Net Income Per Share

9 Months Ended

Sep. 30, 2021

The following table reconciles the shares used in the calculation of basic net income per share to those used for diluted net income per share:


	Three Months Ended September 30,				Nine Months Ended September 30,
(in millions)	2021		2020		2021		2020
Net income	$	175.6	$	82.3	$	514.1	$	247.8
Weighted average common shares outstanding	74.1		73.9		74.0		73.9
Dilutive effect of equity awards, based on the treasury stock method	1.9		1.9		1.8		1.7
Weighted average shares assuming dilution	76.0		75.8		75.8		75.6

During the three months ended September 30, 2021 and 2020, there were 0.0 million and 0.0 million shares, respectively, from stock-based compensation plans not included in the computation of diluted net income per share because their impact was antidilutive. There were 0.0 million and 0.2 million antidilutive shares outstanding during the nine months ended September 30, 2021 and 2020, respectively.

In December 2020, we announced a share repurchase program for calendar-year 2021 authorizing the repurchase of up to 631,000 shares of our common stock from time to time on the open market or in privately-negotiated transactions as permitted under Exchange Act Rule 10b-18. The number of shares to be repurchased and the timing of such transactions will depend on a variety of factors, including market conditions. There were no shares purchased during the three months ended September 30, 2021. During the nine months ended September 30, 2021, we purchased 479,000 shares of our common stock under the program at a cost of $137.1 million, or an average price of $286.23 per share. This share repurchase program is expected to be completed by December 31, 2021.