In connection with the Merger, the Company assumed Private Aadi Plan, which was amended and restated in February 2017, and the issued and outstanding stock options under the Private Aadi Plan (the Private Aadi common stock underlying the awards was adjusted for shares of the Company’s common stock pursuant to the Merger Agreement). The Private Aadi Plan allowed for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock unit awards and other stock awards. In connection with the closing of the Merger and the adoption of the 2021 Plan (as defined below), no further awards will be issued under the Private Aadi Plan.

The options that are granted from the Private Aadi Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant. The Private Aadi Plan stock options generally vest over a four-year term.

In connection with the closing of the Merger, the Company assumed the Aerpio 2011 Equity Incentive Plan (the “2011 Plan”) and the Aerpio 2017 Stock Option and Incentive Plan (the “2017 Plan,” and collectively with the 2011 Plan, the “Prior Plans”). No new awards will be granted under the Prior Plans effective upon the closing of the Merger and adoption of the 2021 Plan (as defined below).

At the closing of the Merger, the Company adopted the Aadi Bioscience, Inc. 2021 Equity Incentive Plan (the “2021 Plan”), which also permits stock options and restricted stock unit grants to employees, members of the board of directors, and outside consultants.

Subject to the adjustment provisions contained in the 2021 Plan and the evergreen provision described below, a total of 2,070,784 shares of common stock were initially reserved for issuance pursuant to the 2021 Plan. In addition, the shares reserved for issuance under the 2021 Plan include any shares of common stock (i) subject to awards of stock options or other awards granted under the Prior Plans that expire or otherwise terminate without having been exercised in full and shares of common stock granted under the Prior Plans that are forfeited or repurchased by the Company, and (ii) any shares of common stock subject to stock options or similar awards granted under the Private Aadi Plan that were assumed in the Merger (provided that the maximum number of shares that may be added to the 2021 Plan pursuant to this sentence is 764,154 shares).

The number of shares available for issuance under the 2021 Plan also will include an annual increase, or the evergreen feature, on the first day of each of the Company’s fiscal years, beginning with the Company’s fiscal year 2022, equal to the least of:

As a result of the evergreen increase, a total of 835,787 shares were added to the 2021 Plan on January 1, 2022.

Shares issuable under the 2021 Plan are authorized, but unissued, or reacquired shares of common stock. If an award expires or becomes unexercisable without having been exercised in full, is surrendered pursuant to an exchange program, or, with respect to restricted stock, restricted stock units, performance units or performance shares, is forfeited to or repurchased by the combined company due to failure to vest, the unpurchased shares (or for awards other than stock options or stock appreciation rights, the forfeited or repurchased shares) will become available for future grant or sale under the 2021 Plan (unless the 2021 Plan has terminated).

As of December 31, 2021, zero, 432,978, 126,267 and 1,190,631 shares were subject to awards outstanding under the 2011 Plan, Private Aadi Plan, 2017 Plan and 2021 Plan, respectively.

The following table summarizes the stock option activity during the twelve months ended December 31, 2021 and December 31, 2020:

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)		Aggregate Intrinsic Value (in thousands)
Outstanding, January 1, 2021		390,949		$	2.11		7.26	$	505
Granted		1,248,520			26.05
Assumed through Merger		248,258			29.20
Exercised		(72,316	)		11.52
Expired/cancelled		(65,535	)		53.99
Outstanding as of December 31, 2021		1,749,876		$	20.71		8.48	$	10,007
Vested and exercisable as of December 31, 2021		444,700		$	8.63	$	5.05	$	7,585
Vested and expected to vest as of December 31, 2021		1,749,876		$	20.71		8.48	$	10,007

As of December 31, 2021, the aggregate intrinsic value of options outstanding was $10.0 million. The intrinsic value for stock options is calculated based on the difference between the exercise prices of the underlying awards and the quoted stock price of the Company’s common stock as of the reporting date.

As of December 31, 2021, there was $22.1 million of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted average period of 2.9 years.

As of December 31, 2021, zero and 1,390,606 shares were reserved for issuance under the Private Aadi Plan and 2021 Plan, respectively.

