Share-Based Compensation Arrangements, Vested Stock Grants

Stock-based compensation expense related to vested stock grants were included in General and administrative expenses within the Consolidated Statements of Income (Loss). The Company’s vested stock grants to the Board and related expense for the years ended December 31, 2022, 2021 and 2020, was as follows:


	Year Ended December 31,
(millions, except stock grants)	2022		2021		2020
Vested stock grants		14,635		13,420		25,066
Stock-based compensation expense	$	0.4	$	0.5	$	0.5

Summary of Compensation Expense Related to Restricted Stock Units

The Company's stock-based compensation expense related to restricted stock units during the years ended December 31, 2022, 2021 and 2020, which was included in General and administrative expenses within the Consolidated Statements of Income (Loss), was as follows:


	Year Ended December 31,
(millions)	2022		2021		2020
Stock-based compensation expense	$	5.7	$	4.6	$	1.1

The Company's stock-based compensation expense (net reduction of expense) related to PSU’s during the years ended December 31, 2022, 2021 and 2020, which was included in General and administrative expenses within the Consolidated Statements of Income (Loss), was as follows:


	Year Ended December 31,
(millions)	2022		2021		2020
Stock-based compensation expense	$	2.9	$	1.0	$	(1.0	)

Summary of Nonvested PSU's and Changes During the Period

Nonvested PSU’s as of December 31, 2022, and changes during the year ended December 31, 2022 were as follows:


	Shares			Weighted Average Grant-Date Fair Value
Nonvested as of December 31, 2021		135,383		$	36.79
Granted		132,304			30.80
Forfeited		(9,103	)		34.62
Expired		(80,979	)		37.89
Nonvested as of December 31, 2022		177,605		$	31.94

Summary of Unrecognized Compensation Expense Related to Share Based Payment

Unrecognized stock-based compensation expense related to PSU’s and the respective weighted average periods in which the expense will be recognized as of December 31, 2022 was as follows:


	Year Ended December 31,
(millions)	2022
Unrecognized stock-based compensation	$	5.3
Weighted average (years)		1.8