SEC Form 424B7 filed by StoneX Group Inc.

Filed Pursuant to Rule 424(b)(7)
Registration No. 333-285071

PROSPECTUS SUPPLEMENT
(To Prospectus dated February 19, 2025)

StoneX Group Inc.

3,085,554 Shares of Common Stock

This prospectus supplement relates to the offer and sale from time to time of up to 3,085,554 shares of common stock, par value $0.01 per share (“common stock”), of StoneX Group Inc. (the “Company”), by the selling stockholders identified in this prospectus supplement (the “selling stockholders”). The shares of common stock represent the equity consideration the selling stockholders received in connection with the Company’s acquisition of the business of RTS Investor Corp., a Delaware corporation (“RJO” and collectively, the “RJO Acquisition”).

The Company’s common stock is listed on the NASDAQ Global Select Market (“NASDAQ”) under the symbol “SNEX.” On August 28, 2025, the last sale price of the common stock as reported on NASDAQ was $101.05 per share.

The Company is not selling any shares of common stock under this prospectus supplement and will not receive any proceeds from the sale of shares by the selling stockholders. The selling stockholders may, from time to time, offer and sell shares of Class A common stock held by them directly or indirectly through agents or broker-dealers on terms to be determined at the time of sale. See “Plan of Distribution.”

Investing in our common stock involves risks. See “Risk Factors“ beginning on page S-3 and in the documents we have incorporated by reference herein.

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is August 29, 2025.

TABLE OF CONTENTS

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Prospectus Supplement

Prospectus

About This Prospectus Supplement

This document consists of two parts. The first part is this prospectus supplement, which describes the common stock that the selling stockholders may offer and sell and supplements information contained in the accompanying prospectus and the documents incorporated by reference in this prospectus supplement and the accompanying prospectus. To the extent required by applicable law, each time the selling stockholders sell shares of common stock under this prospectus supplement, the selling stockholders will provide you with this prospectus supplement. The second part is the accompanying prospectus, which describes more general information, some of which may not apply to this offering. You should read both this prospectus supplement and the accompanying prospectus, including the documents incorporated by reference.

If the description of the offering varies between this prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement.

Any statement made in this prospectus supplement, the accompanying prospectus or in a document incorporated or deemed to be incorporated by reference in this prospectus supplement will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement or in any other subsequently filed document that is also incorporated or deemed to be incorporated by reference in this prospectus supplement modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. See “Where You Can Find More Information; Incorporation of Certain Documents by Reference” in this prospectus supplement.

Neither the Company nor the selling stockholders have authorized anyone to provide you with any information or to make any representations about anything not contained or incorporated by reference in this prospectus supplement, any accompanying prospectus or in any free writing prospectus filed by us with the U.S. Securities and Exchange Commission (“SEC”). We do not take any responsibility for, and can provide no assurance as to the reliability of, any other information or representations that others may give you.

Neither the Company nor the selling stockholders are making an offer to sell or soliciting offers to buy these securities in any jurisdiction where, or to any person to whom, the offer or sale is not permitted. The information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus and any free writing prospectus that we may provide you in connection with this offering or other offering material filed by us with the SEC is accurate only as of the date of those documents or such information, regardless of the time of delivery of the documents or information or the time of any sale of the securities. Our business, financial condition, results of operations and future growth prospects may have changed since those dates.

On April 13, 2025, the Company and certain of its affiliate entities entered into a definitive agreement with RJO and certain affiliated entities and equity holders thereof, including affiliates of the selling stockholders, to acquire RJO (as amended, the “RJO Merger Agreement”). A portion of the consideration for the RJO Acquisition consisted of shares in the form of common stock issued by the Company to the selling stockholders. Pursuant to the RJO Merger Agreement, we agreed to register with the SEC the resale of all the shares of common stock issued to the selling stockholders in connection with the RJO Acquisition.

