INCOME PER COMMON SHARE

12 Months Ended

Dec. 31, 2023

S. INCOME PER COMMON SHARE

Reconciliations of the numerators and denominators used in the computations of basic and diluted income per common share were as follows, in millions:


	Year Ended December 31,
	2023		2022		2021
Numerator (basic and diluted):
Net income	$	908	$	844	$	410
Less: Allocation to redeemable noncontrolling interest	—		(2)		2
Less: Allocation to unvested restricted stock awards	—		4		2




Net income attributable to common shareholders	$	908	$	842	$	406

Denominator:
Basic common shares (based upon weighted average)	225		231		249
Add: Stock option dilution	1		1		2
Diluted common shares	226		232		251

We follow accounting guidance regarding determining whether instruments granted in share-based payment transactions are participating securities. This accounting guidance clarifies that share-based payment awards that entitle their holders to receive non-forfeitable dividends prior to vesting should be considered participating securities. The dividends associated with the unvested restricted stock units are forfeitable, and consequently, the restricted stock units are not considered a participating security and are not accounted for under the two-class method. We have also granted restricted stock awards that contain non-forfeitable rights to dividends on unvested shares; such unvested restricted stock awards are considered participating securities. As participating securities, the unvested shares are required to be included in the calculation of our basic income per common share, using the two-class method. The two-class method of computing income per common share is an allocation method that calculates income per share for each class of common stock and participating security according to dividends declared and participation rights in undistributed earnings. For the years ended December 31, 2023, 2022 and 2021, we allocated dividends and undistributed earnings to the participating securities.

The following stock options, restricted stock units and performance restricted stock units were excluded from the computation of weighted-average diluted common shares outstanding due to their anti-dilutive effect, in thousands:


	Year Ended December 31,
	2023	2022	2021
Number of stock options	871	635	296
Number of restricted stock units	5	20	—
Number of performance restricted stock units	—	15	—

Common shares outstanding included on our balance sheet and for the calculation of income per common share do not include unvested stock awards (79,000 and 273,000 common shares at December 31, 2023 and 2022, respectively). Shares outstanding for legal requirements included all common shares that have voting rights (including unvested stock awards).