Form 4 Filing for ATI INC.

Timothy J. Harris, Senior VP and CDIO of ATI INC., reported the sale of 16,500 shares of common stock on September 14, 2026. The shares were sold at a price of $193.06 per share, totaling $3,185,490. This transaction was executed as part of a 10b5-1 Trading Plan established on May 21, 2026, for personal tax and estate planning purposes. Following the sale, Mr. Harris owns 97,187 shares of ATI INC. common stock. The filing is Form 4, indicating a change in beneficial ownership.