Korro Bio (NASDAQ: KRRO) venture backer lines up more stock sales

Rhea-AI Filing Summary

Korro Bio, Inc. (KRRO) is the issuer of common stock for which Atlas Venture Opportunity Fund II, L.P. has filed a notice of proposed resale under Rule 144. The fund indicates an intention to sell 4,884 shares of Korro Bio common stock through Merrill Lynch on Nasdaq.

The shares to be sold were originally acquired on April 22, 2024 in a private placement for cash. The notice also lists multiple Korro Bio share sales during the past three months by Atlas Venture Fund XI, L.P. and Atlas Venture Opportunity Fund II, L.P., with individual transactions ranging from hundreds to over one hundred thousand shares.

Key Figures

Shares proposed to be sold: 4,884 shares Market value of shares proposed: $64,566.48 Acquisition date of shares to be sold: 04/22/2024 +4 more

7 metrics

Shares proposed to be sold 4,884 shares Korro Bio common stock listed in the securities information section

Market value of shares proposed $64,566.48 Associated with the 4,884 Korro Bio shares in the Form 144 table

Acquisition date of shares to be sold 04/22/2024 Date the 4,884 shares were acquired in a private placement for cash

Largest recent single sale by related fund 101,579 shares Korro Bio common stock sale by Atlas Venture Fund XI, L.P. on 06/23/2026

Dollar amount for 101,579‑share sale $1,447,785.17 Listed for the 06/23/2026 Korro Bio share sale by Atlas Venture Fund XI, L.P.

Second large related-fund sale 85,955 shares Korro Bio common stock sale by Atlas Venture Fund XI, L.P. on 07/02/2026

Dollar amount for 85,955‑share sale $1,206,249.49 Listed for the 07/02/2026 Korro Bio share sale by Atlas Venture Fund XI, L.P.

Key Terms

Rule 144, private placement, Merrill Lynch, Nasdaq

4 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 | 04/22/2024 | 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.

Merrill Lynch financial

"Common Stock | Merrill Lynch 555 California Street 18th Floor"

Nasdaq financial

"| 14725646 | 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 mean for Korro Bio (KRRO)?

The filing shows a shareholder, Atlas Venture Opportunity Fund II, L.P., plans to sell 4,884 shares of Korro Bio common stock under Rule 144. This is a planned resale by an existing holder, not a new share issuance by Korro Bio.

How many Korro Bio (KRRO) shares are proposed to be sold under this Form 144?

Atlas Venture Opportunity Fund II, L.P. has filed to sell 4,884 shares of Korro Bio common stock. The filing lists an associated market value of $64,566.48 for these shares in the securities information section.

When and how were the Korro Bio (KRRO) shares to be sold originally acquired?

The 4,884 Korro Bio shares were acquired on April 22, 2024 in a private placement for cash from the issuer. This acquisition date and method are disclosed in the securities-to-be-sold section of the notice.

Which shareholder is selling Korro Bio (KRRO) shares in this Form 144?

The seller named is Atlas Venture Opportunity Fund II, L.P.. The filing provides this fund’s name and address and identifies Korro Bio, Inc. as the issuer of the common stock being sold.

Are there other recent sales of Korro Bio (KRRO) stock by related funds?

Yes. The notice lists multiple Korro Bio common stock sales from May 28, 2026 to August 11, 2026 by Atlas Venture Fund XI, L.P. and Atlas Venture Opportunity Fund II, L.P., including individual transactions as large as 101,579 shares.

Through which broker and market are the Korro Bio (KRRO) shares expected to be sold?

The planned sales are listed through Merrill Lynch, with the broker’s San Francisco address provided, and identify the market as Nasdaq, where Korro Bio’s common stock is traded.

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	0001885327
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 Opportunity Fund II, 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	4884	64566.48	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	04/22/2024	Private Placement	Issuer			4884	04/22/2024	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

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)