RA CAPITAL MANAGEMENT, L.P. - 17 Nov 2025 Form 4 Insider Report for Sionna Therapeutics, Inc. (SION)

Signature
/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.
Issuer symbol
SION
Transactions as of
17 Nov 2025
Net transactions value
-$5,500,158
Form type
4
Filing time
19 Nov 2025, 20:43:43 UTC
Previous filing
14 Nov 2025
Next filing
24 Nov 2025

Reporting Owners (6)

Name Relationship Address Signature Signature date CIK
RA CAPITAL MANAGEMENT, L.P. Director, 10%+ Owner 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 19 Nov 2025 0001346824
RA Capital Healthcare Fund LP Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P. 19 Nov 2025 0001315082
RA Capital Nexus Fund, L.P. Director C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC, the General Partner of RA Capital Nexus Fund, L.P. 19 Nov 2025 0001780117
RA Capital Nexus Fund III, L.P. Director C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P. 19 Nov 2025 0001883840
Kolchinsky Peter Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, individually 19 Nov 2025 0001384859
Shah Rajeev M. Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Rajeev Shah, individually 19 Nov 2025 0001619841

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction SION Common Stock Sale $87,716 -2,182 -0.03% $40.20 6,903,443 17 Nov 2025 See footnotes F1, F2, F3
transaction SION Common Stock Sale $720,103 -17,913 -2.5% $40.20 698,075 17 Nov 2025 See footnotes F1, F3, F4
transaction SION Common Stock Sale $467,365 -11,626 -0.52% $40.20 2,229,082 17 Nov 2025 See footnotes F1, F3, F5
transaction SION Common Stock Sale $552,107 -13,734 -6.6% $40.20 195,657 17 Nov 2025 See footnotes F1, F3, F6
transaction SION Common Stock Sale $69,826 -1,701 -0.02% $41.05 6,901,742 17 Nov 2025 See footnotes F2, F3, F7
transaction SION Common Stock Sale $573,222 -13,964 -2% $41.05 684,111 17 Nov 2025 See footnotes F3, F4, F7
transaction SION Common Stock Sale $372,036 -9,063 -0.41% $41.05 2,220,019 17 Nov 2025 See footnotes F3, F5, F7
transaction SION Common Stock Sale $439,522 -10,707 -5.5% $41.05 184,950 17 Nov 2025 See footnotes F3, F6, F7
transaction SION Common Stock Sale $2,231 -53 -0% $42.10 6,901,689 17 Nov 2025 See footnotes F2, F3, F8
transaction SION Common Stock Sale $18,229 -433 -0.06% $42.10 683,678 17 Nov 2025 See footnotes F3, F4, F8
transaction SION Common Stock Sale $11,788 -280 -0.01% $42.10 2,219,739 17 Nov 2025 See footnotes F3, F5, F8
transaction SION Common Stock Sale $13,935 -331 -0.18% $42.10 184,619 17 Nov 2025 See footnotes F3, F6, F8
transaction SION Common Stock Sale $13,137 -332 -0% $39.57 6,901,357 18 Nov 2025 See footnotes F2, F3, F9
transaction SION Common Stock Sale $107,947 -2,728 -0.4% $39.57 680,950 18 Nov 2025 See footnotes F3, F4, F9
transaction SION Common Stock Sale $70,039 -1,770 -0.08% $39.57 2,217,969 18 Nov 2025 See footnotes F3, F5, F9
transaction SION Common Stock Sale $82,780 -2,092 -1.1% $39.57 182,527 18 Nov 2025 See footnotes F3, F6, F9
transaction SION Common Stock Sale $91,063 -2,276 -0.03% $40.01 6,899,081 19 Nov 2025 See footnotes F2, F3, F10
transaction SION Common Stock Sale $747,547 -18,684 -2.7% $40.01 662,266 19 Nov 2025 See footnotes F3, F4, F10
transaction SION Common Stock Sale $485,161 -12,126 -0.55% $40.01 2,205,843 19 Nov 2025 See footnotes F3, F5, F10
transaction SION Common Stock Sale $573,143 -14,325 -7.8% $40.01 168,202 19 Nov 2025 See footnotes F3, F6, F10
transaction SION Common Stock Sale $81.22 -2 -0% $40.61 6,899,079 19 Nov 2025 See footnotes F2, F3
transaction SION Common Stock Sale $487 -12 -0% $40.61 662,254 19 Nov 2025 See footnotes F3, F4
transaction SION Common Stock Sale $325 -8 -0% $40.61 2,205,835 19 Nov 2025 See footnotes F3, F5
transaction SION Common Stock Sale $365 -9 -0.01% $40.61 168,193 19 Nov 2025 See footnotes F3, F6
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 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.
F2 Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").
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.
F4 Held directly by the Nexus Fund.
F5 Held directly by the Nexus Fund III.
F6 Held directly by the Account.
F7 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.
F8 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.
F9 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.
F10 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.