For investors outside the United States (“U.S.”): neither the Company nor the selling stockholders have done anything that would permit this offering or possession or distribution of this prospectus supplement, the accompanying prospectus or any free writing prospectus we may provide to you in connection with this offering in any jurisdiction where action for that purpose is required, other than in the U.S. You are required to inform yourselves about and to observe any restrictions relating to this offering and the distribution of this prospectus supplement, the accompanying prospectus and any such free writing prospectus outside of the U.S.

As used in this prospectus supplement, unless the context otherwise requires, references to “StoneX,” “the Company,” “we,” “our” and “us,” or like terms, refer to StoneX Group Inc. and its consolidated subsidiaries taken as a whole.

Where You Can Find More Information; Incorporation
of Certain Documents by Reference

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website (http://www.sec.gov) from which interested persons can electronically access our reports, proxy statements and other information regarding us.

We are incorporating by reference into this prospectus supplement certain information that we have filed with the SEC, which means that we are disclosing important information to you by referring you to documents we have filed separately with the SEC. The documents incorporated by reference are considered part of this prospectus supplement. This prospectus supplement incorporates by reference the following (excluding any portions of such documents that have been “furnished” but not “filed” for purposes of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)):

In addition, we incorporate by reference any filings made with the SEC in accordance with Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of this prospectus supplement and before the date all of the securities offered hereby are sold or the offering is otherwise terminated, with the exception of any information furnished under Item 2.02 or Item 7.01 (including any financial statements or exhibits relating thereto furnished pursuant to Item 9.01) of Form 8-K, which is not deemed filed and which is not incorporated by reference herein. Any such filings shall be deemed to be incorporated by reference and to be a part of this prospectus supplement from the respective dates of filing of those documents. Any statement contained in a document or report incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained herein or in any subsequently filed document or report that also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

You can obtain any of the filings incorporated by reference into this prospectus supplement through us or from the SEC through the SEC’s website at http://www.sec.gov. We will provide, without charge, to each person, including any beneficial owner, to whom a copy of this prospectus supplement is delivered, upon written or oral request of such person, a copy of any or all of the reports and documents referred to above which have been or may be incorporated by reference into this prospectus supplement. You should direct requests for those documents to:

StoneX Group Inc.
Attention: Investor Relations
230 Park Ave, 10th Floor,
New York, NY 10169
Telephone Number: (212) 485-3500

We maintain an internet site at https://www.stonex.com. Our SEC filings are also available free of charge at our website. Our website and the information contained on or connected to it shall not be deemed to be incorporated into this prospectus supplement or the registration statement of which it forms a part.

Cautionary Note Regarding Forward-Looking Statements

This prospectus supplement and the documents incorporated by reference herein may contain certain “forward-looking statements” within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. The words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “expect,” and similar expressions are intended to identify forward-looking statements.

These forward-looking statements involve known and unknown risks and uncertainties, many of which are beyond the control of the Company, including statements about the benefits of the RJO acquisition, including expected synergies and future financial and operating results, the plans, objectives, expectations and intentions of StoneX after the acquisition, adverse changes in economic, political and market conditions, including losses from our market-making and trading activities arising from counterparty failures, global trade policies and tariffs, the loss of key personnel, the impact of increasing competition, the impact of changes in government regulation, uncertainty concerning fiscal or monetary policies established by central banks and financial regulators, the possibility of liabilities arising from violations of foreign, U.S. federal and U.S. state securities laws, the impact of changes in technology in the securities and commodities trading industries, and other risks discussed in our filings with the SEC, including in our Annual Report.

Although we believe that our forward-looking statements are based upon reasonable assumptions regarding our business and future market conditions, there can be no assurances that our actual results will not differ materially from any results expressed or implied by our forward-looking statements. We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law. We caution investors that any forward-looking statements are not guarantees of future performance.

Risk Factors

Investing in our common stock involves risks. You should carefully review the risk factors and other cautionary statements described under the section entitled “Risk Factors” in our Annual Report which is incorporated by reference in this prospectus supplement, or any similar caption in the documents that we subsequently file with the SEC that are deemed to be incorporated by reference in this prospectus supplement, and in any free writing prospectus that we provide you in connection with the offering of common stock pursuant to this prospectus supplement. The risks and uncertainties discussed in the documents referred to above, as well as other matters discussed in this prospectus supplement and in those documents, could materially and adversely affect our business, financial condition, liquidity and results of operations and the market price of the common stock. Moreover, the risks and uncertainties discussed in the foregoing documents are not the only risks and uncertainties that we face, and our business, financial condition, liquidity and results of operations and the market price of the common stock could be materially adversely affected by other matters that are not known to us or that we currently do not consider to be material risks to our business.

