Atlas Venture funds and Bruce Booth report KYMR share sales (KYMR)

Rhea-AI Filing Summary

KYMR files Form 144 reporting proposed sales of Common Stock by certain holders, primarily Atlas Venture funds and an individual, Bruce Booth. The excerpt lists multiple sale dates in April–June 2026 with individual transactions ranging from hundreds to hundreds of thousands of shares (examples include 243,976 shares on 06/22/2026 and 118,178 shares on 06/24/2026).

Insights

Securities Counsel

Form 144 disclosures list proposed resale transactions by affiliates and a related individual.

These entries register proposed sales under securities resale rules and show a sequence of transactions dated in April–June 2026. The filings identify the sellers (Atlas Venture Fund X, Atlas Venture Opportunity Fund I, and Bruce Booth) and per-trade share counts and dollar amounts.

Cash-flow treatment and any trading plan or Rule 10b5-1 applicability are not stated in the excerpt; subsequent broker reports or resale confirmations would show execution details.

Key Figures

Example sale: 243,976 shares Example sale: 118,178 shares Example sale: 100,928 shares +2 more

5 metrics

Example sale 243,976 shares sale dated 06/22/2026 by Atlas Venture Fund X

Example sale 118,178 shares sale dated 06/24/2026 by Atlas Venture Fund X

Example sale 100,928 shares sale dated 06/18/2026 by Atlas Venture Fund X

Bruce Booth example 11,741 shares sale dated 06/17/2026 by Bruce Booth

Private placement date 03/11/2020 original private placement of Common Stock

Key Terms

Form 144, Private Placement, Issuer

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 market

"Common Stock | 03/11/2020 | Private Placement"

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.

Issuer regulatory

"Private Placement | Issuer"

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Available on EDGAR 06/25/2026 - 05:25 PM Accepted by SEC EDGAR 06/25/2026 - 05:25 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
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	480992	48036671.04	82257588	06/25/2026	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	03/11/2020	Private Placement	Issuer			480992	03/11/2020	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 X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/15/2026	2750	247765.57
Atlas Venture Fund X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/22/2026	88	7926.6
Atlas Venture Fund X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/17/2026	92169	8330667.41
Atlas Venture Fund X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/18/2026	100928	9185730.49
Atlas Venture Fund X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/22/2026	243976	24182608.35
Atlas Venture Fund X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/23/2026	1235	123470.07
Atlas Venture Fund X, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/24/2026	118178	11877944.68
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/15/2026	385	34687.18
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/22/2026	12	1080.9
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/17/2026	12902	1166143.4
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/18/2026	14128	1285827.52
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/22/2026	34152	3385105.26
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/23/2026	173	17295.81
Atlas Venture Opportunity Fund I, L.P. 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/24/2026	16542	1662618.77
Bruce Booth 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/14/2026	4159	374199.56
Bruce Booth 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/15/2026	2200	197895.00
Bruce Booth 300 Technology Sq Ste 8 Cambridge MA 02139	Common	04/22/2026	5900	530746.25
Bruce Booth 300 Technology Sq Ste 8 Cambridge MA 02139	Common	06/17/2026	11741	1056443.24

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 KYMR's Form 144 disclose about Atlas Venture's activity?

The Form 144 lists multiple proposed sales by Atlas Venture entities in April–June 2026, including transactions such as 243,976 shares on 06/22/2026 and other dated entries showing shares and proceeds.

Who else is reported selling KYMR shares on the Form 144?

The filing also shows sales attributed to individual Bruce Booth, with transactions dated in April and June 2026 totaling multiple trades and reported dollar amounts alongside share counts.

Do the Form 144 entries confirm completed sales or proceeds recipient?

The entries report proposed resale transactions with share counts and dollar figures but do not state final execution status or who received proceeds; the excerpt lists the trades and reported amounts only.

Are the listed transactions from a private placement or secondary resale?

The excerpt references an earlier Private Placement dated 03/11/2020 and identifies the securities as Common Stock; the Form 144 entries report resales by holders rather than a new primary issuance.