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v3.25.1

Per Share Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 30, 2025 | Mar. 31, 2024 | Sep. 03, 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |
Net income attributable to ATI | $ 97.0 | $ 66.1 |
Net income attributable to ATI after assumed conversions | $ 97.0 | $ 68.2 |
Denominator for basic net income per common share – weighted average shares | 141.7 | 126.2 |
Share-based compensation | 2.5 | 2.5 |
Denominator for diluted net income per common share – adjusted weighted average shares and assumed conversions | 144.2 | 147.5 |
Basic net income attributable to ATI per common share (in dollars per share) | $ 0.68 | $ 0.52 |
Diluted net income attributable to ATI per common share (in dollars per share) | $ 0.67 | $ 0.46 |
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount | 0.0 | 0.0 |
Purchase of treasury stock | $ (70.0) | $ (150.0) |
Stock repurchase plan, authorized amount |  |  | $ 700.0
Treasury Stock, Shares, Acquired | 1.2 | 3.4 |
Share Repurchase Program, Utilized, Amount | $ 180.0 |  |
Purchase of treasury stock | (70.2) | $ (151.2) |
3.5% Convertible Senior Notes due 2025 |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |
Convertible Senior Notes- Effect on numerator | $ 0.0 | $ 2.1 |
Convertible Senior Notes- Effect on denominator | 0.0 | 18.8 |
3.5% Convertible Senior Notes due 2025 | Convertible Debt |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  | 3.50% |
Interest rate |  | 3.50% |
Treasury Stock |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |
Purchase of treasury stock | $ (70.2) | $ (151.2) |

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