The statement of members' deficit for the three months ended June 30, 2020 is as follows (in thousands, except unit amounts):


	Class C Preferred Units				Class A Units				Additional Paid-in		Accumulated			Noncontrolling			Total Members’
	Units		Amount		Units		Amount		Capital		Deficit			Interest			Deficit
Balance at March 31, 2020		23,968,178	$	89,345		54,600,000	$	750	$	2,295	$	(149,958	)	$	(47	)	$	(57,615	)
Net loss		—		—		—		—		—		(6,222	)		—			(6,222	)
Balance at June 30, 2020		23,968,178	$	89,345		54,600,000	$	750	$	2,295	$	(156,180	)	$	(47	)	$	(63,837	)

The statement of members' deficit for the six months ended June 30, 2020 is as follows (in thousands, except unit amounts):


	Class C Preferred Units				Class A Units				Additional Paid-in		Accumulated			Noncontrolling			Total Members’
	Units		Amount		Units		Amount		Capital		Deficit			Interest			Deficit
Balance at December 31, 2019		23,968,178	$	89,345		54,600,000	$	750	$	2,295	$	(148,354	)	$	(47	)	$	(56,011	)
Net loss		—		—		—		—		—		(7,826	)		—			(7,826	)
Balance at June 30, 2020		23,968,178	$	89,345		54,600,000	$	750	$	2,295	$	(156,180	)	$	(47	)	$	(63,837	)

In December 2020, the Company completed its IPO selling 12,075,000 shares of its common stock at $18.00 per share. Proceeds from the Company’s IPO, net of underwriting discounts and commissions and other offering costs, were $198.3 million. In connection with the IPO, all 199,791,519 shares of convertible preferred stock outstanding at the time of the IPO converted into 13,876,510 shares of the Company’s common stock and 1,492,059 shares of the Company’s Class B common stock.

On October 29, 2020, the Company’s board of directors approved the adoption of the BioAtla, Inc. 2020 Equity Incentive Plan (the “2020 Plan”) and approved certain amendments to the 2020 Plan in December 2020. The Company’s stockholders approved the 2020 Plan, as amended, in December 2020. Under the 2020 Plan, the Company may grant awards of common stock to the Company’s employees, consultants and non-employee directors pursuant to option awards, stock appreciation rights awards, restricted stock

awards, restricted stock unit awards, performance stock awards, performance stock unit awards and other stock-based awards. As of June 30, 2021 and December 31, 2020, the total number of common shares authorized for issuance under the 2020 Plan was 6,226,540 and 4,939,678, respectively. On January 1st of each year, commencing with the first January 1st following the effective date of the 2020 Plan, the shares authorized for issuance under the 2020 Plan shall be increased by a number of shares equal to the lesser of 4% of the total number of shares outstanding on the immediately preceding December 31st and such lesser number of shares determined by the Company’s board of directors. The maximum term of the options granted under the 2020 Plan is no more than ten years. Awards under the 2020 Plan generally vest at 25% one year from the vesting commencement date and ratably each month thereafter for a period of 36 months, subject to continuous service.

There was no stock-based compensation expense reported for the three and six months ended June 30, 2020 as the 2020 Plan was not yet adopted. Stock-based compensation expense for the three and six months ended June 30, 2021 has been reported in the consolidated statements of operations and comprehensive loss as follows (in thousands):

As of June 30, 2021, total unrecognized stock-based compensation expense for RSUs was $23.0 million, which is expected to be recognized over a remaining weighted-average period of approximately 2.7 years. During the six months ended June 30, 2021, the Company modified 138,461 RSU's under the Transition Agreement (See Note 9).

The following table summarizes stock option activity under the 2020 Plan for the six months ended June 30, 2021 (in thousands, except share and per share data and years):


	Number of Options		Weighted - Average Exercise Price Per Share		Weighted -Average Remaining Contractual Term (In Years)		Aggregate Intrinsic Value
Balance at December 31, 2020		615,106	$	18.00		9.95	$	9,848
Granted		235,043	$	44.57
Balance at June 30, 2021		850,149	$	25.35	9.48		$	15,199
Vested and expected to vest at June 30, 2021		850,149	$	25.35	9.48		$	15,199
Exercisable at June 30, 2021		7,747	$	18.00	0.16		$	189

As of June 30, 2021, total unrecognized stock-based compensation cost for unvested common stock options was $12.6 million, which is expected to be recognized over a remaining weighted-average period of approximately 3.4 years. The weighted- average grant date fair value of stock options granted during the six months ended June 30, 2021 was $28.91 per share. During the six months ended June 30, 2021, the Company modified 7,747 stock options under the Transition Agreement (See Note 9).

Expected volatility. As the Company’s common stock does not have a significant trading history, the expected volatility assumption is based on volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on companies in the biotechnology industry.

Risk-free interest rate. The Company bases the risk-free interest rate assumption on the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the award being valued.

Expected dividend yield. The Company bases the expected dividend yield assumption on the fact that it has never paid cash dividends and has no present plans to pay cash dividends.

Expected term. For employees, the expected term represents the period of time that options are expected to be outstanding. Because the Company has minimal historical exercise behavior, it determines the expected life assumption using the simplified method, which is an average of the contractual term of the option and its vesting period. For nonemployees, the expected term is generally the contractual term of the option.

In December 2020, the Company’s board of directors and stockholders approved the BioAtla, Inc. Employee Stock Purchase Plan (the “ESPP”). The ESPP permits participants to purchase common stock through payroll deductions of up to 15% of their eligible compensation. As of June 30, 2021 and December 31, 2020, a total of 833,993 shares and 464,829 shares, respectively, of common stock were authorized for issuance under the ESPP. The number of shares of common stock authorized for issuance will automatically increase on January 1 of each calendar year, from January 1, 2021 through January 1, 2030 by the least of (i) 1.0% of the total number of common shares of our common stock outstanding on December 31 of the preceding calendar year (calculated on a fully diluted basis), (ii) 929,658 common shares or (iii) a number determined by the Company’s board of directors that is less than (i) and (ii). In February 2021, employees began to enroll in the ESPP and the Company’s first offering period commenced. The Company's first ESPP purchase transaction occurred on June 30, 2021. During the six months ended June 30, 2021, the Company issued 5,280 shares of common stock under the ESPP. As of June 30, 2021, 828,713 shares of common stock remained available for issuance under the ESPP. Stock-based compensation expense related to the ESPP for the three and six months ended June 30, 2021 was immaterial.

Upon adoption of ASU No. 2018-07 on October 1, 2020, the measurement date of the warrants described below became fixed in accordance with the guidance, and such fair value was nominal since the warrants were deeply out-of-the-money. As of June 30, 2021 all the common stock warrants below are exercisable and expire as follows:

Common stock reserved for future issuance are as follows in common equivalent shares:


	June 30, 2021		December 31, 2020
Warrants for the purchase of common stock		717,674		717,674
Common stock options and restricted stock units issued and outstanding		2,631,725		2,535,143
Awards available for future issuance under the 2020 Plan		3,456,354		2,404,535
Awards available for future issuance under the ESPP		828,713		464,829
Total common stock reserved for future issuance		7,634,466		6,122,181