Under each of the legal entity’s equity plans, we recorded stock-based compensation in the following expense categories in our condensed consolidated statements of operations for employees and non-employees:


	Three Months Ended March 31, 2023
	BridgeBio Equity Plan		Other Subsidiaries Equity Plan		Total
	(in thousands)
Research and development	$	11,737	$	42	$	11,779
Selling, general and administrative		11,698		—		11,698
Restructuring, impairment and related charges		—		—		—
Total stock-based compensation	$	23,435	$	42	$	23,477


	Three Months Ended March 31, 2022
	BridgeBio Equity Plan		Other Subsidiaries Equity Plan		Total
	(in thousands)
Research and development	$	8,486	$	71	$	8,557
Selling, general and administrative		14,523		29		14,552
Restructuring, impairment and related charges		1,172		—		1,172
Total stock-based compensation	$	24,181	$	100	$	24,281

We recorded $1.6 million and $0.2 million of stock-based compensation expense for the three months ended March 31, 2023 and 2022, respectively, for performance-based milestone awards that were achieved during the periods and were settled in cash.

In February 2023, the 2019 Inducement Equity Plan was amended and restated to increase the total number of shares authorized for issuance from 1,000,000 shares to 2,000,000 shares. As of March 31, 2023, 7,282,843 shares and 1,290,150 shares were reserved for future issuances under our 2021 Amended and Restated Stock Option and Incentive Plan (the “2021 A&R Plan”) and the Amended and Restated 2019 Inducement Equity Plan (the “A&R 2019 Inducement Plan”), respectively. Pursuant to the Merger Transactions, we also reserved 2,802,644 shares in 2021 specifically under the Eidos Award Exchange (the “Eidos Award Exchange Plan”), all of which were issued upon execution of the Eidos Award Exchange as discussed below. The 2021 A&R Plan, the A&R 2019 Inducement Plan and the Eidos Award Exchange Plan are collectively referred herein as the “Plans”.

On April 22, 2020, we completed our 2020 Stock and Equity Award Exchange Program (the “Exchange Program”) for certain subsidiaries, which was an opportunity for eligible controlled entities’ employees and consultants to exchange their subsidiary equity (including common stock, vested and unvested stock options and RSAs) for BridgeBio equity (including common stock, vested and unvested stock options and RSAs) and/or performance-based milestone awards tied to the achievement of certain development and regulatory milestones. The Exchange Program aligns our incentive compensation structure for employees and consultants across the BridgeBio group of companies to be consistent with the achievement of our overall corporate goals. In connection with the Exchange Program, we issued awards of BridgeBio equity under the then 2019 Amended and Restated Stock Option and Incentive Plan (the “2019 A&R Plan”), which was amended and restated into the 2021 A&R Plan mentioned above, to 149 grantees covering 554,064 shares of common stock, 1,268,110 stock options to purchase common stock, 50,145 shares of RSAs and 22,611 shares of performance-based RSAs. The exchange also included performance-based milestone awards of up to $183.4 million to be settled in fully-vested RSAs in the future upon achievement of the milestones. In consideration for all the subsidiaries’ shares tendered, BridgeBio increased its ownership in controlled entities included in the Exchange Program and the corresponding noncontrolling interest decreased.

On November 18, 2020, we completed a stock and equity award under our Exchange Program for a subsidiary. We issued awards of BridgeBio equity under the then 2019 A&R Plan to 16 grantees covering 24,924 shares of common stock, 70,436 stock options to purchase common stock, and 10,772 shares of performance-based stock options to purchase common stock. The exchange also included performance-based milestone awards of up to $11.7 million to be settled in fully-vested RSAs in the future upon achievement of the milestones.

We considered the total shares of common stock and equity awards, whether vested or unvested, held by each participant in each controlled entity as the unit of account. The controlled entity’s common stock and equity awards in each unit of account was exchanged for a combination of BridgeBio’s common stock, time-based vesting equity awards and/or performance-based milestone awards. Other than the exchange of the controlled entity equity awards for performance-based milestone awards, all other exchanged BridgeBio equity awards retained the original vesting conditions. As a result, there was no incremental stock-based compensation expense resulting from the exchange of time-based equity awards.

At the completion of the Exchange Program, we determined $17.4 million of the performance-based milestone awards were probable of achievement and represented the incremental stock-based compensation cost resulting from the modification of time-based equity awards to performance-based milestone awards. These performance-based milestone awards were to be recognized over a period ranging from 0.7 year to 1.7 years. There was no incremental stock-based compensation cost arising from the completion of the Exchange Program on November 18, 2020. Under ASC 718, we account for such performance-based milestone awards as a liability in “Accrued compensation and benefits” and in “Other long-term liabilities” in the condensed consolidated balance sheets due to the fixed milestone amount that will be converted into a variable number of shares of BridgeBio common stock to be granted upon the achievement date.

For the three months ended March 31, 2023 we recognized $1.7 million for stock-based compensation cost associated with performance-based milestone awards whereby the milestones were determined to be probable of achievement as of March 31, 2023. Stock-based compensation cost associated with performance-based milestone awards whereby the milestones were determined to be probable of achievement as of March 31, 2022, were not material for the three months ended March 31, 2022. Refer to Note 8 for contingent compensation accrued associated with performance-based milestones that are determined to be probable as of March 31, 2023.

