Earnings Per Share

12 Months Ended

Dec. 31, 2023

We calculate basic and diluted earnings per share using the two-class method. Earnings per share under the two-class method is calculated using net income attributable to common stockholders, which is net income reduced by the earnings allocated to participating securities. Our participating securities include share-based payment awards that contain a non-forfeitable right to receive dividends and are considered to participate in undistributed earnings with common shareholders. Participating securities excluded from weighted average common shares outstanding were 207,000 for the year ended December 31, 2023, 221,000 for the year ended December 31, 2022 and 268,000 for the year ended December 31, 2021.

The table below presents the computation of earnings per share, including the reconciliation of basic and diluted weighted average shares outstanding (in thousands, except per share data):


	Year Ended December 31,
	2023		2022		2021
Net income	$	523,229	$	748,462	$	650,624
Amounts allocated to participating securities	(2,771)		(4,151)		(4,321)
Net income attributable to common stockholders	$	520,458	$	744,311	$	646,303

Weighted average common shares outstanding:
Basic	38,704		39,409		39,876
Effect of dilutive securities:
Stock options and employee stock purchase plan	293		397		604
Diluted	38,997		39,806		40,480

Earnings per share attributable to common stockholders:
Basic	$	13.45	$	18.89	$	16.21
Diluted	$	13.35	$	18.70	$	15.97

Anti-dilutive stock options excluded from diluted earnings per share computations (1)	64		34		1

(1)Since these options have exercise prices that are higher than the average market prices of our common stock, including them in the calculation would have an anti-dilutive effect on earnings per share.