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

Rhea-AI Filing Summary

Caroline Stark Beer, Chief Business Officer of Sionna Therapeutics, Inc. (SION), was granted a non‑qualified stock option to purchase 255,000 shares of common stock with an exercise price of $28.47. The grant was reported with a transaction date of 10/01/2025 and the filing was signed on 10/03/2025. The option becomes exercisable under a vesting schedule where 25% of the shares vest on September 8, 2026, with the remaining shares vesting in 36 equal monthly installments thereafter, contingent on continued service. The option expires on 09/30/2035.

Positive

• 255,000 option award disclosed with full vesting schedule and expiration date
• Vesting schedule provides clear timelines: 25% on 09/08/2026 then 36 monthly installments
• Form 4 filed promptly with signature dated 10/03/2025

Negative

• None.

Insights

Compensation Analyst

Executive granted 255,000 options at $28.47, standard multi‑year vesting.

The filing shows a single non‑qualified stock option award of 255,000 shares exercisable at $28.47 with an expiration of 09/30/2035. The vesting schedule is time‑based: 25% at 09/08/2026 then monthly over 36 months, which ties long‑term incentive to continued service rather than immediate transferability.

This is a standard executive compensation tool; it creates potential upside if share price exceeds the exercise price before expiration, but no cash proceeds or sales are recorded in this Form 4.

Corporate Governance Specialist

Insider reporting is timely and discloses full vesting terms.

The Form 4 names the reporting person as Chief Business Officer and lists the grant date 10/01/2025 with a signature date of 10/03/2025 by an attorney‑in‑fact. The filing includes the exercise price, expiration, and detailed vesting schedule, meeting Section 16 disclosure norms.

No disposition or sale is reported; the filing records only an acquisition of derivative securities (options).

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).

1. Name and Address of Reporting Person^*

Beer Caroline Stark

(Last) (First) (Middle)

C/O SIONNA THERAPEUTICS, INC.

21 HICKORY DRIVE, SUITE 500

(Street)

WALTHAM MA 02451

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Business Officer

3. Date of Earliest Transaction (Month/Day/Year)
10/01/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	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

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
Non-Qualified Stock Option (right to buy)	$28.47	10/01/2025		A		255,000		(1)	09/30/2035	Common Stock	255,000	$0.0	255,000	D

Explanation of Responses:

1. 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.

	Jennifer Fitzpatrick, Attorney-in-Fact	10/03/2025
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Sionna (SION) report on this Form 4?

The company reported a non‑qualified stock option grant of 255,000 shares to Chief Business Officer Caroline Stark Beer with an exercise price of $28.47 and a transaction date of 10/01/2025.

When do the options granted to the CBO begin to vest?

The options vest 25% on September 8, 2026, with the remaining shares vesting in 36 equal monthly installments thereafter, contingent on continued service.

What is the expiration date and exercise price of the option?

The option has an exercise price of $28.47 and an expiration date of 09/30/2035.

Does the Form 4 report any sale of shares by the reporting person?

No. The Form 4 reports only the acquisition of a derivative security (a stock option); there are no dispositions or sales recorded.

Who signed the Form 4 and when was it signed?

The Form 4 was signed by Jennifer Fitzpatrick, Attorney‑in‑Fact on behalf of the reporting person on 10/03/2025.