Dyne officer plans 5,000-share stock sale

Dyne Therapeutics, Inc. (DYN) had an officer, Doug Kerr, file a Rule 144 notice covering a planned sale of 5,000 shares of common stock through broker Stifel Nicolaus & Company.

Rhea-AI Filing Summary

Dyne Therapeutics, Inc. (DYN) had an officer, Doug Kerr, file a Rule 144 notice covering a planned sale of 5,000 shares of common stock through broker Stifel Nicolaus & Company. The filing also lists prior sales of Dyne common stock by Kerr over the preceding three months.

Key Figures

Proposed shares to be sold: 5,000 shares Associated value of proposed sale: $121,745.00 Shares sold June 16, 2026: 887 shares +5 more

8 metrics

Proposed shares to be sold 5,000 shares Common stock under Rule 144 notice for Doug Kerr

Associated value of proposed sale $121,745.00 Total value entry tied to 5,000 shares in securities information

Shares sold June 16, 2026 887 shares Past 3 months sale of common stock for $16,263.00

Proceeds June 16, 2026 sale $16,263.00 Sale of 887 common shares by Doug Kerr

Shares sold August 13, 2026 1,556 shares Past 3 months sale of common stock for $40,892.00

Proceeds August 13, 2026 sale $40,892.00 Sale of 1,556 common shares by Doug Kerr

RSU-related shares entry 1 11,875 shares Common stock from Restricted Stock Units dated September 3, 2026

RSU-related shares entry 2 3,000 shares Common stock from Restricted Stock Units dated September 4, 2026

Key Terms

Rule 144, Restricted Stock Units, Equity Compensation, attorney-in-fact, +1 more

5 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.

Restricted Stock Units financial

"Common Stock | 09/03/2026 | Restricted Stock Units | Issuer"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Equity Compensation financial

"11875 | 09/03/2026 | Equity Compensation"

Equity compensation is pay given to employees, executives or contractors in the form of company ownership—such as stock, stock options or restricted shares—rather than just cash. It matters to investors because it can align workers' incentives with shareholders (like paying someone in slices of the same pie they help grow), but it also increases the number of shares outstanding and company expenses, affecting ownership percentages and earnings per share.

attorney-in-fact regulatory

"as a duly authorized representative of STIFEL, as attorney-in-fact for Doug Kerr"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

Nasdaq market

"186746431 | 09/04/2026 | 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 Dyne Therapeutics (DYN)?

The filing discloses that officer Doug Kerr intends to sell 5,000 shares of Dyne Therapeutics common stock under Rule 144 through broker Stifel Nicolaus & Company, with the shares listed on Nasdaq.

How many Dyne Therapeutics (DYN) shares are proposed to be sold under this Form 144?

The notice covers a proposed sale of 5,000 shares of common stock of Dyne Therapeutics. The filing associates this block with a total value entry of $121,745.00 in the securities information section.

Who is the insider selling Dyne Therapeutics (DYN) stock and what is their role?

The selling person is Doug Kerr, identified as an officer of Dyne Therapeutics, Inc. The Form 144 is signed on his behalf by James Weimer as a duly authorized representative of Stifel acting as attorney-in-fact.

What Dyne Therapeutics (DYN) shares has Doug Kerr sold in the past three months?

Over the prior three months, Doug Kerr sold 887 shares of Dyne common stock on June 16, 2026 for $16,263.00 and 1,556 shares on August 13, 2026 for $40,892.00, as listed in the filing.

What is the source of the Dyne Therapeutics (DYN) shares to be sold under this Form 144?

The securities to be sold are common stock that relate to Restricted Stock Units granted as equity compensation by the issuer, with entries for 11,875 and 3,000 RSU-related shares dated September 3 and 4, 2026.

On which market are the Dyne Therapeutics (DYN) shares listed in this Form 144?

The common stock covered by the notice is listed on the Nasdaq market. The securities information section identifies the class as Dyne Therapeutics common stock traded on Nasdaq.

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

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Available on EDGAR 09/04/2026 - 04:03 PM Accepted by SEC EDGAR 09/04/2026 - 04:02 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	0001814189
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	Dyne Therapeutics, Inc.
SEC File Number	001-39509
Address of Issuer	1560 TRAPELO ROAD WALTHAM MASSACHUSETTS 02451
Phone	(781) 786-8230
Name of Person for Whose Account the Securities are To Be Sold	Kerr Douglas
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	Officer

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	Stifel Nicolaus & Company Inc 501 N Broadway St. Louis MO 63102	5000	121745.00	186746431	09/04/2026	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	09/03/2026	Restricted Stock Units	Issuer			11875	09/03/2026	Equity Compensation
Common Stock	09/04/2026	Restricted Stock Units	Issuer			3000	09/04/2026	Equity Compensation

* 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
Doug Kerr 1560 Trapelo Rd Waltham MA 02451	Common Stock	06/16/2026	887	16263.00
Doug Kerr 1560 Trapelo Rd Waltham MA 02451	Common Stock	08/13/2026	1556	40892.00

144: Remarks and Signature

Remarks
Date of Notice	09/04/2026
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	/s/ James Weimer, as a duly authorized representative of STIFEL, as attorney-in-fact for Doug Kerr
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)