Holders of vested Cellectis stock options and warrants are entitled to exercise such options and warrants to purchase Cellectis Ordinary shares at a fixed exercise price established at the time of such options and warrants are granted during their useful life.

For stock options and warrants, we estimate the fair value of each option on the grant date or other measurement date if applicable using a Black-Scholes option-pricing model, which requires us to make predictive assumptions regarding future stock price volatility, employee exercise behavior, risk free rates, dividend yield, and forfeiture rate. We estimate our future stock price volatility based on Cellectis historical closing share prices over the expected term. Our expected term represents the period of time that options granted are expected to be outstanding determined using the simplified method. The risk-free interest rate is based on the French government securities with maturities similar to the expected term of the options at grant date. We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, we used an expected dividend yield of zero. Options may be priced at 100 percent or more of the fair market value on the date of grant, and generally vest over four years after the date of grant. Options generally expire within ten years after the date of grant.

Following AstraZeneca's equity investment of 28 million shares on May 3, 2024, including 10,000,000 Class A Preferred Shares and 18,000,000 Class B Preferred Shares, the board of directors implemented measures to protect the interests of the holders of share warrants, stock options and free shares (in accordance with the provisions of article L. 228-99 3° of the French Code de commerce). The board of directors, assisted by an independent expert, concluded it was necessary to adjust the rights of holders of share warrants, stock options and free shares, on the basis of an adjustment ratio set at 1.06x. Stock options and share warrants ("BSA") outstanding as of May 3, 2024 benefited from an increase in their conversion ratio from 1 share to 1.06 share per option/warrant exercised. Holders of outstanding free shares as of May 3, 2024 benefited from a 6% increase in the number of free shares granted. The additional stock-based compensation expense is $0.1 million for the year 2024.

The weighted-average fair values of stock options granted and the assumptions used for the Black-Scholes option pricing model were as follows:


	For the twelve-month period ended December 31,
	2023	2024	2025

Weighted-Average fair values of stock options granted	1.65€	1.41€	0.89€
Assumptions:
Risk-free interest rate	2.45% - 2.75%	2.51% - 2.99%	2.78% - 3.06%
Share entitlement per options	1	1 - 1.06	1
Exercise price	1.74€ - 3.17€	1.70€ - 2.82€	1.26€ - 4.07€
Underlying stock price at grant date	1.70€-3.09€	1.67€-2.76€	1.26€-4.02€
Expected volatility	63.7% - 64.4%	64.6%- 65.2%	65.0%- 72.2%
Expected term (in years)	6.03 - 6.15	6.03 - 6.17	5.93 - 6.16
Vesting conditions	Performance & Service or Service	Performance & Service or Service	Performance & Service or Service only
Vesting period	Graded	Graded	Graded

Our vesting performance conditions comprise a mix of financial (non-related to the price of Cellectis' ordinary shares or ADS), manufacturing and clinical objectives to be met.

Information on stock option activity follows:


	Options Exercisable		Weighted-Average Exercise Price Per Share (in €)		Options Outstanding			Weighted-Average Exercise Price Per Share (in €)		Remaining Average contractual Life (in years)

Balance as of January 1, 2023		7,400,519		24.58		8,787,264			22.31		4.6
Granted						1,835,411			2.86
Exercised						-			-
Forfeited or Expired						(79,516	)		22.86

Balance as of December 31, 2023		7,913,183		23.63		10,543,159			18.92		4.6
Granted						3,054,163			2.51
Exercised						-			-
Forfeited or Expired						(1,078,028	)		4.50

Balance as of December 31, 2024		8,546,368		22.34		12,519,294			16.16		4.6
Granted						6,346,033			1.49
Exercised						(13,438	)		2.17
Forfeited or Expired						(2,811,646	)		31.33

Balance as of December 31, 2025		7,523,716		14.42		16,040,242			7.71		6.4

Share-based compensation expense related to stock option awards was $5.6 million in 2025, $2.6 million in 2024, and $2.3 million in 2023.

