X0306 4 2023-01-03 0 0001018963 ATI INC ATI 0001520037 Davis Elliot S C/O ATI INC. 116 15TH STREET, SUITE 301 PITTSBURGH PA 15222 0 1 0 0 Chief Legal & Compl. Officer Common Stock, par value $0.10 per share 2023-01-03 4 A 0 10453 0.00 A 170802.6389 D Common Stock, par value $0.10 per share 2023-01-04 4 F 0 6096 30.38 D 164706.6389 D Common Stock, par value $0.10 per share 2023-01-04 4 F 0 3465 30.38 D 161241.6389 D Award of restricted stock units, which are settled in shares of stock upon vesting. The award vests in three equal annual installments on each of the first three anniversaries of the grant date. Awarded under ATI's 2022 Incentive Plan. Shares withheld for payment of taxes on restricted stock units awarded on January 4, 2021. One-third of such restricted stock units vested by their terms on January 4, 2023. 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 ("NYSE") on January 4, 2023. Shares withheld for payment of taxes on restricted stock units awarded on January 4, 2022. One-third of such restricted stock units vested by their terms on January 4, 2023. /s/ Elliot S. Davis 2023-01-05