Thompson Peter A. 4
4 · Sionna Therapeutics, Inc. · Filed Apr 16, 2026
Research Summary
AI-generated summary of this filing
Sionna (SION) Director Peter Thompson Sells 510,583 Shares
What Happened
Peter A. Thompson, a director of Sionna Therapeutics (SION), disposed of a total of 510,583 shares in three open‑market sales executed April 14–16, 2026. The sales were: 47,814 shares at $44.51 (≈ $2,128,201) on 2026‑04‑14; 235,863 shares at $44.64 (≈ $10,528,924) on 2026‑04‑15; and 226,906 shares at $45.34 (≈ $10,287,918) on 2026‑04‑16. Total gross proceeds across the three transactions were about $22.95 million. These sales were made pursuant to a 10b5‑1 trading plan (prearranged plan), which typically indicates the trades were scheduled in advance rather than spontaneous.
Key Details
- Transaction dates and prices:
- 2026-04-14: Sold 47,814 @ $44.51 — $2,128,201
- 2026-04-15: Sold 235,863 @ $44.64 — $10,528,924
- 2026-04-16: Sold 226,906 @ $45.34 — $10,287,918
- Total shares sold: 510,583; total proceeds ≈ $22,945,043.
- Shares owned after transaction: Not specified in this Form 4.
- Footnotes:
- F1: Sales were made pursuant to a 10b5‑1 plan (preplanned trading).
- F2/F3: The reported securities are held of record by OrbiMed Private Investments VIII, LP (an institutional vehicle). OrbiMed Advisors and its GP may be deemed to have voting/investment power; the reporting person is a member of OrbiMed Advisors. Those parties disclaim beneficial ownership except to the extent of any pecuniary interest.
- Filing/timeliness: Form filed 2026‑04‑16 (no late‑filing flag indicated on the form).
Context
These were sales, not purchases, and were executed under a 10b5‑1 plan, which generally signals preplanned disposition rather than an immediate opinion about company prospects. The reporting person is linked to an institutional investor (OrbiMed vehicle) rather than acting solely as an individual insider; the filing includes disclaimers about beneficial ownership. For retail investors, purchases by insiders tend to be more informative than routine, planned sales; this Form 4 documents a large, prearranged sale by an entity-affiliated director.
Insider Transaction Report
- Sale
Common Stock
[F1][F2][F3]2026-04-14$44.51/sh−47,814$2,128,201→ 3,482,888 total(indirect: See footnotes) - Sale
Common Stock
[F1][F2][F3]2026-04-15$44.64/sh−235,863$10,528,924→ 3,247,025 total(indirect: See footnotes) - Sale
Common Stock
[F1][F2][F3]2026-04-16$45.34/sh−226,906$10,287,918→ 3,020,119 total(indirect: See footnotes)
Footnotes (3)
- [F1]These securities were sold pursuant to a 10b5-1 plan.
- [F2]These securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. OrbiMed Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by OPI VIII. The Reporting Person is a member of OrbiMed Advisors.
- [F3]Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.