Korro Bio (KRRO) fund eyes new sale after $1.45M June trade

Rhea-AI Filing Summary

Korro Bio, Inc. (KRRO) has a notice of proposed resale of restricted common stock under Rule 144 by Atlas-affiliated funds. Atlas Venture Fund XI, L.P. plans to sell 23,584 shares, while disclosures list prior open-market sales by Atlas Venture Fund XI and Atlas Venture Opportunity Fund II over the past three months.

Key Figures

Shares to be sold: 23,584 shares Aggregate market value of proposed sale: $311,780.48 Shares outstanding: 14,725,646 shares +4 more

7 metrics

Shares to be sold 23,584 shares Common stock proposed for sale by Atlas Venture Fund XI, L.P. under Rule 144

Aggregate market value of proposed sale $311,780.48 Market value of 23,584 Korro Bio common shares referenced in the notice

Shares outstanding 14,725,646 shares Korro Bio common stock outstanding as referenced in the Form 144

Sale on 06/23/2026 (Atlas Venture Fund XI) 101,579 shares for $1,447,785.17 Common stock sold by Atlas Venture Fund XI, L.P.

Sale on 06/24/2026 (Atlas Venture Fund XI) 41,345 shares for $603,694.88 Common stock sold by Atlas Venture Fund XI, L.P.

Sale on 06/23/2026 (Atlas Venture Opportunity Fund II) 17,426 shares for $248,369.29 Common stock sold by Atlas Venture Opportunity Fund II, L.P.

Sale on 07/02/2026 (Atlas Venture Opportunity Fund II) 14,745 shares for $206,923.96 Common stock sold by Atlas Venture Opportunity Fund II, L.P.

Key Terms

Rule 144, Private Placement, Nasdaq

3 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Private Placement financial

"Common Stock | 03/23/2023 | Private Placement | Issuer"

A private placement is a sale of securities directly to a selected group of investors, typically institutions or accredited investors, instead of through a public offering. It lets a company raise money faster and with fewer regulatory steps; for existing shareholders it matters because the newly issued shares, often sold at a discount, increase the share count and can dilute their ownership.

Nasdaq market

"08/19/2026 | Nasdaq"

The Nasdaq is a stock exchange where many companies' shares are bought and sold, functioning much like a marketplace for investments. It matters to investors because it provides a platform to buy and sell ownership stakes in companies, helping them track the value of those companies and make informed decisions. As one of the largest and most technology-focused markets, it also reflects trends and developments in the business world.

FAQ

What does the Form 144 filing disclose for Korro Bio, Inc. (KRRO)?

The filing discloses a planned Rule 144 resale of Korro Bio common stock by Atlas-affiliated funds. It reports proposed sales, prior sales in the last three months, and share and dollar amounts for these transactions, but does not change Korro Bio’s capital structure directly.

How many KRRO shares are proposed to be sold under this Form 144?

Atlas Venture Fund XI, L.P. proposes to sell 23,584 shares of Korro Bio common stock. The notice lists these as common stock held for resale through a broker, alongside historical sales data for additional shares sold in prior transactions.

What is the aggregate market value of the KRRO shares covered by the proposed sale?

The proposed 23,584 shares of Korro Bio common stock have an aggregate market value of $311,780.48. This value is based on market pricing at the time referenced in the notice and is used for Rule 144 disclosure purposes.

How many Korro Bio (KRRO) shares were outstanding as referenced in the Form 144?

The notice reports 14,725,646 shares of Korro Bio common stock outstanding. This figure provides context for the size of the proposed and recent sales under Rule 144 relative to the total shares currently outstanding.

What notable recent KRRO share sales by Atlas Venture Fund XI are disclosed?

One notable transaction shows Atlas Venture Fund XI, L.P. selling 101,579 shares of Korro Bio common stock on 06/23/2026 for $1,447,785.17. Several additional smaller sales in May, June, July, and August 2026 are also reported.

What KRRO sales by Atlas Venture Opportunity Fund II, L.P. are shown in the filing?

The filing lists multiple sales, including 17,426 shares on 06/23/2026 for $248,369.29 and 14,745 shares on 07/02/2026 for $206,923.96. These transactions reflect ongoing Rule 144 resales by Atlas Venture Opportunity Fund II, L.P.

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

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Available on EDGAR 08/19/2026 - 05:37 PM Accepted by SEC EDGAR 08/19/2026 - 05:36 PM 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	0001708269
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	Korro Bio, Inc.
SEC File Number	001-39062
Address of Issuer	60 First Street 2nd Floor, Suite 250 Cambridge MASSACHUSETTS 02141
Phone	6174681999
Name of Person for Whose Account the Securities are To Be Sold	Atlas Venture Fund XI, 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	Shareholder

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	Merrill Lynch 555 California Street 18th Floor San Francisco CA 94104	23584	311780.48	14725646	08/19/2026	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 Stock	03/23/2023	Private Placement	Issuer			23584	03/23/2023	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

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	05/28/2026	2441	34051.95
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	06/22/2026	3382	47178.9
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	06/23/2026	101579	1447785.17
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	06/24/2026	41345	603694.88
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	07/02/2026	85955	1206249.49
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	07/06/2026	817	11405.24
Atlas Venture Fund XI, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	08/11/2026	1775	24772.79
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	05/28/2026	419	5845.05
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	06/22/2026	580	8091
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	06/23/2026	17426	248369.29
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	06/24/2026	7093	103567.73
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	07/02/2026	14745	206923.96
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	07/06/2026	8506	118742.91
Atlas Venture Opportunity Fund II, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common Stock	08/11/2026	368	5135.99

144: Remarks and Signature

Remarks
Date of Notice	08/19/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	04/08/2026
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	Ommer Chohan
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)