T. Rowe Price reports 10.7% stake in Dyne Therapeutics (DYN) common stock

Rhea-AI Filing Summary

T. Rowe Price Investment Management, Inc. filed a Schedule 13G reporting beneficial ownership of 17,540,089 shares of Dyne Therapeutics Inc. common stock, representing 10.7% of the class as of the event date. The firm has sole power to vote 17,517,597 of these shares and sole power to dispose of 17,540,089 shares, with no shared voting or dispositive power. T. Rowe Price classifies itself as an investment adviser and states that the securities were acquired and are held in the ordinary course of business, not for the purpose of changing or influencing control of Dyne Therapeutics.

Insights

Institutional Ownership Analyst

T. Rowe Price discloses a passive 10.7% stake in Dyne.

T. Rowe Price Investment Management, Inc. reports beneficial ownership of 17,540,089 Dyne Therapeutics common shares, equal to 10.7% of the outstanding class. It also reports sole voting power over 17,517,597 shares and sole dispositive power over 17,540,089 shares, indicating centralized control of this position within the adviser.

The filer identifies itself as an investment adviser and certifies that the shares were acquired and are held in the ordinary course of business, explicitly stating they are not held to change or influence control of Dyne Therapeutics. This aligns with a passive ownership stance typical of a Schedule 13G, rather than an activist or control-seeking position.

The declaration that beneficial ownership is expressly denied, despite reporting for Schedule 13G purposes, reflects common institutional caution around legal definitions of ownership. Future ownership updates, if any, would typically appear in amended beneficial ownership reports as holdings change.

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)

12/31/2025

(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 No. 26818M108

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 17,517,597.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 17,540,089.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

17,540,089.00

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)

10.7 %

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: 17540089
(b)	Percent of class: 10.7 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 17517597
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 17540089
	(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:	01/08/2026

FAQ

How many Dyne Therapeutics (DYN) shares does T. Rowe Price report owning?

T. Rowe Price Investment Management, Inc. reports beneficial ownership of 17,540,089 shares of Dyne Therapeutics Inc. common stock.

What percentage of Dyne Therapeutics (DYN) does T. Rowe Price beneficially own?

T. Rowe Price reports that its 17,540,089 Dyne Therapeutics common shares represent 10.7% of the class.

Does T. Rowe Price have voting and dispositive power over its Dyne Therapeutics (DYN) shares?

Yes. T. Rowe Price reports sole voting power over 17,517,597 shares and sole dispositive power over 17,540,089 shares, with no shared voting or dispositive power.

Is T. Rowe Price’s stake in Dyne Therapeutics (DYN) passive or activist?

T. Rowe Price certifies the Dyne Therapeutics securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of the company.

What type of reporting person is T. Rowe Price in this Dyne Therapeutics Schedule 13G?

T. Rowe Price Investment Management, Inc. identifies its reporting status as an investment adviser (IA) under the Schedule 13G classification.

When was the Dyne Therapeutics (DYN) ownership position measured for this Schedule 13G?

The date of the event requiring this Schedule 13G filing is listed as 12/31/2025.