will be realized, the appropriate amount of the valuation allowance, if any, is released. Deferred tax assets and liabilities are also re-measured to reflect changes in underlying tax rates due to law changes and the grant and lapse of tax holidays.

Arconic applies a tax law ordering approach when considering the need for a valuation allowance on net operating losses expected to offset Global Intangible Low Taxed Income (GILTI) income inclusions. Under this approach, reductions in cash tax savings are not considered as part of the valuation allowance assessment. Instead, future GILTI inclusions are considered a source of taxable income that support the realizability of deferred tax assets.

Tax benefits related to uncertain tax positions taken or expected to be taken on a tax return are recorded when such benefits meet a more likely than not threshold. Otherwise, these tax benefits are recorded when a tax position has been effectively settled, which means that the statute of limitations has expired or the appropriate taxing authority has completed its examination even though the statute of limitations remains open. Interest and penalties related to uncertain tax positions are recognized as part of the provision for income taxes and are accrued beginning in the period that such interest and penalties would be applicable under relevant tax law until such time that the related tax benefits are recognized.

Foreign Currency. The local currency is the functional currency for the Company’s operations outside the United States with the following exception. The U.S. dollar was the functional currency for Arconic’s former operations in Russia (divested in November 2022 - see Note S). The determination of the functional currency for the Company’s operations is made based on the appropriate economic and management indicators.

Recently Adopted Accounting Guidance. There was no relevant guidance previously issued by the Financial Accounting Standards Board (FASB) requiring adoption in 2022 by Arconic. FASB guidance adopted in 2021 and 2020 by the Company related to accounting and/or reporting for income taxes, credit losses, and employee defined benefit plans did not have a material impact as previously disclosed in Arconic’s Consolidated Financial Statements issued in the respective periods.

Recently Issued Accounting Guidance. In March 2020, the FASB issued guidance that provides optional expedients and exceptions for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. These expedients and exceptions may be used when applying GAAP, if certain criteria are met, to contracts, hedging relationships, and other transactions that reference London Inter-Bank Offered Rate (LIBOR) or

another reference rate expected to be discontinued because of such reform. The purpose of this guidance is to provide relief to entities from experiencing unintended accounting and/or financial reporting outcomes or consequences due to reference rate reform. This guidance became effective immediately on March 12, 2020 and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022, after which time the expedients and exceptions expire (see below). In January 2021, the FASB issued clarifying guidance to specify that certain of the optional expedients and exceptions apply to derivatives that use an interest rate for margining, discounting, or contract price alignment that is modified as a result of reference rate reform. This additional guidance may be applied on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively in the manner previously described for the guidance issued on March 12, 2020. In December 2022, the FASB extended the expiration of the optional expedients and exceptions to June 30, 2023. Through December 31, 2022, the Company has not experienced any unintended outcomes or consequences of reference rate reform that would necessitate the adoption of this guidance. Additionally, Arconic’s credit agreement, which previously provided a credit facility that was referenced to LIBOR in certain borrowing situations, was amended in February 2022 to replace LIBOR with the Secured Oversight Financing Rate (SOFR) (see Note Q). Management will continue to closely monitor all potential instances of reference rate reform to determine if adoption of this guidance becomes necessary in the future.

In September 2022, the FASB issued guidance to enhance the transparency of supplier finance programs. Under the new guidance, a buyer in a supplier finance program must disclose at least annually qualitative and quantitative information about its supplier finance programs to allow a user of financial statements to understand the program’s nature, activity during the period, changes from period to period, and potential magnitude. These changes become effective for Arconic on January 1, 2023. The Company has an existing arrangement with a financial institution that provides for a capacity of up to $250. Other than complying with the disclosure requirements, management has determined that the adoption of this guidance will not have an impact on the Consolidated Financial Statements.