[144] Sionna Therapeutics, Inc. SEC Filing

Rhea-AI Filing Summary

Sionna Therapeutics (SION) submitted a Form 144 notice indicating a proposed sale of 11,468 common shares through Merrill Lynch in San Francisco. The filing lists an aggregate market value of $331,883.92 and shows 44,139,823 shares outstanding for the issuer. The shares were originally acquired by private placement from the issuer on 03/04/2024 and were paid in cash on that date. The filing states the approximate sale date as 09/29/2025 and names NASDAQ as the exchange. No securities were reported sold in the past three months.

Insights

Securities Analyst

TL;DR: Form 144 notifies a planned sale of 11,468 common shares valued at $331,883.92, acquired via private placement on 03/04/2024.

The filing documents a proposed sale through Merrill Lynch on NASDAQ with an approximate sale date of 09/29/2025. It discloses acquisition details showing the shares came from a private placement and were paid for in cash on 03/04/2024. The filer reports no sales in the prior three months. From a disclosure standpoint, the notice meets Rule 144 presentation requirements by naming broker, share count, market value, acquisition date and payment method.

Corporate Governance Expert

TL;DR: The Form 144 provides required seller and transaction details but contains no additional context on insider status or trading plan.

The form affirms the seller represents no undisclosed material adverse information and includes standard cautions about misstatements. It notes the securities were acquired in a private placement and will be sold via Merrill Lynch on NASDAQ. The filing does not include any plan adoption date or 10b5-1 plan specifics, and it reports no securities sold in the past three months.

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

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

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

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	Merrill Lynch 555 California Street 18th Floor San Francisco CA 94104	11468	331883.92	44139823	09/29/2025	NASDAQ

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	03/04/2024	Private Placement	Issuer			11468	03/04/2024	Cash

* 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

Date of Notice

Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1

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

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does the Form 144 for SION report?

The Form 144 reports a proposed sale of 11,468 common shares with an aggregate market value of $331,883.92 via Merrill Lynch, with an approximate sale date of 09/29/2025.

When and how were the shares being sold on the Form 144 acquired?

The shares were acquired in a private placement from the issuer on 03/04/2024 and paid for in cash on that date.

Which broker and exchange are listed on the SION Form 144?

The broker is listed as Merrill Lynch, 555 California Street, 18th Floor, San Francisco, CA 94104 and the exchange is NASDAQ.

Does the Form 144 show recent sales by the same person?

No. The filing indicates Nothing to Report for securities sold during the past three months by the person for whose account the securities are to be sold.

What representation does the filer make about material information?

The filer represents by signing the notice that they do not know any material adverse information about the issuer that has not been publicly disclosed.