DYN: Form 144 Notice for Restricted Stock Units

DYN filer submitted a Form 144 notice relating to proposed sales of Common Stock consisting of 11,250 Restricted Stock Units and disclosing a prior disposition of 2,732 shares on 03/05/2026.

Rhea-AI Filing Summary

DYN filer submitted a Form 144 notice relating to proposed sales of Common Stock consisting of 11,250 Restricted Stock Units and disclosing a prior disposition of 2,732 shares on 03/05/2026. The filing lists 165,313,769 shares outstanding as of 05/13/2026.

Insights

Securities Attorney

Form 144 notice for resale of restricted securities; transactional details are procedural.

The excerpt lists 11,250 Restricted Stock Units offered under equity compensation and a prior sale of 2,732 shares on 03/05/2026. Form 144 is a notice required when affiliates intend to resell restricted or control securities.

Cash‑flow treatment and whether sales will occur under an exemption are not stated in the excerpt; subsequent filings or broker confirmations would show execution details and actual trading methods.

Key Figures

Restricted Stock Units: 11,250 shares Prior disposition: 2,732 shares Shares outstanding: 165,313,769 shares

3 metrics

Restricted Stock Units 11,250 shares Granted/identified 05/12/2026 as Equity Compensation

Prior disposition 2,732 shares Sold on 03/05/2026 (listed under Securities Sold During The Past 3 Months)

Shares outstanding 165,313,769 shares As of 05/13/2026

Key Terms

Restricted Stock Units, Form 144, Equity Compensation

3 terms

Restricted Stock Units financial

"Restricted Stock Units | Issuer | 11250 | 05/12/2026 | Equity Compensation"

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.

Form 144 regulatory

"Filer Information | 144: Filer Information"

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.

Equity Compensation financial

"Restricted Stock Units | Issuer | 11250 | 05/12/2026 | 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.

FAQ

What does the DYN Form 144 disclose?

The notice discloses 11,250 Restricted Stock Units for resale and a prior disposition of 2,732 common shares on 03/05/2026. It provides procedural resale information rather than execution details.

Who is the reported filer on the DYN Form 144?

The excerpt names John Cox as a filer with an address in Waltham, MA. The filing lists the securities and transaction dates but does not state his ownership percentage.

How many shares does DYN report outstanding in the excerpt?

The excerpt shows 165,313,769 shares outstanding as of 05/13/2026. That figure is presented as an as‑of snapshot in the filing metadata.

Are sale proceeds or pricing disclosed in this Form 144 excerpt?

No pricing or proceeds information is provided in the excerpt. The filing lists securities and quantities but does not state sale prices or cash‑flow treatment.

Does the Form 144 show how the RSUs will be sold?

The excerpt classifies the securities as Equity Compensation and notes an issuer source, but it does not specify distribution methods such as block trades or broker transactions.

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

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Accepted by SEC EDGAR 05/13/2026 - 04:57 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	0001498428
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	Cox John
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	3311	60805.00	165313769	05/13/2026	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	05/12/2026	Restricted Stock Units	Issuer			11250	05/12/2026	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
John Cox 1560 Trapelo Rd Waltham MA 02451	Common Stock	03/05/2026	2732	40707.00

144: Remarks and Signature

Remarks
Date of Notice	05/13/2026
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 John Cox
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)