StoneX (SNEX) 10-K 29 Nov 24 2024 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Nov. 22, 2024	Mar. 31, 2024
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2024
Current Fiscal Year End Date	--09-30
Document Transition Report	false
Entity File Number	000-23554
Entity Registrant Name	StoneX Group Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	59-2921318
Entity Address, Address Line One	230 Park Ave
Entity Address, Address Line Two	10th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10169
City Area Code	212
Local Phone Number	485-3500
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	SNEX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 1,678.9
Entity Common Stock, Shares Outstanding		31,929,644
Documents Incorporated by Reference	Certain portions of the definitive Proxy Statement for the Registrant’s Annual Meeting of Stockholders to be held on March 5, 2025 are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0000913760
Document Fiscal Year Focus	2024
Amendment Flag	false
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Sep. 30, 2024
Auditor Information [Abstract]
Auditor Name	KPMG LLP
Auditor Location	Kansas City, MO
Auditor Firm ID	185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
ASSETS
Cash and cash equivalents	$ 1,269	$ 1,108.3
Cash, securities and other assets segregated under federal and other regulations (including $51.8 million and $5.8 million at fair value at September 30, 2024 and 2023, respectively)	2,841.2	2,426.3
Collateralized transactions:
Securities purchased under agreements to resell	5,201.5	2,979.5
Securities borrowed	1,662.3	1,129.1
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net (including $3,287.5 million and $4,248.3 million at fair value at September 30, 2024 and 2023, respectively)	7,283.2	7,443.8
Receivable from clients, net (including $(8.4) million and $(7.9) million at fair value at September 30, 2024 and 2023, respectively)	1,013.1	683.1
Notes receivable, net	0	5.2
Income taxes receivable	19.3	25.1
Financial instruments owned, at fair value (includes securities pledged as collateral that can be sold or repledged of $2,172.0 million and $1,466.4 million at September 30, 2024 and 2023, respectively)	6,767.1	5,044.8
Physical commodities inventory, net (including $376.6 million and $386.5 million at fair value at September 30, 2024 and 2023, respectively)	681.1	537.3
Deferred tax assets	46.3	45.4
Property and equipment, net	143.1	123.5
Operating right of use assets	157	122.1
Goodwill and intangible assets, net	80.6	82.4
Other assets	301.5	182.8
Total assets	27,466.3	21,938.7
Liabilities:
Accounts payable and other accrued liabilities (including $2.3 million and $1.5 million at fair value at September 30, 2024 and 2023, respectively)	522.1	533
Operating lease liabilities	195.9	149.3
Payables to:
Clients (including $265.9 million and $79.8 million at fair value at September 30, 2024 and 2023, respectively)	10,345.9	9,976
Broker-dealers, clearing organizations and counterparties (including $(1.4) million and $10.2 million at fair value at September 30, 2024 and 2023, respectively)	734.2	442.4
Lenders under loans	338.8	341
Senior secured borrowings, net	543.1	342.1
Income taxes payable	18.1	38.2
Deferred tax liabilities	8.6	8.1
Collateralized transactions:
Securities sold under agreements to repurchase	8,581.3	4,526.6
Securities loaned	1,615.9	1,117.3
Financial instruments sold, not yet purchased, at fair value	2,853.3	3,085.6
Total liabilities	25,757.2	20,559.6
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.01 par value. Authorized 200,000,000 shares; 35,785,432 issued and 31,874,447 outstanding at September 30, 2024 and 35,105,852 issued and 31,194,867 outstanding at September 30, 2023	0.4	0.4
Common stock in treasury, at cost. 3,910,985 shares at September 30, 2024 and September 30, 2023	(69.3)	(69.3)
Additional paid-in-capital	414.3	371.7
Retained earnings	1,388.9	1,128.1
Accumulated other comprehensive loss, net	(25.2)	(51.8)
Total equity	1,709.1	1,379.1
Total liabilities and stockholders' equity	$ 27,466.3	$ 21,938.7

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Statement of Financial Position [Abstract]
Cash, securities and other assets segregated under federal and other regulations at fair value	$ 51.8	$ 5.8
Deposits with and receivables from broker-dealers, clearing organizations and counterparties at fair value	3,287.5	4,248.3
Receivables from clients at fair value	(8.4)	(7.9)
Financial instruments owned, securities pledged as collateral that can be sold or repledged	2,172	1,466.4
Physical commodities inventory at fair value	376.6	386.5
Accounts payable and other accrued liabilities at fair value	2.3	1.5
Payables to client at fair value	265.9	79.8
Payables to broker-dealers, clearing organizations and counterparties at fair value	$ (1.4)	$ 10.2
Preferred stock, par value (in dollar per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollar per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	35,785,432	35,105,852
Common stock, outstanding (in shares)	31,874,447	31,194,867
Common stock in treasury (in shares)	3,910,985	3,910,985

