ATI Inc.
Ownership
Ownership Structure
Who owns ATI Inc. (ATI)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 99.1% of the shares are freely tradable; institutional investors hold 96.9%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 13.74 | 18,708,922 | +13.8 | 06/30/2026 |
| Vanguard Portfolio Management, LLC | 4.57 | 6,219,875 | +6.8 | 06/30/2026 |
| Vanguard Capital Management, LLC | 4.53 | 6,162,418 | +0.6 | 06/30/2026 |
| Capital World Investors | 3.85 | 5,249,249 | -8.1 | 06/30/2026 |
| State Street Corp | 3.85 | 5,237,299 | -2.7 | 06/30/2026 |
| Capital Research Global Investors | 3.74 | 5,093,768 | -17.3 | 06/30/2026 |
| FMR Inc | 3.66 | 4,989,171 | -4.9 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| iShares Core S&P Mid-Cap ETF | 3.56 | 4,850,420 | +0.0 | 09/30/2026 |
| Vanguard MStar Total Stk Mkt Idx Invest | 3.17 | 4,319,576 | -0.4 | 09/30/2026 |
| American Funds SMALLCAP World A | 2.95 | 4,014,385 | -4.7 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Fields Kimberly A | Chair, President and CEO | 100,719 | 16,679,066 $ | Aug 17, 2026 | direct |
| Harris Timothy J | Senior VP and CDIO | 88,187 | 14,603,767 $ | Sep 21, 2026 | direct |
| Morehouse David J | Director | 35,826 | 5,932,786 $ | Sep 2, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Sep 21, 2026 | Harris Timothy J | Senior VP and CDIO | Sell | 9,000 | 191.82 | 1,726,380 |
| Sep 14, 2026 | Harris Timothy J | Senior VP and CDIO | Sell | 16,500 | 193.06 | 3,185,490 |
| Sep 8, 2026 | Harris Timothy J | Senior VP and CDIO | Sell | 16,500 | 207.54 | 3,424,410 |
| Sep 2, 2026 | Morehouse David J | Director | Sell | 2,485 | 201.61 | 501,001 |
| Aug 31, 2026 | Harris Timothy J | Senior VP and CDIO | Sell | 16,500 | 210.01 | 3,465,165 |
| Aug 24, 2026 | Harris Timothy J | Senior VP and CDIO | Sell | 16,500 | 206.92 | 3,414,180 |
| Aug 17, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 4,598 | 232.43 | 1,068,713 |
| Aug 17, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 9,116 | 231.72 | 2,112,360 |
| Aug 17, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 8,131 | 230.66 | 1,875,496 |
| Aug 17, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 2,000 | 229.56 | 459,120 |
| Aug 17, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 1,000 | 228.32 | 228,320 |
| Jul 28, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 31,757 | 190.99 | 6,065,269 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 400 | 187.50 | 75,000 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 388 | 185.10 | 71,819 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 4,878 | 184.34 | 899,211 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 15,908 | 183.50 | 2,919,118 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 11,826 | 182.66 | 2,160,137 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 2,200 | 181.36 | 398,992 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 200 | 186.36 | 37,272 |
| Jul 7, 2026 | Fields Kimberly A | Chair, President and CEO | Sell | 2,000 | 180.00 | 360,000 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: October 30, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.