Under the Stock Incentive Plan of 2017 (the 2017 Plan), up to 17 million shares of common stock are available for awards to our employees, officers, consultants, and directors. Awards may be in the form of stock options, stock appreciation rights, restricted stock, restricted stock units, performance share units, and other stock-based awards. Each full-value award, defined as any award other than a stock option or stock appreciation right, is counted as 1.76 shares. The exercise price for stock options issued cannot be less than the fair value of the underlying common stock as of the grant date. Stock options generally have a term of eight years after the date of grant and fully vest after three years. At December 31, 2021, approximately 8.3 million shares were available for future grants under the 2017 Plan.


		Weighted Average
	Shares	Grant Date
	(000s)	Fair Value
Outstanding at December 31, 2020	321	$	18.78

Vested	(102)	18.78
Forfeited	(11)	18.78
Outstanding at December 31, 2021	208	18.78

During 2020, we issued SSUs with a weighted average grant date fair value per share of $18.78. There were no issuances of SSUs during 2021. SSUs vest over a six year period, beginning at the date of grant. One-third of the SSUs are eligible for accelerated vesting on a cumulative basis at the end of each of the one-, three-, and five-year service periods that began on January 1, 2021, if certain performance goals are achieved. Forfeitable dividends on SSUs are accrued in the form of cash. Compensation cost for SSUs subject to accelerated vesting due to the achievement of certain performance conditions at the end of the one-, three-, and five-year service periods is recognized over the implicit service period.

The total fair value of SSUs that vested during 2021 was $1.9 million. No SSUs vested during 2020. At December 31, 2021, we had $2.6 million of unrecognized compensation cost related to SSUs that will be recognized over a remaining weighted average period of 1.6 years.


		Weighted Average
	Shares	Grant Date
	(000s)	Fair Value
Outstanding at December 31, 2020	517	$	30.31
Granted1	(30)	51.26
Vested	(169)	38.81
Forfeited	(10)	31.12
Outstanding at December 31, 2021	308	23.58

1Reflects adjustments made as a result of the application of the performance factor, which was less than 100 percent for the 2018 PSU grant.

During 2020 and 2019, we issued PSUs with a weighted average grant date fair value per share of $23.49 and $41.57, respectively. There were no new issuances of PSUs during 2021. Vesting for the PSUs occurs at the end of a three-year period and is contingent upon our achievement of prospective company performance goals and our total shareholder return relative to a board-approved peer group during the three-year period. Actual performance, including modification for relative total shareholder return, may result in the ultimate award of 40 percent to 180 percent of the initial number of PSUs issued, with the potential for no award if company performance goals are not achieved during the three-year period. Forfeitable dividend equivalents on PSUs have previously been accrued in the form of additional PSUs. Beginning with the March 1, 2020 grant, forfeitable dividends are accrued as cash.

PSU shares in the preceding table represent aggregate initial target awards and accrued dividend equivalents and do not reflect potential increases or decreases resulting from the application of the performance factor determined after the end of the performance periods. At December 31, 2021, the three-year performance period for the 2019 PSU grant was completed and the related shares vested, but the performance factor had not yet been applied. The performance factor will be applied during the first quarter of 2022, with distribution of the stock at that time. Granted and vested amounts in the preceding table also include an adjustment to reflect the application of the performance factor to the 2018 PSU grant, which occurred during the first quarter of 2021.

The total fair value of shares vested during 2021, 2020, and 2019 was $6.6 million, $6.5 million, and $6.5 million, respectively. At December 31, 2021, we had approximately $2.2 million of unrecognized compensation cost related to PSUs that will be recognized in 2022. The estimated compensation expense is adjusted for actual performance experience and is recognized ratably during the service period, or remaining service period, if and when it becomes probable that the performance conditions will be satisfied. Compensation cost for PSUs subject to accelerated vesting at the date of retirement eligibility is recognized over the implicit service period.

The fair value of PSUs is estimated on the date of initial grant using the Monte-Carlo simulation model. Key assumptions used to value PSUs granted during the years shown are as follows:


	Year Ended December 31
	2020		2019
Expected Volatility (based on our and our peer group historical daily stock prices)	23	%	23	%
Expected Life (equals the performance period)	3 years		3 years
Risk Free Interest Rate (based on U.S. Treasury yields at the date of grant)	0.85	%	2.53	%

During 2021, we issued CIUs with a weighted average grant date fair value per unit of $1.02. CIUs are denominated and settled in cash. Vesting for the CIUs occurs at the end of a three-year period and is based upon prospective company performance measures and our total shareholder return relative to a board-approved peer group during the three-year period. Actual performance, including modification for relative total shareholder return, may result in the ultimate award of 0 percent to 200 percent of the initial number of CIUs issued.

