T. Rowe Price reports 26.58M DYN shares (16.2%)

Dyne Therapeutics reports a Schedule 13G/A from T. Rowe Price Investment Management showing beneficial ownership of 26,578,437 shares of common stock, representing 16.2% of the class.

Rhea-AI Filing Summary

Dyne Therapeutics reports a Schedule 13G/A from T. Rowe Price Investment Management showing beneficial ownership of 26,578,437 shares of common stock, representing 16.2% of the class.

The filing shows sole voting power for 26,223,470 shares and sole dispositive power for 26,578,437. The filing includes a statement denying beneficial ownership by T. Rowe Price Investment Management. The form is signed by Ellen York on 03/06/2026.

Insights

Institutional Ownership Analyst

T. Rowe Price reports a substantial passive stake in Dyne Therapeutics at 16.2%.

The filing lists 26,578,437 shares beneficially owned with 26,223,470 shares of sole voting power as of the amendment date. The filer also includes an explicit denial of beneficial ownership in the text.

Institutional filings like this commonly reflect investment management positions; the exact economic interest attribution is subject to the filer’s reservation language. Subsequent filings or disclosures could clarify voting or investment authority.

FAQ

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

What does the T. Rowe Price 13G/A filing for DYN mean?

It reports that T. Rowe Price Investment Management holds 26,578,437 shares of Dyne common stock, equal to 16.2% of the class. The filing documents voting and dispositive power and includes a denial of beneficial ownership by the filer.

How many Dyne shares does T. Rowe Price have voting power over?

The filing shows sole voting power over 26,223,470 shares. It lists 0 shared voting power and cites sole dispositive power over 26,578,437 shares.

Does the filing prove T. Rowe Price is the beneficial owner of DYN shares?

No; the filing includes an explicit statement in which T. Rowe Price Investment Management "expressly denied" beneficial ownership. The form still reports amounts and voting/dispositive powers as required by SEC rules.

When was the Schedule 13G/A signed and filed for DYN?

The signature block shows the filing was signed by Ellen York, Vice President, on 03/06/2026. The cover line references the relevant record date of 02/28/2026.

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

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Accepted by SEC EDGAR 03/06/2026 - 12:57 PM Learn about SEC filing dates

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)

02/28/2026

(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)

SCHEDULE 13G

CUSIP Number(s):

1

Names of Reporting Persons

T. Rowe Price Investment Management, Inc.

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

MARYLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 26,223,470.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 26,578,437.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

26,578,437.00

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)

16.2 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: DYNE THERAPEUTICS INC
(b)	Address of issuer's principal executive offices: 1560 TRAPELO ROAD, WALTHAM, MA, 02451
Item 2.
(a)	Name of person filing: T. Rowe Price Investment Management, Inc.
(b)	Address or principal business office or, if none, residence: 1307 Point Street, Baltimore, MD 21231
(c)	Citizenship: Maryland
(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: 26578437
(b)	Percent of class: 16.2 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 26223470
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 26578437
	(iv) Shared power to dispose or to direct the disposition of: 0
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.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
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. T. Rowe Price Investment Management, Inc. hereby declares and affirms that the filing of Schedule 13G shall not be construed as an admission that Price Investment Management is the beneficial owner of the securities referred to, which beneficial ownership is expressly denied.

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.

T. Rowe Price Investment Management, Inc.

Signature:	Ellen York
Name/Title:	Vice President
Date:	03/06/2026