Solid Biosciences Inc. Stock Compensation Disclosure

9. Equity-Based Compensation

Equity-Based Compensation Expense

Equity Incentive Plans

As of December 31, 2025, the Company’s approved equity incentive plans include: the 2018 Omnibus Incentive Plan (the “2018 Plan”); Amended and Restated 2020 Equity Incentive Plan, as amended (the “2020 Plan”); the Amended and Restated 2021 Employee Stock Purchase Plan; and the 2024 Inducement Stock Incentive Plan (the “2024 Plan”). These plans are administered by the Board of Directors (the “Board”) and permit the granting of stock options, stock appreciation rights, restricted stock, restricted stock units (the “RSUs”), performance awards, and other stock‑based or cash-based awards. Upon the adoption of the 2020 Plan, the Company no longer grants new equity awards under its 2018 Plan. Service based awards to employees generally vest over a four-year period with 25% of such awards vesting following twelve months of continued employment or service. The remaining awards vest in either monthly or yearly installments over the following three years. Stock options granted under the Company’s equity incentive plans expire ten years from the date of grant.

Amended and Restated 2020 Equity Incentive Plan

On June 12, 2025 and June 11, 2024, the Company’s stockholders approved amendments to the 2020 Plan to increase the number of shares of common stock reserved for issuance under the plan by 9,000,000 shares and 2,000,000 shares, respectively. As of December 31, 2025, there were 3,519,002 stock options outstanding, 2,959,311 RSUs outstanding, 2,074,188 performance stock units outstanding, and 7,554,772 shares remained available for future issuance under the 2020 Plan.

2024 Inducement Stock Incentive Plan

In March 2024, the Board approved the 2024 Plan, which provides for the reservation of 1,000,000 shares of common stock for equity granted as an inducement material to the individuals entering into employment with the Company and in accordance with the requirements of Nasdaq Stock Market Rule 5635(c)(4). As of December 31, 2025, there were 100,000 stock options outstanding, 751,045 RSUs outstanding, and 73,947 shares remained available for future issuance under the 2024 Plan.

Amended and Restated 2021 Employee Stock Purchase Plan

The ESPP was adopted by the Company’s Board of Directors on April 14, 2021, approved by the stockholders on June 16, 2021, and became effective on June 16, 2021. The first offering period under the ESPP commenced on September 1, 2021.

On June 6, 2023, the Company’s stockholders approved an amendment and restatement of the ESPP to (i) increase the number of shares of common stock reserved for issuance under the ESPP from 73,525 to 473,525 and (ii) provide for an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2024 and ending with the fiscal year ending December 31, 2033, equal to the least of (a) 293,597 shares of common stock, (b) one percent (1%) of the outstanding shares of common stock on such date and (c) the number of shares of common stock determined by the Board of Directors. The Company’s Board of Directors amended and restated the ESPP on November 12, 2023 to provide for 24-month offering periods.

The number of shares of the Company’s common stock reserved for issuance under the ESPP is 970,988 shares. At December 31, 2025, 614,225 shares remained available for future issuance under the ESPP.

Stock Options

The weighted average grant date fair values of stock options granted during the years ended December 31, 2025 and 2024 were $4.77 and $6.96, respectively.

The Company recognized $5.9 million and $5.1 million of equity-based compensation expense in connection with stock options during the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025, there was $10.9 million of total unrecognized equity-based compensation cost related to unvested stock options. This cost is expected to be recognized over a weighted average period of 2.3 years. The intrinsic value of stock options exercised during the years ended December 31, 2025 and 2024 was $0 and $0.3 million, respectively.

Restricted Stock Units

The Company recognized $4.9 million and $3.0 million of equity-based compensation expense in connection with RSUs during the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025, there was $15.0 million of total unrecognized equity-based compensation expense related to nonvested RSUs. This cost is expected to be recognized over a weighted average period of 3.0 years. The aggregate grant date fair value of RSUs vested during the years ended December 31, 2025 and 2024 was $3.2 million and $2.2 million, respectively.

Performance Stock Units

In June 2024, the Board approved a grant of performance-based restricted stock unit awards (“PSUs” or “Performance Awards”) to the Company’s executive team. Each PSU represents the contingent right to receive one share of the Company’s common stock. These Performance Awards provide for the vesting of 25% of the target number of underlying RSUs granted upon the achievement of each of four independent performance milestones predetermined by the Board (“Performance Milestones”), subject to the grantee’s continued service with the Company (the “Approval Conditions”).

The Performance Milestones are tied to the achievement of certain business objectives and are non-market and non-financial in nature. The Board will determine that all Approval Conditions have been satisfied and the number of units that will ultimately vest on the 2026 Evaluation Date, which will occur in the first quarter of 2026, and the 2027 Evaluation Date, which will occur in the first quarter of 2027. A maximum of 25% of the target number of RSUs may vest at the 2026 Evaluation Date and the percentage of the target number of RSUs allocable to any Performance Milestone that has not been achieved on or prior to the 2027 Evaluation Date shall be cancelled.

The Company recognized $5.9 million and $2.2 million of equity-based compensation expense in connection with PSUs during the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025, there was $3.6 million of unrecognized equity-based compensation cost related to nonvested PSUs based on the achievement of all Performance Milestones. This cost is expected to be recognized over a weighted average period of 0.9 years.