Jason P. Rhodes - 13 Aug 2026 Form 4 Insider Report for Dyne Therapeutics, Inc. (DYN)

Reporting relationship: Director
Issuer ticker: DYN
Reported as of: 13 Aug 2026
Net transaction value: -$65,184,894
SEC form: 4
Accepted by SEC: 17 Aug 2026, 17:30:08 UTC
Prior SEC filing: 08 Jul 2026
Source filing: View source filing
Reporting owner signature: /s/ Ommer Chohan, Attorney-in-Fact

Key filing fact

Jason P. Rhodes filed Form 4 for Dyne Therapeutics, Inc. (DYN) on 17 Aug 2026.

Key facts

This page summarizes Jason P. Rhodes's Form 4 filing for Dyne Therapeutics, Inc. (DYN).
6 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 17 Aug 2026, 17:30.

Change

Previous filing in this sequence was filed on 08 Jul 2026.
Current net transaction value: -$65,184,894.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001577014 Primary reporting owner

Rhodes Jason P

Relationship: Director
Address: C/O DYNE THERAPEUTICS, INC., 1560 TRAPELO ROAD, WALTHAM
Signature: /s/ Ommer Chohan, Attorney-in-Fact
Signature date: 17 Aug 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

DYN transaction

Common Stock

Sale

Transaction value: $7,030,875
Shares: -268,354
Change %: -6.6%
Price: $26.20
Shares after: 3,801,128
Date: 13 Aug 2026
Ownership: See footnote
Footnotes: F1, F2, F3

DYN transaction

Common Stock

Sale

Transaction value: $2,473,673
Shares: -94,415
Change %: -8.3%
Price: $26.20
Shares after: 1,045,735
Date: 13 Aug 2026
Ownership: See footnote
Footnotes: F1, F2, F4

DYN transaction

Common Stock

Sale

Transaction value: $1,667,447
Shares: -63,643
Change %: -7.8%
Price: $26.20
Shares after: 751,411
Date: 13 Aug 2026
Ownership: See footnote
Footnotes: F1, F2, F5

DYN transaction

Common Stock

Sale

Transaction value: $33,991,850
Shares: -1,359,674
Change %: -36%
Price: $25.00
Shares after: 2,441,454
Date: 14 Aug 2026
Ownership: See footnote
Footnotes: F1, F3, F6

DYN transaction

Common Stock

Sale

Transaction value: $11,959,425
Shares: -478,377
Change %: -46%
Price: $25.00
Shares after: 567,358
Date: 14 Aug 2026
Ownership: See footnote
Footnotes: F1, F4, F6

DYN transaction

Common Stock

Sale

Transaction value: $8,061,625
Shares: -322,465
Change %: -43%
Price: $25.00
Shares after: 428,946
Date: 14 Aug 2026
Ownership: See footnote
Footnotes: F1, F5, F6

DYN holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 2,962
Date: 13 Aug 2026
Ownership: See footnote
Footnotes: F7

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 7 footnotes

Footnote F1

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on July 13, 2026.

Footnote F2

The price reported in Column 4 is a weighted average price. These securities were sold in multiple transactions at prices ranging from $25.8788 to $26.48 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of securities sold at each separate price within the ranges set forth in footnotes (2) and (6).

Footnote F3

The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. The Reporting Person is a member of AVA XI LLC and disclaims Section 16 beneficial ownership of such securities held by Atlas Venture Fund XI, except to the extent of his pecuniary interest therein, if any.

Footnote F4

The shares are owned directly by Atlas Venture Opportunity Fund II, L.P. ("AVOF II"). Atlas Venture Associates Opportunity II, LP ("AVAO II LP") is the general partner of AVOF II. Atlas Venture Associates Opportunity II, LLC ("AVAO II LLC") is the general partner of AVAO II LP. The Reporting Person is a member of AVAO II LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF II, except to the extent of his pecuniary interest therein, if any.

Footnote F5

The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("AVOF I"). The general partner of AVOF I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. The Reporting Person is a member of AVAO I LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF I, except to the extent of his pecuniary interest therein, if any.

Footnote F6

The price reported in Column 4 is a weighted average price. These securities were sold in multiple transactions at prices ranging from $25.00 to $25.8916 inclusive.

Footnote F7

The shares are held directly by AVA XI LP. AVA XI LLC is the general partner of AVA XI LP. The Reporting Person is a member of AVA XI LLC and disclaims Section 16 beneficial ownership of the securities held by AVA XI LP, except to the extent of his pecuniary interest therein, if any.