Note 5 - Share-Based Compensation

6 Months Ended

Jun. 30, 2026

Notes to Financial Statements

Share-Based Payment Arrangement [Text Block]

5. Share-Based Compensation

Harvard Apparatus Regenerative Technology Amended and Restated Equity Incentive Plan

The Company maintains the Amended and Restated Equity Incentive Plan, or the Plan, for the benefit of certain officers, employees, non-employee directors, and other key persons (including consultants and advisory board members). All options and awards granted under the Plan consist of shares of Common Stock. The Company’s policy is to issue stock available from its registered but unissued stock pool through its transfer agent to satisfy stock option exercises and the vesting of restricted stock units. The vesting period for awards is generally four years and the contractual life is ten years. Canceled and forfeited options and awards are available to be reissued under the Plan.

As of June 30, 2026, the Company’s Plan has 9,098,000 authorized shares to be issued under the Plan. There were 4,019,038 shares available for issuance as of June 30, 2026.

The following table summarizes information concerning options outstanding and exercisable:

						*Weighted-*				*Weighted-*				*Aggregate*
						*average*				*average*				*intrinsic*
						*exercise*				*contractual*				*value*
		*Amount*				*price*				*life (years)*				*(in thousands)*
Outstanding at December 31, 2025			4,641,685			$	3.72				6.2			$	200
Granted			351,326				1.39
Outstanding at June 30, 2026			4,993,011				3.56				6.0				—
Options exercisable			3,767,547				3.58				5.8				—
Options vested and expected to vest			4,971,465				3.55				6.0				—

Total unrecognized compensation expense for the remaining 858,645 performance-based awards is approximately $3.1 million as of June 30, 2026.

During the six months ended June 30, 2026, the Company determined that the performance condition for certain performance-based awards was probable of achievement and recognized a cumulative catch-up adjustment of $194,870 to share-based compensation expense related to those awards. The Company recognized approximately $0.2 million and $0.9 million in share-based compensation during the three and six months ended June 30, 2026, respectively, and approximately $0.5 million and $1.0 million during the three and six months ended June 30, 2025, respectively.

Aggregate intrinsic value for outstanding options as of June 30, 2026 was $0, as the Company’s closing stock price of $1.28 per share as of June 30, 2026 was below the weighted-average exercise price of $3.56. As of June 30, 2026, unrecognized compensation cost related to unvested non-performance-based awards amounted to $0.4 million, which will be recognized over a weighted-average period of 1 year.

The weighted average assumptions for valuing the Company's stock options granted were as follows:

		Six Months Ended
		June 30,
		2026				2025
Risk-free interest rate			4.13	%			3.85	%
Expected volatility			106.21	%			116.11	%
Expected term (in years)			5.2				5.2
Expected dividend yield			—	%			—	%

The weighted average estimated fair value of stock options granted using the Black-Scholes model was $1.11 and $1.33 per share for the period ended June 30, 2026 and 2025, respectively.

The Company recorded share-based compensation expense in the following expense categories of its condensed consolidated statements of operations and comprehensive loss:

		*Three Months Ended*								*Six Months Ended*
		*June 30,*								*June 30,*
		*2026*				*2025*				*2026*				*2025*
		(In thousands)								(In thousands)
Research and development		$	46			$	58			$	215			$	117
General and administrative			177				479				640				905
Total		$	223			$	537			$	855			$	1,022