Key facts
- This page summarizes Peter A. Thompson's Form 4 filing for Sionna Therapeutics, Inc. (SION).
- 1 reported transaction and 0 derivative rows are listed below.
- Accepted by SEC: 29 May 2026, 21:02.
Peter A. Thompson - 27 May 2026 Form 4 Insider Report for Sionna Therapeutics, Inc. (SION)
- Reporting relationship
- Director
- Issuer ticker
- SION
- Reported as of
- 27 May 2026
- Net transaction value
- -$4,493
- SEC form
- 4
- Accepted by SEC
- 29 May 2026, 21:02:49 UTC
- Prior SEC filing
- 11 May 2026
- Next SEC filing
- 17 Jun 2026
- Source filing
- View source filing
- Reporting owner signature
- /s/ Peter A. Thompson
Source evidence
Original filing metadata and source links for verification.
5 source fields
Reporting owner
1 detail
Key filing fact
Peter A. Thompson filed Form 4 for Sionna Therapeutics, Inc. (SION) on 29 May 2026.
Change
- Previous filing in this sequence was filed on 11 May 2026.
- Current net transaction value: -$4,493.
Research use
- This tells you what this filing adds before you inspect full transaction and derivative tables.
- You can trace every row back to the original SEC filing document.
Evidence
Filed on Form 4
View source filing
Ownership activity is grounded in SEC Form 4 disclosures.
Reporting Owners (1)
CIK 0001357522
Primary reporting owner
Thompson Peter A.
- Relationship
- Director
- Address
- C/O SIONNA THERAPEUTICS, INC., 21 HICKORY DRIVE, SUITE 500, WALTHAM
- Signature
- /s/ Peter A. Thompson
- Signature date
- 29 May 2026
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
SION
transaction
Common Stock
Sale
- Transaction value
- $4,493
- Shares
- -101
- Change %
- -0%
- Price
- $44.49
- Shares after
- 2,671,721
- Date
- 27 May 2026
- Ownership
- See footnotes
- Footnotes
- F1, F2, F3
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Rule 10b5-1 trading plan
These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.
Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).
Explanation of responses 3 footnotes
Footnote F1
These securities were sold pursuant to a 10b5-1 plan.
Footnote 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.
Footnote 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.