Polar Asset reports 1.8M shares (11.1%) in GP-Act III

GP-Act III Acquisition Corp Schedule 13G shows Polar Asset Management Partners Inc., as investment advisor to Polar Multi-Strategy Master Fund, reports beneficial ownership of 1,800,000 Class A ordinary shares, representing 11.1% of the class.

Rhea-AI Filing Summary

GP-Act III Acquisition Corp Schedule 13G shows Polar Asset Management Partners Inc., as investment advisor to Polar Multi-Strategy Master Fund, reports beneficial ownership of 1,800,000 Class A ordinary shares, representing 11.1% of the class.

The filing states the reporting entity has sole power to vote and sole power to dispose for all 1,800,000 shares. The statement is signed by the Chief Compliance Officer on 06/04/2026.

Insights

Institutional Ownership Analyst

Passive holder reports an 11.1% stake with full voting and disposal power.

Polar Asset Management Partners Inc. reports it advises Polar Multi-Strategy Master Fund and beneficially owns 1,800,000 shares of GP-Act III Acquisition Corp, listed with CUSIP G4035N103. The filing designates sole voting and dispositive authority over these shares.

Disclosure is typical for a large fund manager; subsequent filings would show any trading or change in percentage. Holdings are shown as of the filing signature date 06/04/2026.

Key Figures

Beneficial ownership: 1,800,000 shares Ownership percent: 11.1% CUSIP: G4035N103 +1 more

4 metrics

Beneficial ownership 1,800,000 shares Class A ordinary shares

Ownership percent 11.1% Percent of class reported

CUSIP G4035N103 Identifier for Class A ordinary shares

Signature date 06/04/2026 Date filing signed by Chief Compliance Officer

Key Terms

Schedule 13G, beneficially owned, sole power to vote, dispositive power

4 terms

Schedule 13G regulatory

"Item 1. (a) Name of issuer: GP-Act III Acquisition Corp"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

beneficially owned financial

"Item 4. (a) Amount beneficially owned: 1800000"

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.

sole power to vote regulatory

"Item 4. (c)(i) Sole power to vote or to direct the vote: 1800000"

dispositive power financial

"Item 4. (c)(iii) Sole power to dispose or to direct the disposition of: 1800000"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

FAQ

What stake does Polar Asset report in GPAT?

Polar Asset Management Partners Inc. reports beneficial ownership of 1,800,000 shares of GP-Act III Acquisition Corp, equal to 11.1% of the Class A ordinary shares, per the Schedule 13G filing signed 06/04/2026.

Does Polar Asset have voting control over GPAT shares?

Yes. The filing states Polar has sole power to vote and sole power to dispose of all 1,800,000 shares it reports, as indicated in the ownership section of the Schedule 13G.

Which entity holds the reported GPAT shares?

The Schedule 13G identifies Polar Multi-Strategy Master Fund (PMSMF) as the direct holder, with Polar Asset Management Partners Inc. acting as investment advisor reporting beneficial ownership on behalf of PMSMF.

What CUSIP and class are reported for GPAT holdings?

The filing lists the securities as Class A ordinary shares, par value $0.0001, with CUSIP G4035N103, referenced in Item 2 of the Schedule 13G disclosure.

Who signed the Schedule 13G for Polar Asset?

The Schedule 13G is signed by Andrew Ma, Chief Compliance Officer, with the signature date shown as 06/04/2026, certifying the reported ownership information.

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Accepted by SEC EDGAR 06/04/2026 - 04:45 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

GP-Act III Acquisition Corp

(Name of Issuer)

Class A ordinary shares, par value $0.0001 per share

(Title of Class of Securities)

G4035N103

(CUSIP Number)

05/31/2026

(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): G4035N103

1

Names of Reporting Persons

Polar Asset Management Partners 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

ONTARIO, CANADA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 1,800,000.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,800,000.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,800,000.00

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)

11.1 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: GP-Act III Acquisition Corp
(b)	Address of issuer's principal executive offices: 300 Park Avenue, 2nd Floor, New York, New York, 10022
Item 2.
(a)	Name of person filing: This statement is filed by Polar Asset Management Partners Inc., a company incorporated under the laws of Ontario, Canada, which serves as the investment advisor to Polar Multi-Strategy Master Fund, a Cayman Islands exempted company ("PMSMF") with respect to the shares directly held by PMSMF.
(b)	Address or principal business office or, if none, residence: 16 York Street, Suite 2900, Toronto, Ontario, M5J 0E6
(c)	Citizenship: Canada
(d)	Title of class of securities: Class A ordinary shares, par value $0.0001 per share
(e)	CUSIP Number(s): G4035N103
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).
	The Reporting Person is an investment fund manager, portfolio manager, exempt market dealer and commodity trading manager registered with the Ontario Securities Commission.
Item 4.	Ownership
(a)	Amount beneficially owned: 1800000
(b)	Percent of class: 11.1 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1800000
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 1800000
	(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.

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.

Polar Asset Management Partners Inc.

Signature:	Andrew Ma
Name/Title:	Chief Compliance Officer
Date:	06/04/2026