Share-Based Compensation Plans

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

The following table summarizes share-based compensation expense recognized in the Consolidated Statements of Income in Compensation and benefits (in millions):


	Years Ended December 31
	2023		2022		2021
Restricted share units	$	283	$	251	$	204
Performance share awards	143		134		189

Employee share purchase plans and other (1)	12		12		56
Total share-based compensation expense	438		397		449
Tax benefit	91		83		87
Share-based compensation expense, net of tax	$	347	$	314	$	362

(1) 2021 includes expenses related to the Aon United Growth Ownership Plan.

Restricted Share Units

RSUs generally vest between three and five years. The fair value of RSUs is based upon the market value of the Company’s class A ordinary shares at the date of grant. With certain limited exceptions, any break in continuous employment will cause the forfeiture of all non-vested awards. Compensation expense associated with RSUs is recognized on a straight-line basis over the requisite service period. Dividend equivalents are paid on certain RSUs, based on the initial grant amount.

The following table summarizes the status of the Company’s RSUs (shares in thousands, except fair value):


	Shares	Fair Value (1)
Non-vested balance at December 31, 2022	2,863	$	238
Granted	1,128	$	302
Vested	(1,124)	$	221
Forfeited	(193)	$	254
Non-vested balance at December 31, 2023	2,674	$	271

(1)Represents per share weighted average fair value of award at date of grant.

The weighted-average grant date fair value of the Company's RSU awards granted during the years ended December 31, 2023, December 31, 2022, and December 31, 2021 was $302, $279, and $253, respectively. The fair value of RSUs that vested during 2023, 2022, and 2021 was $248 million, $216 million, and $189 million, respectively.

Unamortized deferred compensation expense amounted to $477 million as of December 31, 2023, with a remaining weighted average amortization period of approximately 2.0 years.

Performance Share Awards

The vesting of PSAs is contingent upon meeting a cumulative level of adjusted diluted earnings per share related performance over a three-year period. The actual issuance of shares may range from 0-200% of the target number of PSAs granted, based on the terms of the plan and level of achievement of the related performance target. The grant date fair value of PSAs is based upon the market price of the Company’s class A ordinary shares at the date of grant, reduced by the present value of estimated dividends foregone during the vesting period. The performance conditions are not considered in the determination of the grant date fair value for these awards. Compensation expense is recognized over the performance period based on management’s estimate of the number of units expected to vest. Management evaluates its estimate of the actual number of shares expected to be issued at the end of the programs on a quarterly basis. The cumulative effect of the change in estimate is recognized in the period of change as an adjustment to Compensation and benefits in the Consolidated Statements of Income, if necessary. Dividend equivalents are not paid on PSAs.

The following table summarizes the status of the Company's PSAs at 100% of the targeted amount (shares in thousands, except fair value):


	Shares	Fair Value (1)
Non-vested balance at December 31, 2022	1,136	$	222
Granted	331	$	298
Vested	(478)	$	163
Forfeited	(12)	$	285
Non-vested balance at December 31, 2023	977	$	275

(1)Represents per share weighted average fair value of award at date of grant.

The per share weighted-average grant date fair value of the Company's PSA awards granted during the years ended December 31, 2023, December 31, 2022, and December 31, 2021 was $298, $311, and $225, respectively. The payout of shares in 2023 with respect to the PSA awards granted in 2020 based on performance for the three-year performance period ended 2022 was, in aggregate, 956 thousand shares. The fair value of PSAs that vested during 2023, 2022, and 2021 was $156 million, $145 million, and $112 million, respectively.

Unamortized compensation expense, based on current performance levels, amounted to $112 million as of December 31, 2023, with a remaining weighted average amortization period of approximately 1.3 years.