Picton Mahoney discloses 5.07% stake in Cartesian Growth III (CGCT)

Rhea-AI Filing Summary

Picton Mahoney Asset Management has filed an amended Schedule 13G reporting a significant ownership position in Cartesian Growth Corporation III. As of the event date of 12/31/2025, Picton Mahoney beneficially owned 1,400,000 Class A ordinary shares, with sole power to vote and dispose of all of these shares.

This stake represents 5.07% of the Class A ordinary shares, based on 27,600,000 Class A shares outstanding as of November 14, 2025, as referenced from the issuer’s Form 10-Q. Picton Mahoney is identified as a Canadian investment fund manager, and it certifies that it is subject to a foreign regulatory regime comparable to that of a functionally equivalent U.S. institution.

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

CARTESIAN GROWTH CORPORATION III

(Name of Issuer)

Class A ordinary shares, par value $0.0001 per share

(Title of Class of Securities)

G19307100

(CUSIP Number)

12/31/2025

(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. G19307100

1

Names of Reporting Persons

Picton Mahoney Asset Management

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

CANADA (FEDERAL LEVEL)

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 1,400,000.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,400,000.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,400,000.00

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)

5.07 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Based on the Form 10-Q filed November 14, 2025; as of November 14, 2025, there were 27,600,000 Class A. ordinary shares outstanding.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: CARTESIAN GROWTH CORPORATION III
(b)	Address of issuer's principal executive offices: 505 Fifth Avenue, 15th Floor, New York, NEW YORK, 10017
Item 2.
(a)	Name of person filing: Picton Mahoney Asset Management
(b)	Address or principal business office or, if none, residence: 33 Yonge Street, #320, Toronto, ON M5E 1G4
(c)	Citizenship: Canada
(d)	Title of class of securities: Class A ordinary shares, par value $0.0001 per share
(e)	CUSIP No.: G19307100
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).
	Investment Fund Manager
Item 4.	Ownership
(a)	Amount beneficially owned: 1,400,000
(b)	Percent of class: 5.07 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1,400,000
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 1,400,000
	(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 foreign regulatory scheme applicable to [insert particular category of institutional investor] is substantially comparable to the regulatory scheme applicable to the functionally equivalent U.S. institution(s). I also undertake to furnish to the Commission staff, upon request, information that would otherwise be disclosed in a Schedule 13D.

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.

Picton Mahoney Asset Management

Signature:	Catrina Duong
Name/Title:	Chief Compliance Officer
Date:	01/12/2026

Comments accompanying 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.

FAQ

What percentage of CGCT does Picton Mahoney Asset Management own?

Picton Mahoney Asset Management reports beneficial ownership of 5.07% of Cartesian Growth Corporation III’s Class A ordinary shares.

How many CGCT Class A shares are beneficially owned by Picton Mahoney?

Picton Mahoney Asset Management beneficially owns 1,400,000 Class A ordinary shares of Cartesian Growth Corporation III.

Does Picton Mahoney have voting and dispositive power over its CGCT shares?

Yes. Picton Mahoney reports sole voting power and sole dispositive power over all 1,400,000 shares, with no shared power.

What share count was used to calculate Picton Mahoney’s 5.07% CGCT stake?

The 5.07% figure is based on 27,600,000 Class A ordinary shares outstanding as of November 14, 2025, as cited from a Form 10-Q.

What type of investor is Picton Mahoney in this CGCT filing?

Picton Mahoney Asset Management is identified as an investment fund manager and a Canadian institutional investor under a foreign regulatory scheme.

What is the event date for Picton Mahoney’s reported CGCT ownership?

The date of the event requiring this ownership report is 12/31/2025.