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  4. [Form 4] Sionna Therapeutics, Inc. Insider Trading Activity

RA Capital insider transactions disclosed in Sionna Therapeutics Form 4

Filing Impact
(Very High)
Filing Sentiment
(Very Negative)
Form Type
4

Rhea-AI Filing Summary

Sionna Therapeutics (SION) reported insider activity on a Form 4 showing that RA Capital–affiliated entities, which are identified as both directors and 10% owners, sold shares of Sionna common stock over several days. On November 17, 2025, they executed multiple sales, including a sale of 17,913 shares of common stock at a weighted average price of $40.2 per share, in transactions within a price range of $40.00 to $40.85.

Additional sales took place on November 17–19, 2025 at weighted average prices described in the footnotes as ranging from $39.40 to $42.13 per share, all through various RA Capital funds and accounts. The filing notes that detailed breakdowns of the individual trade prices within each range are available upon request, and that the RA Capital entities and individuals disclaim beneficial ownership beyond their economic interest.

Positive

  • None.

Negative

  • None.
Insider RA CAPITAL MANAGEMENT, L.P., RA Capital Healthcare Fund LP, RA Capital Nexus Fund, L.P., RA Capital Nexus Fund III, L.P., Kolchinsky Peter, Shah Rajeev M.
Role Director, 10% Owner | Director, 10% Owner | Director | Director | Director, 10% Owner | Director, 10% Owner
Sold 136,351 shs ($5.50M)
Type Security Shares Price Value
Sale Common Stock 2,276 $40.01 $91K
Sale Common Stock 18,684 $40.01 $748K
Sale Common Stock 12,126 $40.01 $485K
Sale Common Stock 14,325 $40.01 $573K
Sale Common Stock 2 $40.61 $81.22
Sale Common Stock 12 $40.61 $487.32
Sale Common Stock 8 $40.61 $324.88
Sale Common Stock 9 $40.61 $365.49
Sale Common Stock 332 $39.57 $13K
Sale Common Stock 2,728 $39.57 $108K
Sale Common Stock 1,770 $39.57 $70K
Sale Common Stock 2,092 $39.57 $83K
Sale Common Stock 2,182 $40.20 $88K
Sale Common Stock 17,913 $40.20 $720K
Sale Common Stock 11,626 $40.20 $467K
Sale Common Stock 13,734 $40.20 $552K
Sale Common Stock 1,701 $41.05 $70K
Sale Common Stock 13,964 $41.05 $573K
Sale Common Stock 9,063 $41.05 $372K
Sale Common Stock 10,707 $41.05 $440K
Sale Common Stock 53 $42.10 $2K
Sale Common Stock 433 $42.10 $18K
Sale Common Stock 280 $42.10 $12K
Sale Common Stock 331 $42.10 $14K
Holdings After Transaction: Common Stock — 6,899,081 shares (Indirect, See footnotes)
Footnotes (1)
  1. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.00 to $40.85 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. Held directly by RA Capital Healthcare Fund, L.P. (the "Fund"). 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. Held directly by the Nexus Fund. Held directly by the Nexus Fund III. Held directly by the Account. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $41.00 to $41.21 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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $42.00 to $42.13 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. 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 $40.02 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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.59 to $40.45 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.
Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0287
Estimated average burden
hours per response: 0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
RA CAPITAL MANAGEMENT, L.P.
(Last) (First) (Middle)
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Sionna Therapeutics, Inc. [ SION ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
X Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
11/17/2025
4. If Amendment, Date of Original Filed (Month/Day/Year)
 6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
X Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 11/17/2025 S 2,182 D $40.2(1) 6,903,443 I See footnotes(2)(3)
Common Stock 11/17/2025 S 17,913 D $40.2(1) 698,075 I See footnotes(3)(4)
Common Stock 11/17/2025 S 11,626 D $40.2(1) 2,229,082 I See footnotes(3)(5)
Common Stock 11/17/2025 S 13,734 D $40.2(1) 195,657 I See footnotes(3)(6)
