Earnings per Share

12 Months Ended

Dec. 31, 2021

EARNINGS PER SHARE

Basic and diluted shares outstanding used in our earnings per share calculation are calculated as follows:


	For the Years Ended December 31,
(In millions)	2021		2020		2019
Numerator:
Net income attributable to Biogen Inc.	$	1,556.1	$	4,000.6	$	5,888.5
Denominator:
Weighted average number of common shares outstanding	149.1		160.9		187.1
Effect of dilutive securities:

Time-vested restricted stock units	0.3		0.2		0.2
Market stock units	0.1		0.1		0.1
Performance stock units settled in stock	0.1		0.1		—
Dilutive potential common shares	0.5		0.4		0.3
Shares used in calculating diluted earnings per share	149.6		161.3		187.4

Amounts excluded from the calculation of net income per diluted share because their effects were anti-dilutive were insignificant.

Earnings per share for the years ended December 31, 2021, 2020 and 2019, reflects the repurchase of approximately 6.0 million shares, 22.4 million shares and 23.6 million shares of our common stock, respectively, under our share repurchase programs. For additional information on our share repurchase programs, please read Note 13, Equity, to these consolidated financial statements.