Alcoa Corp

ATTACHMENT A — Additional Information Regarding Performance Measures

We have included in this proxy statement certain business measures and performance metrics that are used for our incentive compensation programs (collectively, “metrics”) which are not calculated in accordance with U.S. GAAP. These metrics should be reviewed in conjunction with the relevant GAAP financial measure and may not be comparable to similarly titled measures reported by other companies.

2024 Annual Incentive Compensation and 2020-2024 Pay Versus Performance (PVP)

2024 Annual Incentive Compensation and Pay Versus Performance—Reconciliation of Adjusted EBITDA, Excluding Special Items—Non-Normalized (in millions)

(1)

Special items are comprised of costs related to restart processes, costs related to closures, the net cost of power associated with the Portland smelter, certain external costs related to portfolio actions, and other items management deems appropriate to exclude from non-GAAP performance measures.

(2)

The 2024 Company IC Plan Adjusted EBITDA, excluding special items result of $1,554 reflects a People and Compensation Committee approved exception related to removing a $35 benefit of the Inflation Reduction Act, which was not included in the IC Plan target.

2024 Annual Incentive Compensation—Reconciliation of Free Cash Flow (in millions)

2024 Annual Incentive Compensation—Normalization applied to “Free Cash Flow—Normalized” metric

For incentive compensation purposes, the Company’s Free Cash Flow—Normalized metric is calculated by taking Alcoa’s Free Cash Flow for the fiscal year ended December 31, 2024 and normalizing the metric for certain factors not in management’s control.

We normalize for the following items, each of which may have significant effects on financial results but are not impacted by management performance or otherwise within management’s control. Because we generally do not hedge against fluctuations in LME and API prices and foreign exchange rates, normalization adjustments were made relative to certain described metrics in determining the 2024 IC awards. For 2024, the most significant normalization impacts were driven by LME, API, regional premiums and tariffs, and currencies, offset by raw material prices. Additionally, we adjust for certain items deemed to be special items to the Company’s financial results.

A description of the normalization of these factors follows:

•

LME Pricing and API: Without normalization, in years when the LME price of aluminum, or the price of alumina through the API, rises rapidly relative to plan (i.e., our forecasts), annual incentive compensation would be less effective as a performance incentive because management would receive an unearned benefit. Conversely, when LME and API prices for aluminum and alumina, respectively, fall dramatically relative to our plan, failure to normalize would demotivate employees by placing annual incentive compensation awards out of reach for reasons beyond their control. Our use of normalization enables us to drive operational and financial performance, particularly in recent years of volatile prices.

•

Currency Exchange Rates: Because our revenues are largely U.S. dollar-denominated, while costs in non-U.S. locations are largely denominated in local currency, the volatility of currency exchange rates may have a significant impact on earnings. As our commodities are traded in U.S. dollars, we typically have seen an inverse correlation to foreign currency exchange. Therefore, to avoid double counting, the normalization for the commodity price swings needs to be corrected by concurrent normalization of foreign exchange.

•

Regional Premiums and Tariffs: In addition to LME, API, and foreign currency normalization, results historically have been adjusted to neutralize 50% of the fluctuations in regional aluminum premiums compared to plan as well as 50% of the benefit from tariffs.

•

Raw Material Prices: For 2024, results were normalized to neutralize 100% of the fluctuations in raw material prices compared to the plan. Similar to LME and API, when raw material prices rise rapidly relative to plan, failure to normalize would demotivate employees by placing annual incentive compensation awards out of reach for reasons beyond their control; and conversely, in scenarios of lower raw material prices, annual incentive compensation would be less effective as a performance incentive because management would receive an unearned benefit.

2024 Annual Incentive Compensation—Cash Net Conversion Cost

Cash Net Conversion Cost is used internally to measure total controllable costs of production of saleable product (alumina or aluminum). The measure is calculated by subtracting uncontrollable raw and direct material costs from total production costs.

Long-Term Equity Incentive Compensation

2024-2026 PRSUs and 2022-2024 PRSUs—Average ROE

The Company’s Average ROE metric is calculated by dividing net income (loss) attributable to Alcoa plus special items by stockholder’s equity at the end of each fiscal year in the 2024-2026 performance period, then dividing by three years to calculate the average.

Special items are comprised of restructuring and other charges, various tax items, and other items management deemed appropriate to exclude from non-GAAP performance measures such as Adjusted EBITDA.

Stockholder’s equity is determined as follows: Total assets minus total liabilities minus non-controlling interest (four quarter average).

2024-2026 and 2022-2024 PRSUs—Carbon Intensity

For our Alumina segment goal, carbon (CO2e) reduction in our refining operations is measured using tons of CO2e per tons of alumina produced, relative to refineries with greater than 2.5M metric tons of annual production, based on Scope 1 and Scope 2 emissions information provided by independent third-party CRU.

Aluminum segment renewable energy production in smelting operations includes both direct and purchased renewable energy and is calculated as a percentage of renewable energy versus total megawatt hours purchased. Measure excludes closed smelters but includes San Ciprián, which is currently curtailed but has planned to restart. The underlying power purchase agreements, which require specific renewable percentages for the energy procured for our smelters, are considered when calculating this metric with respect to our long- term incentive plan. Renewable energy means energy (including electricity and heat) derived from natural processes that are replenished constantly, such as sunlight, wind, and hydropower; nuclear power is excluded.