Consolidated Income Statements

Consolidated Income Statements - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Revenues:
Total revenues	$ 99,887.8	$ 60,856.1	$ 66,036
Cost of sales of physical commodities	96,451.6	57,942	63,928.6
Operating revenues	3,436.2	2,914.1	2,107.4
Transaction-based clearing expenses	319.3	271.8	291.2
Introducing broker commissions	166.2	161.6	160.1
Interest expense	1,115.7	802.2	135.5
Interest expense on corporate funding	67.8	57.5	44.7
Net operating revenues	1,767.2	1,621	1,475.9
Compensation and other expenses:
Compensation and benefits	942.4	868.6	794.8
Trading systems and market information	79.1	74	66.2
Professional fees	69.7	57	54.3
Non-trading technology and support	73.4	61.6	52.4
Occupancy and equipment rental	49	40.4	36.1
Selling and marketing	52.6	54	55.3
Travel and business development	28.4	24.8	16.9
Communications	8.5	9.1	8.3
Depreciation and amortization	53.1	51	44.4
Bad debts, net of recoveries	0.6	16.5	15.8
Other	65.1	66.4	60.6
Total compensation and other expenses	1,421.9	1,323.4	1,205.1
Gain on acquisitions and other gains, net	8.8	25.4	6.4
Income before tax	354.1	323	277.2
Income tax expense	93.3	84.5	70.1
Net income	$ 260.8	$ 238.5	$ 207.1
Earnings per share:
Basic (in dollar per share)	$ 8.24	$ 7.71	$ 6.85
Diluted (in dollar per share)	$ 7.96	$ 7.45	$ 6.67
Weighted-average number of common shares outstanding:
Basic (in shares)	30,539,237	29,936,000	29,355,605
Diluted (in shares)	31,625,029	30,929,011	30,101,311
Sales of physical commodities
Revenues:
Total revenues	$ 96,586.2	$ 58,131.2	$ 64,052.6
Principal gains, net
Revenues:
Total revenues	1,189.6	1,079.9	1,145.2
Commission and clearing fees
Revenues:
Total revenues	548	498.4	507.9
Consulting, management, and account fees
Revenues:
Total revenues	167.2	159	111.3
Interest income
Revenues:
Total revenues	$ 1,396.8	$ 987.6	$ 219

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 260.8	$ 238.5	$ 207.1
Other comprehensive income/(loss), net of tax:
Foreign currency translation adjustment	(0.1)	3.2	(11.7)
Cash flow hedges	25.7	35.1	(53.5)
Pension liabilities adjustment	1	0.5	(0.3)
Other comprehensive income/(loss)	26.6	38.8	(65.5)
Comprehensive income	$ 287.4	$ 277.3	$ 141.6

