Company: SION
Filing Date: 2025-01-24
Form Type: CORRESP
Source: 0001193125-25-012256
Chunk: 7

Company: Sionna Therapeutics, Inc.
Filing Date: 2025-01-24
Form: CORRESP
Chunk 7
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2,066,646 shares of Common Stock to AbbVie as partial initial consideration for the license. This did not represent a significant development in the business, as it was not a business combination or restructuring, nor did it significantly further develop the Company’s other programs within its pipeline. As a result, the Company determined that no developments that would affect the valuation occurred from February 13, 2023 through July 15, 2024. August 9, 2024 Valuation The fair value of the Common Stock of $5.53 per share at August 9, 2024 was determined with the assistance of an independent third-party valuation firm and approved by the Board on September 11, 2024. This valuation was used to support the fair market value of the Common Stock in accordance with Section 409A of the IRC with respect to options granted on September 11, 2024, along with other factors determined by the Board to be relevant at the time of each such grant of options. The August 9, 2024 valuation utilized the hybrid method of both an OPM and a PWERM, which included three scenarios that were probability weighted based on their expected likelihoods of occurring. The scenarios identified included a near-term IPO scenario, a base case IPO scenario and a trade sale scenario. The IPO near-term scenario was assigned a probability weight of 5.0% and the IPO base case scenario was assigned a probability weight of 25.0%. The IPO scenarios considered guideline IPO transactions identified within the last several years and the Company’s progress towards an IPO, as adjusted by a DLOM of 9.0% for the IPO near-term scenario and 15.0% for the IPO base case scenario. The Company’s trade sale scenario under an OPM to allocate the fair value of the Company’s equity to various securities within the Company’s capital structure was assigned a probability weight of 70.0% and reflected the market adjustment to the Company’s equity value since February 13, 2024 based on consideration given to the performance of the biotechnology indices as well as the Company’s entity-specific factors. A DLOM of 28.0% was then applied to arrive at an indication of value for the Common Stock under the trade sale scenario. FOIA CONFIDENTIAL TREATMENT REQUESTED BY SIONNA THERAPEUTICS, INC.

Division of Corporation Finance Office of Life Sciences U.S. Securities and Exchange Commission January 24, 2025 Page 6