Apart from the Exchange Program discussed above, we have performance-based milestone compensation arrangements with certain employees and consultants whose vesting is contingent upon meeting various regulatory and development milestones, with fixed monetary amounts known at inception that can be settled in the form of cash or equity at our sole discretion, upon achievement of each contingent milestone. Upon achievement of a contingent milestone and if such performance-based milestone awards are settled in the form of equity, these are satisfied in the form of fully-vested RSAs. We recognize such contingent stock-based compensation expense when the milestone is probable of achievement. For the three months ended March 31, 2023, we recognized $1.0 million of stock-based compensation cost associated with performance-based milestone awards whereby the milestones were determined to be probable of achievement as of the reporting date. The stock-based compensation cost for milestone awards associated with performance-based milestone awards that were determined to be probable of achievement was not material for the three months ended March 31, 2022. Refer to Note 8 for contingent compensation accrued associated with performance-based milestone awards that are determined to be probable as of March 31, 2023.

The following table summarizes BridgeBio’s stock option activity under the Plans for the three months ended March 31, 2023:


	Options Outstanding					Weighted- Average Exercise Price per Option		Weighted- Average Remaining Contractual Life (years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2022				11,637,861
Regular equity program		9,811,936				$	28.00		7.7	$	—
Eidos Awards Exchange		1,445,885				$	14.96		5.9	$	1,427
Exchange Program		380,040				$	2.35		6.2	$	2,246
Granted				1,106,897
Regular equity program		1,106,897				$	11.48
Exercised				(44,464	)
Eidos Awards Exchange		(5,776	)			$	11.82
Exchange Program		(38,688	)			$	3.22
Cancelled				(437,941	)
Regular equity program		(434,179	)			$	23.90
Eidos Awards Exchange		(1,852	)			$	19.75
Exchange Program		(1,910	)			$	4.03
Outstanding as of March 31, 2023				12,262,353
Regular equity program		10,484,654				$	26.43		7.6	$	15,878
Eidos Awards Exchange		1,438,257				$	14.96		5.5	$	7,445
Exchange Program		339,442				$	2.24		6.1	$	5,040
Exercisable as of March 31, 2023				7,456,207
Regular equity program		5,832,486				$	27.68		6.6	$	102
Eidos Awards Exchange		1,289,387				$	13.75		5.4	$	7,425
Exchange Program		334,334				$	2.18		6.0	$	4,977

The options granted to employees and non-employees are exercisable at the price of BridgeBio’s common stock at the respective grant dates. The options granted have a service condition and generally vest over a period of four years.

The weighted-average grant date fair value of options granted during the three months ended March 31, 2023 was $6.28.

The aggregate intrinsic value of options outstanding and exercisable as of March 31, 2023 in the table above are calculated based on the difference between the exercise price and the current fair value of BridgeBio common stock. The total intrinsic value of options exercised for the three months ended March 31, 2023 was $0.5 million.

For the three months ended March 31, 2023 and 2022, we recognized stock-based compensation expense of $6.9 million and $10.8 million, respectively, related to stock options under the Plans. As of March 31, 2023, there was $50.7 million of total unrecognized compensation cost related to stock options under the Plans that is expected to be recognized over a weighted-average period of 2.3 years.

For the three months ended March 31, 2023 and 2022 we recognized stock-based compensation expense of $12.3 million and $11.9 million, respectively, related to RSUs under the Plans. As of March 31, 2023, there was $155.5 million of total unrecognized compensation cost related to RSUs under the Plans that is expected to be recognized over a weighted-average period of 3.3 years.

As of March 31, 2023, there was $3.6 million of total unrecognized compensation cost related to RSAs under the Plans that is expected to be recognized over a weighted-average period of 0.9 years. The respective balances of unvested RSAs as of March 31, 2023 and December 31, 2022 are included as outstanding shares disclosed in the condensed consolidated balance sheets as the shares were issued but are subject to forfeiture per the terms of the awards.

On June 22, 2019, we adopted the 2019 ESPP, which became effective on June 25, 2019 and was amended and restated effective as of December 12, 2019. The ESPP initially reserves and authorizes the issuance of up to a total of 2,000,000 shares of common stock to participating employees. The ESPP provides that the number of shares reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2020, by the lower of: i) 1% of the outstanding number of shares of common stock on the immediately preceding December 31, ii) 2,000,000 shares or iii) such lesser number of shares as determined by the Compensation Committee.

Under the ESPP, eligible employees may purchase shares of BridgeBio common stock through payroll deductions at a price equal to 85% of the lower of the fair market values of the stock as of the beginning or the end of six-month offering periods. An employee’s payroll deductions under the ESPP are limited to 15% of the employee’s compensation and employees may not purchase more than 3,500 of shares of BridgeBio common stock during any offering period.

For the three months ended March 31, 2023, stock-based compensation expense related to our ESPP was $0.5 million. For the three months ended March 31, 2022, stock-based compensation expense related to the ESPP was not material. As of March 31, 2023, 3,703,691 shares were reserved for future issuance under the ESPP.

Prior to the Eidos Merger Transactions in 2021, Eidos issued its own equity-based awards under the Eidos 2016 Equity Incentive Plan and the Eidos 2018 Stock Option and Incentive Plan (collectively, the “Eidos Plans”). Upon closing of the Eidos Merger Transactions, we issued 2,776,672 stock options to purchase common stock of BridgeBio and 25,972 shares of BridgeBio RSUs to 88 employees of Eidos under the Eidos Award Exchange in exchange for their then outstanding common stock options and RSUs under the Eidos Plans (the “Replaced Awards”). The awards issued in the Eidos Award Exchange have the same vesting terms and conditions as the Replaced Awards. We evaluated the exchange of the awards as a modification under ASC 718 and recognized no incremental compensation cost from such modification.