The Sionna Therapeutics, Inc. (Nasdaq: SION) SEC filings page on Stock Titan provides access to the company’s regulatory disclosures as filed with the U.S. Securities and Exchange Commission. Sionna describes itself as a clinical-stage biopharmaceutical company focused on developing CFTR-targeted therapies for cystic fibrosis, and its filings offer detail on this business and its financial position.
Among the key documents available are current reports on Form 8-K, where Sionna furnishes press releases announcing quarterly financial results and business highlights. For example, the company has used Form 8-K to present information on research and development expenses, general and administrative expenses, net loss, cash and cash equivalents, and progress across its clinical pipeline of NBD1 stabilizers and complementary CFTR modulators.
In addition to 8-Ks, investors typically look to annual reports on Form 10-K and quarterly reports on Form 10-Q for broader discussions of risk factors, research and development activities, and the company’s focus on cystic fibrosis therapies. These filings can also describe Sionna’s status as an emerging growth company, its operating segment dedicated to CF drug development, and other structural aspects of the business.
Stock Titan enhances access to SION filings by pairing real-time updates from the EDGAR system with AI-powered summaries that explain the significance of each document in clear language. Users can quickly identify items related to clinical trial progress, financial condition, and other material events, and can review insider and management-related disclosures where applicable. This page serves as a central location for reviewing Sionna’s regulatory history and understanding how its CF-focused strategy is reflected in formal SEC documents.
Sionna Therapeutics, Inc. (SION) filed a Form 144 notice reporting a proposed sale of 9,753 common shares valued at $292,687.53 to be sold through Merrill Lynch on 10/06/2025 on NASDAQ. The shares were acquired in a private placement on 03/04/2024 and paid for in cash.
The filing also lists recent open-market sales by related funds between 09/29/2025 and 10/03/2025, totaling approximately $3,499,940.95 across several transactions. The filer affirms no undisclosed material adverse information and includes the standard certification language regarding Rule 10b5-1 trading plans.
Sionna Therapeutics filed a Form 144 notifying a proposed sale of 31,198 common shares acquired in a private placement on 03/04/2024. The filing reports an aggregate market value of $914,101.40 and lists the approximate sale date as 10/03/2025, with Merrill Lynch named as the broker and the securities listed on NASDAQ. The company shows 44,139,823 shares outstanding. The filing also discloses recent sales by related funds in late September–early October 2025 totaling multiple transactions (largest: 54,637 shares for $1,644,065.58 on 09/29/2025).
Caroline Stark Beer, Chief Business Officer of Sionna Therapeutics, Inc. (SION), was granted a non‑qualified stock option to purchase 255,000 shares of common stock with an exercise price of $28.47. The grant was reported with a transaction date of 10/01/2025 and the filing was signed on 10/03/2025. The option becomes exercisable under a vesting schedule where 25% of the shares vest on September 8, 2026, with the remaining shares vesting in 36 equal monthly installments thereafter, contingent on continued service. The option expires on 09/30/2035.
Sionna Therapeutics, Inc. (SION) filed an Initial Statement of Beneficial Ownership (Form 3) for Caroline Stark Beer, who is identified as the company's Chief Business Officer and an officer/director. The form shows the reportable event date of 10/01/2025 and is signed on 10/03/2025. The filing explicitly states: No securities are beneficially owned by the reporting person, and no non‑derivative or derivative holdings are reported.
Director Bruce Booth reported sales of 78,693 shares of Sionna Therapeutics, Inc. (SION) under Rule 10b5-1 plans. The sales occurred on 09/29/2025, 09/30/2025 and 10/01/2025 at weighted-average prices between $29.95 and $30.41, generating dispositions across two Atlas Venture funds. After the reported transactions, Atlas Venture Fund XI, L.P. is shown as beneficially owning 2,821,252 shares and Atlas Venture Opportunity Fund II, L.P. is shown as beneficially owning 794,075 shares. The filing clarifies that the reporting person is a member of the general partner entities and disclaims beneficial ownership except to the extent of any pecuniary interest.
Sionna Therapeutics filed a Form 144 reporting a proposed sale of 165 common shares acquired in a private placement on 03/04/2024. The sale is to be executed through Merrill Lynch (San Francisco) for an approximate aggregate market value of $4,852.65 with an approximate sale date of 10/01/2025. The company notes 44,139,823 shares outstanding. Related recent dispositions by affiliated funds include four sales on 09/29/2025–09/30/2025 totaling 78,493 shares for aggregate gross proceeds of $2,389,102.99.
Sionna Therapeutics (SION) filed a Form 144 reporting a proposed sale of 35 common shares through Merrill Lynch with an approximate sale date of 10/01/2025. The shares were acquired in a private placement on 03/04/2024 for cash. The filing lists 44,139,823 shares outstanding and an aggregate market value for the proposed sale of 1,029.35. The filing also discloses recent sales by affiliated funds: Atlas Venture Opportunity Fund II and Atlas Venture Fund XI executed multiple common-stock sales on 09/29/2025 and 09/30/2025, including transactions of 11,468, 2,149, 54,637, and 10,239 shares with gross proceeds reported for each sale. The notice includes the required representation that the seller is unaware of undisclosed material adverse information.
Sionna Therapeutics, Inc. (SION) Form 144 notice reports a proposed sale of 10,239 common shares through Merrill Lynch on NASDAQ with an aggregate market value of $302,255.28 and an approximate sale date of 09/30/2025. The shares were acquired in a private placement from the issuer on 03/04/2024 for cash. The filing also discloses related secondary sales on 09/29/2025: Atlas Venture Fund XI, LP sold 54,637 shares for $1,644,065.58 and Atlas Venture Opportunity Fund II, L.P. sold 11,468 shares for $345,080.15. The filer certifies no undisclosed material adverse information.
Sionna Therapeutics notice reports a proposed sale under Rule 144 of 2,149 common shares through Merrill Lynch (San Francisco) with an approximate aggregate market value of $63,438.48 and an intended sale date of 09/30/2025 on NASDAQ. The filing shows the shares were acquired on 03/04/2024 in a private placement from the issuer, paid in cash. The filing also discloses related sales in the prior three months: 11,468 shares (gross proceeds $345,080.15) by Atlas Venture Opportunity Fund II, L.P. and 54,637 shares (gross proceeds $1,644,065.58) by Atlas Venture Fund XI, LP on 09/29/2025.
Michael Cloonan, President & CEO and Director of Sionna Therapeutics, Inc. (SION), reported option exercises and concurrent sales executed under a Rule 10b5-1 trading plan adopted May 21, 2025. On 09/26/2025 he exercised 17,207 non-qualified stock options at an exercise price of $6.11 and sold 17,207 shares at a weighted average price of $28.8456, bringing beneficial ownership to 564,550 then 547,343 after the sale. On 09/29/2025 he exercised 7,793 options at $6.11 and sold 7,793 shares at a weighted average price of $29.6999, leaving total beneficial ownership at 547,343. The options vest monthly in 48 equal installments following February 2, 2022, and carry an expiration/other date listed as 03/01/2032. The Form 4 was signed by an attorney-in-fact on 09/30/2025.