Common Stock 11/17/2025 S 1,701 D $41.05(7) 6,901,742 I See footnotes(2)(3)
Common Stock 11/17/2025 S 13,964 D $41.05(7) 684,111 I See footnotes(3)(4)
Common Stock 11/17/2025 S 9,063 D $41.05(7) 2,220,019 I See footnotes(3)(5)
Common Stock 11/17/2025 S 10,707 D $41.05(7) 184,950 I See footnotes(3)(6)
Common Stock 11/17/2025 S 53 D $42.1(8) 6,901,689 I See footnotes(2)(3)
Common Stock 11/17/2025 S 433 D $42.1(8) 683,678 I See footnotes(3)(4)
Common Stock 11/17/2025 S 280 D $42.1(8) 2,219,739 I See footnotes(3)(5)
Common Stock 11/17/2025 S 331 D $42.1(8) 184,619 I See footnotes(3)(6)
Common Stock 11/18/2025 S 332 D $39.57(9) 6,901,357 I See footnotes(2)(3)
Common Stock 11/18/2025 S 2,728 D $39.57(9) 680,950 I See footnotes(3)(4)
Common Stock 11/18/2025 S 1,770 D $39.57(9) 2,217,969 I See footnotes(3)(5)
Common Stock 11/18/2025 S 2,092 D $39.57(9) 182,527 I See footnotes(3)(6)
Common Stock 11/19/2025 S 2,276 D $40.01(10) 6,899,081 I See footnotes(2)(3)
Common Stock 11/19/2025 S 18,684 D $40.01(10) 662,266 I See footnotes(3)(4)
Common Stock 11/19/2025 S 12,126 D $40.01(10) 2,205,843 I See footnotes(3)(5)
Common Stock 11/19/2025 S 14,325 D $40.01(10) 168,202 I See footnotes(3)(6)
Common Stock 11/19/2025 S 2 D $40.61 6,899,079 I See footnotes(2)(3)
Common Stock 11/19/2025 S 12 D $40.61 662,254 I See footnotes(3)(4)
Common Stock 11/19/2025 S 8 D $40.61 2,205,835 I See footnotes(3)(5)
Common Stock 11/19/2025 S 9 D $40.61 168,193 I See footnotes(3)(6)
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
1. Name and Address of Reporting Person*
RA CAPITAL MANAGEMENT, L.P.
(Last) (First) (Middle)
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
X Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
RA Capital Healthcare Fund LP
(Last) (First) (Middle)
C/O RA CAPITAL MANAGEMENT, L.P.
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
X Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
RA Capital Nexus Fund, L.P.
(Last) (First) (Middle)
C/O RA CAPITAL MANAGEMENT, L.P.
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
X Director 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
RA Capital Nexus Fund III, L.P.
(Last) (First) (Middle)
C/O RA CAPITAL MANAGEMENT, L.P.
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
X Director 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Kolchinsky Peter
(Last) (First) (Middle)
C/O RA CAPITAL MANAGEMENT, L.P.
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
X Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
Shah Rajeev M.
(Last) (First) (Middle)
C/O RA CAPITAL MANAGEMENT, L.P.
200 BERKELEY STREET, 18TH FLOOR
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
X Director X 10% Owner
Officer (give title below) Other (specify below)
Explanation of Responses:
1. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.00 to $40.85 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.
2. Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").
3. 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.
4. Held directly by the Nexus Fund.
5. Held directly by the Nexus Fund III.
6. Held directly by the Account.
7. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $41.00 to $41.21 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.
8. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $42.00 to $42.13 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.
9. 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 $40.02 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.
10. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.59 to $40.45 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.
Remarks:
Joshua Resnick, a Partner of the Adviser, serves on the Issuer's board of directors.
/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 11/19/2025
/s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P. 11/19/2025
/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC, the General Partner of RA Capital Nexus Fund, L.P. 11/19/2025
/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P. 11/19/2025
/s/ Peter Kolchinsky, individually 11/19/2025
/s/ Rajeev Shah, individually 11/19/2025
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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Source: View Original Filing on SEC EDGAR