Elena Ridloff - Aug 29, 2025 Form 4 Insider Report for Sionna Therapeutics, Inc. (SION)

Role
CFO & Head of Corp. Dev.
Signature
Jennifer Fitzpatrick, Attorney-in-Fact
Stock symbol
SION
Transactions as of
Aug 29, 2025
Transactions value $
-$240,442
Form type
4
Date filed
9/3/2025, 05:16 PM
Previous filing
Aug 28, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Ridloff Elena CFO & Head of Corp. Dev. C/O SIONNA THERAPEUTICS, INC., 21 HICKORY DRIVE, SUITE 500, WALTHAM Jennifer Fitzpatrick, Attorney-in-Fact 2025-09-03 0001772518

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction SION Common Stock Sale -$18.8K -748 -1.55% $25.18 47.4K Aug 29, 2025 Direct F1, F2
transaction SION Common Stock Sale -$222K -8.84K -18.65% $25.08 38.5K Sep 2, 2025 Direct F1, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 This transaction was automatically executed pursuant to a Rule 10b5-1 trading plan adopted on May 20, 2025.
F2 The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $25.00 to $25.34, inclusive. The Reporting Person undertakes 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 at which the transactions were effected.
F3 The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $25.00 to $25.30, inclusive. The Reporting Person undertakes 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 at which the transactions were effected.