Earnings per Share

3 Months Ended

Mar. 31, 2017

Basic and diluted earnings per share are calculated as follows:



	For the Three Months Ended March 31,
(In millions)	2017		2016
Numerator:
Net income attributable to Biogen Inc.	$	747.6	$	970.9
Denominator:
Weighted-average number of common shares outstanding	215.6		218.9
Effect of dilutive securities:
Stock options and employee stock purchase plan	—		0.1
Time-vested restricted stock units	0.2		0.2
Market stock units	0.1		0.1
Dilutive potential common shares	0.3		0.4
Shares used in calculating diluted earnings per share	215.9		219.3

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

The adjustments related to the spin-off of our hemophilia business did not have a material impact on the potentially dilutive securities to be considered in the calculation of diluted earnings per share of common stock.