Logo 201 ISABELLA STREET, SUITE 500 PITTSBURGH, PA 15212 SCAN TO VIEW MATERIALS & VOTE VOTE BY INTERNET Before The Meeting - Go to www.proxyvote.com or scan the QR Barcode above Use the Internet to transmit your voting instructions and for electronic delivery of information up until 11:59 p.m. Eastern Daylight Time on May 7, 2025 or by 11:59 p.m. Eastern Daylight Time on May 5, 2025 for shares held in an Alcoa savings plan. Have your proxy card in hand when you access the website and follow the instructions to obtain your records and to create an electronic voting instruction form. During The Meeting - Go to www.virtualshareholdermeeting.com/AA2025 You may attend the meeting via the Internet and vote during the meeting. Have the information that is printed in the box marked by the arrow available and follow the instructions. VOTE BY PHONE - 1-800-690-6903 Use any touch-tone telephone to transmit your voting instructions up until 11:59 p.m. Eastern Daylight Time on May 7, 2025 or by 11:59 p.m. Eastern Daylight Time on May 5, 2025 for shares held in an Alcoa savings plan. Have your proxy card in hand when you call and then follow the instructions. VOTE BY MAIL Mark, sign and date your proxy card and return it in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: V62368-P25758 KEEP THIS PORTION FOR YOUR RECORDS DETACH AND RETURN THIS PORTION ONLY THIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED. ALCOA CORPORATION THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR EACH NOMINEE LISTED IN ITEM 1, AND FOR ITEMS 2 AND 3. 1. Election of 11 director nominees to serve for one-year terms expiring in 2026 For Against Abstain 1a. John A. Bevan 1b. Mary Anne Citrino 1c. Alistair Field 1d. Pasquale (Pat) Fiore 1e. Thomas J. Gorman 1f. James A. Hughes 1g. Roberto O. Marques 1h. William F. Oplinger 1i. Carol L. Roberts 1j. Jackson (Jackie) P. Roberts 1k. Ernesto Zedillo For Against Abstain 2. Ratification of the appointment of PricewaterhouseCoopers LLP as the Company’s independent auditor for 2025 3. Approval, on an advisory basis, of the Company's 2024 named executive officer compensation Please sign exactly as your name or names appear(s) on this proxy card. If shares are held jointly, EACH holder should sign. When signing as executor, administrator, attorney, trustee or guardian, please give full title as such. If signer is a corporation, please sign full corporate name by duly authorized officer, giving full title as such. If signer is a partnership, please sign in partnership name by authorized person. Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date

Alcoa Corporation Annual Meeting of Stockholders Thursday, May 8, 2025, 5:30 p.m. Eastern Daylight Time www.virtualshareholdermeeting.com/AA2025 Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Stockholders to be held on May 8, 2025 The Notice, Proxy Statement, and Annual Report on Form 10-K are available at www.proxyvote.com V62369-P25758 Alcoa Corporation 201 Isabella Street, Suite 500 Pittsburgh, PA 15212 THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS The undersigned hereby appoint(s) William F. Oplinger, Andrew Hastings, and Marissa P. Earnest, and each of them, attorneys and proxies with full power of substitution, to represent and to vote on behalf of the undersigned all of the shares of common stock of Alcoa Corporation the undersigned is/are entitled to vote, including with all the powers which the undersigned would possess if personally present at the Annual Meeting of Stockholders of Alcoa Corporation to be held on May 8, 2025, and at any adjournment or postponement thereof. The shares represented by this proxy will be voted as directed by the stockholder. If no such directions are indicated, the proxies will vote FOR each nominee listed in Item 1 (Election of 11 Director Nominees to Serve for One-Year Terms Expiring in 2026), FOR Item 2 (Ratification of the Appointment of PricewaterhouseCoopers LLP as the Company’s Independent Auditor for 2025), and FOR Item 3 (Approval, on an Advisory Basis, of the Company's 2024 Named Executive Officer Compensation). The proxies are authorized to vote, in their discretion and to the extent permitted by applicable law or rule, upon other matters that may arise during the 2025 Annual Meeting (including, without limitation, to adjourn the 2025 Annual Meeting). The deadline for voting online or by telephone is 11:59 p.m. Eastern Daylight Time on May 7, 2025. If you vote by mail, your proxy card must be received before the 2025 Annual Meeting for your vote to be counted. This card also serves as voting instructions to the trustee of each employee savings plan sponsored by Alcoa, its subsidiaries or affiliates with respect to shares of common stock of Alcoa Corporation held by the undersigned under any such plans. If you hold shares in an Alcoa savings plan, your voting instructions must be received by 11:59 p.m. Eastern Daylight Time on May 5, 2025, or the trustee will vote your plan shares in the same proportion as those plan shares for which instructions have been received. Your vote on the election of directors and the other proposals described in the accompanying Proxy Statement may be specified on the reverse side. If properly signed, dated and returned, this proxy will be voted as specified on the reverse side or, if no choice is specified, this proxy will be voted in accordance with the recommendations of the Board of Directors. Continued and to be signed on reverse side