Dyne Therapeutics Inc ownership disclosure: Janus Henderson Group plc reports beneficial ownership of 13,647,376 shares of Dyne common stock, representing 8.3% of the class. The filing states the Asset Managers exercise shared voting and shared dispositive power over these shares. The filing is submitted on behalf of Janus Henderson Group plc and describes that the Managed Portfolios hold the securities and have the right to receive dividends and sale proceeds.
Positive
None.
Negative
None.
Insights
Janus Henderson reports an 8.3% passive stake via managed accounts.
Janus Henderson Group plc states it is the ultimate parent of multiple registered investment advisers whose Managed Portfolios may be deemed beneficial owners of 13,647,376 shares. The filing shows shared voting and shared dispositive power of the same amount.
Disclosure indicates holdings are held in client accounts rather than for the parent’s proprietary account; subsequent filings may identify which affiliated advisers report voting or dispositive authority.
Ownership is reported collectively by the parent with disclaimers on dividend/proceeds rights.
The schedule explains the Asset Managers exercise discretion for Managed Portfolios and disclaim rights to dividends/proceeds on behalf of Janus Henderson; the Managed Portfolios themselves retain rights to dividends and proceeds.
Investors tracking ownership should note the filing attributes power to the Asset Managers and references Exhibit 99 for subsidiary detail.
Key Figures
Shares beneficially owned:13,647,376 sharesPercent of class:8.3%Shared voting power:13,647,376 shares+2 more
5 metrics
Shares beneficially owned13,647,376 sharesamount reported as beneficially owned by Janus Henderson Group plc
Percent of class8.3%percent of Dyne common stock represented by the reported shares
Shared voting power13,647,376 sharesshared power to vote as reported in Item 4
Shared dispositive power13,647,376 sharesshared power to dispose or direct disposition as reported in Item 4
Signees/filing dateSigned 5/15/2026signature date shown on the filing
"May be deemed to be the beneficial owner of 13,647,376 common stock"
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.
Managed Portfoliosfinancial
"clients which include investment companies, other investment advisers, institutional separate accounts"
Shared dispositive powergovernance
"Shared power to dispose or to direct the disposition of: 13647376"
Schedule 13G/Aregulatory
"Item 1. (a) Name of issuer: DYNE THERAPEUTICS INC ..."
A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.
Janus Henderson Group plc reports beneficial ownership of 13,647,376 shares, equal to 8.3% of Dyne Therapeutics' common stock according to the filing.
Does Janus Henderson have voting control over the DYN shares?
The filing reports shared voting power of 13,647,376 shares, indicating voting authority is held jointly by the listed Asset Managers rather than solely by the parent.
Who actually holds the shares reported by Janus Henderson?
The shares are held in client Managed Portfolios across affiliated advisers; the filing states the Managed Portfolios have the right to receive dividends and sale proceeds.
Does Janus Henderson claim sole dispositive power over DYN shares?
No. The filing shows sole dispositive power: 0 and shared dispositive power: 13,647,376, indicating disposition authority is shared among the Asset Managers.
When was this Schedule 13G/A signed?
The signature block shows the filing was signed by Kristin Mariani, Head of North America Compliance, on 5/15/2026.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 6)
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
JANUS HENDERSON GROUP PLC
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
JERSEY
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
13,647,376.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
13,647,376.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
13,647,376.00
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)
8.3 %
12
Type of Reporting Person (See Instructions)
HC
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:
Janus Henderson Group plc
(b)
Address or principal business office or, if none, residence:
201 Bishopsgate
EC2M 3AE, United Kingdom
(c)
Citizenship:
Y9
(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:
Janus Henderson Group plc (JHG) is the ultimate parent of a number of SEC-registered investment advisers and foreign equivalents thereof, including but not limited to Janus Henderson Investors US LLC, Janus Henderson Investors UK Limited, Janus Henderson Investors Australia Institutional Funds Management Limited, Janus Henderson Investors Middle East Limited, Janus Henderson Investors (Jersey) Limited, Janus Henderson Investors (Japan) Limited, Janus Henderson Investors (Singapore) Limited, Kapstream Capital Pty Limited, Privacore Capital Advisors LLC, Tabula Investment Management Limited, and Victory Park Capital Advisors LLC (each, an Asset Manager and together, the Asset Managers). The Asset Managers generally exercise investment and/or voting discretion on behalf of their clients which include investment companies, other investment advisers, institutional separate accounts and retail separate accounts (collectively referred to herein as Managed Portfolios).
As a result of their exercise of investment and/or voting discretion on behalf of the Managed Portfolios, the Asset Managers may be deemed to be the beneficial owner of 13,647,376 common stock of Dyne Therapeutics Inc. However, the Asset Managers do not have the right to receive any dividends from, or the proceeds from the sale of, the securities held in the Managed Portfolios and disclaim any ownership associated with such rights.
(b)
Percent of class:
8.3 %
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
0
(ii) Shared power to vote or to direct the vote:
13647376
(iii) Sole power to dispose or to direct the disposition of:
0
(iv) Shared power to dispose or to direct the disposition of:
13647376
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.
The Managed Portfolios have the right to receive all dividends from, and the proceeds from the sale of, the securities held in their respective accounts.
Of the Managed Portfolios, none own more than five percent of the common stock of Dyne Therapeutics,Inc.
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.
Please refer to Exhibit 99.
Item 8.
Identification and Classification of Members of the Group.
If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group.
N/A
Item 9.
Notice of Dissolution of Group.
Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5.
N/A
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.
