The calculation of basic earnings per share is computed by dividing net income available to common stockholders by the weighted-average number of shares of common stock outstanding for the period. Outstanding options to purchase Western Union stock and unvested shares of restricted stock are excluded from basic shares outstanding. Diluted earnings per share reflects the potential dilution that could occur if outstanding stock options at the presented dates are exercised and shares of restricted stock have vested, using the treasury stock method. The treasury stock method assumes proceeds from the exercise price of stock options and the unamortized compensation expense of options and restricted stock are available to acquire shares at an average market price throughout the period, and therefore, reduce the dilutive effect.

For the three months ended March 31, 2022 and 2021, there were 7.2 million and 1.4 million, respectively, of shares excluded from the diluted earnings per share calculation under the treasury stock method, primarily due to outstanding options to purchase shares of Western Union stock and restricted stock units, as the assumed proceeds of the options and restricted stock per unit were above the Company’s weighted-average share price during the periods and their effect was anti-dilutive.

The following table provides the calculation of diluted weighted-average shares outstanding (in millions):


	Three Months Ended
	March 31,
	2022		2021
Basic weighted-average shares outstanding		393.1		411.7
Common stock equivalents		1.4		2.6
Diluted weighted-average shares outstanding		394.5		414.3