Caroline Stark Beer - 01 Oct 2025 Form 4 Insider Report for Sionna Therapeutics, Inc. (SION)

Role: Chief Business Officer
Signature: Jennifer Fitzpatrick, Attorney-in-Fact
Issuer symbol: SION
Transactions as of: 01 Oct 2025
Net transactions value: $0
Form type: 4
Filing time: 03 Oct 2025, 16:14:59 UTC
Next filing: 06 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Beer Caroline Stark	Chief Business Officer	C/O SIONNA THERAPEUTICS, INC., 21 HICKORY DRIVE, SUITE 500, WALTHAM	Jennifer Fitzpatrick, Attorney-in-Fact	03 Oct 2025	0002085679

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	SION	Non-Qualified Stock Option (right to buy)	Award	$0	+255,000		$0.000000	255,000	01 Oct 2025	Common Stock	255,000	$28.47	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	25% of the shares underlying this option shall vest on September 8, 2026, with the remainder vesting in thirty-six equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.