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2022
Cash flows from operating activities:
Net income		$ 260.8	$ 238.5		$ 207.1
Adjustments to reconcile net income to net cash provided by/(used in) operating activities:
Depreciation and amortization		53.1	51		44.4
Amortization of operating right of use assets		21.5	14		15.9
Provision for bad debts, net of recoveries		0.6	16.5		15.8
Deferred income taxes		(10.5)	(2.4)		(0.3)
Loss on extinguishment of debt		3.7	0		0
Amortization and extinguishment of debt issuance costs		5.4	5.8		4.5
Actuarial adjustment on pension and postretirement benefits		0.1	0.3		(0.1)
Amortization of share-based compensation expense		37.2	28		17.8
Gain on acquisition		0	(23.5)		0
Changes in operating assets and liabilities, net:
Securities and other assets segregated under federal and other regulations		(46)	599.5		(591.5)
Securities purchased under agreements to resell		(2,222)	(1,307.5)		567.9
Securities borrowed		(533.2)	80.7		953.3
Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net		262.5	(595.6)		(2,174.3)
Receivable from clients, net		(330.3)	(80.5)		(119.7)
Notes receivable, net		0.2	(0.1)		1
Income taxes receivable		7.2	(13.4)		10.4
Financial instruments owned, at fair value		(1,714.4)	(857.9)		187.3
Physical commodities inventory, net		(144.1)	(1.3)		(67.2)
Other assets		(119.8)	(60.4)		(9.8)
Accounts payable and other accrued liabilities		(5.3)	82.5		101.4
Operating lease liabilities		(9.8)	(8)		(16)
Payable to clients		369.9	81.4		2,055.1
Payable to broker-dealers, clearing organizations and counterparties		291.8	(217.8)		46.3
Income taxes payable		(19.6)	29.3		2.8
Securities sold under agreements to repurchase		4,054.7	1,331		(1,145.3)
Securities loaned		498.6	(72.2)		(964.1)
Financial instruments sold, not yet purchased, at fair value		(205.4)	658.4		627.8
Net cash provided by/(used in) operating activities		506.9	(23.7)		(229.5)
Cash flows from investing activities:
Collection of notes receivable		5	0		0
Proceeds from stock sales of clearing organization memberships		0	0		0.2
Cash paid for acquisitions of businesses and assets, net of cash acquired		(2.3)	(6.1)		(0.2)
Purchase of exchange memberships and common stock		(1.2)	0		0
Purchase of property and equipment and internally developed software		(65.2)	(46.9)		(49.5)
Net cash used in investing activities		(63.7)	(53)		(49.5)
Cash flows from financing activities:
Net change in lenders under loans with maturities 90 days or less		(2.2)	(119.3)		211.5
Proceeds from lenders under loans with maturities greater than 90 days		10	187		547
Repayments of lenders under loans with maturities greater than 90 days		(10)	(222)		(522)
Repayments of senior secured term loan		0	0		(170.3)
Proceeds from issuance of senior secured notes		550	0		0
Repayment of senior secured notes		(347.9)	0		(0.5)
Deferred payments on acquisitions		(9.6)	(18.7)		(3)
Payment of contingent consideration		0	0		(3.6)
Debt issuance costs		(7.7)	0		0
Shares withheld to cover taxes on vesting of equity awards		(2.3)	0		0
Exercise of stock options		7.7	3.7		6.7
Net cash provided by/(used in) financing activities		188	(169.3)		65.8
Effect of exchange rates on cash, segregated cash, cash equivalents, and segregated cash equivalents		(0.3)	2.6		(11.2)
Net increase/(decrease) in cash, segregated cash, cash equivalents, and segregated cash equivalents		630.9	(243.4)		(224.4)
Cash, segregated cash, cash equivalents, and segregated cash equivalents at beginning of period		6,041.7	6,285.1		6,509.5
Cash, segregated cash, cash equivalents, and segregated cash equivalents at end of period		6,672.6	6,041.7		6,285.1
Supplemental disclosure of cash flow information:
Cash paid for interest		1,230.2	786.5		149.2
Income taxes paid, net of cash refunds		117.8	71		56.3
Supplemental disclosure of non-cash investing and financing activities:
Identified intangible assets and goodwill on acquisitions		5.6	10.6		0.2
Additional consideration payable related to acquisitions		3.7	11.1		0
Acquisition of businesses:
Assets acquired		0.7	141.6		0
Liabilities acquired		0.6	84.1		0
Total net assets acquired		0.1	57.5		0
Cash and cash equivalents		1,269	1,108.3		1,108.5
Cash segregated under federal and other regulations	[1]	2,789.4	2,420.5		2,461.6
Securities segregated under federal and other regulations	[1]	0	0		200
Cash segregated and deposited with or pledged to exchange-clearing organizations and other futures commission merchants (“FCMs”)	[2]	1,688.5	1,256.5		2,138.2
Securities segregated and pledged to exchange-clearing organizations	[2]	925.7	1,256.4		376.8
Total cash, segregated cash, cash equivalents and segregated cash equivalents shown in the consolidated statements of cash flows		6,672.6	6,041.7		6,285.1
Non cash equivalent segregated assets		51.8	5.8	[1]	605.6
Non segregated cash and other non cash equivalent assets included with in deposits and receivables from broker dealers clearing organizations and counter parties		$ 4,669	$ 4,930.9		$ 4,327.6
[1] Represents segregated client cash held at third-party banks. Excludes segregated commodity warehouse receipts, segregated United States (“U.S.”) Treasury obligations with original or acquired maturities of greater than 90 days, and other assets, combined totaling $51.8 million , $5.8 million, and $605.6 million as of September 30, 2024, 2023, and 2022, respectively, included within Cash, securities and other assets segregated under federal and other regulations on the Consolidated Balance Sheets. Represents segregated client cash and U.S. Treasury obligations on deposit with, or pledged to, exchange clearing organizations and other FCMs. Excludes non-segregated cash, segregated securities pledged to exchange-clearing organizations with original or acquired maturities greater than 90 days, and other assets, combined totaling $4,669.0 million , $4,930.9 million, and $4,327.6 million as of September 30, 2024, 2023, and 2022, respectively, included within Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net on the Consolidated Balance Sheets.