Use of Proceeds

The selling stockholders will receive all of the net proceeds from the sale of the shares of common stock offered from time to time under this prospectus supplement. We will not receive any proceeds from the sale of shares of common stock by the selling stockholders. We have agreed to pay certain expenses incurred in connection with the registration of the resale of shares of common stock under this prospectus supplement. See “Selling Stockholders” and “Plan of Distribution.”

Selling Stockholders

This prospectus supplement relates to the resale by the selling stockholders from time to time of up to  3,085,554 shares of common stock that the selling stockholders received in the form of common stock as partial consideration for the RJO Acquisition. The selling stockholders may from time to time offer and sell any or all of the shares of common stock set forth below pursuant to this prospectus supplement or any further supplements.

Pursuant to the RJO Merger Agreement, we agreed to register with the SEC the resale of all the shares of common stock issued to the selling stockholders in connection with the RJO Acquisition.

The following table shows information as of August 25, 2025 regarding the beneficial ownership of our common stock by the selling stockholders and sets forth the maximum number of shares of common stock eligible for resale by the selling stockholders under this prospectus supplement. The selling stockholders may in the future sell or transfer some or all of the securities indicated below in transactions exempt from the registration requirements of the Securities Act rather than under this prospectus supplement. The number of shares of common stock owned by the selling stockholders assumes that they do not beneficially own any shares of common stock other than the shares of common stock that the Company has issued to them in connection with the RJO Acquisition. We have prepared the following table based on information given to us by, or on behalf of, the selling stockholders. Information about the selling stockholders may change over time.

Beneficial ownership of shares is determined under the rules of the SEC and generally includes any shares over which a person exercises sole or shared voting or investment power. Except as noted by footnote, and subject to community property laws where applicable, we believe based on the information provided to us that the entities named in the table below have sole voting and investment power with respect to all shares of our common stock shown as beneficially owned by them.

Material U.S. Federal Income and Estate Tax Considerations to Non-U.S. Holders

The following is a general discussion of the material U.S. federal income and estate tax consequences of the ownership and disposition of our common stock by a “non-U.S. holder.” A “non-U.S. holder” is a beneficial owner of a share of our common stock that is, for U.S. federal income tax purposes:

If an entity or arrangement treated as a partnership or other type of pass-through entity for U.S. federal income tax purposes owns our common stock, the tax treatment of a partner or beneficial owner of the entity may depend upon the status of the partner or beneficial owner, the activities of the entity and certain determinations made at the partner or beneficial owner level. Partners and beneficial owners in partnerships or other pass-through entities that own our common stock should consult their own tax advisors as to the particular U.S. federal income and estate tax consequences applicable to them.

This discussion is based on the Internal Revenue Code of 1986, as amended to the date hereof (the “Code”), administrative pronouncements, judicial decisions and final, temporary and proposed Treasury regulations, changes to any of which subsequent to the date of this prospectus supplement may affect the tax consequences described herein (possibly with retroactive effect). This discussion does not address all aspects of U.S. federal income and estate taxation that may be relevant to non-U.S. holders in light of their particular circumstances and does not address any U.S. federal gift, alternative minimum tax or Medicare contribution tax considerations or any tax consequences arising under the laws of any state, local or non-U.S. jurisdiction. Prospective holders are urged to consult their tax advisors with respect to the particular tax consequences to them of owning and disposing of our common stock, including the consequences under the laws of any state, local or non-U.S. jurisdiction.

