1. Description of Plans

General

The Retirement Savings Plan for Hourly Employees of Alcoa USA Corp. (“Hourly Plan”) and the Retirement Savings Plan for Salaried Employees of Alcoa USA Corp. (“Salaried Plan”), (collectively, the “Plans”) are defined contribution savings plans maintained pursuant to a master trust agreement (the “Master Trust”) between Alcoa USA Corp. (the “Company”) and the trustee, The Bank of New York Mellon (“Trustee”). In general, the Plans provide various investment options for amounts withheld from employees’ salaries and for company contributions. Plan documents are available to participants upon request.

Reference should be made to the basic prospectus and to the Summary Plan Description for a summary of the important features of each Plan, including eligibility, vesting, employee and company contributions, loans, withdrawals and compliance with the Employee Retirement Income Security Act of 1974 (“ERISA”).

Eligibility and Vesting

The Plans are available to eligible employees of the Company and certain subsidiary locations that have adopted the Plans. Employees are immediately eligible for plan participation. At all times, participants are fully vested in the value of their contributions plus actual earnings thereon. A participant is immediately vested in company contributions.

Employee Contributions

Eligible employees may elect to contribute to the Plans a percentage of eligible compensation as pre‑tax or Roth after-tax, when combined not to exceed the Internal Revenue Service (“IRS”) limit, or up to 10% as non-Roth after-tax, with a maximum of 25% in the aggregate. Certain eligible employees in the Hourly Plan may defer as pre-tax savings, a maximum of 50% of amounts earned under the applicable pay for performance plan in increments of 10% and subject to the maximums allowable by the Internal Revenue Code (“IRC”) and Department of Treasury regulations.

Negotiated deferrals, as defined in the Hourly Plan document, for certain eligible collective bargained employees will be contributed to their plan accounts as a separate, pre-tax contribution.

Eligible employees of age 50 or older or who become age 50 during the plan year and meet certain requirements may elect to make additional pre‑tax and/or Roth catch‑up contributions not to exceed the IRS limit. Certain participants may be eligible for enhanced catch-up contribution limits, and, for participants whose prior-year wages exceed applicable thresholds, catch-up contributions are required to be made on a Roth basis.

Elections can be changed effective for the first full payroll period following the election. Participants direct their contributions in multiples of 1% into various investment options offered by the Plans.

Certain eligible employees will be automatically enrolled in the Plans after 60 days of hire or rehire and subject to automatic payroll deductions, which will be contributed to the Plans as pre-tax savings, unless the employee chooses to enroll sooner or not to participate. Effective March 1, 2025, automatic payroll deductions are equal to 6% (3% if hired prior to March 1, 2025) of eligible compensation and increase by 1% annually each April 1 (following at least three months of participation) until the target rate of 10% (6% if hired prior to March 1, 2025) is attained. The employee can change the contribution rate, annual rate increase and target contribution rate or stop automatic enrollment at any time.

2. Summary of Accounting Policies

3. Master Trust

The Plans offer a variety of investment options which are held in safekeeping in a Master Trust under a trust arrangement by the Trustee. Each participating Plan has a divided interest in the Master Trust based on individual participant investment elections.

4. Fair Value Measurements

Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 820, Fair Value Measurements and Disclosures, provides the framework for measuring fair value. That framework provides a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under ASC 820 are described below:

Level 1 Inputs to the valuation methodology are unadjusted quoted prices for identical assets or liabilities in active markets that the Plan has the ability to access.

Level 2 Inputs to the valuation methodology include:

Level 3 Inputs to the valuation methodology are unobservable and significant to the fair value measurement.

The asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs.

Following is a description of the valuation methodologies used for assets measured at fair value. There have been no changes in methodologies used at December 31, 2025 and 2024.

5. Investment Contracts

The Plans hold a portfolio of investment contracts, all of which are synthetic. The Investment Contracts are held in the Fixed Income Fund (the “Fund”) and are credited with earnings on the underlying investments and charged for participant withdrawals and administrative expenses. The wrap providers are contractually obligated to repay the principal by providing a guarantee that the crediting rate will not fall below 0%.

Contract value, as reported to the Plans by the investment manager, represents contributions made under contract, plus earnings, less participant withdrawals and administrative expenses. Participants may ordinarily direct the withdrawal or transfer of all or a portion of their investment at contract value.

