Earnings per Share

3 Months Ended

Mar. 31, 2024

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


	For the Three Months Ended March 31,
(In millions)	2024		2023
Numerator:
Net income attributable to Biogen Inc.	$	393.4	$	387.9
Denominator:
Weighted average number of common shares outstanding	145.2		144.4
Effect of dilutive securities:

Time-vested restricted stock units	0.5		0.6
Market stock units	—		0.1
Performance stock units settled in stock	0.2		0.1
Dilutive potential common shares	0.7		0.8
Shares used in calculating diluted earnings per share	145.9		145.2

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