Earnings per Share (Tables)

6 Months Ended

Jun. 30, 2026

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


	For the Three Months Ended June 30,				For the Six Months Ended June 30,
(In millions)	2026		2025		2026		2025
Numerator:
Net income attributable to Biogen Inc.	$	97.5	$	634.8	$	417.0	$	875.3
Denominator:
Weighted average number of common shares outstanding	147.7		146.5		147.4		146.3
Effect of dilutive securities:

Time-vested restricted stock units	0.8		0.2		1.0		0.3

Performance stock units settled in stock	0.2		—		0.2		0.1
Dilutive potential common shares	1.0		0.2		1.2		0.4
Shares used in calculating diluted earnings per share	148.7		146.7		148.6		146.7