Stock-Based Compensation

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

The 2014 Omnibus Incentive Compensation Plan is Ameren’s long-term stock-based compensation plan for eligible employees and directors. It provides for a maximum of 8 million common shares to be available for grant to eligible employees and directors. At December 31, 2020, there were 2.3 million common shares remaining for grant. Awards may be stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance share units, cash-based awards, and other stock-based awards. Ameren used newly issued shares to fulfill its stock-based compensation obligations for 2020, 2019, and 2018, and intends to use newly issued shares to fulfill its stock-based compensation obligations for 2021.

The following table summarizes Ameren’s nonvested performance share unit and restricted stock unit activity for the year ended December 31, 2020:


	Performance Share Units – Market Condition(a)			Performance Share Units – Performance Condition(b)			Restricted Stock Units
	Share Units	Weighted-average Fair Value per Share Unit		Shares	Weighted-average Fair Value per Share Unit		Stock Units	Weighted-average Fair Value per Stock Unit
Nonvested at January 1, 2020(c)	539,877	$	63.79	—	$	—	220,277	$	61.13
Granted(d)	267,154	82.49		43,052	76.69		173,571	76.91
Forfeitures	(16,303)	73.42		(1,155)	76.80		(7,507)	69.89
Vested and undistributed(e)	(178,802)	69.87		(7,607)	76.78		(80,180)	66.72
Vested and distributed	(147,787)	59.16		—	—		(2,466)	54.30
Performance share adjustment	—	—		(2,394)	76.66		—	—
Nonvested at December 31, 2020(f)	464,139	$	73.34	31,896	$	76.66	303,695	$	68.52

(a)The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the specified market conditions. Compensation cost on nonforfeited awards is recognized regardless of whether Ameren achieves the specified market conditions.

(b)The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the performance goals. Compensation cost is recognized ratably over the requisite service period only for awards for which it is probable that the performance condition will be satisfied. The performance share adjustment represents the change in the probability that a performance condition will be satisfied.

(c)Does not include 503,283 performance share units for market performance and 79,854 restricted stock units that were vested and undistributed.

(d)In September 2020, certain executive officers were granted an additional 37,104 restricted stock units with a grant date fair value of $3 million, which will vest after three years on September 17, 2023. The awards do not provide for pro rata vesting in connection with the executive officer’s retirement.

(e)Vested and undistributed units are awards that vest on a pro-rata basis due to attainment of retirement eligibility by certain employees, but have not yet been distributed. For vested and undistributed performance share units, the number of shares issued for retirement-eligible employees will vary depending on actual performance over the three-year performance period.

(f)Does not include 366,243 of performance share units for market performance, 7,607 of performance share units based on the achievement of renewable generation and energy storage installation targets, and 160,034 of restricted stock units that were vested and undistributed.

Performance Share Units – Market Condition

A market condition performance share unit vests and entitles an employee to receive shares of Ameren common stock (plus accumulated dividends) if, at the end of the three-year performance period, certain specified market conditions have been met and if the individual remains employed by Ameren through the required vesting period. The vesting period for share units awarded extends beyond the three-year performance period to the payout date, which is approximately 38 months after the grant date. In the event of a participant’s death or retirement at age 55 or older with five years or more of service, awards vest on a pro-rata basis over the three-year performance period. The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the specified market conditions.

The fair value of each share unit is based on Ameren’s closing common share price at December 31st of the year prior to the award year and a Monte Carlo simulation. The Monte Carlo simulation is used to estimate expected share payout based on Ameren’s TSR for a three-year performance period relative to the designated peer group beginning January 1st of the award year. The simulation can produce a greater fair value for the share unit than the applicable closing common share price because it includes the weighted payout scenarios in which an increase in the share price has occurred. The significant assumptions used to calculate fair value also include a three-year risk-free rate, Ameren’s common stock volatility, volatility for the peer group, and Ameren’s attainment of a three-year average earnings per share threshold during the performance period. The following table presents the fair value of each share unit along with the significant assumptions used to calculate the fair value of each share unit for the years ended December 31, 2020, 2019, and 2018:


	2020	2019	2018
Fair value of share units awarded	$82.49	$67.42	$62.88

Three-year risk-free rate	1.62%	2.46%	1.98%
Ameren’s common stock volatility(a)	15%	17%	17%
Volatility range for the peer group(a)	14% – 28%	15% – 25%	15% – 23%

(a)Based on a historical period that is equal to the remaining term of the performance period as of the grant date.

Performance Share Units – Performance Condition

A performance condition share unit vests and entitles an employee to receive shares of Ameren common stock (plus accumulated dividends) if, at the end of the three-year performance period, Ameren has met the specified performance condition and if the individual remains employed by Ameren through the required vesting period. The vesting period for share units awarded extends beyond the three-year performance period to the payout date, which is approximately 38 months after the grant date. In the event of a participant’s death or retirement at age 55 or older with five years or more of service, awards vest on a pro-rata basis over the three-year performance period. The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual performance conditions achieved. The specified performance condition is based on Ameren’s clean energy goals, specifically the achievement of renewable generation and energy storage installation targets. The grant-date fair value for an individual outcome of a performance condition is determined by Ameren’s closing common share price on the grant date.

Restricted Stock Units

Restricted stock units vest and entitle an employee to receive shares of Ameren common stock (plus accumulated dividends) if the individual remains employed with Ameren through the payment date of the awards. Generally, in the event of a participant’s death or retirement at age 55 or older with five years or more of service, awards vest on a pro-rata basis, except for retention RSUs that are periodically granted, which do not provide for pro rata vesting in connection with the employee’s retirement. The payout date of the awards is approximately 38 months after the grant date. The fair value of each restricted stock unit is determined by Ameren’s closing common share price on the grant date.

Stock-Based Compensation Expense

The following table presents the stock-based compensation expense for the years ended December 31, 2020, 2019, and 2018:


	2020		2019		2018
Ameren Missouri	$	5	$	4	$	4
Ameren Illinois	3		3		3
Other(a)	13		13		13
Ameren	21		20		20
Less income tax benefit	6		5		6
Stock-based compensation expense, net	$	15	$	15	$	14

(a)Represents compensation expense for employees of Ameren Services. These amounts are not included in the Ameren Missouri and Ameren Illinois amounts above.

Ameren settled performance share units and restricted stock units of $58 million, $83 million, and $54 million for the years ended December 31, 2020, 2019, and 2018. There were no significant stock-based compensation costs capitalized during the years ended December 31, 2020, 2019, and 2018. As of December 31, 2020, total compensation cost of $34 million related to nonvested awards not yet recognized is expected to be recognized over a weighted-average period of 22 months.

For the years ended December 31, 2020, 2019, and 2018, excess tax benefits associated with the settlement of stock-based compensation awards reduced income tax expense by $8 million, $15 million, and $6 million, respectively.