CIUs in the preceding table represent aggregate initial target awards and do not reflect potential increases or decreases resulting from the application of the performance factor determined after the end of the performance periods. No CIUs vested as of December 31, 2021.

At December 31, 2021, we had approximately $5.3 million of unrecognized compensation cost related to CIUs that will be recognized over a weighted average period of 2.0 years. The estimated compensation expense is adjusted for actual performance experience and is recognized ratably during the service period, or remaining service period, if and when it becomes probable that the performance conditions will be satisfied. Compensation cost for CIUs subject to accelerated vesting at the date of retirement eligibility is recognized over the implicit service period.

The fair value of CIUs is estimated at each reporting period using the Monte-Carlo simulation model. Key assumptions used to value CIUs granted during current year are as follows:


	Year Ended December 31, 2021

Expected Volatility (based on our and our peer group historical daily stock prices)	50	%
Expected Life (equals the performance period)	3 years
Risk Free Interest Rate (based on U.S. Treasury yields at the date of grant)	0.71	%


		Weighted Average
	Shares	Grant Date
	(000s)	Fair Value
Outstanding at December 31, 2020	1,593	$	27.57
Granted	1,373	27.02
Vested	(820)	29.09
Forfeited	(130)	26.84
Outstanding at December 31, 2021	2,016	26.63

During 2021, 2020, and 2019, we issued RSUs with a weighted average grant date fair value per share of $27.02, $22.71, and $37.07, respectively. RSUs vest over a one to three-year service period, beginning at the date of grant, and the compensation cost is recognized ratably during the vesting period. Forfeitable dividend equivalents on RSUs have previously been accrued in the form of additional RSUs. Beginning with the March 1, 2020 grant, forfeitable dividends are accrued as cash. Compensation cost for RSUs subject to accelerated vesting at the date of retirement eligibility is recognized over the implicit service period.

The total fair value of shares vested during 2021, 2020, and 2019 was $23.9 million, $25.1 million, and $19.5 million, respectively. At December 31, 2021, we had $29.9 million of unrecognized compensation cost related to RSUs that will be recognized over a weighted average period of 0.9 years.

During 2020, we issued cash-settled RSUs with a weighted average grant date fair value per share of $22.94. There were no new issuances of cash-settled RSUs during 2021 Cash-settled RSUs vest over a one to three-year service period, beginning at the date of grant, and the compensation cost is recognized ratably during the vesting period. Forfeitable dividends on cash-settled RSUs are accrued in the form of cash. Compensation cost for cash-settled RSUs subject to accelerated vesting at the date of retirement eligibility is recognized over the implicit service period. The total fair value of cash-settled RSUs that vested during 2021 was $0.6 million. No cash-settled RSUs vested during 2020.

The amount payable per unit awarded is equal to the price per share of Unum Group's common stock at settlement of the award, and as such, we measure the value of the award each reporting period based on the current stock price. The effects of changes in the stock price during the service period are recognized as compensation cost over the service period. Changes in the amount of the liability due to stock price changes after the service period are recognized as compensation cost during the period in which the changes occur. At December 31, 2021, we had $0.7 million of unrecognized compensation cost related to cash-settled RSUs that will be recognized over a weighted average period of 0.6 years.


				Remaining	Intrinsic
	Shares	Weighted Average		Contractual Term	Value
	(000s)	Exercise Price		(in years)	(in millions)
Outstanding at December 31, 2020	40	$	24.25

Exercised	(40)	24.25

Outstanding at December 31, 2021	—			—	$	—

Stock options vested over a one to three-year service period, beginning at the date of grant, and the compensation cost is recognized ratably during the vesting period. Compensation cost for stock options subject to accelerated vesting at the date of retirement eligibility was recognized over the implicit service period. The intrinsic value of options exercised in 2021, 2020, and 2019 was $0.1 million, $0.1 million, and $0.3 million, respectively. There were no stock options granted or vested in the years 2019 through 2021. At December 31, 2021, we had no unrecognized compensation cost related to stock options as there are no exercisable stock options outstanding.


	Year Ended December 31
	2021		2020		2019
	(in millions of dollars)
Performance Share Units	$	3.3	$	5.6	$	5.0
Cash Incentive Units	3.2		—		—
Restricted Stock Units and Cash-Settled Restricted Stock Units	25.5		23.9		21.0

Stock Success Units	2.8		0.4		—
Other	0.6		0.5		0.6
Total Compensation Expense, Before Income Tax	$	35.4	$	30.4	$	26.6

Total Compensation Expense, Net of Income Tax	$	31.1	$	26.1	$	22.7