The Company recognized the following compensation cost related to employee and non-employee stock-based compensation activity for the periods presented (amounts in thousands):

	Year Ended December 31,
	2021		2020
Research and development	$	657	$	94
General and administrative		1,449		45
Total	$	2,106	$	139

Included in the twelve months ended December 31, 2021 is $0.3 million of expense related to the acceleration of vesting associated with individual awards assumed in the Merger.

The Company uses the Black-Scholes option pricing model to determine the estimated fair value for stock-based awards. Option pricing and models require the input of various assumptions, including the option’s expected life, expected dividend yield, price volatility and risk-free interest rate of the underlying stock. Accordingly, the weighted-average fair value of the options granted during the twelve months ended December 31, 2021 and 2020 was $18.88 and $2.56 per share, respectively.

	Year Ended December 31,
	2021		2020
Weighted average grant date fair value (per share)	$	18.88	$	2.56
Risk-free interest rate	0.84% - 1.38%		0.34% - 0.80%
Expected volatility	85.21% - 87.88%		89.57% - 92.52%
Expected term (in years)	5.1 - 6.3		5.3 - 6.3
Expected dividend yield		—		—

The Company determines the assumptions used in the option pricing model in the following manner:

Risk-Free Interest Rate – For the determination of the risk-free interest rates, the Company utilizes the U.S. Treasury yield curve for instruments in effect at the time of measurement with a term commensurate with the expected term assumption.

Expected Volatility – Due to the Company’s limited historical stock price volatility data, the Company based its estimate of expected volatility on the estimated and expected volatilities of a guideline group of publicly traded companies. For these analyses, the Company selected companies with comparable characteristics including enterprise value, risk profiles, and with historical share price information sufficient to meet the expected life of the stock-based awards. The Company computes the historical volatility data using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of its stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

Expected Dividend – The expected dividend yield is assumed to be zero since the Company has never paid dividends and does not have current plans to pay any dividends on its common stock.

Expected Term – The Company estimates the expected term of its stock options granted to employees and non-employee directors using the simplified method, whereby, the expected term equals the average of the vesting term and the original contractual term of the option. The Company utilizes this method since it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term.

Prior to the Company’s Merger, given the absence of a public trading market for the Company’s common stock, its board of directors exercised their judgment and considered a number of objective and subjective factors to determine the best estimate of the fair value of the Company’s common stock underlying the stock options, such as: contemporaneous valuations performed by independent third-party specialists, its stage of development, including the status of its research and development efforts of its therapeutic candidates and the material risks related to its business and industry, its results of operations and financial condition, including its levels of capital resources, the prices at which its sold shares of its convertible preferred stock, the rights, preferences and privileges of its convertible preferred stock relative to those of its common stock, the conditions in the biotechnology industry and the economy in general, the stock price performance and volatility of comparable life sciences public companies, as well as recently completed mergers and acquisitions of peer companies, the likelihood of achieving a liquidity event for the holders of its common stock or convertible preferred stock, such as an IPO or a sale of the Company given prevailing market conditions, trends and developments in its industry, external market conditions affecting the life sciences and biotechnology sectors, and the lack of liquidity of its common stock, among other factors.

Subsequent to the Company’s Merger, the fair value of the Company’s common stock is determined based on its closing market price on the date of the grant. The Company’s board of directors intended all options granted to be exercisable at a price per share not less than the per share fair value of its common stock underlying those options on the grant date.

The Company had warrants outstanding for the purchase of 36,666 shares of the Company’s common stock at December 31, 2021. There were no warrants outstanding as of December 31, 2020. These warrants were assumed in the Merger and were issued by Aerpio in October 2019, for the purchase of 40,000 shares (after taking into account the Reverse Stock Split) of the Company’s common stock at an exercise price of $7.29 per share (after taking into account the Reverse Stock Split). These warrants were fully vested as of the date of the Merger and expire on October 24, 2024.

The number of shares and the exercise price shall be adjusted for standard anti-dilution events such as stock splits, combinations, reorganizations, or issue shares as part of a stock dividend. The warrants meet the criteria to be classified within stockholders’ equity (deficit).