RA CAPITAL MANAGEMENT, L.P. - 20 Nov 2025 Form 4 Insider Report for Sionna Therapeutics, Inc. (SION)

Reporting relationship: Director, 10%+ Owner
Issuer ticker: SION
Reported as of: 20 Nov 2025
Net transaction value: -$1,200,704
SEC form: 4
Accepted by SEC: 24 Nov 2025, 17:43:18 UTC
Prior SEC filing: 19 Nov 2025
Next SEC filing: 10 Dec 2025
Source filing: View source filing
Reporting owner signature: /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.

Key filing fact

RA CAPITAL MANAGEMENT, L.P. filed Form 4 for Sionna Therapeutics, Inc. (SION) on 24 Nov 2025.

Key facts

This page summarizes RA CAPITAL MANAGEMENT, L.P.'s Form 4 filing for Sionna Therapeutics, Inc. (SION).
12 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 24 Nov 2025, 17:43.

Change

Previous filing in this sequence was filed on 19 Nov 2025.
Current net transaction value: -$1,200,704.

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

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (6)

CIK 0001346824 Primary reporting owner

RA CAPITAL MANAGEMENT, L.P.

Relationship: Director, 10%+ Owner
Address: 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.
Signature date: 24 Nov 2025

CIK 0001315082

RA Capital Healthcare Fund LP

Relationship: Director, 10%+ Owner
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P.
Signature date: 24 Nov 2025

CIK 0001780117

RA Capital Nexus Fund, L.P.

Relationship: Director
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC, the General Partner of RA Capital Nexus Fund, L.P.
Signature date: 24 Nov 2025

CIK 0001883840

RA Capital Nexus Fund III, L.P.

Relationship: Director
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P.
Signature date: 24 Nov 2025

CIK 0001384859

Kolchinsky Peter

Relationship: Director, 10%+ Owner
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Peter Kolchinsky, individually
Signature date: 24 Nov 2025

CIK 0001619841

Shah Rajeev M.

Relationship: Director, 10%+ Owner
Address: C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON
Signature: /s/ Rajeev Shah, individually
Signature date: 24 Nov 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

SION transaction

Common Stock

Sale

Transaction value: $5,984
Shares: -150
Change %: -0%
Price: $39.89
Shares after: 6,898,929
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F1, F2, F3

SION transaction

Common Stock

Sale

Transaction value: $49,264
Shares: -1,235
Change %: -0.19%
Price: $39.89
Shares after: 661,019
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F1, F3, F4

SION transaction

Common Stock

Sale

Transaction value: $31,952
Shares: -801
Change %: -0.04%
Price: $39.89
Shares after: 2,205,034
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F1, F3, F5

SION transaction

Common Stock

Sale

Transaction value: $37,776
Shares: -947
Change %: -0.56%
Price: $39.89
Shares after: 167,246
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F1, F3, F6

SION transaction

Common Stock

Sale

Transaction value: $3,888
Shares: -96
Change %: -0%
Price: $40.50
Shares after: 6,898,833
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F2, F3, F7

SION transaction

Common Stock

Sale

Transaction value: $31,914
Shares: -788
Change %: -0.12%
Price: $40.50
Shares after: 660,231
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F3, F4, F7

SION transaction

Common Stock

Sale

Transaction value: $20,736
Shares: -512
Change %: -0.02%
Price: $40.50
Shares after: 2,204,522
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F3, F5, F7

SION transaction

Common Stock

Sale

Transaction value: $24,462
Shares: -604
Change %: -0.36%
Price: $40.50
Shares after: 166,642
Date: 20 Nov 2025
Ownership: See footnotes
Footnotes: F3, F6, F7

SION transaction

Common Stock

Sale

Transaction value: $47,795
Shares: -1,210
Change %: -0.02%
Price: $39.50
Shares after: 6,897,623
Date: 21 Nov 2025
Ownership: See footnotes
Footnotes: F2, F3, F8

SION transaction

Common Stock

Sale

Transaction value: $391,998
Shares: -9,924
Change %: -1.5%
Price: $39.50
Shares after: 650,307
Date: 21 Nov 2025
Ownership: See footnotes
Footnotes: F3, F4, F8

SION transaction

Common Stock

Sale

Transaction value: $254,380
Shares: -6,440
Change %: -0.29%
Price: $39.50
Shares after: 2,198,082
Date: 21 Nov 2025
Ownership: See footnotes
Footnotes: F3, F5, F8

SION transaction

Common Stock

Sale

Transaction value: $300,556
Shares: -7,609
Change %: -4.6%
Price: $39.50
Shares after: 159,033
Date: 21 Nov 2025
Ownership: See footnotes
Footnotes: F3, F6, F8

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 8 footnotes

Footnote F1

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.40 to $40.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Footnote F2

Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

Footnote F3

RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus III Fund, L.P. (the "Nexus Fund III"), and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

Footnote F4

Held directly by the Nexus Fund.

Footnote F5

Held directly by the Nexus Fund III.

Footnote F6

Held directly by the Account.

Footnote F7

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.50 to $40.51 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Footnote F8

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.50 to $40.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

SEC remarks

Joshua Resnick, a Partner of the Adviser, serves on the Issuer's board of directors.