Basis of Presentation and Consolidation and Accounting Standards Adopted	6 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation and Accounting Standards Adopted	Basis of Presentation and Consolidation and Accounting Standards Adopted StoneX Group Inc., a Delaware corporation, and its consolidated subsidiaries (collectively “StoneX” or “the Company”), is a global financial services network that connects companies, organizations, traders and investors to the global market ecosystem through a unique blend of digital platforms, end-to-end clearing and execution services, high touch service, and deep expertise. The Company strives to be the one trusted partner to its clients, providing its network, products and services to allow them to pursue trading opportunities, manage their market risks, make investments and improve their business performance. The Company offers a vertically integrated product suite, beginning with high-touch and electronic access to nearly all major financial markets worldwide, as well as numerous liquidity venues. The Company delivers access and services through the entire lifecycle of a trade, by delivering deep market expertise and on-the-ground intelligence, best execution, and finally post-trade clearing, custody, as well as settlement services. The Company has created revenue streams, diversified by asset class, client type and geography, that earn commissions, spreads, and principal revenue as clients execute transactions across its financial network, while monetizing non-trading client activity including interest and fee earnings on client balances as well as earning consulting fees for market intelligence and risk management services. The Company provides its services to a diverse group of clients in more than 180 countries. These clients include more than 54,000 commercial, institutional, and payments clients and over 400,000 retail clients. The Company’s clients include commercial entities, asset managers, regional, national and introducing broker-dealers, insurance companies, brokers, institutional investors and professional traders, commercial and investment banks and government and non-governmental organizations (“NGOs”). The Company’s common stock trades on The NASDAQ Global Select Market under the symbol “SNEX”. Basis of Presentation and Consolidation The accompanying unaudited Condensed Consolidated Balance Sheet as of September 30, 2023, which has been derived from the audited consolidated balance sheet of September 30, 2023, and the unaudited interim condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and disclosures normally included in annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to those rules and regulations. The Company believes that the included disclosures clearly and fairly present the information within. In management’s opinion, all adjustments, generally consisting of normal accruals, considered necessary to fairly present the condensed consolidated financial statements for the interim periods presented have been reflected as required by Rule 10-01 of Regulation S-X. Operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes contained in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2023, as filed with the SEC. These condensed consolidated financial statements include the accounts of StoneX Group Inc. and all entities in which the Company has a controlling financial interest. All material intercompany transactions and balances have been eliminated in consolidation. The Company’s fiscal year end is September 30, and its fiscal quarters end on December 31, March 31, June 30 and September 30. Unless otherwise stated, all dates refer to fiscal years and fiscal interim periods. Preparing condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The most significant of these estimates and assumptions relate to fair value measurement for financial instruments, revenue recognition, valuation of inventories, and income taxes. These estimates are based on management’s best knowledge of current events and actions the Company may undertake in the future. The Company reviews all significant estimates affecting the financial statements on a recurring basis and records the effect of any necessary adjustments prior to financial statement issuance. Although these and other estimates and assumptions are based on the best available information, actual results could be materially different from these estimates. Estimates and assumptions were considered and made in context with the information reasonably available to the Company as of March 31, 2024 and through the date of this Form 10-Q. In the Condensed Consolidated Income Statements, the total revenues reported combine gross revenues for the physical commodities business and net revenues for all other businesses. The subtotal Operating revenues in the Condensed Consolidated Income Statements is calculated by deducting Cost of sales of physical commodities from Total revenues. The subtotal Net operating revenues in the Condensed Consolidated Income Statements is calculated as Operating revenues less Transaction-based clearing expenses, Introducing broker commissions, Interest expense, and Interest expense on corporate funding. Transaction-based clearing expenses represent variable expenses paid to executing brokers, exchanges, clearing organizations and banks in relation to transactional volumes. Introducing broker commissions include commission paid to certain non-employee third parties that have introduced clients to the Company. Net operating revenues represent revenues available to pay variable compensation to risk management consultants and traders, direct non-variable expenses, as well as variable and non-variable expenses to operational and administrative employees. Common Stock Split On November 7, 2023, the Company’s Board of Directors approved a three-for-two split of its common stock, to be effected as a stock dividend. The stock split was effective on November 24, 2023, and entitled each shareholder of record as of November 17, 2023 to receive one additional share of common stock for every two shares owned and cash in lieu of fractional shares. The stock split increased the number of shares of common stock outstanding. All share and per share amounts contained herein have been retroactively adjusted for the stock split. The shares of common stock retain a par value of $0.01 per share. Accordingly, an amount equal to the par value of the increased shares resulting from the stock split was reclassified from Additional paid-in-capital to Common stock. Restricted Cash During the three months ended March 31, 2024, the Company established an escrow account designated to hold immediately available funds deposited by the Company and distribute the same amount on June 15, 2024, the intended redemption date, for the settlement of its 8.625% Senior Secured Notes due 2025. The Company has classified these funds as restricted because the funding is irrevocable, and the Company does not have the ability to withdraw the funds. See Note 9. Gain on Acquisition In October 2022, the Company’s wholly owned subsidiary, StoneX Netherlands B.V., acquired CDI-Societe Cotonniere De Distribution S.A. The fair value of identifiable net assets acquired was approximately $66.2 million and the purchase price was approximately $42.7 million. The value that the Company acquired in excess of consideration paid resulted in a gain on acquisition of $23.5 million for the six months ended March 31, 2023. Accounting Standards The Company did not adopt any new accounting standards during the three and six months ended March 31, 2024.