Marex Group plc Ordinary Shares (MRX) F-1Registration statement (foreign)

INTRODUCTION AND SCOPE

We have acted as English legal advisers to Marex Group plc, a public limited company organised under the laws of England and Wales (the “Company”), in connection with the registration statement on Form F-1 (the “Registration Statement”) filed by the Company with the U.S. Securities and Exchange Commission (the “SEC”) under the U.S. Securities Act of 1933 (the “Securities Act”) relating to the proposed offering and registration of Ordinary Shares of nominal value of US$0.001551 each of the Company (the “Shares”) (the “Offering”).

We are solicitors qualified in England and Wales. We express no opinion as to any law other than English law as applied by English courts and reported and in effect on the date of this opinion.

This opinion and any non-contractual obligations arising out of it or in connection with it are governed by and shall be construed in accordance with English law.

This opinion is limited to the matters in paragraph 4 and does not extend, and it is not to be read as extended by implication, to any other matters. No opinion is expressed as to matters of fact.

By giving this opinion we do not assume any obligation to notify you of changes in law following the date of this opinion which may affect the opinions expressed herein or to otherwise update this opinion in any respect.

This opinion is not designed to and is not likely to reveal fraud, misrepresentation, bribery or corruption by any person.

The term “Shares” shall include any additional Shares registered by the Company pursuant to Rule 462(b) under the Securities Act in connection with the Offering contemplated by the Registration Statement.

DOCUMENTS AND ENQUIRIES

For the purpose of giving this opinion, we have examined such records and registers of the Company as have been made available to us and such questions of law as we have considered appropriate, including, amongst other things, the following documents:

the Registration Statement;

copies of the following documents:

the certificate of incorporation of the Company dated 4 November 2005, certificates of incorporation on change of name of the Company dated 16 December 2005 and 4 July 2011 and certificate of incorporation on re-registration as a public limited company of the Company dated 24 May 2021;

the articles of association of the Company adopted on 21 March 2024 and effective from 25 April 2024 (the “Articles”); and

a certificate of the Company Secretary dated 21 October 2024 certifying certain records of the Company and resolutions of the board of directors of the Company and the shareholders of the Company (the “Secretary’s Certificate”).

For the purpose of giving this opinion, we have made the following enquiries:

On 21 October 2024 at 09:04 a.m., we carried out a search of the Companies House Service operated by the Registrar of Companies in England and Wales in respect of the Company (the “Company Register Search”); and

on 21 October 2024 at 10:16 a.m., a search of the Insolvency and Companies List at the Royal Courts of Justice was carried out (by us or by CRO Info (a brand name of Company Registrations Online Limited (company number 3638753) on our behalf) in relation to the Company (the “Central Registry Search”).

Except as stated above, we have not for the purpose of this opinion examined any agreements, documents or corporate records entered into by or affecting the Company or made any other enquiries concerning the Company.

ASSUMPTIONS

This opinion is based upon the assumption (which may or may not be the case) that:

Authenticity: all documents (including copy documents) examined by us are authentic, complete and accurate and all signatures and seals thereon (if any) are genuine;

Documents up-to-date etc: all documents which we have reviewed are and remain up-to-date and have not been terminated or rescinded;

Extracts: in the case of any document from which extracts only have been supplied to us, the extracts do not reveal a misleading view of the document as a whole;

Due execution: each of the signed documents examined by us have been duly executed and, where applicable, delivered on behalf of the Company;

Secretary’s Certificate: the contents of the Secretary’s Certificate were true, accurate and not misleading when given and remain true, accurate and not misleading as at the date of this opinion, and there is no fact or matter referred to in the Secretary’s Certificate which would make any of the information in the Secretary’s Certificate inaccurate or misleading;

Administration etc.: no step has been taken to wind-up, strike off or dissolve the Company or to place the Company into administration and no receiver has been appointed over or in respect of the assets of the Company, nor has any analogous procedure or step been taken in any jurisdiction, which (in either case) has or have not been revealed by the searches referred to in paragraph 2.2 above;

Filings: the information disclosed by the Company Register Search and the Central Registry Search was and remains complete, accurate and up-to-date;

No breach: the Company will not, by reason of the transactions contemplated by the Corporate Approvals, be in breach of any of its obligations under any licence, authorisation, consent or similar document;

Directors: the directors of the Company have acted in good faith and have complied with their duties under all applicable laws;

Misconduct, etc.: there has not been and will not be any bad faith, breach of trust, fraud, coercion, duress or undue influence on the part of any of the directors in relation to any allotment and issue of Shares; and

Regulatory requirements: no Shares or rights to subscribe for Shares have been or will be offered to the public in the United Kingdom in breach of the Financial Services and Markets Act 2000, as amended (“FSMA”) or of any other United Kingdom laws or regulations concerning offers of securities to the public, and no communication has been or shall be made in relation to the Shares in breach of section 21 of FSMA or any other United Kingdom laws or regulations relating to offers or invitations to subscribe for, or to acquire rights to subscribe for or otherwise acquire, shares or other securities.

OPINION

QUALIFICATIONS

This opinion is subject to the qualifications contained in this section:

Creditors: This opinion is subject to any limitations arising from (a) bankruptcy, insolvency and liquidation, (b) reorganisation and (c) laws of general application relating to or affecting the rights of creditors.

Records: The records of the Registrar of Companies and the Insolvency and Companies List may not be complete or up-to-date and do not contain details of foreign insolvency proceedings. In particular, the Insolvency and Companies List may not contain details of moratoria applications filed, administration applications filed, or appointments recorded in or orders made by, district registries and county courts outside London. Searches at Companies House and at the Insolvency and Companies List are not capable of revealing whether or not a winding-up petition or a petition for the making of an administration order has been presented and, further, notice of a winding-up order or resolution, notice of an administration order and notice of the appointment of a receiver may not be filed at Companies House immediately and there may be a delay in the relevant notice appearing on the file of the company concerned.

Company search: A search at Companies House may not reveal whether the Shares or any of them are subject to a charge, encumbrance or other security interest because particulars of such security interests may not be filed at Companies House immediately, there may be a delay in the relevant registration appearing on the file of the Company concerned, not all security interests are registrable, such security interests have not in fact been registered or such security interests have been created by an individual or an entity which is not registered in Great Britain.

CONSENT

This opinion is addressed to you personally and is provided solely in connection with the Registration Statement. We hereby consent to the filing of this opinion as Exhibit 5.1 to the Registration Statement and to the reference to Herbert Smith Freehills LLP under the caption “Legal Matters” in the Registration Statement. We further consent to the incorporation by reference of this opinion and consent into any registration statement filed pursuant to Rule 462(b) under the Securities Act with respect to the Shares. In giving such consent, we do not thereby admit that we are included in the category of persons whose consent is required under Section 7 of the Securities Act, or the rules and regulations of the SEC promulgated thereunder.

This opinion may not be relied upon by you for any other purpose, and, other than as set out in this paragraph 6, may not be assigned to any other entity or person for any purpose (including, without limitation, by any entity or person that acquires Shares from the Company) without our prior written consent.

This opinion is given by Herbert Smith Freehills LLP which assumes liability for and is solely responsible for it.