Marex appoints John Pietrowicz as new board chair

The transition includes assistance from outgoing Chair Robert Pickering, who completed his appointed three-year term.

Rhea-AI Filing Summary

Marex Group Ltd (MRX) reported a change in Board leadership: Robert Pickering gave notice on October 6, 2026, that he is stepping down after completing his appointed three-year term as Chair. The Board appointed existing director John Pietrowicz as the new Chair. Pietrowicz joined the Board in April 2024 and chairs the Mergers and Acquisitions Committee; Pickering will assist with the transition.

Filing Explained

Beyond the leadership change, this Form 6-K incorporates its disclosure into Marex's two Form F-3 and two Form S-8 registration statements, amending those registrations from the filing date, October 7, 2026, to the extent later filings do not supersede it.

Key Figures

Appointed term as Chair: 3 years Board membership began: April 2024 Notice date: October 6, 2026

3 metrics

Appointed term as Chair 3 years Term completed by Robert Pickering

Board membership began April 2024 John Pietrowicz joined the Board

Notice date October 6, 2026 Robert Pickering gave notice of stepping down

Key Terms

incorporated by reference, Form F-3, Form S-8, foreign private issuer

4 terms

incorporated by reference regulatory

"information in this Form 6-K is hereby incorporated by reference"

Form F-3 regulatory

"Registration Statements on Form F-3"

Form F-3 is a U.S. securities filing that lets eligible foreign companies pre-register and then quickly sell shares or other securities to raise money, because they already meet ongoing reporting and size tests. For investors it signals that the company is up-to-date with regulatory disclosure and has an efficient way to issue new securities — similar to a pre-approved credit line — which can mean faster capital raises but also potential dilution of existing holdings.

Form S-8 regulatory

"Registration Statements on Form S-8"

A Form S-8 is a U.S. Securities and Exchange Commission registration that lets a public company set aside shares for employee benefit plans and stock-based compensation. Think of it as opening a dedicated account that authorizes the company to issue or reserve stock for workers and directors; it matters to investors because it enables share dilution when those awards are granted or exercised and signals how management is compensated and incentivized.

foreign private issuer regulatory

"REPORT OF FOREIGN PRIVATE ISSUER"

A foreign private issuer is a company organized outside the United States that meets tests showing it is primarily foreign-controlled and therefore qualifies for a different set of U.S. reporting rules. For investors, that means the company files less frequent or differently formatted disclosures with U.S. regulators and may follow home-country accounting and governance practices, so buying its stock is like dining at a well-reviewed restaurant that follows its home kitchen’s rules instead of the local menu — you get access but should check what standards apply.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

Who is the new board chair at MRX?

Marex Group Ltd appointed John Pietrowicz as Chair of the Board. He joined the Board in April 2024 and also chairs the company’s Mergers and Acquisitions Committee.

Why is Robert Pickering stepping down from the MRX board?

Robert Pickering gave notice on October 6, 2026, that he is stepping down from the Board after completing his appointed three-year term as Chair. He will assist John Pietrowicz with the transition.

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

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO SECTION 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of October 2026

Commission File Number: 001-42020

MAREX GROUP LIMITED

(Translation of registrant’s name into English)

Crawford House

50 Cedar Avenue

Hamilton, HM 11

Bermuda

+1 441-295-6500

(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒   Form 40-F ☐

INCORPORATION BY REFERENCE

The information in this Form 6-K is hereby incorporated by reference into the Company’s Registration Statements on Form F-3 (Registration No. 333-286884 and 333-289203) and Registration Statements on Form S-8 (Registration No. 333-278953 and 333-298462) (including any prospectuses forming a part of such registration statements), hereby amending them, and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

EXPLANATORY NOTE

Departure of Director; Chair of the Group Board

On October 6, 2026, Robert Pickering gave notice that he is stepping down from the Board of Marex Group Limited (the “Company”) having completed his appointed three-year term as Chair.

The Board of the Company has appointed John Pietrowicz as the new Chair of the Board. Mr Pietrowicz is an existing member of the Board, having joined in April 2024, and is also the Chair of the Company’s Mergers and Acquisitions Committee. Mr Pickering will provide Mr Pietrowicz with assistance to ensure a smooth transition into his new role.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Marex Group Limited
By:		/s/ Robert Irvin
Name:		Robert Irvin
Title:		Chief Financial Officer

Dated: October 7, 2026