Company: SION
Filing Date: 2025-01-17
Form Type: S-1
Source: 0001193125-25-008474
Chunk: 340

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-17
Form: S-1
Chunk 340
---
3 and 2022, the liability related to the payments received for shares of unvested restricted stock was de minimis. The aggregate fair value of restricted stock awards that vested during the years ended December 31, 2023 and 2022 was $1.4 million and $2.0 million, respectively. Stock Option Valuation The assumptions used to determine the fair values of stock options granted to employees and directors during the years ended December 31, 2023 and 2022 are presented as follows:

|                          |     | Year Ended December 31, |  2023 |   |     |     | 2022 |   |
|:-------------------------|:----|:------------------------|------:|:--|:----|:----|-----:|:--|
| Expected term (in years) |     |                         |   6.0 |   |     |     |  6.0 |   |
| Volatility               |     |                         | 107.0 | % |     |     | 96.4 | % |
| Interest rate            |     |                         |   4.1 | % |     |     |  2.2 | % |
| Dividend yield           |     |                         |     — |   |     |     |    — |   |

F-24

Stock Option Activity The following table summarizes the Company’s stock option activity under the 2020 Plan for the year ended December 31, 2023:

|                                     |     | Number of 
 Shares    |           |     | Weighted-Average 
 Exercise Price   |      |     | Weighted-Average 
 Remaining        
 Contractual Term 
 (in years)       |     |     | Aggregate       
 Intrinsic Value 
 (in thousands)  |       |
|:------------------------------------|:----|:----------|----------:|:----|:-----------------|-----:|:----|:-----------------|----:|:----|:----------------|------:|
| Outstanding as of December 31, 2022 |     |           | 2,842,147 |     | $                | 3.55 |     |                  | 9.1 |     | $               | 1,797 |
| Granted                             |     |           |   262,473 |     |                  | 4.18 |     |                  |     |     |                 |       |
| Exercised                           |