Atlas Venture sells large KRRO positions (KRRO) in June–July 2026

Rhea-AI Filing Summary

The filing by an issuer shows proposed and recent resale activity in Common Stock related to a Private Placement dated 03/23/2023. The Form 144 lists multiple sales by Atlas Venture affiliates during May–July 2026, including large dispositions on 06/23/2026 and 07/02/2026.

Examples include Atlas Venture Fund XI, L.P.: 101,579 shares sold on 06/23/2026 for $1,447,785.17, and Atlas Venture Opportunity Fund II, L.P.: 17,426 shares sold on 06/23/2026 for $248,369.29.

Key Figures

Private placement date: 03/23/2023 Sale example - Fund XI: 101,579 shares Proceeds example - Fund XI: $1,447,785.17 +2 more

5 metrics

Private placement date 03/23/2023 Issuer-side Private Placement

Sale example - Fund XI 101,579 shares Sold on 06/23/2026 by Atlas Venture Fund XI, L.P.

Proceeds example - Fund XI $1,447,785.17 Proceeds from 101,579 shares on 06/23/2026

Sale example - Opportunity Fund II 17,426 shares Sold on 06/23/2026 by Atlas Venture Opportunity Fund II, L.P.

Proceeds example - 07/02/2026 $1,206,249.49 Proceeds for 85,955 shares on 07/02/2026

Key Terms

Form 144, Private Placement, Proceeds

3 terms

Form 144 regulatory

"144: Securities Sold During The Past 3 Months"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

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.

Proceeds financial

"Atlas Venture Fund XI, L.P. ... 101579 | 1447785.17"

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Available on EDGAR 07/06/2026 - 05:16 PM Accepted by SEC EDGAR 07/06/2026 - 05:15 PM Learn about SEC filing dates

FAQ

What does KRRO's Form 144 disclose about recent insider sales?

The Form 144 reports multiple sales of Common Stock by Atlas Venture affiliates during May–July 2026. It lists trade dates, share counts, and gross proceeds for each sale, with several large transactions recorded on 06/23/2026 and 07/02/2026.

Which Atlas Venture entities sold KRRO shares and when?

The filing lists Atlas Venture Fund XI, L.P. and Atlas Venture Opportunity Fund II, L.P. among sellers. Representative sale dates include 05/28/2026, 06/22/2026, 06/23/2026, 06/24/2026, and 07/02/2026, with specific share counts shown per date.

Was the registered security originally issued in a private placement for KRRO?

Yes. The document references a Private Placement of Common Stock with an issuer-side transaction dated 03/23/2023. The filing ties the resales listed to that issuance context.

How large were some individual KRRO transactions in dollar terms?

Individual proceeds shown include $1,447,785.17 for 101,579 shares on 06/23/2026 and $1,206,249.49 for 85,955 shares on 07/02/2026, as reported in the filing's sales table.

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 Stock	Merrill Lynch 555 California Street 18th Floor San Francisco CA 94104	817	11438	14422571	07/06/2026	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			817	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 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

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)