ATI(ATI) - 2025 Q4 - Annual Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the fiscal year ended December 28, 2025 OR ☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to Commission file number 1-12001 ATI Inc. (Exact name of registrant as specified in its charter) Delaware 25-1792394 (State or other jurisdiction of incorporation ...