The Company granted 14,635 and 13,420 shares of common stock to the Board during the nine months ended September 30, 2022 and 2021, respectively. The Company recognized $0.4 million and $0.5 million of stock-based compensation expense related to the stock grants during the nine months ended September 30, 2022 and 2021, respectively.

During the nine months ended September 30, 2022, the Company granted 1,057 and 135,054 restricted stock units to certain executives that vest over one and three years, respectively. During the nine months ended September 30, 2021, the Company granted 160,843 and 152,659 restricted stock units to certain executives and employees that vest over two and three years, respectively.

Nonvested restricted stock units as of September 30, 2022, and changes during the nine months ended September 30, 2022 (unaudited) were as follows:


	Shares			Weighted Average Grant-Date Fair Value
Nonvested as of December 31, 2021		355,434		$	34.40
Granted		136,111			30.76
Vested		(37,235	)		33.61
Forfeited		(7,178	)		34.33
Nonvested as of September 30, 2022		447,132		$	33.36

The Company's stock-based compensation expense related to the restricted stock units during the three and nine months ended September 30, 2022 and 2021 (unaudited), respectively, which was included in General and administrative expenses within the Condensed Consolidated Statements of Income, was as follows:


	Three Months Ended				Nine Months Ended
(millions)	September 30, 2022		September 30, 2021		September 30, 2022		September 30, 2021
Stock-based compensation expense	$	1.5	$	1.2	$	4.3	$	3.3

As of September 30, 2022, there was $6.3 million of unrecognized stock-based compensation expense related to restricted stock units that are expected to be recognized over a weighted average remaining period of approximately 1.7 years.

During the nine months ended September 30, 2022 and 2021, the Company granted 132,304 and 50,868 PSUs, respectively, to certain executives. The performance target is based on the achievement of a certain level of operating income, excluding depreciation and amortization, as well as certain other discretionary adjustments by the Board, over three-year performance periods. The performance period for the PSUs granted in 2022 (“2022 PSUs”) is from 2022 through 2024, while the performance period for the PSUs granted in 2021 (“2021 PSUs”) is from 2021 through 2023. The ultimate number of shares issued could change depending on the Company’s results over the performance period. The maximum amount of shares that could be issued for the 2022 PSUs and 2021 PSUs are 264,608 and 99,952, respectively. The Company is currently recognizing expense for the 2022 PSUs based on a payout of 157,445 shares and the maximum payout of 99,952 shares for the 2021 PSUs.

Due to the impact of COVID-19 on the Company’s operations, the Company expects the targets for the PSU awards granted in 2020 (“2020 PSUs) to not be achieved. Therefore, no compensation expense was recognized related to the 2020 PSUs during the three and nine months ended September 30, 2022 and 2021. The performance target for the 2020 PSUs is based on the achievement of certain free cash flow targets before cash taxes and interest payments, subject to certain discretionary adjustments by the Board, over the three-year performance period of 2020 through 2022.

Nonvested PSUs as of September 30, 2022, and changes during the nine months ended September 30, 2022 (unaudited) 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		(2,660	)		36.91
Nonvested as of September 30, 2022		265,027		$	33.80

The Company's stock-based compensation expense related to PSUs during the three and nine months ended September 30, 2022 and 2021 (unaudited), which is included in General and administrative expenses within the Condensed Consolidated Statements of Income, was as follows:


	Three Months Ended				Nine Months Ended
(millions)	September 30, 2022		September 30, 2021		September 30, 2022		September 30, 2021
Stock-based compensation expense	$	0.7	$	0.3	$	1.9	$	0.7

As of September 30, 2022, there was $5.4 million of unrecognized stock-based compensation expenses related to PSU awards that are expected to be recognized over a weighted average remaining period of approximately 2.0 years. Since the Company no longer expects the required performance targets to be achieved for the 2020 PSUs, no future compensation expense is expected to be recognized; however, future compensation expense for the 2020 PSUs could reach a maximum of $6.3 million if the performance targets are achieved. In addition, the Company could recognize additional future stock-based compensation expense of $3.3 million for the 2022 PSUs if the maximum performance target is achieved.