FMR LLC (DYN) discloses 6.8% Dyne Therapeutics stake in amended ownership filing

Rhea-AI Filing Summary

FMR LLC filed an amended beneficial ownership report for Dyne Therapeutics Inc. common stock. FMR LLC reports beneficial ownership of 11,206,999.89 shares, representing 6.8% of the outstanding common stock as of June 30, 2026. FMR LLC has sole voting power over 11,206,231.00 shares and sole dispositive power over 11,206,999.89 shares, with no shared voting or dispositive power.

Abigail P. Johnson is reported as having sole dispositive power over the same 11,206,999.89 shares, with no voting or shared powers. One or more other persons have rights to receive dividends or sale proceeds from these securities, but no such person holds an interest exceeding five percent of Dyne Therapeutics’ common stock.

Key Figures

Beneficial Ownership: 11,206,999.89 shares Percent of Class: 6.8% Sole Voting Power: 11,206,231.00 shares +3 more

6 metrics

Beneficial Ownership 11,206,999.89 shares Common stock beneficially owned by FMR LLC

Percent of Class 6.8% Portion of Dyne Therapeutics common stock class held by FMR LLC

Sole Voting Power 11,206,231.00 shares Shares over which FMR LLC has sole power to vote

Sole Dispositive Power 11,206,999.89 shares Shares over which FMR LLC has sole power to dispose

CUSIP 26818M108 CUSIP for Dyne Therapeutics Inc. common stock

As-of Date 06/30/2026 Date for reported ownership information

Key Terms

beneficially owned, Sole Voting Power, Sole Dispositive Power, parent holding company, +1 more

5 terms

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 11206999.89"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Sole Voting Power financial

"5 | Sole Voting Power 11,206,231.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Sole Dispositive Power financial

"7 | Sole Dispositive Power 11,206,999.89 8 | Shared Dispositive Power 0.00"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

parent holding company financial

"If a parent holding company has filed this schedule, pursuant to (ii)(G)"

Schedule 13G regulatory

"Please see Exhibit 99 for 13d-1(k) (1) agreement."

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

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

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Available on EDGAR 08/06/2026 - 10:21 AM Accepted by SEC EDGAR 08/06/2026 - 10:20 AM Learn about SEC filing dates

FAQ

How many Dyne Therapeutics (DYN) shares does FMR LLC report owning?

FMR LLC reports beneficial ownership of 11,206,999.89 shares of Dyne Therapeutics Inc. common stock. This position represents 6.8% of the company’s outstanding common stock as of June 30, 2026.

What percentage of Dyne Therapeutics (DYN) is held by FMR LLC according to this filing?

FMR LLC reports holding 6.8% of Dyne Therapeutics Inc.’s common stock. This percentage is based on 11,206,999.89 shares beneficially owned as disclosed for the period ended June 30, 2026.

What voting power does FMR LLC have over Dyne Therapeutics (DYN) shares?

FMR LLC has sole voting power over 11,206,231.00 shares of Dyne Therapeutics common stock and no shared voting power. It also has sole dispositive power over 11,206,999.89 shares.

What role does Abigail P. Johnson have in the Dyne Therapeutics (DYN) ownership reported?

Abigail P. Johnson is listed with sole dispositive power over 11,206,999.89 shares of Dyne Therapeutics common stock and no voting or shared powers. Her authority is exercised under a power of attorney dated January 26, 2023.

Do other investors share in the economic interest of FMR LLC’s Dyne Therapeutics (DYN) holdings?

Yes. One or more other persons have the right to receive dividends or sale proceeds from Dyne Therapeutics common stock held by FMR LLC. However, no such person’s interest exceeds five percent of the total outstanding common stock.

What is the significance of Amendment No. 1 to the Dyne Therapeutics (DYN) ownership report?

Amendment No. 1 updates the Schedule 13G reporting by FMR LLC and Abigail P. Johnson. It restates their 11,206,999.89-share, 6.8% beneficial ownership position and clarifies voting, dispositive powers, and third-party economic interests.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

DYNE THERAPEUTICS INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

26818M108

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 26818M108

1

Names of Reporting Persons

FMR LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 11,206,231.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 11,206,999.89
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

11,206,999.89

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.8 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP Number(s): 26818M108

1

Names of Reporting Persons

Abigail P. Johnson

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 11,206,999.89
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

11,206,999.89

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.8 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: DYNE THERAPEUTICS INC
(b)	Address of issuer's principal executive offices: 1560 TRAPELO ROAD,WALTHAM,MA,USA,02451
Item 2.
(a)	Name of person filing: FMR LLC
(b)	Address or principal business office or, if none, residence: 245 Summer Street, Boston, Massachusetts 02210
(c)	Citizenship: Not applicable
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 26818M108
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 11206999.89
(b)	Percent of class: 6.8 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Please see the responses to Items 5 and 6 on the cover page.
	(ii) Shared power to vote or to direct the vote: 0.00
	(iii) Sole power to dispose or to direct the disposition of: 11206999.89
	(iv) Shared power to dispose or to direct the disposition of: 0.00
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. One or more other persons are known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the COMMON STOCK of DYNE THERAPEUTICS INC. No one other person's interest in the COMMON STOCK of DYNE THERAPEUTICS INC is more than five percent of the total outstanding COMMON STOCK.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See attached Exhibit 99.
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

FMR LLC

Signature:	Stephanie J. Brown
Name/Title:	Duly authorized under Power of Attorney effective as of January 3, 2023, by and on behalf of FMR LLC and its direct and indirect subsidiaries*
Date:	08/05/2026

Abigail P. Johnson

Signature:	Stephanie J. Brown
Name/Title:	Duly authorized under Power of Attorney effective as of January 26, 2023, by and on behalf of Abigail P. Johnson**
Date:	08/05/2026

Comments accompanying signature: * This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on January 10, 2023, accession number: 0000315066-23-000003. ** This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on January 31, 2023, accession number: 0000315066-23-000038.

Exhibit Information

Please see Exhibit 99 for 13d-1(k) (1) agreement.