Dividends

To the extent that we make a distribution of cash or other property (other than certain pro rata distributions of our stock) in respect of our common stock, the distribution generally will be treated as a dividend for U.S. federal income tax purposes to the extent it is paid out of our current or accumulated earnings and profits (as determined under U.S. federal income tax principles). Any portion of a distribution that exceeds our current and accumulated earnings and profits generally will be treated first as a tax-free return of capital that reduces a non-U.S. holder’s adjusted tax basis in our common stock, and to the extent the amount of the distribution exceeds a non-U.S. holder’s adjusted tax basis in our common stock, the excess will be treated as gain from the disposition of our common stock (the tax treatment of which is discussed below under “—Gain on Disposition of Common Stock”).

Dividends paid to a non-U.S. holder generally will be subject to U.S. federal withholding tax at a 30% rate, or a reduced rate specified by an applicable income tax treaty. In order to obtain a reduced rate of withholding under an applicable income tax treaty, a non-U.S. holder generally will be required to provide a properly executed Internal Revenue Service (the “IRS”) Form W-8BEN or IRS Form W-8BEN-E, as applicable, certifying its entitlement to benefits under the treaty.

A non-U.S. holder eligible for a reduced rate of U.S. federal withholding tax pursuant to an income tax treaty may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

However, dividends paid to a non-U.S. holder that are effectively connected with the non-U.S. holder’s conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, are attributable to a permanent establishment or fixed base maintained by the non-U.S. holder in the United States) will not be subject to U.S. federal withholding tax if the non-U.S. holder provides a properly executed IRS Form W-8ECI. Instead, the effectively connected dividend income will generally be subject to regular U.S. income tax as if the non-U.S. holder were a U.S. person as defined under the Code. A non-U.S. holder that is treated as a corporation for U.S. federal income tax purposes receiving effectively connected dividend income may also be subject to an additional “branch profits tax” imposed at a rate of 30% (or a lower treaty rate) on its effectively connected earnings and profits (subject to certain adjustments).

Gain on Disposition of Common Stock

Subject to the discussions of backup withholding and FATCA withholding taxes below, a non-U.S. holder generally will not be subject to U.S. federal income tax on gain realized on a sale or other disposition of common stock unless:

We will be a United States real property holding corporation at any time that the fair market value of our “United States real property interests,” as defined in the Code and applicable Treasury regulations, equals or exceeds 50% of the aggregate fair market value of our worldwide real property interests and our other assets used or held for use in a trade or business (all as determined for U.S. federal income tax purposes). We believe that we are not, and do not anticipate becoming in the foreseeable future, a United States real property holding corporation.

Information Reporting and Backup Withholding

Distributions paid to a non-U.S. holder and the amount of any tax withheld with respect to such distributions generally will be reported to the IRS. Copies of the information returns reporting such distributions and any withholding may also be made available to the tax authorities in the country in which the non-U.S. holder resides under the provisions of an applicable income tax treaty.

A non-U.S. holder will not be subject to backup withholding on dividends received if such holder certifies under penalty of perjury that it is a non-U.S. holder (and the payor does not have actual knowledge or reason to know that such holder is a U.S. person as defined under the Code), or such holder otherwise establishes an exemption.

Information reporting and, depending on the circumstances, backup withholding will apply to the proceeds of a sale or other disposition of our common stock made within the U.S. or conducted through certain U.S.-related financial intermediaries, unless the non-U.S. holder complies with certification procedures to establish that it is not a U.S. person in order to avoid additional information reporting and backup withholding. The certification procedures required to claim a reduced rate of withholding under a treaty will generally satisfy the certification requirements necessary to avoid backup withholding as well.

Backup withholding is not an additional tax and the amount of any backup withholding from a payment to a non-U.S. holder will be allowed as a credit against the non-U.S. holder’s U.S. federal income tax liability and may entitle the non-U.S. holder to a refund, provided that the required information is furnished to the IRS in a timely manner.

