Company: SION
Filing Date: 2025-01-17
Form Type: S-1
Source: 0001193125-25-008474
Chunk: 339

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-17
Form: S-1
Chunk 339
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 and consultants of the Company. The 2020 Plan is administered by the Board, or at the discretion of the Board, by a committee of the Board. The exercise prices, vesting and other restrictions are determined at the discretion of the Board, or their committee if so delegated, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the share of common stock on the date of grant and the term of stock option may not be greater than ten years. F-23

The total number of shares of common stock that may be issued under the 2020 Plan is 5,770,730 shares, of which 1,132,950 remained available for future grant as of December 31, 2023. Vesting periods are determined at the discretion of the Board. Stock options and restricted stock granted to-datetypically vest over four years. Restricted Common Stock The Company did not issue shares of restricted common stock to founders and officers during the years ended December 31, 2023 or 2022. The outstanding restricted shares are subject to a vesting schedule that varies among the grants, and vesting may be accelerated upon a change in control, as defined in the agreements. If the holders cease to have a business relationship with the Company, the Company may repurchase any unvested shares of common stock held by these individuals at their original purchase price. The unvested shares of common stock are not considered outstanding shares and are recorded as a liability until the shares vest. A summary of the Company’s restricted stock activity during the year ended December 31, 2023 is presented below:

|                                  |     | Number of  
 Restricted 
 Shares     |          |   |     | Weighted-Average 
 Per-Share        
 Grant-Date       
 Fair Value       |      |
|:---------------------------------|:----|:-----------|---------:|:--|:----|:-----------------|-----:|
| Unvested as of December 31, 2022 |     |            |  707,953 |   |     | $                | 0.52 |
| Vested                           |     |            | (324,922 | ) |     | $                | 0.51 |
| Unvested as of December 31, 2023 |     |            |  383,031 |   |     | $                | 0.53 |

For the years ended December 31, 202