Quarterly report [Sections 13 or 15(d)]

Stock-Based Compensation

Stock-Based Compensation

9 Months Ended

Sep. 30, 2025

On December 22, 2005, our Board of Directors adopted Tecogen's 2006 Stock Option and Incentive Plan ("2006 Plan") under which the Board of Directors or a committee appointed by the Board of Directors may grant incentive stock

options to officers and employees and may grant non-qualified stock options, restricted stock and stock to officers, employees, directors, advisors and consultants. The 2006 Plan was amended at various dates by the Board of Directors to increase the number of shares of common stock reserved for issuance under the Plan to 3,838,750, and, in June 2017, stockholders approved an amendment to extend the termination date of the Plan to January 1, 2026 (2006 Plan as amended, "Amended Plan").

Stock options vest based upon the terms of each individual option grant with an acceleration of the unvested portion of such options upon a change of control event, as defined in the Amended Plan. The options are not transferable except by will or domestic relations order. Under the Internal Revenue Code, the option exercise price per share under the Amended Plan cannot be less than the fair market value of the underlying shares on the date of the grant. Incentive stock options granted to an officer or employee owning more than 10% of the combined voting power of the Company, are required to be exercisable at a price per share equal to 110% of the fair market value of a share on the date of grant. The number of shares remaining available for future issuance under the Amended Plan as of September 30, 2025 was 1,151,068.

During the nine months ended September 30, 2025, we granted non-qualified options to purchase an aggregate of 58,500 shares of common stock to certain employees at prices between $2.14 per share and $8.61 per share under the Amended Plan. The fair value of the options issued in 2025 was $137,413. The weighted-average grant date fair-value of stock options granted in 2025 was $2.35 per share.

On March 8, 2022, our Board of Directors adopted Tecogen's 2022 Stock Incentive Plan ("2022 Plan"), under which the Board of Directors or a committee appointed by the Board of Directors may grant incentive stock options to officers and employees and grant non-qualified stock options, restricted stock, and stock grants to officers, employees, directors, advisors and consultants. We have reserved 3,800,000 shares of our common stock for issuance pursuant to awards under the 2022 Plan. The adoption of the 2022 Plan was approved by our shareholders on June 9, 2022. The 2022 Plan expires ten years from its effective date or March 1, 2032.

Under the 2022 Plan, stock options vest based upon the terms of each individual option grant with an acceleration of the unvested portion of such options upon a change of control event, as defined in the 2022 Plan. The options are not transferable except by will or domestic relations order. Under the Internal Revenue Code, the option exercise price per share under the Amended Plan cannot be less than the fair market value of the underlying shares on the date of the grant. Incentive stock options granted to an officer or employee owning more than 10% of the combined voting power of the Company are required to be exercisable at a price per share equal to 110% of the fair market value of a share on the date of grant. The number of shares remaining available for future issuance under the Plan as of September 30, 2025 was 2,632,856.

During the nine months ended September 30, 2025, we granted non-qualified and incentive stock options to purchase an aggregate of 221,336 shares of common stock to certain employees priced at $8.35 per share under the 2022 Plan. The fair value of the options issued in 2025 was $918,035. The weighted-average grant date fair-value of stock options granted in 2025 was $4.15 per share. Also, during the nine months ended September 30, 2025 we granted restricted stock awards, with respect to 95,808 shares of common stock priced at $8.35 per share and which vest in equal annual installments over the four year period commencing on the first anniversary of the date of grant.

Stock option activity for the nine months ended September 30, 2025 was as follows:


Common Stock Options	Number of Options	Exercise Price Per Share			Weighted Average Exercise Price		Weighted Average Remaining Life	Aggregate Intrinsic Value
Outstanding, December 31, 2024	2,752,962	$0.71	—	$3.93	$	1.14	6.70 years	$	1,348,684
Granted	279,836	$2.14	—	$8.61	$	7.60
Exercised	(547,654)	$0.71	—	$3.93	$	1.20		$	4,166,480
Canceled and forfeited	(110,600)	$0.71	—	$3.48	$	0.95
Outstanding, September 30, 2025	2,374,544	$0.71	—	$8.61	$	1.90	6.06 years	$	16,412,063
Exercisable, September 30, 2025	1,480,958				$	1.24		$	11,217,693
Vested and expected to vest, September 30, 2025	2,240,506				$	1.83		$	15,632,907

We used a forfeiture rate of 15% to calculate the shares which are expected to vest in the table above. We use the Black-Scholes option pricing model to determine the fair value of stock options granted as of the date of grant. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs. Expected volatility was calculated based on the average volatility of four comparable publicly traded companies. The average expected life was estimated using the simplified method to determine the expected life based on the vesting period and contractual terms, since we do not have the necessary historical exercise data to determine an expected life for stock options. We use a single weighted-average expected life to value option awards and recognize compensation on a straight-line basis over the requisite service period for each separately vesting portion of the awards. The risk-free interest rate is based on U.S. Treasury zero-coupon issues

with a remaining term which approximates the expected life assumed at the date of grant.

The weighted average assumptions used in the Black-Scholes option pricing model for options granted in nine months ended September 30, 2025 and 2024 are as follows:


Stock Option Award Assumptions	September 30, 2025	September 30, 2024
Expected dividend yield	—%	—%
Expected life	6.25 years	6.25 years
Risk-free interest rate	4.10%	4.28%
Expected volatility	44.32%	40.17%

Consolidated stock-based compensation expense for stock options for the three and nine months ended September 30, 2025 and 2024 was $88,714 and $172,153 and $41,908 and $131,906, respectively. Stock-based compensation for restricted stock awards granted for the three and nine months ended September 30, 2025 was $37,705. No tax benefit was recognized related to the stock-based compensation recorded during the period.

At September 30, 2025, the total compensation cost related to unvested stock options and restricted stock awards not yet recognized is $1,924,038 and this amount will be recognized over a weighted average period of 2.39 years.