Investment Contracts use the crediting rate formula to convert market value changes in the covered assets into income distributions to minimize the difference between the market and contract value of covered assets over time. Using the crediting rate formula, an estimated future market value is calculated by compounding the Fund’s current market value at the Fund’s current yield to maturity for a period equal to the Fund’s duration. The crediting rate is the discount rate that equates estimated future market value with the Fund’s current contract value, but it may not be less than zero.

The crediting rate, and hence the Fund’s return, may be affected by many factors, including purchases and redemptions by shareholders. If the market value of the covered assets is higher than their contract value, the crediting rate will ordinarily be higher than the yield of the covered assets. Under these circumstances, cash from new investors will tend to lower the crediting rate, and redemptions by existing shareholders will tend to increase the crediting rate. The opposite is ordinarily true if the market value of the covered assets is lower than their contract value. There are no reserves against contract value for credit risk of the insurance companies or otherwise.

Certain events limit the ability of the Plans to transact at contract value with the issuer. Such events include the following: (1) the Plan’s failure to qualify under Section 401(a) or Section 401(k) of the IRC, (2) the establishment of a defined contribution plan that competes with the Plan for employee contributions, (3) any substantive modification of the Plan or the administration of the Plan that is not consented to by the insurance companies, (4) complete or partial termination of the Plan, (5) any change in law, regulation or administration ruling applicable to the Plan that could have a material adverse effect on the Fund’s cash flow, (6) merger or consolidation of the Plans with another plan, the transfers of the Plans’ assets to another plan, or the sale, spin‑off or merger of a subsidiary or division of the plan sponsor, (7) any communication given to participants by the plan sponsor or any other plan

6. Related-Party and Party-In-Interest Transactions

The Plans own shares of common stock of Alcoa Corporation through the investment in the Alcoa Corporation Stock Fund and, therefore, these transactions qualify as party-in-interest transactions. These transactions are exempt as defined in ERISA Section 408 and the regulations there under. During 2025, the market value of purchases and sales of shares of common stock of the Alcoa Corporation Stock Fund were $2,990,770 and $5,138,270, respectively. Dividends earned on Alcoa Corporation common stock during 2025 were $132,787. As of December 31, 2025 and 2024, the Plans owned 259,732 and 291,433 shares of Alcoa Corporation common stock, respectively.

The Company may pay certain administrative expenses or perform administrative functions on behalf of the Plans.

The Plans invest in funds managed by The Bank of New York Mellon. The Bank of New York Mellon is the trustee as defined by the Plans, and therefore these transactions, and expenses paid to Bank of New York Mellon, qualify as party-in-interest transactions.

Participants may borrow from their individual account balances in the Plans. The loan program is discussed in Note 1. These transactions qualify as party-in-interest transactions.

7. Tax Status

The IRS determined and informed the Company by letters dated February 1, 2018 that the Plans are qualified and the Master Trust established under the Plans is tax-exempt under the appropriate sections of the IRC. These plans were amended since receiving the determination letters; however, the Plans’ administrator and the Sponsor’s tax advisor believe that the Plans are currently designed and being operated in compliance with the applicable requirements of the IRC. Therefore, they believe the Plans are qualified and the related Master Trust is tax-exempt as of the financial statement date.

U.S. GAAP requires the Plans’ management to evaluate tax positions taken by the Plans and recognize a tax liability (or asset) if the organization has taken an uncertain position that would not be sustained upon examination by the IRS. The Plans’ administrator and the Sponsor’s tax advisor analyzed the tax positions taken by the Plans and concluded that as of December 31, 2025 and 2024, there are no uncertain tax positions taken or expected to be taken that would require recognition of a liability (or asset) or disclosure in the financial statements. As such, no reserve is required under U.S. GAAP. The Plans are subject to audit by the IRS; however, there are no current IRS audits in progress for any tax periods.

8. Subsequent Events

Management has evaluated the events and transactions that have occurred through June 11, 2026, the date the financial statements were issued, and noted no items requiring adjustment of the financial statements or additional disclosures, other than that which is described below.

Retirement Savings Plan for Hourly Employees of Alcoa USA Corp.

EIN #37-1808900, Plan 004

Schedule H, Line 4(i) – Schedule of Assets (Held at End of Year)

December 31, 2025

* A party-in-interest as defined by ERISA.

** Cost omitted for participant-directed investments.

Retirement Savings Plan for Salaried Employees of Alcoa USA Corp.

EIN #37-1808900, Plan 003

Schedule H, Line 4(i) – Schedule of Assets (Held at End of Year)

December 31, 2025

* A party-in-interest as defined by ERISA.

** Cost omitted for participant-directed investments.