ATI CEO Kimberly A. Fields Sells Shares

What Happened
Kimberly A. Fields — Chair, President & CEO and a director of ATI Inc. (ATI) — sold a total of 24,845 ATI shares in open-market transactions on August 17, 2026, generating about $5,744,009 in proceeds. The sales were executed in five tranches:

• 1,000 shares at $228.32 — $228,320 (weighted-average price; trades ranged $228.02–$228.73)
• 2,000 shares at $229.56 — $459,120 (weighted-average; range $229.14–$230.07)
• 8,131 shares at $230.66 — $1,875,496 (weighted-average; range $230.17–$231.16)
• 9,116 shares at $231.72 — $2,112,360 (weighted-average; range $231.20–$232.18)
• 4,598 shares at $232.43 — $1,068,713 (weighted-average; range $232.19–$232.74)

Key Details

• Transaction date: August 17, 2026; Form 4 filed August 19, 2026 (appears timely under the two‑business‑day rule).
• Total shares sold: 24,845; total proceeds: approximately $5.74 million.
• Shares owned after transaction: not specified in the provided filing summary.
• Footnotes: Sales were made pursuant to a 10b5‑1 trading plan dated Feb 5, 2026 (for personal tax and estate planning) and each reported price is a weighted average for multiple trades; exact per‑trade prices are available upon request to the issuer/SEC staff.

Context
Sales under a 10b5‑1 plan are pre‑arranged transactions that allow insiders to sell shares according to a preset schedule; such sales are often routine and do not necessarily indicate a change in the insider’s view of the company. This filing reports dispositions (S = sale), not purchases or option exercises.