Westchester/Virtus disclose ~4.7% stakes in Plum Acquisition Corp. IV (PLMK)

Rhea-AI Filing Summary

Plum Acquisition Corp. IV Schedule 13G/A: three affiliated reporting persons jointly disclose beneficial ownership positions in the issuer. Westchester Capital Management, LLC reports 921,100 shares (representing 4.98%), while Virtus Investment Advisers, LLC and The Merger Fund each report 873,367 shares (each 4.72%), based on 18,492,875 shares outstanding as of March 31, 2026.

The filing breaks out voting and dispositive powers: Westchester holds 47,733 shares of sole voting/dispositive power and shares power over 873,367 shares; Virtus and The Merger Fund report only shared voting and dispositive power over 873,367 shares. The statement is signed by compliance officers and counsel.

Insights

Compliance Counsel

Joint Schedule 13G/A reports passive institutional holdings just under 5%

The filing documents that Westchester, Virtus and The Merger Fund collectively report overlapping positions in PLMK, with the largest reported holding at 921,100 shares by Westchester. The percentages are calculated using the issuer's reported March 31, 2026 outstanding share figure.

Key dependencies include the advisory/sub-advisory relationships (Virtus advises MF; Westchester sub-advises the Funds) and the shared dispositive power disclosures. Subsequent filings would show any change in percent ownership if holdings move above filing thresholds.

Institutional Investor Relations

Ownership is fragmented and disclosed as shared voting/control across related entities

The report clarifies that the Funds directly hold ordinary shares for investors while advisory entities report shared power over the same 873,367-share block. Westchester separately reports 47,733 shares of sole voting and dispositive power.

The practical effect is transparent attribution of positions for market and regulatory recordkeeping; any material change in holdings would trigger a different reporting obligation.

Key Figures

Shares outstanding: 18,492,875 shares Westchester beneficial ownership: 921,100 shares Virtus beneficial ownership: 873,367 shares +3 more

6 metrics

Shares outstanding 18,492,875 shares as of <date>March 31, 2026</date>

Westchester beneficial ownership 921,100 shares reported on Schedule 13G/A

Virtus beneficial ownership 873,367 shares reported on Schedule 13G/A

The Merger Fund beneficial ownership 873,367 shares reported on Schedule 13G/A

Westchester percent of class 4.98% based on shares outstanding as of <date>March 31, 2026</date>

Virtus percent of class 4.72% based on shares outstanding as of <date>March 31, 2026</date>

Key Terms

beneficially owned, shared dispositive power, Schedule 13G/A

3 terms

beneficially owned regulatory

"Amount beneficially owned: Westchester Capital Management, LLC: 921,100"

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.

shared dispositive power regulatory

"Shared Dispositive Power 873,367.00"

Schedule 13G/A regulatory

"This statement is being filed jointly by the following"

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.

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

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Accepted by SEC EDGAR 05/15/2026 - 06:48 AM Learn about SEC filing dates

FAQ

What percent of PLMK does Westchester Capital Management report owning?

Westchester reports 921,100 shares, representing 4.98%. This percentage uses the issuer's stated 18,492,875 shares outstanding as of March 31, 2026 from the company 10-K cited in the filing.

Do Virtus Investment Advisers and The Merger Fund report the same holdings in PLMK?

Yes; both Virtus and The Merger Fund each report owning 873,367 shares, representing 4.72% each. The filing notes these amounts overlap and are included within Westchester's reported totals.

What voting and dispositive powers are disclosed for these reporting persons?

Westchester reports 47,733 shares of sole voting and dispositive power and shared power over 873,367 shares. Virtus and The Merger Fund report only shared voting and dispositive power over 873,367 shares.

Why are multiple entities filing jointly for the PLMK holdings?

The filing states the entities have advisory/sub-advisory relationships: Virtus advises The Merger Fund and Westchester sub-advises the Funds, so they file jointly to attribute beneficial ownership and shared control over the same share block.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Plum Acquisition Corp. IV

(Name of Issuer)

Class A ordinary shares, $0.0001 par value per share

(Title of Class of Securities)

G7134A104

(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): G7134A104

1

Names of Reporting Persons

Westchester Capital Management, 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 47,733.00
6	Shared Voting Power 873,367.00
7	Sole Dispositive Power 47,733.00
8	Shared Dispositive Power 873,367.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

921,100.00

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)

4.98 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: * Based on 18,492,875 Shares outstanding as of March 31, 2026, as reported in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 31, 2026.

