Michael Cloonan - 02 Jan 2026 Form 4 Insider Report for Sionna Therapeutics, Inc. (SION)

Role: President & CEO, Director
Signature: Jennifer Fitzpatrick, Attorney-in-Fact
Issuer symbol: SION
Transactions as of: 02 Jan 2026
Net transactions value: $0
Form type: 4
Filing time: 06 Jan 2026, 16:19:13 UTC
Previous filing: 22 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Cloonan Michael	President & CEO, Director	C/O SIONNA THERAPEUTICS, INC., 21 HICKORY DRIVE, SUITE 500, WALTHAM	Jennifer Fitzpatrick, Attorney-in-Fact	06 Jan 2026	0001704336

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	+436,100		$0.000000	436,100	02 Jan 2026	Common Stock	436,100	$39.21	Direct	F1

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

Explanation of Responses:

Id	Content
F1	The shares underlying this option vest in forty-eight equal monthly installments following January 2, 2026, subject to the Reporting Person's continued service on each such vesting date.