Per Share Information

12 Months Ended

Dec. 31, 2020

The following table sets forth the computation of basic and diluted net income (loss) per common share:

(In millions, except per share amounts)


For the Years Ended December 31,	2020		2019		2018
Numerator:
Numerator for basic net income (loss) per common share -
Net income (loss) attributable to ATI	$	(1,572.6)	$	257.6	$	222.4
Effect of dilutive securities:
4.75% Convertible Senior Notes due 2022	—		12.8		12.9
3.5% Convertible Senior Notes due 2025	—		—		—
Numerator for diluted net income (loss) per common share -
Net income (loss) attributable to ATI after assumed conversions	$	(1,572.6)	$	270.4	$	235.3
Denominator:
Denominator for basic net income (loss) per common share—weighted average shares	126.5		125.8		125.2
Effect of dilutive securities:
Share-based compensation	—		0.8		0.8
4.75% Convertible Senior Notes due 2022	—		19.9		19.9
3.5% Convertible Senior Notes due 2025	—		—		—
Denominator for diluted net income (loss) per common share—adjusted weighted average shares and assumed conversions	126.5		146.5		145.9
Basic net income (loss) attributable to ATI per common share	$	(12.43)	$	2.05	$	1.78
Diluted net income (loss) attributable to ATI per common share	$	(12.43)	$	1.85	$	1.61

Common stock that would be issuable upon the assumed conversion of the 2022 Convertible Notes and the 2025 Convertible Notes and other option equivalents and contingently issuable shares are excluded from the computation of contingently issuable shares, and therefore, from the denominator for diluted earnings per share, if the effect of inclusion is anti-dilutive. There were 22.8 million anti-dilutive shares for 2020. There were no anti-dilutive shares for 2019 and 2018.