SION holder plans sale of 195,667 shares

SION filed a Form 144 for a planned stock sale.

Rhea-AI Filing Summary

SION filed a Form 144 for a planned stock sale. A holder has notified the SEC of an intention to sell 195,667 shares of SION common stock, $0.001 par value per share, through Goldman Sachs & Co. LLC on or about 01/22/2026 on the Nasdaq Global Market. The filing lists an aggregate market value of $8,173,010.59 for these shares and notes that there were 44,628,788 shares of common stock outstanding at the time of the notice. The seller’s shares were originally acquired from the issuer on 02/10/2025 for cash and/or upon the automatic conversion of preferred stock into common stock.

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Accepted by SEC EDGAR 01/22/2026 - 08:47 PM EST Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0002103170
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Sionna Therapeutics, Inc.
SEC File Number	001-42504
Address of Issuer	21 Hickory Drive Suite 500 Waltham MASSACHUSETTS 02451
Phone	617-819-2020
Name of Person for Whose Account the Securities are To Be Sold	Rise Fund Sling, L.P.
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Stockholder

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common Stock, $0.001 par value per share	Goldman Sachs & Co. LLC 200 West Street New York NY 10282	195667	8173010.59	44628788	01/22/2026	Nasdaq Global Market

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common Stock, $0.001 par value per share	02/10/2025	The shares of Common Stock reported herein were originally acquired by Seller from Issuer and/or upon the automatic conversion of shares of Preferred Stock of the Issuer into shares of Common Stock.	Issuer			5476598	02/10/2025	Cash and/or automatic conversion of shares of Preferred Stock of the Issuer into shares of Common Stock.

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks	Sales by Seller should be aggregated with the sales of shares of Common Stock of the Issuer by Rise Fund Sling II, L.P. (together with Seller, the "Selling Stockholders"). The Selling Stockholders have filed separate Forms 144 for aggregate sales of 250,000 shares of Common Stock of the Issuer during the past three months.
Date of Notice	01/22/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Martin Davidson
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)