Company: SION
Filing Date: 2025-02-07
Form Type: 424B4
Source: 0001193125-25-022709
Chunk: 343

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-07
Form: 424B4
Chunk 343
---
30 |     |                  | 7.9 |     | $               | 1,549 |
| Exercisable as of December 31, 2023 |     |           |   848,368 |     | $                | 4.89 |     |                  | 7.2 |     | $               | 1,032 |

The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the estimated fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The weighted-average grant date fair value in the years ended December 31, 2023 and 2022, was $5.10 and $4.76, respectively. The total intrinsic value of options exercised in the years ended December 31, 2023 and 2022 was $0.2 million and $0.4 million, respectively. Stock-Based Compensation Expense During the years ended December 31, 2023 and 2022, the Company recorded stock-based compensation in the accompanying consolidated statements of operations and comprehensive loss as follows (in thousands):

|                                    |     | Year Ended December 31, |  2023 |     |   |  2022 |
|:-----------------------------------|:----|:------------------------|------:|:----|:--|------:|
| Research and development expense   |     | $                       | 1,135 |     | $ |   859 |
| General and administrative expense |     |                         | 1,124 |     |   |   827 |
| Total                              |     | $                       | 2,259 |     | $ | 1,686 |

As of December 31, 2023, there was $4.4 million of unrecognized stock-based compensation expense for stock option awards that are expected to be recognized over a weighted average period of 2.4 years. As of December 31, 2023, there was $0.2 million of unrecognized stock-based compensation expense for restricted stock awards that are expected to be recognized over a weighted average period of 1.3 years. 13. Income Taxes The Company had no federal or state income tax expense due to operating losses incurred for the years ended December 31, 2023 and 2022. F-25

A reconciliation of income tax expense (benefit) from continuing operations to the amount computed by applying the statutory