Note 12 — Share-based compensation

The Company grants options over ordinary shares in Adaptimmune Therapeutics plc under the following option plans: (i) the Adaptimmune Therapeutics plc Employee Share Option Scheme (adopted on January 14, 2016), (ii) the Adaptimmune Therapeutics plc 2015 Share Option Scheme (adopted on March 16, 2015) and (iii) the Adaptimmune Therapeutics plc Company Share Option Plan (adopted on March 16, 2015).

The Adaptimmune Therapeutics plc Company Share Option Plan is a tax efficient option scheme intended to comply with the requirements of Schedule 4 to the Income Tax (Earnings and Pensions) Act 2003 of the United

Kingdom, which provides for the grant of company share option plan (“CSOP”) options. Grants may not exceed the maximum value of £60,000 per participant for the shares under the option, which is a CSOP compliance requirement.

Generally, the vesting dates for the options granted under these plans up to December 31, 2023 are 25% on the first anniversary of the grant date and 75% in monthly installments over the following three years. However, the options granted to non-executive directors under the Adaptimmune Therapeutics plc 2015 Share Option Scheme vest and become exercisable as follows:

Effective from January 2018, the Company has also granted restricted stock unit style options (“RSU-style”). The RSU-style options over ordinary shares in Adaptimmune Therapeutics plc are granted under the Adaptimmune Therapeutics plc Employee Share Option Scheme (adopted on January 14, 2016). These options have an exercise price equal to the nominal value of an ordinary share, of £0.001, and generally vest over four years, with 25% on the first, and each subsequent, anniversary of the grant date.

Options granted under these plans are not subject to performance conditions. The contractual term of options granted under these plans is ten years.

The maximum aggregate number of options which may be granted under these plans and any incentive plans adopted by the Company cannot exceed a scheme limit that equates to 8% of the initial fully diluted share capital of the Company immediately following its IPO plus an automatic annual increase of an amount equivalent to 4% of the issued share capital on each 30 June (or such lower number as the Board, or an appropriate committee of the Board, may determine). The automatic increase is effective from July 1, 2016.

Prior to December 31, 2014, the Company granted options to purchase ordinary shares in Adaptimmune Limited under three option schemes:

(i)   The Adaptimmune Limited Share Option Scheme was adopted on May 30, 2008. Under this scheme Enterprise Management Incentive (“EMI”) options (which are potentially tax-advantaged in the United Kingdom) have

been granted (subject to the relevant conditions being met) to its employees who are eligible to receive EMI options under applicable U.K. tax law and unapproved options (which do not attract tax advantages) have been granted to its employees who are not eligible to receive EMI options, and to its Directors and consultants. In May 2014, the Company no longer qualified for EMI status and since that date, no further EMI options were granted under this scheme; however, unapproved options have been under granted under this scheme since that date.

(ii)  The Adaptimmune Limited 2014 Share Option Scheme was adopted on April 11, 2014. EMI options were granted (subject to the relevant conditions being met) under this scheme to our employees who are eligible to receive EMI options under applicable U.K. tax law. Unapproved options were granted to its employees who are not eligible to receive EMI options and to directors. In May 2014, the Company no longer qualified for EMI status and since that date, no further EMI options were granted under this scheme; however, unapproved options have been under granted under this scheme since that date.

(iii) The Adaptimmune Limited Company Share Option Plan was adopted on December 16, 2014. This scheme allowed the grant of options to our eligible employees prior to the Company’s corporate reorganization in 2015. This scheme is a tax efficient option scheme and options were granted on December 19, 2014 and on December 31, 2014 to our part-time and full-time employees.

As part of the corporate reorganization in connection with our IPO, the holders of options granted under these schemes over ordinary shares of Adaptimmune Limited were granted equivalent options on substantially the same terms over ordinary shares of Adaptimmune Therapeutics plc (“Replacement Options”) in exchange for the release of these options. The Company does not intend to grant any further options under these schemes.

As of December 31, 2023, all the Replacement Options under the Adaptimmune Limited schemes have vested.

The contractual life of options granted under these schemes is ten years.

The following table shows the total share-based compensation expense included in the Consolidated Statements of Operations (in thousands):

​

As of December 31, 2023, there was $9,702,000 of total unrecognized compensation cost related to stock options granted but not vested under the plans. That cost will be recognized over an expected remaining weighted-average period of 2.4 years. The following table shows information about share options granted:

​

​

The following table summarizes all stock option activity for the year ended December 31, 2023:

​

The following table summarizes information about stock options granted based on the market value at grant date which were outstanding as of December 31, 2023:

​

The following table summarizes information about RSU-style options which were outstanding as of December 31, 2023:

​

There were 14,614,410, 5,823,534 and 5,723,646 share options exercised in the years ended December 31, 2023, 2022 and 2021 respectively. In the years ended December 31, 2023, 2022 and 2021 the total intrinsic value of stock options exercised was $2,527,000, $2,368,000 and $4,321,000, respectively and the cash received from exercise of stock options was $256,000, $50,000 and $759,000 respectively. The Company recognizes tax benefits arising on the exercise of stock options regardless of whether the benefit reduces current taxes. The tax benefit arising on

the exercise of stock options was $541,000, $488,000 and $862,000 for the years ended December 31, 2023, 2022 and 2021 respectively. The Company satisfies the exercise of stock options through newly issued shares.

​

​

The fair value of the stock options granted during the period was calculated using the Black-Scholes option-pricing model using the following assumptions:

​

​

The expected term of the option is based on management judgment. The life of the options depends on the option expiration date, volatility of the underlying shares and vesting features. We do not have sufficient history to determine the expected life based on internal data and therefore the estimate is based on empirical data. For Replacement Options issued former to TCR² employees as part of the acquisition of TCR² the expected term of the options was adjusted to account for options that were already fully or partially vested on the grant date and for known factors that would impact the expected term such as redundancy post-acquisition.

​

Management uses historical data to determine the volatility of the Company’s share price. The risk-free rate is based on the Bank of England’s estimates of the gilt yield curve as of the respective grant dates.