[SCHEDULE 13G] Rithm Acquisition Corp. SEC Filing

Rhea-AI Filing Summary

Rithm Acquisition Corp. Schedule 13G filings show two related First Trust reporting groups disclosed sizable passive positions in the issuer. First Trust Merger Arbitrage Fund (VARBX) beneficially owned 1,245,249 Class A Ordinary Shares, equal to 5.26% of the class as of the event date 06/30/2025. First Trust Capital Management L.P., First Trust Capital Solutions L.P. and FTCS Sub GP LLC collectively beneficially owned 1,512,450 shares, equal to 6.39%. Each reporting person reports sole voting and dispositive power over the shares they disclose. The filings are joint and are signed on 08/14/2025. The issuer CUSIP is G75751100 and the issuer address is provided in the filing.

Positive

• Beneficial ownership exceeds 5% for both VARBX (5.26%) and the First Trust group (6.39%), triggering required SEC disclosure
• Sole voting and dispositive power reported for the disclosed shares, clarifying which entities hold control over voting and disposition
• Joint filing executed and signed by the reporting persons on 08/14/2025, including an exhibit referencing a Joint Filing Statement

Negative

• None.

Insights

Securities Analyst

TL;DR: Passive holdings above 5% disclosed; indicates material share ownership without stated intent to influence control.

The Schedule 13G disclosure documents that VARBX holds 1,245,249 shares (5.26%) and the First Trust group holds 1,512,450 shares (6.39%), with sole voting and dispositive power reported for each holder. Because the filing is a Schedule 13G rather than a 13D, the reporting persons represent passive investors rather than active acquirers, based on the filing type stated. The joint filing and explicit ownership percentages meet SEC disclosure thresholds and provide clarity on ownership concentration for investors monitoring significant holders.

Corporate Governance Expert

TL;DR: Ownership concentrations disclosed surpass 5% thresholds and are formally documented with signatures, standard governance disclosure practice.

The filing names each reporting entity, provides principal business addresses, and certifies sole voting and dispositive power for the reported shares. The joint filing agreement is referenced as an exhibit. These elements satisfy regulatory transparency requirements for substantial passive holdings. The document does not state any arrangements, shared voting rights, or plans to influence control, and contains the customary certification language regarding ordinary-course acquisition and lack of intent to change control.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Rithm Acquisition Corp.

(Name of Issuer)

Class A Ordinary Shares, par value $0.0001 per share ("Ordinary Shares")

(Title of Class of Securities)

G75751100

(CUSIP Number)

06/30/2025

(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. G75751100

1

Names of Reporting Persons

First Trust Merger Arbitrage Fund

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 1,245,249.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,245,249.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,245,249.00

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)

5.26 %

12

Type of Reporting Person (See Instructions)

IV

SCHEDULE 13G

CUSIP No. G75751100

1

Names of Reporting Persons

First Trust Capital Management L.P.

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 1,512,450.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,512,450.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,512,450.00

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)

6.39 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP No. G75751100

1

Names of Reporting Persons

First Trust Capital Solutions L.P.

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 1,512,450.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,512,450.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,512,450.00

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)

6.39 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. G75751100

1

Names of Reporting Persons

FTCS Sub GP 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 1,512,450.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,512,450.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,512,450.00

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)

