Thompson Peter A. 4
4 · Sionna Therapeutics, Inc. · Filed May 11, 2026
Research Summary
AI-generated summary of this filing
Sionna (SION) Director Peter A. Thompson Sells 292,952 Shares
What Happened
Peter A. Thompson, a director of Sionna Therapeutics (SION), disposed of a total of 292,952 shares in three open-market sales on May 7, May 8 and May 11, 2026. The sales were: 48,546 shares at $44.61 ($2,165,637), 59,767 shares at $44.58 ($2,664,413), and 184,639 shares at $46.22 ($8,534,015), for aggregate proceeds of approximately $13.36 million. These sales were made pursuant to a pre-established 10b5-1 trading plan (footnote F1), which typically indicates pre-planned, routine dispositions rather than discretionary trades.
Key Details
- Transaction dates and prices:
- 2026-05-07: 48,546 shares @ $44.61 — $2,165,637
- 2026-05-08: 59,767 shares @ $44.58 — $2,664,413
- 2026-05-11: 184,639 shares @ $46.22 — $8,534,015
- Total shares sold: 292,952; total proceeds: ~$13.36 million.
- Shares owned after transaction: Not specified in the provided filing excerpt.
- Footnotes of note:
- F1: Sales were executed under a 10b5-1 plan (pre-arranged trading plan).
- F2/F3: The shares are held of record by OrbiMed Private Investments VIII, LP; OrbiMed Advisors and its GP may be deemed to have voting/investment power. The reporting person is a member of OrbiMed Advisors; the entities disclaim beneficial ownership except to the extent of any pecuniary interest.
- Filing: Form 4 was filed on 2026-05-11; the reported transactions fall within the usual two-business-day reporting window and appear to be timely.
Context
- 10b5-1 plan trades are generally considered pre-arranged and reduce the extent to which the sale signals current insider sentiment. For retail investors, outright purchases are usually a stronger signal than routine sales.
- The filing indicates institutional record-holders (OrbiMed entities) and contains standard disclaimers about beneficial ownership; this suggests these transactions relate to managed/institutional holdings rather than a direct personal stock grant or option exercise by an individual executive.
Insider Transaction Report
Form 4
Thompson Peter A.
Director
Transactions
- Sale
Common Stock
[F1][F2][F3]2026-05-07$44.61/sh−48,546$2,165,637→ 2,916,228 total(indirect: See footnotes() - Sale
Common Stock
[F1][F2][F3]2026-05-08$44.58/sh−59,767$2,664,413→ 2,856,461 total(indirect: See footnotes() - Sale
Common Stock
[F1][F2][F3]2026-05-11$46.22/sh−184,639$8,534,015→ 2,671,822 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.
Signature
/s/ Peter A. Thompson|2026-05-11