KYMR (NASDAQ) insiders and Atlas Venture entities report April 2026 share sales

Rhea-AI Filing Summary

KYMR filed notices of proposed sales of Common Stock by affiliated holders, listing multiple transactions dated 04/14/2026 through 04/22/2026. The filing shows individual sales by insiders/holders including Bruce Booth and Atlas Venture Fund X, L.P., with examples of specific share amounts and dollar amounts.

Examples include Bruce Booth selling 4,159 shares on 04/14/2026 for $374,199.56 and Atlas Venture Fund X, L.P. selling 2,750 shares on 04/15/2026 for $247,765.57. The notice lists multiple small secondary sales by founders and venture funds across April 2026.

Insights

Securities Compliance Counsel

TL;DR: Multiple insider/resale notices filed under Form 144 show discrete secondary sales by founders and venture investors in April 2026.

The filing lists proposed sales of Common Stock by named holders with transaction dates from 04/14/2026 to 04/22/2026. Each row shows share counts and corresponding dollar amounts, indicating resale activity rather than an issuer primary offering.

These notices are administrative disclosures under Rule 144; cash‑flow treatment is proceeds to the selling holders as shown in the per‑trade dollar figures. Subsequent SEC filings or Form 4 amendments could report actual sale execution or changes to quantities.

Key Figures

Bruce Booth sale: 4,159 shares Atlas Venture Fund X, L.P. sale: 2,750 shares Bruce Booth additional sale: 5,900 shares +1 more

4 metrics

Bruce Booth sale 4,159 shares sale dated 04/14/2026 for $374,199.56

Atlas Venture Fund X, L.P. sale 2,750 shares sale dated 04/15/2026 for $247,765.57

Bruce Booth additional sale 5,900 shares sale dated 04/22/2026 for $530,746.25

Form reference date 06/17/2026 date shown on the securities information line

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 |"

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Available on EDGAR 06/17/2026 - 05:26 PM Accepted by SEC EDGAR 06/17/2026 - 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	92169	8059257.36	82257588	06/17/2026	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			92169	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 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
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

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

Who is selling shares of KYMR according to this Form 144?

The filing lists sales by insiders and venture holders, including Bruce Booth and Atlas Venture Fund X, L.P.. The excerpt shows specific trades dated 04/14/2026 through 04/22/2026 with listed share counts and dollar amounts.

How many shares did Bruce Booth propose to sell in the filing?

Bruce Booth is shown proposing sales such as 4,159 shares on 04/14/2026 for $374,199.56. The filing includes multiple Bruce Booth entries across April 2026 with separate share amounts and proceeds.

What dates are covered by the proposed sales in the KYMR excerpt?

The listed transactions occur between 04/14/2026 and 04/22/2026. Each trade line pairs a transaction date with the share count and a dollar amount, indicating separate resale events during that period.

Does this Form 144 show proceeds from the sales and who receives them?

Yes; each trade row includes a dollar amount next to the share count (e.g., $247,765.57 for 2,750 shares). The proceeds are shown per selling holder, indicating the selling holders, not the issuer, receive cash.

Does the filing indicate these are issuer primary offerings or secondary sales?

The excerpt identifies these entries as Private Placement and shows named holders selling shares, which reflects secondary/resale transactions by holders rather than a primary issuance by the company.