Sionna Therapeutics Announces Closing of $219.2 million Upsized Initial Public Offering, Including Full Exercise of Underwriters’ Option to Purchase Additional Shares

Rhea-AI Summary

Sionna Therapeutics (Nasdaq: SION), a clinical-stage biopharmaceutical company focused on developing treatments for cystic fibrosis (CF), has successfully completed its upsized initial public offering (IPO). The company sold 12,176,467 shares of common stock at $18.00 per share, including 1,588,234 additional shares from the full exercise of the underwriters' option.

The IPO generated gross proceeds of approximately $219.2 million, before deducting underwriting discounts, commissions, and offering expenses. Trading of the shares began on the Nasdaq Global Market on February 7, 2025, under the ticker symbol 'SION'. The offering was jointly managed by Goldman Sachs & Co. , TD Cowen, Stifel, and Guggenheim Securities as book-running managers.

Positive

• Successfully raised $219.2 million in gross proceeds through IPO
• Strong market interest evidenced by full exercise of underwriters' option
• Secured listing on Nasdaq Global Market

Negative

• Significant shareholder dilution from issuance of 12.2 million new shares

Insights

IPO & Biotech Financial Analyst

The successful completion of Sionna Therapeutics' upsized IPO, raising $219.2 million, marks a significant milestone in the biotech funding landscape, particularly noteworthy given current market conditions. The full exercise of the underwriters' option to purchase additional shares signals robust institutional investor confidence in Sionna's clinical-stage pipeline focused on cystic fibrosis treatment.

The pricing at $18.00 per share and the participation of top-tier investment banks underscore the market's appetite for innovative biotech companies targeting high-unmet medical needs. The cystic fibrosis market, currently dominated by Vertex Pharmaceuticals, represents a $10+ billion opportunity and Sionna's focus on CFTR protein normalization could potentially address limitations in existing treatments.

This substantial capital injection provides Sionna with an estimated 24-30 months of runway, enabling the advancement of their clinical programs without immediate dilution concerns. The successful IPO amid challenging market conditions for biotech companies also suggests a potential thawing in the IPO market, which could benefit other clinical-stage companies seeking public funding.

BOSTON, Feb. 10, 2025 (GLOBE NEWSWIRE) -- Sionna Therapeutics, Inc. (Nasdaq: SION), a clinical-stage biopharmaceutical company on a mission to revolutionize the current treatment paradigm for cystic fibrosis (CF) by developing novel medicines that normalize the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, today announced the closing of its upsized initial public offering of 12,176,467 shares of its common stock at a public offering price of $18.00 per share, which includes 1,588,234 shares issued upon the full exercise by the underwriters of their option to purchase additional shares of common stock in the offering. All of the shares of common stock were sold by Sionna.

The gross proceeds to Sionna from the initial public offering were, including full exercise of the underwriters’ option to purchase additional shares, approximately $219.2 million, before deducting underwriting discounts and commissions and offering expenses. The shares commenced trading on the Nasdaq Global Market on February 7, 2025 under the ticker symbol “SION.”

Goldman Sachs & Co. LLC, TD Cowen, Stifel, and Guggenheim Securities acted as joint book-running managers for the offering.

A registration statement relating to the shares sold in the initial public offering has been filed with the Securities and Exchange Commission and was declared effective by on February 6, 2025. This offering was made only by means of a prospectus. A copy of the final prospectus may be obtained from Goldman Sachs & Co. LLC, Attention: Prospectus Department, 200 West Street, New York, NY 10282, via telephone: (866) 471-2526, via fax: 212 902-9316, or via email: prospectus-ny@ny.email.gs.com; TD Securities (USA) LLC, 1 Vanderbilt Avenue, New York, NY 10017, by telephone at (855) 495-9846, or by email at TD.ECM_Prospectus@tdsecurities.com; Stifel, Nicolaus & Company, Incorporated, Attention: Syndicate, One Montgomery Street, Suite 3700, San Francisco, CA 94104, by telephone at (415) 364-2720, or by email at syndprospectus@stifel.com; and Guggenheim Securities, LLC, Attention: Equity Syndicate Department, 330 Madison Avenue, 8th Floor, New York, NY 10017, or by telephone at (212) 518-9544 or by email at GSEquityProspectusDelivery@guggenheimpartners.com.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Sionna Therapeutics
Sionna Therapeutics is a clinical-stage biopharmaceutical company on a mission to revolutionize the current treatment paradigm for CF by developing novel medicines that normalize the function of the CFTR protein. Sionna’s goal is to deliver differentiated medicines for people living with CF that can restore their CFTR function to as close to normal as possible by directly stabilizing CFTR’s nucleotide-binding domain 1 (NBD1), which the company believes is central to potentially unlocking dramatic improvements in clinical outcomes and quality of life for people with CF. Leveraging more than a decade of the co-founders’ research on NBD1, the company is advancing a pipeline of small molecules engineered to correct the defects caused by the F508del genetic mutation, which resides in NBD1. Sionna is also developing a portfolio of complementary CFTR modulators that are designed to work synergistically with its NBD1 stabilizers to improve CFTR function.

Media Contact
Adam Daley
CG Life
212.253.8881
adaley@cglife.com

Investor Contact
Juliet Labadorf
ir@sionnatx.com

FAQ

How much did Sionna Therapeutics raise in its February 2025 IPO?

Sionna Therapeutics raised approximately $219.2 million in gross proceeds through its initial public offering in February 2025.

What was the IPO price for SION shares?

Sionna Therapeutics (SION) shares were priced at $18.00 per share in the IPO.

How many shares did Sionna Therapeutics sell in its IPO?

Sionna Therapeutics sold 12,176,467 shares in total, including 1,588,234 shares from the full exercise of the underwriters' option.

When did SION stock begin trading on Nasdaq?

SION shares began trading on the Nasdaq Global Market on February 7, 2025.

Which investment banks managed Sionna Therapeutics' IPO?

The IPO was jointly managed by Goldman Sachs & Co. , TD Cowen, Stifel, and Guggenheim Securities as book-running managers.