Korsana Biosciences director plans $3.5K stock sale

De Souza’s notice also reports 2,139 common shares sold on September 18, 2026, for gross proceeds of $74,843.61.

Available on EDGAR 09/22/2026 - 04:57 PM EDT Accepted by SEC EDGAR 09/22/2026 - 04:56 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Korsana Biosciences, Inc. (KRSA) director Errol B. de Souza reported an intended sale of 100 common shares, with an aggregate market value of $3,499.00 and an approximate sale date of September 22, 2026. Morgan Stanley Smith Barney LLC is named as broker. The listed outstanding share count is 45,541,425. De Souza also reported selling 2,139 common shares on September 18, 2026, for gross proceeds of $74,843.61. The securities were acquired through restricted stock vesting from September 1 through October 1, 2024.

Key Figures

Shares to be sold: 100 shares Aggregate Market Value: $3,499.00 Shares sold: 2,139 shares +2 more

5 metrics

Shares to be sold 100 shares Intended sale; approximate sale date September 22, 2026

Aggregate Market Value $3,499.00 Intended sale

Shares sold 2,139 shares Sale on September 18, 2026

Gross Proceeds $74,843.61 Sale on September 18, 2026

Shares outstanding 45,541,425 shares Common shares

Key Terms

Restricted Stock, Aggregate Market Value, Gross Proceeds

3 terms

Restricted Stock financial

"Nature of Acquisition Transaction: Restricted Stock"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

Aggregate Market Value financial

"Aggregate Market Value: 3499.00"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

Gross Proceeds financial

"Gross Proceeds: 74843.61"

The total amount of cash a company receives from a financing event or sale before any fees, expenses, taxes or deductions are taken out. Investors watch gross proceeds because it shows the raw scale of new capital being raised—think of it as the paycheck amount before withholdings—which helps assess how much funding is available for operations, growth, debt payoff or how much shareholder dilution might occur once costs are removed.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many KRSA shares did Errol B. de Souza report he plans to sell?

Errol B. de Souza, a director of Korsana Biosciences, Inc. (KRSA), reported an intended sale of 100 common shares, with an aggregate market value of $3,499.00 and an approximate sale date of September 22, 2026. Morgan Stanley Smith Barney LLC is named as broker.

How many KRSA shares did Errol B. de Souza sell in the prior three months?

Errol B. de Souza reported selling 2,139 common shares on September 18, 2026, for gross proceeds of $74,843.61.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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	0001213895
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	KORSANA BIOSCIENCES, INC.
SEC File Number	001-38787
Address of Issuer	203 Crescent Street, Bldgs. #3/3A/4, Suite 503, Waltham MASSACHUSETTS 02453
Phone	(781) 516-2325
Name of Person for Whose Account the Securities are To Be Sold	ERROL B DE SOUZA
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	Director

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	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	100	3499.00	45541425	09/22/2026	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	09/01/2024	Restricted Stock	Issuer			100	09/01/2024	Not Applicable

* 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

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
ERROL B DE SOUZA 203 Crescent Street, Bldgs. #3/3A/4, Suite 503, Waltham MA 02453	Common	09/18/2026	2139	74843.61

144: Remarks and Signature

Remarks	The securities to be sold were acquired upon the vesting of restricted stock during the period of 09/01/2024 through 10/01/2024.
Date of Notice	09/22/2026
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/ Errol B Desouza
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)