FMR LLC reports 5.4% stake in Dyne Therapeutics

FMR LLC reported beneficial ownership of 8,908,979.89 shares of Dyne Therapeutics common stock, representing 5.4% of the class as of 03/31/2026.

Rhea-AI Filing Summary

FMR LLC reported beneficial ownership of 8,908,979.89 shares of Dyne Therapeutics common stock, representing 5.4% of the class as of 03/31/2026. The filing shows sole voting power of 8,900,472 shares and sole dispositive power of 8,908,979.89 shares, and references a 13d-1(k) agreement in Exhibit 99.

Insights

Institutional Ownership Analyst

FMR LLC discloses a passive >5% stake in DYN, reported under Schedule 13G.

Schedule 13G filings indicate substantial passive or investment-manager holdings rather than activist intent. The filing lists 8,908,979.89 shares (5.4%) with sole dispositive and voting powers shown in the cover data.

Future filings may show changes in position; the referenced 13d-1(k) agreement (Exhibit 99) is included but not summarized here.

Governance & Voting Specialist

Voting and disposition figures suggest FMR controls voting and sale decisions for the reported shares.

The cover lists sole voting power of 8,900,472 shares and sole dispositive power of 8,908,979.89 shares as of 03/31/2026, implying centralized authority over these shares. Item 6 notes other persons may receive proceeds, consistent with pooled investment structures.

Stake size is disclosed; any governance impact depends on future increases or voting actions disclosed in subsequent schedules.

Key Figures

Beneficial ownership: 8,908,979.89 shares Percent of class: 5.4% Sole voting power: 8,900,472 shares +2 more

5 metrics

Beneficial ownership 8,908,979.89 shares reported as of 03/31/2026

Percent of class 5.4% percent of common stock class

Sole voting power 8,900,472 shares cover-page voting power figure

Sole dispositive power 8,908,979.89 shares cover-page dispositive power figure

Reporting date 03/31/2026 date tied to ownership figures on the cover

Key Terms

Schedule 13G, Beneficial ownership, Sole dispositive power, 13d-1(k) agreement

4 terms

Schedule 13G regulatory

"Item 1 lists issuer and the form type Schedule 13G"

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.

Beneficial ownership financial

"Item 4 states Amount beneficially owned: 8908979.89"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Sole dispositive power regulatory

"Cover page shows Sole Dispositive Power 8,908,979.89"

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.

13d-1(k) agreement regulatory

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

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does FMR LLC report in Dyne Therapeutics (DYN)?

FMR LLC reports beneficial ownership of 8,908,979.89 shares, equal to 5.4% of Dyne Therapeutics common stock as of 03/31/2026. The Schedule 13G lists voting and dispositive power figures on the cover page.

Who holds voting and dispositive power for the reported DYN shares?

The filing shows sole voting power of 8,900,472 shares and sole dispositive power of 8,908,979.89 shares attributed to FMR LLC. These figures are reported on the cover page and in Item 4 of the Schedule 13G.

Does the Schedule 13G indicate other parties benefit from the DYN shares?

Item 6 states that one or more other persons are known to have rights to dividends or sale proceeds, but no single other person holds more than 5% of the class. That language is typical for pooled investment vehicles.

What is the significance of Exhibit 99 referenced in the filing?

Exhibit 99 is cited as a 13d-1(k) agreement. The Schedule 13G references Exhibit 99 but does not include its text in this excerpt; the exhibit likely documents the agreement among reporting persons or subsidiaries.

Who signed the Schedule 13G for FMR LLC and Abigail P. Johnson?

The signature block shows Richard Bourgelas signing as duly authorized under a power of attorney dated April 13, 2026, on behalf of both FMR LLC and Abigail P. Johnson, with signature dates of 05/05/2026.

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

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Accepted by SEC EDGAR 05/06/2026 - 11:13 AM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

DYNE THERAPEUTICS INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

26818M108

(CUSIP Number)

03/31/2026

(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 8,900,472.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 8,908,979.89
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

8,908,979.89

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)

5.4 %

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 8,908,979.89
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

8,908,979.89

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)

5.4 %

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 Number(s): 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: 8908979.89
(b)	Percent of class: 5.4 %
(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: 8908979.89
	(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:	Richard Bourgelas
Name/Title:	Duly authorized under Power of Attorney effective as of April 13, 2026, by and on behalf of FMR LLC and its direct and indirect subsidiaries*
Date:	05/05/2026

Abigail P. Johnson

Signature:	Richard Bourgelas
Name/Title:	Duly authorized under Power of Attorney effective as of April 13, 2026, by and on behalf of Abigail P. Johnson*
Date:	05/05/2026

Comments accompanying signature: *This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on April 29,2026, accession number: 0000315066-26-000738.

Exhibit Information

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