Karyopharm Therapeutics Inc. Stock Compensation Disclosure

9. Stock-based Compensation

On May 19, 2022, our stockholders approved the 2022 Equity Incentive Plan (the “2022 Plan”), succeeding our 2013 Stock Incentive Plan (the “2013 Plan”), which has expired and under which no further grants may be made. The 2022 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, RSU awards and other stock-based awards. On May 24, 2023, May 29, 2024, and May 28, 2025 our stockholders approved an amendment to the 2022 Plan to increase the number of shares of our common stock available for issuance under the 2022 Plan by 333,333 shares, 400,000 shares, and 450,000 shares, respectively. As of December 31, 2025, there were 283,228 shares available for future grants under the 2022 Plan.

Under the terms of the 2022 Plan, we granted stock options, RSUs, and PSUs to our employees, officers, directors, consultants and advisors. Stock options have a ten-year term and an exercise price equal to the fair market value of a share of our common stock on the grant date. Stock options and RSUs vest over a period of one to four years. PSUs will vest if certain performance goals are achieved over a certain performance period. Certain portions of certain PSU awards vest based on continuous service to the Company throughout the performance period even if the performance goal is not achieved.

During 2025, 2024, and 2023, we also granted stock options and RSUs through inducement grants outside of our stockholder approved equity compensation plans as permitted under the Nasdaq Stock Market listing rules to certain employees to induce them to accept employment with us (collectively, “Inducement Awards” which are made under the “2022 Inducement Plan”). In 2023 and 2024, the Board increased the number of shares reserved for issuance under the 2022 Inducement Plan by 80,000 shares and 66,667 shares, respectively. We assessed the terms of these Inducement Awards and determined there was no possibility that we would have to settle these awards in cash and therefore, equity accounting was applied. As of December 31, 2025, there were 39,626 shares available for future grants under the 2022 Inducement Plan.

As of December 31, 2025, we had 2,123,671 shares reserved for issuance, which includes shares available for future grants and outstanding stock options, RSUs and PSUs under the 2013 Plan, the 2022 Plan, and Inducement Awards (including the Inducement Awards granted under the 2022 Inducement Plan).

Stock-based Compensation Expense

Stock Options

There were no stock options exercised during the years ended December 31, 2025 and 2024. The total intrinsic value of stock options exercised for the year ended December 31, 2023 was less than $0.1 million.

We use the simplified method to calculate the expected term as our historical exercise data does not provide a reasonable basis upon which to estimate the expected term. The expected term is applied to the stock option grant group as a whole, as we do not expect substantially different exercise or post-vesting termination behavior among our employee population. Our expected stock price volatility assumption is based on the historical volatility of our publicly traded stock. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. We account for forfeitures as they occur.

Using the Black-Scholes option-pricing model, the weighted-average grant date fair values of options granted during the years ended December 31, 2025, 2024 and 2023 was $5.86, $9.53 and $23.03 per share, respectively.

As of December 31, 2025, there was $1.5 million of unrecognized compensation expense related to unvested stock option awards, which is expected to be recognized over a weighted-average period of 2.7 years.

Restricted Stock Units and Performance-Based Restricted Stock Units

The total fair value of RSUs and PSUs that vested during the years ended December 31, 2025, 2024 and 2023 was $1.6 million, $2.8 million, and $2.9 million, respectively. As of December 31, 2025, there was $8.7 million of unrecognized compensation expense related to unvested RSUs and PSUs, which is expected to be recognized over a weighted-average period of 1.3 years.

Employee Stock Purchase Plan

We have an ESPP that permits eligible employees to enroll in six-month offering periods. Participants may purchase shares of our common stock, through payroll deductions, at a price equal to 85% of the fair market value of the common stock on the first or last day of the applicable offering period, whichever is lower. Purchase dates under the ESPP occur on or about May 1 and November 1 each year. On May 24, 2023, our stockholders approved an amendment and restatement of our ESPP (the “Amended & Restated ESPP”), which increased the number of shares of common stock authorized for issuance under the ESPP by 100,000 shares. On May 29, 2024, our stockholders approved an amendment to the Amended & Restated ESPP to increase the number of shares of our common stock available for issuance under the Amended & Restated ESPP by 333,333 shares. As of December 31, 2025, 165,461 shares of our common stock remained available for issuance under the Amended & Restated ESPP.

During the years ended December 31, 2025, 2024 and 2023, $0.8 million, $1.5 million and $1.1 million, respectively, was withheld from employees, on an after-tax basis, in order to purchase 145,936, 131,698 and 42,391 shares of our common stock, respectively. As of December 31, 2025, there was $0.1 million of total unrecognized stock-based compensation expense related to the Amended & Restated ESPP. The expense is expected to be recognized over a period of four months.