Sionna Therapeutics (SION) CLO trades 10,250 shares in Form 4 filing

Rhea-AI Filing Summary

Sionna Therapeutics, Inc. Chief Legal Officer Jennifer Fitzpatrick reported an option exercise and share sale. On March 5, 2026, she exercised a non-qualified stock option for 10,250 shares of common stock at $6.11 per share and immediately sold the same number of shares in an open-market transaction at a weighted average price of $33.8555 per share.

The sale was automatically executed under a Rule 10b5-1 trading plan adopted on June 5, 2025. The shares were sold in multiple trades at prices ranging from $32.56 to $34.83. Following these transactions, she reported 50,935 option shares remaining from this grant and no directly held common shares from this transaction.

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

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a 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). See Instruction 10.

1. Name and Address of Reporting Person^*

Fitzpatrick Jennifer

(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 Legal Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/05/2026

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
Common Stock	03/05/2026		M(1)		10,250	A	$6.11	10,250	D
Common Stock	03/05/2026		S(1)		10,250	D	$33.8555(2)	0	D

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)	$6.11	03/05/2026		M(1)			10,250	(3)	07/14/2034	Common Stock	10,250	$0.0	50,935	D

Explanation of Responses:

1. This transaction was automatically executed pursuant to a Rule 10b5-1 trading plan adopted on June 5, 2025.

2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $32.56 to $34.83, inclusive. The Reporting Person undertakes to provide to the Issuer, any securityholder 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.

3. 25% of the shares underlying this option vested on June 3, 2025, 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	03/06/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transactions did Sionna Therapeutics (SION) report for Jennifer Fitzpatrick?

Sionna Therapeutics’ Chief Legal Officer Jennifer Fitzpatrick exercised options for 10,250 common shares and sold 10,250 shares in the open market on March 5, 2026. These transactions combined an option exercise with an immediate sale of the resulting common stock.

How many SION shares did the insider sell and at what price?

Jennifer Fitzpatrick sold 10,250 shares of Sionna Therapeutics common stock at a weighted average price of $33.8555 per share. The sale occurred in multiple trades, with individual prices ranging from $32.56 to $34.83 during the same trading day.

What stock option exercise did the Sionna Therapeutics insider report?

The insider exercised a non-qualified stock option for 10,250 Sionna Therapeutics common shares at an exercise price of $6.11 per share. After this transaction, 50,935 option shares from the same grant remained outstanding and subject to the original vesting schedule.

Was the SION insider sale made under a Rule 10b5-1 trading plan?

Yes. The reported sale of 10,250 Sionna Therapeutics shares was automatically executed under a Rule 10b5-1 trading plan. That plan was adopted on June 5, 2025, providing a pre-arranged framework for selling shares according to predetermined instructions.

What is the vesting schedule of the Sionna Therapeutics option exercised?

The option’s vesting schedule provides that 25% of the underlying shares vested on June 3, 2025. The remaining shares vest in thirty-six equal monthly installments thereafter, contingent on Jennifer Fitzpatrick’s continued service on each scheduled vesting date.

How many SION option shares does the insider hold after these transactions?

Following the March 5, 2026 option exercise and related sale, Jennifer Fitzpatrick reported holding 50,935 shares underlying the remaining portion of the non-qualified stock option. She reported no directly held common shares from this specific transaction after completing the open-market sale.