In December 2016, as further amended in December 2017 and September 2019, the Company adopted the Repare Therapeutics Inc. Option Plan (the “Option Plan”) for the issuance of stock options and other share-based awards to directors, officers, employees or consultants. The Option Plan authorized up to 4,074,135 shares of the Company’s common shares to be issued.

In June 2020, the Company’s board of directors adopted, and the Company’s shareholders approved the 2020 Equity Incentive Plan (the “2020 Plan”). The 2020 Plan became effective on the effective date of the IPO, at which time the Company ceased making awards under the Option Plan. The 2020 Plan allows the Company’s compensation committee to make equity-based and cash-based incentive awards to the Company’s officers, employees, directors and consultants. A total of 3,600,000 common shares were initially reserved for issuance under the 2020 Plan, plus the number of shares (not to exceed 3,807,448 shares) consisting of (i) 298,605 common shares that were available for issuance of awards under the Option Plan at the time the 2020 Plan became effective, which ceased to be available for future issuance under the Option Plan at such time and (ii) any shares subject to outstanding options or other share awards that were granted under the Option Plan that terminate or expire prior to exercise or settlement; are forfeited because of the failure to vest; or are reacquired or withheld (or not issued) to satisfy a tax withholding obligation or the purchase or exercise price. In addition, the number of shares reserved and available for issuance under the 2020 Plan will automatically increase each January 1, beginning on January 1, 2021 and each January 1 thereafter through January 1, 2030, by 5% of the outstanding number of common shares on the immediately preceding December 31, or such lesser number of shares as determined by the Company’s board of directors. As of January 1, 2021, the number of common shares reserved for issuance under the 2020 Plan is 5,780,864.

The 2020 Plan is administered by the board of directors. The exercise prices, vesting and other restrictions are determined by the board of directors, except that the exercise price per share of stock option may not be less than 100% of the fair value of the common share on the date of grant, determined based on the average of the daily volume-weighted average trading price of shares on each of the five trading days immediately preceding the date of grant.

Stock options awarded under the 2020 Plan expire 10 years after the grant and generally have vesting conditions of 25% on the first anniversary of the date of grant and 75% on a monthly basis at a rate of 1/36^th unless otherwise decided by the Company’s board of directors.

The assumptions that the Company used in the Black Scholes option-pricing model to determine the grant date fair value of stock options granted to employees and non-employees were as follows, presented on a weighted-average basis:

The grant date fair value of stock options granted was $11.73 per option in 2020 and $1.27 per option in 2019.

	2020									2019
	Number of shares			Weighted average exercise price		Weighted average remaining contractual term (in years)		Intrinsic value (in thousands)		Number of shares			Weighted average exercise price		Weighted average remaining contractual term (in years)
Outstanding, January 1		3,505,119		$	2.07		8.98				907,315		$	1.66		8.55
Granted		1,083,274		$	18.57						2,761,034		$	2.21
Exercised		(416,157	)	$	1.92						-		$	-
Forfeited		(40,113	)	$	3.91						(163,230	)	$	2.06
Outstanding, December 31		4,132,123		$	6.39		8.64	$	115,328		3,505,119		$	2.07		8.98

Options exercisable, December 31		1,217,497		$	1.96		7.87	$	39,374		611,927		$	1.69		6.75
Options unvested, December 31		2,914,626		$	8.25		8.96	$	75,926		2,893,192		$	2.15		9.45

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common shares for those stock options that had an exercise price lower than the fair value of the Company’s common shares.

The aggregate intrinsic value of options exercised during the year ended December 31, 2020 was $5.7 million.

The total fair value of options vested during the years ended December 31, 2020 and 2019 was $1.3 million and $0.3 million, respectively.

During the year ended December 31, 2020, an aggregate of 416,157 options were exercised at a weighted-average exercise price of $1.92 per share, for aggregate proceeds of $0.8 million. As a result, an amount of $0.5 million previously included in additional paid-in-capital related to the exercised options has been credited to common shares and deducted from additional paid-in-capital.

As of December 31, 2020 and 2019, there was $13.6 million and $3.6 million of unrecognized share-based compensation expense related to unvested stock options, respectively. The unrecognized share-based compensation expense is expected to be recognized over a weighted-average remaining vesting period of 2.6 and 3.2 years at December 31, 2020 and 2019, respectively.