Earnings Per Share of Common Stock

3 Months Ended

Mar. 31, 2021

Earnings Per Share of Common Stock

Earnings Per Share of Common Stock

Note 21—Earnings Per Share of Common Stock

Basic earnings per share of common stock is determined by dividing net income by the weighted average number of shares of common stock outstanding during the quarter. Diluted earnings per share of common stock is determined by dividing net income by the weighted average number of shares of common stock outstanding, assuming all dilutive securities were issued.

Potentially dilutive securities include non-vested stock-based compensation awards. The Company applies the treasury stock method to determine the diluted weighted average number of shares of common stock outstanding based on the outstanding stock-based compensation awards.

The following table summarizes the basic and diluted earnings per share calculations:

	Quarter ended March 31,
	2021		2020
	(in thousands, except per share amounts)
Net income	$	376,868	$	306,243
Weighted average basic shares of common stock outstanding		69,113		78,689
Effect of dilutive securities:
Common shares issuable under stock-based compensation plan		4,004		3,319
Weighted average shares of common stock applicable to diluted earnings per share		73,117		82,008
Basic earnings per share of common stock	$	5.45	$	3.89
Diluted earnings per share of common stock	$	5.15	$	3.73

Calculations of diluted earnings per share require certain potentially dilutive shares to be excluded when their inclusion in the diluted earnings per share calculation would be anti-dilutive. The following table summarizes the weighted-average number of anti-dilutive outstanding performance-based RSUs and stock options excluded from the calculation of diluted earnings per share:

	Quarter ended March 31,
	2021		2020
	(in thousands except for weighted-average exercise price)
Performance-based RSUs (1)		120		162
Time-based RSUs		—		117
Stock options (2)		97		105
Total anti-dilutive shares and units		217		384
Weighted average exercise price of anti-dilutive stock options (2)	$	58.85	$	35.03

(1) Certain performance-based RSUs were outstanding but not included in the computation of earnings per share because the performance thresholds included in such RSUs have not been achieved.

(2) Certain stock options were outstanding but not included in the computation of diluted earnings per share because the weighted-average exercise prices were above the average stock prices for the period.