Sionna Therapeutics (SION) stake cut by TPG entities in Form 4

Rhea-AI Filing Summary

TPG-affiliated investment entities that are 10% owners of Sionna Therapeutics, Inc. reported an indirect sale of 250,000 shares of common stock on January 22, 2026. The shares were sold at a price of $40 per share under transaction code "S," which indicates a sale.

After this transaction, entities associated with the reporting group indirectly held 6,494,962 shares of Sionna common stock through The Rise Fund Sling, L.P. and The Rise Fund Sling II, L.P. The filing explains that the reporting persons may be deemed to beneficially own these securities only to the extent of their direct or indirect pecuniary interests and they expressly disclaim beneficial ownership beyond those economic interests.

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

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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).

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^*

TPG GP A, LLC

(Last) (First) (Middle)

C/O TPG INC.

301 COMMERCE STREET, SUITE 3300

(Street)

FORT WORTH TX 76102

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

3. Date of Earliest Transaction (Month/Day/Year)
01/22/2026

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

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

	Form filed by One Reporting Person
X	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	01/22/2026		S		250,000	D	$40	6,494,962	I	See Explanation of Responses(1)(2)(3)(4)

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

1. Name and Address of Reporting Person^*

TPG GP A, LLC

(Last) (First) (Middle)

C/O TPG INC.

301 COMMERCE STREET, SUITE 3300

(Street)

FORT WORTH TX 76102

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

COULTER JAMES G

(Last) (First) (Middle)

C/O TPG GLOBAL, LLC

301 COMMERCE STREET, SUITE 3300

(Street)

FORT WORTH TX 76102

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

WINKELRIED JON

(Last) (First) (Middle)

C/O TPG GLOBAL, LLC

301 COMMERCE STREET, SUITE 3300

(Street)

FORT WORTH TX 76102

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. Each of James G. Coulter and Jon Winkelried own entities that control TPG GP A, LLC (together with Messrs. Coulter and Winkelried, the "Reporting Persons"), which exercises direct or indirect control over entities that collectively hold 100% of the shares of Class B common stock (which represents a majority of the combined voting power of the common stock) of TPG Inc., which is the sole member of TPG GPCo, LLC, which is the sole member of TPG Holdings II-A, LLC, which is the general partner of TPG Operating Group II, L.P., which is the sole member of TPG Holdings I-A, LLC, which is the general partner of TPG Operating Group I, L.P., which is the sole member of The Rise Fund GenPar Advisors, LLC, which is the general partner of The Rise Fund GenPar, L.P., which is the managing member of The Rise Fund SPV GP, LLC.

2. The Rise Fund SPV GP, LLC is the general partner of each of The Rise Fund Sling, L.P., which directly holds 5,340,931 shares of Common Stock ("Common Stock") of Sionna Therapeutics, Inc. (the "Issuer"), and The Rise Fund Sling II, L.P. (together with The Rise Fund Sling, L.P., the "TPG Funds"), which directly holds 1,154,031 shares of Common Stock.

3. Because of the relationship between the Reporting Persons and the TPG Funds, the Reporting Persons may be deemed to beneficially own the securities reported herein to the extent of the greater of their respective direct or indirect pecuniary interests in the profits or capital accounts of the TPG Funds. Each of the TPG Funds and each Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of such TPG Fund's or such Reporting Person's pecuniary interest therein, if any

4. Pursuant to Rule 16a-1(a)(4) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), this filing shall not be deemed an admission that the Reporting Persons are, for purposes of Section 16 of the Exchange Act or otherwise, the beneficial owners of any equity securities in excess of their respective pecuniary interests.

Remarks:

(5) The Reporting Persons are jointly filing this Form 4 pursuant to Rule 16a-3(j) under the Exchange Act. (6) Gerald Neugebauer is signing on behalf of Messrs. Coulter and Winkelried pursuant to authorization and designation letters dated January 10, 2024, which were previously filed with the Securities and Exchange Commission.

	/s/ Martin Davidson, Chief Accounting Officer, TPG GP A, LLC (5)	01/26/2026
	/s/ Gerald Neugebauer, on behalf of James G. Coulter (5) (6)	01/26/2026
	/s/ Gerald Neugebauer, on behalf of Jon Winkelried (5) (6)	01/26/2026
	** 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).
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FAQ

What insider transaction did TPG-related holders report in SION stock?

Entities affiliated with TPG GP A, LLC, as part of a 10% owner group, reported an indirect sale of 250,000 shares of Sionna Therapeutics common stock on January 22, 2026, coded as a sale ("S").

At what price were the Sionna Therapeutics (SION) shares sold by TPG-affiliated holders?

The reported transaction shows 250,000 shares of Sionna Therapeutics common stock sold at a price of $40 per share.

How many Sionna Therapeutics shares do the TPG-related entities hold after the reported sale?

Following the reported transaction, entities associated with the reporting group indirectly held 6,494,962 shares of Sionna Therapeutics common stock.

Is the SION insider transaction held directly or indirectly by the reporting persons?

The Form 4 classifies the position as indirect ownership, with the nature of ownership described in the footnotes, reflecting holdings through TPG-managed funds rather than direct personal ownership.

Which investment funds are involved in the Sionna Therapeutics (SION) holdings reported on this Form 4?

The filing states that The Rise Fund Sling, L.P. directly holds 5,340,931 shares and The Rise Fund Sling II, L.P. directly holds 1,154,031 shares of Sionna Therapeutics common stock.

How do the TPG reporting persons describe their beneficial ownership of SION shares?

The reporting persons state they may be deemed to beneficially own the reported Sionna shares only to the extent of their direct or indirect pecuniary interests in the TPG funds and disclaim beneficial ownership beyond those economic interests.