On May 7, 2014, the stockholders of the Company approved the Air Lease Corporation 2014 Equity Incentive Plan (the “2014 Plan”). Upon approval of the 2014 Plan, no new awards may be granted under the Amended and Restated 2010 Equity Incentive Plan (the “2010 Plan”). As of September 30, 2020, the number of stock options (“Stock Options”) and restricted stock units (“RSUs”) authorized under the 2014 Plan is approximately 4,860,870.

The Company recorded $6.6 million and $4.9 million of stock-based compensation expense for the three months ended September 30, 2020 and 2019, respectively. The Company recorded $15.0 million and $14.9 million of stock-based compensation expense for the nine months ended September 30, 2020 and 2019, respectively.

A summary of stock option activity for the nine months ended September 30, 2020 follows:

(1)	The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the closing stock price of the Company’s Class A common stock as of the respective date.

All of the Company’s outstanding employee stock options had fully vested as of June 30, 2013. As of September 30, 2020 there were no unrecognized compensation costs related to outstanding stock options. For the three and nine months ended September 30, 2020 and 2019 there were no stock-based compensation expenses related to Stock Options.

Restricted Stock Units

Compensation cost for stock awards is measured at the grant date based on fair value and recognized over the vesting period. The fair value of book value and time based RSUs is determined based on the closing market price of the Company’s Class A common stock on the date of grant, while the fair value of RSUs that vest based on the attainment of Total Shareholder Return (“TSR”) goals is determined at the grant date using a Monte Carlo simulation model. Included in the Monte Carlo simulation model were certain assumptions regarding a number of highly complex and subjective variables, such as expected volatility, risk-free interest rate and expected dividends. To appropriately value the award, the risk-free interest rate is estimated for the time period from the valuation date until the vesting date and the historical volatilities were estimated based on a historical timeframe equal to the time from the valuation date until the end date of the performance period.

During the nine months ended September 30, 2020, the Company granted 670,621 RSUs of which 133,699 are TSR RSUs. The following table summarizes the activities for the Company’s unvested RSUs for the nine months ended September 30, 2020:


	Unvested Restricted Stock Units
		Weighted-Average
	Number of	Grant-Date
	Shares	Fair Value
Unvested at December 31, 2019	1,254,904	$	43.62
Granted	670,621	$	42.20
Vested	(406,067)	$	46.96
Forfeited/canceled	(49,407)	$	43.97
Unvested at September 30, 2020	1,470,051	$	42.04
Expected to vest after September 30, 2020	1,470,051	$	42.04

As of September 30, 2020, there was $29.1 million of unrecognized compensation cost related to unvested stock-based payments granted to employees. Total unrecognized compensation cost will be recognized over a weighted-average remaining period of 1.79 years.