Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 248

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 248
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725 |     |                | 197,976 |     |           | 1,300,647 |
| Chief Financial Officer and   
 Head of Corporate Development |     |      | 2023 |     |            | 432,640 |     |        |         — |     |                | 190,362 |     |           |   623,002 |
| Charlotte McKee, M.D.         |     |      | 2024 |     |            | 449,946 |     |        |   635,318 |     |                | 197,976 |     |           | 1,283,240 |
| Chief Medical Officer         |     |      | 2023 |     |            | 432,640 |     |        |         — |     |                | 190,362 |     |           |   623,002 |

| (1) | For fiscal year 2024, the amounts reported represent the aggregate grant date fair value of stock option awards granted                                                                                                                                
 to our NEOs during such fiscal year, computed in accordance with Financial Accounting Standards Board Accounting Standards Codification Topic 718 (“FASB ASC Topic 718”). A discussion of the assumptions used in determining grant date fair          
 value may be found in Note 12 to our financial statements, included elsewhere in this prospectus. Such grant date fair values do not take into account any estimated forfeitures related to service-based vesting. The amounts reported in this column 
 reflect the accounting cost for the stock option award and do not correspond to the actual economic value that may be received by our NEOs upon the vesting of the awards or any sale of the underlying securities.                                    |

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| (2) | Amounts reflect bonuses earned based on our achievement of specified performance metrics for the applicable fiscal year 
 pursuant to our non-equity incentive plan.                                                                              |

Narrative Disclosure to Summary Compensation Table 2024 Salaries Our NEOs each receive a base salary to compensate them for services rendered to us. The base salary payable to each NEO is intended to provide a fixed component of compensation reflecting the executive’s skill set, experience, role and responsibilities. Base salaries are reviewed annually, typically in connection with our annual performance review process, and approved by our board of directors or our compensation committee, and may be adjusted from time to time to realign salaries with market levels after taking into account individual responsibilities, performance and experience. Our board of directors, or our compensation committee, as applicable, generally reviews executive