FATCA

Under Sections 1471 through 1474 of the Code (such Sections commonly referred to as “FATCA”), payments of dividends on and the gross proceeds of dispositions of common stock of a U.S. issuer paid to (i) a “foreign financial institution” (as specifically defined in the Code) or (ii) a “non-financial foreign entity” (as specifically defined in the Code) will be subject to a withholding tax (separate and apart from, but without duplication of, the withholding tax described above) at a rate of 30%, unless various U.S. information reporting and due diligence requirements (generally relating to ownership by U.S. persons of interests in or accounts with those entities) have been satisfied or an exemption from these rules applies. Under proposed U.S. Treasury regulations promulgated by the Treasury Department on December 13, 2018, which state that taxpayers may rely on the proposed Treasury regulations until final Treasury regulations are issued, this withholding tax will not apply to the gross proceeds from the sale or disposition of common stock. An intergovernmental agreement between the United States and an applicable foreign country may modify these requirements. If a dividend payment is both subject to withholding under FATCA and subject to the withholding tax discussed above under “—Dividends,” the withholding under FATCA may be credited against, and therefore reduce, such other withholding tax. Non-U.S. holders should consult their tax advisors regarding the possible implications of this withholding tax on their investment in our common stock.

Federal Estate Tax

Individual non-U.S. holders (as specifically defined for U.S. federal estate tax purposes) and entities the property of which is potentially includible in such an individual’s gross estate for U.S. federal estate tax purposes (for example, a trust funded by such an individual and with respect to which the individual has retained certain interests or powers) should note that the common stock will be treated as U.S. situs property subject to U.S. federal estate tax, unless an applicable estate tax treaty provides otherwise.

Plan of Distribution

This prospectus supplement relates to the offer and sale from time to time of the shares of common stock covered by this prospectus supplement. The shares of common stock received by the selling stockholders as partial consideration pursuant to the RJO Merger Agreement are “restricted securities” within the meaning of Rule 144(a)(3) under the Securities Act and will contain a legend setting out such restriction and will be segregated until such time as they are sold under the registration statement of which this prospectus supplement forms a part. The Company is registering the resale of the shares of common stock to provide the holders thereof with freely tradeable securities, but such shares of common stock will not become freely tradeable until sold pursuant to the registration statement of which this prospectus supplement forms a part. There can be no assurance that the selling stockholders will sell any or all of the shares of common stock registered pursuant to the registration statement of which this prospectus supplement forms a part.

The selling stockholders may, from time to time, sell any or all of the shares of common stock offered hereby directly or indirectly through one or more broker-dealers or agents. The selling stockholders will be responsible for any agent’s commissions. The shares of common stock may be sold in one or more transactions at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale or at negotiated prices. The selling stockholders may use any one or more of the following methods when selling shares of common stock:

The selling stockholders may also sell shares of common stock under Rule 144 under the Securities Act, if available, rather than under this prospectus supplement.

The selling stockholders and any broker-dealers or agents that are involved in selling the shares of common stock may be deemed to be “underwriters” within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the shares of common stock purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act.

Broker-dealers engaged by the selling stockholders may arrange for other broker-dealers to participate in sales. If the selling stockholders effect such transactions through underwriters, broker-dealers or agents, such underwriters, broker-dealers or agents may receive commissions in the form of discounts, concessions or commissions from the selling stockholders or commissions from purchasers of the shares of common stock for whom they may act as agent or to whom they may sell as principal, or both (which discounts, concessions or commissions as to particular underwriters, broker-dealers or agents may be less than or in excess of those customary in the types of transactions involved).

Pursuant to the RJO Merger Agreement, the Company has agreed to bear certain other costs, fees and expenses incurred in connection with the offering of common stock pursuant to this prospectus supplement. However, the Company does not have any obligation to pay any underwriting fees, discounts or commissions attributable to the sale of such shares of common stock, or any fees and expenses of any broker-dealer or other financial intermediary engaged by the selling stockholders.

Legal Matters

Davis Polk & Wardwell LLP, New York, New York, will pass upon the validity of the common stock offered by this prospectus supplement.

Experts

The consolidated financial statements and financial statement schedule of StoneX Group Inc. as of September 30, 2024 and 2023, and for each of the years in the three-year period ended September 30, 2024 and management's assessment of the effectiveness of internal control over financial reporting as of September 30, 2024 have been incorporated by reference herein in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

3,085,554 Shares of Common Stock

Prospectus Supplement

August 29, 2025