DYN files Rule 144: 5,727 shares resold

DYN filed a Rule 144 notice reporting a recent restricted‑stock issuance and a resale by an affiliate.

Rhea-AI Filing Summary

DYN filed a Rule 144 notice reporting a recent restricted‑stock issuance and a resale by an affiliate. The filing lists 4,062 Restricted Stock Units granted on 05/12/2026 and a reported resale of 5,727 shares on 04/01/2026 by Erick Lucera. The excerpt shows 165,313,796 shares outstanding as of 05/13/2026.

Insights

Securities Attorney

Rule 144 notice records a resale and issuer equity grant.

The filing documents a sale of 5,727 common shares by Erick Lucera on 04/01/2026

The report also lists 4,062 Restricted Stock Units issued by the company on 05/12/2026, and an apparent outstanding share count of 165,313,796 as of 05/13/2026.

Key Figures

Resale reported: 5,727 shares RSUs granted: 4,062 Restricted Stock Units Shares outstanding: 165,313,796 shares +1 more

4 metrics

Resale reported 5,727 shares resale by Erick Lucera on 04/01/2026

RSUs granted 4,062 Restricted Stock Units grant dated 05/12/2026 under equity compensation

Shares outstanding 165,313,796 shares as of 05/13/2026

Filer address listed 1560 Trapelo Rd, Waltham, MA Erick Lucera contact line

Key Terms

Rule 144, Restricted Stock Units, Equity Compensation

3 terms

Rule 144 regulatory

"Filer Information | 144: Filer Information"

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

"Restricted Stock Units | Issuer | 4062 | 05/12/2026"

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

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

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

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Accepted by SEC EDGAR 05/13/2026 - 04:55 PM EDT 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	0001697616
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	Lucera Erick
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	1448	26592.00	165313796	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			4062	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
Erick Lucera 1560 Trapelo Rd Waltham MA 02451	Common Stock	04/01/2026	5727	106758.00

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 Erick Lucera
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)