Form 4 Filing for ATI INC. - Harris Timothy J Sells Shares

This Form 4 filing reports a transaction by Harris Timothy J, Senior VP and CDIO of ATI INC. On August 31, 2026, Mr. Harris sold 16,500 shares of common stock with a par value of $0.10 per share. The sale occurred at a price of $210.01 per share, resulting in a post-transaction ownership of 130,187 shares. This transaction was executed as part of a 10b5-1 Trading Plan established on May 21, 2026, for personal tax and estate planning purposes, as indicated by footnote F1. The filing was signed by Amanda J. Skov, acting as Attorney-in-Fact for Timothy J. Harris, on September 2, 2026.