Share-Based Compensation
On April 8, 2021, the Board of the Company adopted the Barinthus Biotherapeutics plc Share Award Plan 2021 (“the Plan”) and the Barinthus Biotherapeutics plc Non-Employee Sub-Plan which is a sub-plan of the Plan. Under the terms of the Plan, the Board is permitted to grant awards to employees as restricted share units, options, share appreciation rights and restricted shares. The aggregate number of shares initially available for issuance under the Plan and the Barinthus Biotherapeutics plc Non-Employee Sub-Plan cannot exceed 3,675,680 ordinary shares (the “Initial Limit”). Beginning calendar year 2022, the total number of ordinary shares available for issuance under the Plan shall be increased on January 1 of each year in an amount equal to the lesser of (i) 4% of the Company’s issued and outstanding ordinary shares (which 4% limit shall be measured as of January 1 of such year) and (ii) such number of ordinary shares as determined by the Compensation Committee of the Board in its discretion (the “Annual Increase”). In accordance with the terms of the Annual Increase, the total number of ordinary shares available for issuance under the Plan increased by 1,609,386 as of January 1, 2025. The awards generally vest based on the grantee’s continued service with the Company during a specified period following grant as determined by the Board and generally expire ten years from the grant date. Option awards generally vest over three years, but vesting conditions can vary at the discretion of the Company’s Board. As of December 31, 2025 and 2024, 3,248,605 and 1,906,080 ordinary shares are available for future grants, respectively.
In 2018, the Company’s board of directors adopted the Enterprise Management Incentive Share Option Scheme (the “EMI Plan”) which provided for the grant of incentive stock options and nonqualified stock options to non-director employees of the Company. The Company also has a nonqualified stock option plan for officers and directors. The awards generally vest based on the grantee’s continued service with the Company during a specified period following grant as determined by the board of directors and generally expire ten years from the grant date. Option awards generally vest over three years, but vesting conditions can vary at the discretion of the Company’s board of directors. A total of 3,530,634 ordinary shares were reserved for issuance in accordance with the provisions of the EMI Plan and restricted stock unit (“RSUs”) plan. Upon adoption of the Plan, no further awards are to be made under the EMI Plan.
The fair value of each stock option issued to employees was estimated at the date of grant using Black-Scholes with the following weighted-average assumptions:
Year Ended,
20252024
Expected volatility114.07 %108.73 %
Expected term (years)66
Risk-free interest rate4.4 %4.0 %
Expected dividend yield— %— %

Expected volatility: Previously there was insufficient trading history for the Company’s ordinary shares, therefore the expected price volatility for our ordinary shares was estimated using the average historical volatility of industry peers’ shares as of the grant date of our options over a period of history commensurate with the expected life of the options. When selecting industry peers used in measuring implied volatility, the Company considered the similarity of their products and business lines, as well as their stage of development, size and financial leverage. The Company applied this process consistently using the same or similar public companies until 2023. For options granted in and after 2023, the Company determined that there is sufficient historical information on volatility of its share price available and the expected volatility used in the fair value calculation of new option grants is calculated based on a blended volatility of both historical volatility of the Company's share price and the expected volatility of the average historical volatility of industry peers’ shares.
Expected term (years): Expected term represents the period that the Company’s option grants are expected to be outstanding. There is not sufficient historical share exercise data to calculate the expected term of the stock options. Therefore, the Company elected to utilize the simplified method to value option grants. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option.
Risk-free interest rate: The Company determined the risk-free interest rate by using a weighted-average equivalent to the expected term based on the daily U.S. Treasury yield curve rate in effect as of the date of grant.
Expected dividend yield: The Company does not anticipate paying any dividends in the foreseeable future.
A summary of stock option activity is presented below:
Number of
Stock Options
Weighted-
average
Exercise
Price Per
Option
Weighted-
average
Remaining
Contractual
Term (Years)
Aggregate
Intrinsic Value
(in thousands)
Outstanding, January 1, 20257,285,275$5.76 7.61$942 
Granted1,470,8121.00 
Exercised(614,230)0.00010 
Forfeited/expired(2,165,700)2.74 
Outstanding, December 31, 20255,976,157$6.28 2.28$37 
Exercisable, December 31, 20254,351,787$7.94 1.81$37 
The weighted-average grant date per-share fair value of stock options granted during the year ended December 31, 2025 was $0.85 per share (December 31, 2024: $2.66 per share). The aggregate intrinsic value of stock options exercised during the year ended December 31, 2025 was $0.2 million (December 31, 2024: $0.4 million). As of December 31, 2025, there was $0.6 million (2024: $3.1 million) of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted-average period of 1.42 years (2024: 1.46 years).
Restricted stock units:
The following table summarizes the Company's restricted stock units ('RSUs") under the Plan since December 31, 2025:
Number of Shares
Underlying RSUs
Weighted-Average
Grant Date Fair Value
Unvested, January 1, 2025— $— 
Granted886,0181.50 
Vested and settled
— — 
Vested and deferred
— — 
Forfeited(21,294)1.50 
Unvested outstanding, December 31, 2025864,7241.50 
Vested but subject to deferred settlement at December 31, 2025
— $— 
Outstanding at December 31, 2025864,724$1.50 
In October 2025, the Company granted an aggregate of 886,018 restricted stock units (“RSUs”) to employees under the Plan. The RSUs will vest in full on the seventh day following the occurrence of either the closing of the Contemplated Transactions or the termination of the Merger Agreement pursuant to its terms, subject to the employee’s continued employment with the Company through such vesting date, and were granted as part of the Company’s equity incentive program to support employee retention and alignment with shareholder interests. The grant date fair value of the RSUs was $1.3 million.
Total share-based compensation expense for RSUs granted for the years ended December 31, 2025 and 2024 was $0.5 million and nil, respectively. As of December 31, 2025, the total unrecognized compensation expense related to RSUs was $0.8 million, which is expected to be recognized over a weighted-average of 0.7 years.
Share based compensation expense is classified in the consolidated statements of operations and comprehensive loss as follows (in thousands):
Year ended
December 31,
2025
Year ended
December 31,
2024
Research and development$133 $1,680 
General and administrative335 3,029 
Total$468 $4,709 

Historical Timeline

Fiscal YearFiled
2025Mar 13, 2026Showing above
2024Mar 20, 2025
2023Mar 20, 2024
2022Mar 24, 2023
2021Mar 25, 2022

About Stock Compensation Disclosures

Stock-based compensation disclosures detail the equity awards granted to employees and executives — including stock options, restricted stock units (RSUs), and performance shares — along with the valuation methods and assumptions used to expense them. This section reveals the true cost of talent retention and the alignment between management incentives and shareholder interests.

Key signals: total unrecognized compensation expense and its expected recognition period signal future earnings headwinds from already-granted awards. For stock options, examine Black-Scholes assumptions — expected volatility, risk-free rate, and expected term — as understating any of these reduces reported compensation expense. Compare stock compensation expense as a percentage of revenue against peers to assess dilution cost. Watch vesting schedules for acceleration clauses tied to change-of-control events. Performance-based awards with undemanding targets may indicate weak governance. Add back stock compensation to operating cash flow to calculate a more conservative free cash flow figure.