Note 19—Earnings Per Share of Common Stock

Basic earnings per share of common stock is determined using net income attributable to the Company’s common stockholders divided by the weighted average number of shares of common stock outstanding during the period. Diluted earnings per share of common stock is determined by dividing net income attributable to the Company’s common stockholders by the weighted average number of shares of common stock outstanding, assuming all dilutive shares of common stock were issued.

Potentially dilutive shares of common stock include non-vested stock-based compensation awards. The Company applies the treasury stock method to determine the diluted weighted average 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,
	2020		2019
	(in thousands, except per share amounts)
Net income	$	306,243	$	46,135

Weighted average basic shares of common stock outstanding		78,689		77,653
Effect of dilutive shares:
Common shares issuable under stock-based compensation plan		3,319		1,633
Weighted average shares of common stock applicable to diluted earnings per share		82,008		79,286
Basic earnings per share of common stock	$	3.89	$	0.59
Diluted earnings per share of common stock	$	3.73	$	0.58

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 anti-dilutive weighted-average number of outstanding performance-based restricted share units (“RSUs”), time-based RSUs, and stock options excluded from the calculation of diluted earnings per share:



	Quarter ended March 31,
	2020		2019
	(in thousands except for weighted-average exercise price)
Performance-based RSUs (1)		162		1,279
Time-based RSUs		117		61
Stock options (2)		105		706
Total anti-dilutive shares and units		384		2,046
Weighted average exercise price of anti-dilutive stock options (2)	$	35.03	$	24.26

(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.