On January 30, 2025, the Board of Directors granted 3,851,783 stock options to executive employees. These stock options will vest over three years based on both service and performance conditions.

On March 13, 2025, the Board of Directors granted 1,866,150 stock options to non-executive employees. These stock options will vest over four years based on service conditions.

On June 23, 2025, the Board of Directors granted 270,500 stock options to executive employees. These stock options will vest over three years solely based on both service and performance conditions. On the same date, the Board of Directors also granted 205,600 stock options to non-executive employees with a four-year vesting period solely based on service conditions.

On November 7, 2025, the Board of Directors granted 132,000 stock options to non-executive employees. These stock options will vest over four years solely based on service conditions.

On December 9, 2025, the Board of Directors granted 20,000 stock options to a non-executive employee. These stock options will vest over four years solely based on service conditions.

No warrants (or “Bons de Souscriptions d’Actions” or “BSAs”) have been granted during the years ended December 31, 2023 and December 31, 2024.

Information on warrants activity is as follows:


	Warrants Exercisable			Weighted-Average Exercise Price Per Share (in €)		Warrants Outstanding			Weighted-Average Exercise Price Per Share (in €)		Remaining Average Useful Life (in years)

Balance as of January 1, 2023		896,225			27.18		896,225			27.18		3.3
Granted							-			-
Exercised							-			-
Forfeited or Expired		(557,350	)		27.48		(557,350	)		27.48

Balance as of December 31, 2023		338,875			26.69		338,875			26.69		2.4
Granted							-			-
Exercised							-			-
Forfeited or Expired							-			-

Balance as of December 31, 2024		338,875			26.69		338,875			26.69		1.4
Granted							75,000			2.59
Exercised							-			-
Forfeited or Expired							(244,375	)		27.91

Balance as of December 31, 2025		117,938			19.35		169,500			14.25		4.8

Share-based compensation expense related to warrant awards was $0.1 million in 2025, and nil in 2024 and 2023.

The free shares granted since 2021 are subject to a three-year vesting period for all employees based on service conditions. Free shares granted to executive officers are also subject to performance conditions.

Our vesting performance conditions comprise a mix of financial (non-related to the price of Cellectis' ordinary shares or ADS), manufacturing and clinical objectives to be met.


	Number of Free shares Outstanding			Weighted-Average Grant Date Fair Value (in €)

Balance as of January 1, 2023		909,113			11.18
Granted		342,900			3.08
Vested		(167,433	)		22.45
Cancelled		(67,042	)		11.40

Balance as of December 31, 2023		1,017,538			6.59
Granted		-			-
Additional shares due to May 2024 modification		44,650			1.71
Vested		(342,675	)		11.89
Cancelled		(210,219	)		6.00

Balance as of December 31, 2024		509,295			2.84
Granted		-			-
Vested		(231,992	)		2.60
Cancelled		(25,356	)		3.21

Balance as of December 31, 2025		251,946			3.02

We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, we used an expected dividend yield of zero in determining fair value.

Share-based compensation expense related to Cellectis' free shares awards was $0.4 million in 2025, $0.5 million in 2024, and $2.9 million in 2023.

No free shares were granted during the years ended December 31, 2025 and December 31, 2024.

Prior to Calyxt’s deconsolidation, stock and share-based compensation expenses related to Calyxt equity awards until May 31, 2023 were classified as discontinued operations.

For the period prior to the Calyxt merger, stock and share-based compensation expense has been estimated considering the existence of vesting acceleration and exit event clauses in the equity award agreements and the probability of the events occurring, as the merger constitutes a triggering event of these clauses under the terms of certain equity award agreements.

Stock-based compensation expense related to stock option awards was $1.8 million for the year ended December 31, 2023.

Share-based compensation expense related to restricted stock unit awards was $2.4 million for the year ended December 31, 2023.

Share-based compensation expense related to performance stock unit awards was a reversal of $0.3 million mainly due to departures, compared to an expense of $0.3 million for the year ended December 31, 2023.