X0306 4/A 2022-01-06 2022-01-07 0 0001018963 ALLEGHENY TECHNOLOGIES INC ATI 0001282236 NEWMAN DONALD P C/O ALLEGHENY TECHNOLOGIES INCORPORATED 1000 SIX PPG PLACE PITTSBURGH PA 15217 0 1 0 0 EVP and CFO Common Stock, par value $0.10 per share 2022-01-06 4 F 0 3570 17.50 D 146773 D Shares withheld for payment of taxes on restricted stock units awarded on January 6, 2020. One-third of such restricted stock units vested by their terms on January 6, 2022. Represents the average of the high and low trading prices for one share of the Issuer's common stock on the New York Stock Exchange on January 6, 2022. This amended Form 4 is filed to reflect an administrative correction to the number of shares withheld for the payment of taxes with respect to the vesting of restricted stock units awarded on January 6, 2020, as reflected on Table I above. /s/ Amanda J. Skov, Attorney-in-Fact for Donald P. Newman 2022-03-25