SCHEDULE 13G

CUSIP Number(s): G7134A104

1

Names of Reporting Persons

Virtus Investment Advisers, 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 0.00
6	Shared Voting Power 873,367.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 873,367.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

873,367.00

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)

4.72 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: * Based on 18,492,875 Shares outstanding as of March 31, 2026, as reported in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 31, 2026. The amounts reported on this page are also included in the amounts reported by Westchester Capital Management, LLC on this Schedule 13G.

SCHEDULE 13G

CUSIP Number(s): G7134A104

1

Names of Reporting Persons

The Merger 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

MASSACHUSETTS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 873,367.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 873,367.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

873,367.00

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)

4.72 %

12

Type of Reporting Person (See Instructions)

IV

Comment for Type of Reporting Person: * Based on 18,492,875 Shares outstanding as of March 31, 2026, as reported in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 31, 2026. The amounts reported on this page are also included in the amounts reported by Virtus Investment Advisers, LLC on this Schedule 13G.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Plum Acquisition Corp. IV
(b)	Address of issuer's principal executive offices: 2021 Fillmore St. #2089, San Francisco, CA, 94115
Item 2.
(a)	Name of person filing: This statement is being filed jointly by the following (each, a "Reporting Person," and collectively, the "Reporting Persons"): Westchester Capital Management, LLC ("Westchester"), a Delaware limited liability company, Virtus Investment Advisers, LLC ("Virtus"), a Delaware limited liability company, and The Merger Fund ("MF"), a Massachusetts business trust. Virtus, a registered investment adviser, serves as the investment adviser to MF. Westchester, a registered investment adviser, serves as sub-advisor to each of MF and JNL Multi-Manager Alternative Fund ("JARB", together with MF, the "Funds"). The Funds directly hold Ordinary Shares of the Company for the benefit of the investors in those Funds. Mr. Roy Behren and Mr. Michael T. Shannon each serve as Co-Presidents of Westchester.
(b)	Address or principal business office or, if none, residence: Westchester Capital Management, LLC 100 Summit Lake Drive, Valhalla, NY 10595 Virtus Investment Advisers, LLC One Financial Plaza, Hartford, CT 06103 The Merger Fund 101 Munson Street, Greenfield, MA 01301-9683
(c)	Citizenship: Each of Westchester and Virtus are organized under the laws of the State of Delaware. MF is organized under the laws of the State of Massachusetts.
(d)	Title of class of securities: Class A ordinary shares, $0.0001 par value per share
(e)	CUSIP No.: G7134A104
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: Westchester Capital Management, LLC: 921,100 Virtus Investment Advisers, LLC: 873,367 The Merger Fund: 873,367
(b)	Percent of class: Westchester Capital Management, LLC: 4.98% Virtus Investment Advisers, LLC: 4.72% The Merger Fund: 4.72%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Westchester Capital Management, LLC: 47,733 Virtus Investment Advisers, LLC: 0 The Merger Fund: 0
	(ii) Shared power to vote or to direct the vote: Westchester Capital Management, LLC: 873,367 Virtus Investment Advisers, LLC: 873,367 The Merger Fund: 873,367
	(iii) Sole power to dispose or to direct the disposition of: Westchester Capital Management, LLC: 47,733 Virtus Investment Advisers, LLC: 0 The Merger Fund: 0
	(iv) Shared power to dispose or to direct the disposition of: Westchester Capital Management, LLC: 873,367 Virtus Investment Advisers, LLC: 873,367 The Merger Fund: 873,367
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.
	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.

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.

Westchester Capital Management, LLC

Signature:	/s/ CaSaundra Wu
Name/Title:	Chief Compliance Officer
Date:	05/15/2026

Virtus Investment Advisers, LLC

Signature:	/s/ Chetram Persaud
Name/Title:	Chief Compliance Officer
Date:	05/15/2026

The Merger Fund

Signature:	/s/ Daphne Chisolm
Name/Title:	Vice President, Counsel and Assistant Secretary
Date:	05/15/2026