144 0001773072 XXXXXXXX LIVE 0001018963 ATI INC 001-12001 2021 MCKINNEY AVENUE DALLAS TX 75201 4123942800 Fields Kimberly A Officer Director Common Fidelity Brokerage Services LLC

900 Salem Street Smithfield RI 02917

59749 10599472.60 136470427 06/02/2026 NYSE Common 01/05/2026 Restricted Stock Vesting Issuer N 59749 01/05/2026 Compensation N Kimberly A. Fields

2021 McKinney Avenue Dallas TX 75201

Common 05/11/2026 40000 6368283.35 06/02/2026 02/05/2026 /s/ Daniel Tucci, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Kimberly Fields