Company: SION
Filing Date: 2025-02-03
Form Type: S-1/A
Source: 0001193125-25-018825
Chunk: 17

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-02-03
Form: S-1/A
Chunk 17
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 companies. We have elected to avail ourselves of this exemption and, therefore, while we are an emerging growth company we will not be subject to new or revised accounting standards at the same time that they become applicable to other public companies that are not emerging growth companies. As a result of this election, our consolidated financial statements may not be comparable to those of other public companies that comply with new or revised accounting pronouncements as of public company effective dates. We may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for private companies.

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We are also a “smaller reporting company,” meaning that the market value of our shares held
by non-affiliates plus the proposed aggregate amount of gross proceeds to us as a result of this offering is less than $700 million and our annual revenue was less than $100 million during the most
recently completed fiscal year. We may continue to be a smaller reporting company after this offering if either (i) the market value of our shares held by non-affiliates is less than $250 million or
(ii) our annual revenue was less than $100 million during the most recently completed fiscal year and the market value of our shares held by non-affiliates is less than $700 million. If we are a
smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting
company, we may choose to present only the two most recent fiscal years of audited consolidated financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller
reporting companies have reduced disclosure obligations regarding executive compensation.

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THE OFFERING

| Common stock offered by us | 8,823,529 shares. |

| Option to purchase additional shares of common stock | We have granted a 30-day option to the underwriters to purchase up to 1,323,529 additional shares of common stock from us at the public offering price, less underwriting discounts and commissions. |

| Common stock to be outstanding immediately after this offering | 40,755,996 shares (or 42,079,525 shares if the underwriters exercise their option to purchase additional shares of common stock in full). |

| Use of proceeds | We estimate that the net proceeds from the sale of our common stock in this offering will be approximately $135.3 million (or approximately $156.2 million if the under