Dianthus Therapeutics ownership update: This Amendment No. 3 to a Schedule 13G/A states that Octagon-related reporting persons collectively beneficially own 1,946,667 shares of Dianthus Therapeutics common stock, equal to 3.6% of the class based on 54,448,771 shares outstanding as of March 30, 2026. The filing attributes shared voting and dispositive power over those shares to Octagon and identifies Octagon and affiliated funds as holders.
Positive
None.
Negative
None.
Insights
Institutional stake disclosed: Octagon-affiliated entities hold 1.95M shares (3.6%).
The filing lists 1,946,667 shares beneficially owned with shared voting and dispositive power. The percentage is calculated using 54,448,771 shares outstanding as of March 30, 2026, per the proxy reference.
Holder structure shows ownership through the Master Fund and Biotech Fund I, with Octagon as investment manager and Dr. Jia as controlling person; cash-flow treatment or sales intent is not stated in the excerpt.
Key Figures
Beneficially owned shares:1,946,667 sharesPercent of class:3.6%Shares outstanding:54,448,771 shares+2 more
5 metrics
Beneficially owned shares1,946,667 sharesAmount beneficially owned reported in Item 4
Percent of class3.6%Percent of class based on outstanding shares
Shares outstanding54,448,771 sharesOutstanding as of March 30, 2026 (proxy reference)
Master Fund holding1,655,000 sharesOctagon Investments Master Fund beneficial ownership listed
Biotech Fund I holding291,667 sharesOctagon Biotech Opportunities Fund I beneficial ownership listed
"Amendment No. 3 to a Schedule 13G/A is the filing type"
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.
Shared dispositive powerfinancial
"Shared Dispositive Power 1,946,667.00 is reported"
Beneficial ownershipregulatory
"Amount beneficially owned: 1,946,667 is disclosed"
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.
What stake does Octagon report in Dianthus Therapeutics (DNTH)?
The filing reports 1,946,667 shares beneficially owned by Octagon-related reporting persons, representing 3.6% of the class based on 54,448,771 shares outstanding as of March 30, 2026. The ownership is reported as shared voting and dispositive power.
Which entities are listed as reporting persons in the 13G/A for DNTH?
The statement is jointly filed by Octagon Capital Advisors LP, Octagon Investments Master Fund LP, Octagon Biotech Opportunities Fund I LP, and Ting Jia as the principal beneficial owner and managing member of Octagon.
How is the reported ownership held according to the filing?
The Master Fund and Biotech Fund I directly hold the shares for their investors; Octagon serves as investment manager and Dr. Jia is the control person. The filing states the funds have the right to receive dividends or proceeds on behalf of their investors.
What voting and disposition powers are reported for the 1,946,667 shares?
The filing shows 0 shares with sole voting or dispositive power and 1,946,667 shares with shared voting power and shared dispositive power, as disclosed in Item 4 of the amendment.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 3)
Dianthus Therapeutics, Inc. /DE/
(Name of Issuer)
Common Stock, $0.001 par value
(Title of Class of Securities)
252828108
(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):
252828108
1
Names of Reporting Persons
Octagon Capital Advisors LP
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
0.00
6
Shared Voting Power
1,946,667.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,946,667.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,946,667.00
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)
3.6 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
252828108
1
Names of Reporting Persons
Octagon Investments Master Fund LP
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
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,655,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,655,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,655,000.00
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)
3.0 %
12
Type of Reporting Person (See Instructions)
PN, OO
SCHEDULE 13G
CUSIP Number(s):
252828108
1
Names of Reporting Persons
Octagon Biotech Opportunities Fund I LP
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
0.00
6
Shared Voting Power
291,667.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
291,667.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
291,667.00
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)
0.6 %
12
Type of Reporting Person (See Instructions)
PN, OO
SCHEDULE 13G
CUSIP Number(s):
252828108
1
Names of Reporting Persons
Ting Jia
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
CHINA
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,946,667.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,946,667.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,946,667.00
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)
3.6 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Dianthus Therapeutics, Inc. /DE/
(b)
Address of issuer's principal executive offices:
7 Times Square, 43rd Floor, New York, NY, 10036
Item 2.
(a)
Name of person filing:
This statement is being jointly filed by:
Octagon Capital Advisors LP ("Octagon")
Octagon Investments Master Fund LP ("Master Fund")
Octagon Biotech Opportunities Fund I LP ("Biotech Fund I")
Ting Jia, as the principal beneficial owner of Octagon ("Dr. Jia")
Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons."
Octagon serves as the investment manager of the Master Fund and Biotech Fund I. Dr. Jia is the managing member of Octagon. By virtue of these relationships each of Octagon and Dr. Jia may be deemed to beneficially own the Issuer's Common Shares directly owned by the Master Fund and by the Biotech Fund I.
(b)
Address or principal business office or, if none, residence:
The address of the business office of each of the Reporting Persons is 654 Madison Avenue, 21st Floor, New York, NY 10065.
(c)
Citizenship:
Octagon is a Delaware limited partnership. The Master Fund is an exempted limited partnership established in the Cayman Islands. The Biotech Fund I is a Delaware limited partnership. Dr. Jia is a Chinese citizen.
(d)
Title of class of securities:
Common Stock, $0.001 par value
(e)
CUSIP No.:
252828108
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:
1,946,667
(b)
Percent of class:
3.6 %
(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:
1,946,667
(iii) Sole power to dispose or to direct the disposition of:
0
(iv) Shared power to dispose or to direct the disposition of:
1,946,667
The percentage reported on this Schedule 13G is calculated based upon 54,448,771 Common Shares outstanding as of March 30, 2026, as reported in the Form DEF 14A filed by the Issuer on April 9, 2026.
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
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.
Octagon is the investment advisor to the Master Fund, the Biotech Fund I and other accounts. Dr. Jia is the control person of Octagon. The Master Fund holds the Common Shares for the benefit of its investors. The Biotech Fund I holds the Common Shares for the benefit of its investors. The Master Fund, the Biotech Fund I and Octagon, for the benefit of its investors, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Common Shares.
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.
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.
Octagon Capital Advisors LP
Signature:
/s/ Ting Jia
Name/Title:
Managing Member
Date:
05/14/2026
Octagon Investments Master Fund LP
Signature:
/s/ Ting Jia
Name/Title:
Managing Member, Octagon Investments GP, LLC, its general partner
Date:
05/14/2026
Octagon Biotech Opportunities Fund I LP
Signature:
/s/ Ting Jia
Name/Title:
Managing Member, Octagon Investments GP, LLC, its general partner
