Insider Selling: Sionna Therapeutics (NASDAQ:SION) Director Sells $38,928.75 in Stock

Sionna Therapeutics, Inc. (NASDAQ:SION) Director Orbimed Advisors Llc sold 875 shares of the firm’s stock in a transaction dated Friday, December 19th. The stock was sold at an average price of $44.49, for a total value of $38,928.75. Following the sale, the director directly owned 3,595,011 shares in the company, valued at approximately $159,942,039.39. This trade represents a 0.02% decrease in their ownership of the stock. The transaction was disclosed in a document filed with the Securities & Exchange Commission, which is available through the SEC website.

Orbimed Advisors Llc also recently made the following trade(s):

• On Thursday, December 18th, Orbimed Advisors Llc sold 100 shares of Sionna Therapeutics stock. The stock was sold at an average price of $44.49, for a total value of $4,449.00.
• On Wednesday, December 17th, Orbimed Advisors Llc sold 900 shares of Sionna Therapeutics stock. The shares were sold at an average price of $44.50, for a total transaction of $40,050.00.
• On Wednesday, November 26th, Orbimed Advisors Llc sold 1,600 shares of Sionna Therapeutics stock. The shares were sold at an average price of $44.49, for a total transaction of $71,184.00.
• On Tuesday, November 25th, Orbimed Advisors Llc sold 11,890 shares of Sionna Therapeutics stock. The stock was sold at an average price of $44.60, for a total transaction of $530,294.00.
• On Monday, November 24th, Orbimed Advisors Llc sold 94,583 shares of Sionna Therapeutics stock. The shares were sold at an average price of $44.54, for a total transaction of $4,212,726.82.

Sionna Therapeutics Stock Performance

SION opened at $42.37 on Monday. The company has a fifty day moving average of $38.80 and a two-hundred day moving average of $27.42. Sionna Therapeutics, Inc. has a fifty-two week low of $7.26 and a fifty-two week high of $45.00. The stock has a market capitalization of $1.89 billion and a price-to-earnings ratio of -8.70.

Sionna Therapeutics (NASDAQ:SION) last announced its quarterly earnings results on Wednesday, November 5th. The company reported ($0.46) earnings per share for the quarter, beating the consensus estimate of ($0.52) by $0.06.

Analyst Ratings Changes

A number of brokerages have recently issued reports on SION. Jones Trading started coverage on Sionna Therapeutics in a research report on Monday, September 8th. They set a “buy” rating and a $46.00 target price on the stock. Raymond James Financial reaffirmed a “strong-buy” rating on shares of Sionna Therapeutics in a report on Wednesday, November 5th. Weiss Ratings reiterated a “sell (e+)” rating on shares of Sionna Therapeutics in a research report on Monday, December 15th. Wall Street Zen upgraded shares of Sionna Therapeutics from a “sell” rating to a “hold” rating in a research report on Saturday, December 13th. Finally, BTIG Research started coverage on shares of Sionna Therapeutics in a research note on Wednesday, November 19th. They issued a “buy” rating and a $50.00 price target on the stock. Two equities research analysts have rated the stock with a Strong Buy rating, four have given a Buy rating and two have issued a Sell rating to the stock. According to data from MarketBeat, Sionna Therapeutics currently has a consensus rating of “Moderate Buy” and an average price target of $40.33.

Institutional Investors Weigh In On Sionna Therapeutics

A number of large investors have recently modified their holdings of SION. RA Capital Management L.P. acquired a new stake in shares of Sionna Therapeutics in the first quarter valued at about $109,258,000. TPG GP A LLC purchased a new stake in Sionna Therapeutics during the 1st quarter valued at about $69,925,000. Atlas Venture Life Science Advisors LLC purchased a new stake in Sionna Therapeutics during the 1st quarter valued at about $38,639,000. Braidwell LP acquired a new stake in Sionna Therapeutics in the 2nd quarter valued at about $18,770,000. Finally, Vanguard Group Inc. lifted its stake in Sionna Therapeutics by 81.4% in the 3rd quarter. Vanguard Group Inc. now owns 1,143,154 shares of the company’s stock worth $33,620,000 after purchasing an additional 512,803 shares in the last quarter.

Sionna Therapeutics News Summary

Here are the key news stories impacting Sionna Therapeutics this week:

• Positive Sentiment: Senior insiders and institutional holders still retain very large stakes (reported holdings ~3.596M shares each, valued ~ $160M), which signals continued alignment with long‑term performance and limits the risk of a meaningful shift in control. SEC filing
• Negative Sentiment: Director Peter A. Thompson sold a total of 1,875 SION shares across Dec. 17–19 at an average price ~ $44.49–44.50 (proceeds ≈ $83.4k). Each sale is small relative to his stake (ownership dipped ~0.03%), but the filings can prompt negative short‑term sentiment. SEC filing
• Negative Sentiment: OrbiMed Advisors LLC (reported as a director-level holder) executed the same pattern of sales (875, 100 and 900 shares on Dec. 17–19) at similar prices, reducing its position by ~0.02–0.03%. Like the individual sales, the absolute size is small versus the owner’s remaining stake but likely contributes to today’s downside pressure. SEC filing

About Sionna Therapeutics

Sionna Therapeutics is a clinical-stage biotechnology company dedicated to developing next-generation RNA therapeutics for oncology and immunology indications. Leveraging proprietary lipid nanoparticle and coacervate delivery technologies, the company aims to overcome key challenges associated with stability, targeting and immune activation that have historically limited the clinical performance of mRNA-based medicines. Its strategic focus spans both solid tumors and hematological malignancies, as well as selected autoimmune disorders, reflecting a broad ambition to harness the power of messenger RNA in diverse therapeutic areas.

At the heart of Sionna’s approach is a platform that combines optimized ionizable lipids with bespoke surface chemistries to enhance payload delivery, intracellular release and endosomal escape.