Officer and Director Stock Transactions

Kimberly A. Fields, Chair, President and CEO of ATI INC, reported the sale of 60,000 shares of common stock on June 2, 2026. The sales were executed under a 10b5-1 Trading Plan established on February 5, 2026, for personal tax and estate planning purposes. The shares were sold in multiple transactions at weighted average prices ranging from $177.42 to $183.18. Following these transactions, Ms. Fields directly owns 218,014 shares of ATI INC common stock. The total value of the shares sold is approximately $10,781,464.