6.39 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Rithm Acquisition Corp.
(b)	Address of issuer's principal executive offices: 799 BROADWAY, 8TH FLOOR, NEW YORK, NY, 10003
Item 2.
(a)	Name of person filing: This Schedule 13G is being filed jointly by First Trust Merger Arbitrage Fund ("VARBX"), First Trust Capital Management L.P. ("FTCM"), First Trust Capital Solutions L.P. ("FTCS") and FTCS Sub GP LLC ("Sub GP"). (1) VARBX, a series of Investment Managers Series Trust II, an investment company registered under the Investment Company Act of 1940. (2) FTCM, an investment adviser registered with the SEC that provides investment advisory services to, among others, (i) series of Investment Managers Series Trust II, an investment company registered under the Investment Company Act of 1940, specifically First Trust Multi-Strategy Fund and VARBX, (ii) First Trust Alternative Opportunities Fund, an investment company registered under the Investment Company Act of 1940, and (iii) Highland Capital Management Institutional Fund II, LLC, a Delaware limited liability company (collectively, the "Client Accounts"). (3) FTCS, a Delaware limited partnership and control person of FTCM. (4) Sub GP, a Delaware limited liability company and control person of FTCM. Each of the persons identified herein is referred to as a "Reporting Person" and, collectively, as the "Reporting Persons." Each of the Reporting Persons is a party to that certain Joint Filing Agreement attached hereto.
(b)	Address or principal business office or, if none, residence: The principal business address of FTCM, FTCS and Sub GP is 225 W. Wacker Drive, 21st Floor, Chicago, IL 60606. The principal business address of VARBX is 235 West Galena Street, Milwaukee, WI 53212.
(c)	Citizenship: United States
(d)	Title of class of securities: Class A Ordinary Shares, par value $0.0001 per share ("Ordinary Shares")
(e)	CUSIP No.: G75751100
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: As investment adviser to the Client Accounts, FTCM has the authority to invest the funds of the Client Accounts in securities (including Ordinary Shares of Rithm Acquisition Corp (the Issuer)) as well as the authority to purchase, vote and dispose of securities, and may thus be deemed the beneficial owner of any shares of the Issuer's Ordinary Shares held in the Client Accounts. As of June 30, 2025 VARBX owned 1,245,249 shares of the outstanding Ordinary Shares of the Issuer FTCM, FTCS and Sub GP collectively owned 1,512,450 shares of the outstanding Ordinary Shares of the Issuer. FTCS and Sub GP may be deemed to control FTCM and therefore may be deemed to be beneficial owners of the Ordinary Shares reported in this Schedule 13G. No one individual controls FTCS or Sub GP. FTCS and Sub GP do not own any Ordinary Shares of the Issuer for their own accounts.
(b)	Percent of class: VARBX: 5.26% FTCM, FTCS and Sub GP: 6.39%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: VARBX: 1,245,249 FTCM, FTCS and Sub GP: 1,512,450
	(ii) Shared power to vote or to direct the vote: VARBX: 0 FTCM, FTCS and Sub GP: 0
	(iii) Sole power to dispose or to direct the disposition of: VARBX: 1,245,249 FTCM, FTCS and Sub GP: 1,512,450
	(iv) Shared power to dispose or to direct the disposition of: VARBX: 0 FTCM, FTCS and Sub GP: 0
Item 5.	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. See Item 4.
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 Item 2.
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.

First Trust Merger Arbitrage Fund

Signature:	/s/ Joy Ausili
Name/Title:	Trustee, Vice President and Assistant Secretary
Date:	08/14/2025

First Trust Capital Management L.P.

Signature:	/s/ Chad Eisenberg
Name/Title:	Chief Operating Officer
Date:	08/14/2025

First Trust Capital Solutions L.P.

Signature:	/s/ Chad Eisenberg
Name/Title:	Chief Operating Officer
Date:	08/14/2025

FTCS Sub GP LLC

Signature:	/s/ Chad Eisenberg
Name/Title:	Chief Operating Officer
Date:	08/14/2025

Exhibit Information

Exhibit I: Joint Filing Statement

FAQ

How many Rithm Acquisition (RAC) shares does First Trust Merger Arbitrage Fund (VARBX) own?

The filing reports VARBX beneficially owns 1,245,249 Class A Ordinary Shares, representing 5.26% of the class as of 06/30/2025.

What stake does First Trust Capital Management and affiliated entities report in Rithm Acquisition (RAC)?

First Trust Capital Management L.P., First Trust Capital Solutions L.P. and FTCS Sub GP LLC collectively beneficially own 1,512,450 shares, equal to 6.39%.

Do the reporting persons have voting or dispositive power over the shares in the Schedule 13G?

Yes. Each reporting person states they have sole voting power and sole dispositive power over the shares reported, and 0 shared voting or dispositive power is reported.

What form was filed and what does the filing date show?

A Schedule 13G was filed reporting ownership as of 06/30/2025, with signatures dated 08/14/2025.

What is the CUSIP for Rithm Acquisition referenced in the filing?

The filing lists the CUSIP as G75751100.