Consolidated Statements of Stoc

Consolidated Statements of Stockholders’ Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss, net
Beginning balance at Sep. 30, 2021	$ 904	$ 0.4	$ (69.3)	$ 315.5	$ 682.5	$ (25.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	207.1				207.1
Other comprehensive income (loss)	(65.5)					(65.5)
Exercise of stock options	6.7			6.7
Share-based compensation	17.8			17.8
Ending balance at Sep. 30, 2022	1,070.1	0.4	(69.3)	340	889.6	(90.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	238.5				238.5
Other comprehensive income (loss)	38.8					38.8
Exercise of stock options	3.7			3.7
Share-based compensation	28			28
Ending balance at Sep. 30, 2023	1,379.1	0.4	(69.3)	371.7	1,128.1	(51.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	260.8				260.8
Other comprehensive income (loss)	26.6					26.6
Exercise of stock options	7.7			7.7
Shares withheld to cover taxes on vesting of equity awards	(2.3)			(2.3)
Share-based compensation	37.2			37.2
Ending balance at Sep. 30, 2024	$ 1,709.1	$ 0.4	$ (69.3)	$ 414.3	$ 1,388.9	$ (25.2)

Description of Business and Sig

Description of Business and Significant Accounting Policies	12 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Description of Business and Significant Accounting Policies	Description of Business and Significant Accounting Policies StoneX Group Inc., a Delaware corporation, and its consolidated subsidiaries (collectively “SNEX” 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 its clients’ sole trusted partner, providing its networks, products, and services to allow them to pursue trading opportunities, manage market risks, make investments and improve 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 service through the entire trade lifecycle, 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 and spreads as clients execute transactions across the Company’s financial networks, while the Company monetizes 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 these 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 self-directed/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”). Basis of Presentation The accompanying 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. In the Consolidated Income Statements, total revenues reported combine gross revenues for the physical commodities business and metals business and net revenues for all other businesses, including metals transacted by broker-dealer subsidiaries. The subtotal Operating revenues in the Consolidated Income Statements is physical commodities cost of sales deducted from total revenues. The subtotal Net operating revenues in the Consolidated Income Statements is operating revenues less transaction-based clearing expenses, introducing broker commissions, and interest expense. Transaction-based clearing expenses are variable expenses paid to executing brokers, exchanges, clearing organizations, and banks, typically related to transactional volumes. Introducing broker commissions include commission paid to 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, certain non-variable expenses, as well as variable and non-variable expenses related to both operational and administrative employees. Use of Estimates Preparing consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires that management make estimates and assumptions affecting the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenue and expense during the reporting period. The most significant of these estimates and assumptions in the current year relate to fair value measurements for financial instruments, revenue recognition, valuation of inventories, acquisition valuation, 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. Foreign Currency Translation The Company’s consolidated financial statements are reported in U.S. dollars. The Company’s subsidiaries maintain their records either in U.S. dollars or, as appropriate, the currencies of the countries in which they operate. The method of translating local currency financial information into U.S. dollars depends on whether the economy in which the foreign subsidiary operates has been designated as highly inflationary. Economies with a three-year cumulative inflation rate of more than 100% are considered highly inflationary. Assets and liabilities of foreign subsidiaries in non-highly inflationary economies are translated into U.S. dollars using rates of exchange at the balance sheet date. Translation adjustments are recorded in other comprehensive income (loss). Revenues and expense are translated at rates of exchange in effect at relevant times during the year. Transaction gains and losses related to changes in currency rates are recorded in earnings. Foreign subsidiaries that operate in highly inflationary countries use the U.S. dollar as their functional currency. Local currency monetary assets and liabilities are remeasured into U.S. dollars using rates of exchange as of each balance sheet date, with remeasurement adjustments and other transaction gains and losses recognized in earnings. Nonmonetary assets and liabilities do not fluctuate with changes in the local currency exchange rates to the dollar as the translated amounts for nonmonetary assets and liabilities at the end of the accounting period in which the economy becomes highly inflationary becomes the accounting basis for those assets and liabilities in the period of change and subsequent periods. Revenues and expenses are translated at rates of exchange in effect at relevant times during the year. The Company operates asset management and debt trading businesses in Argentina. Operating revenues from the Company’s Argentinean subsidiaries were approximately 1% of the consolidated operating revenues for the fiscal year ended September 30, 2024. The Company designated Argentina’s economy as highly inflationary for accounting purposes and has accounted for its Argentinean entities using the U.S. dollar as the functional currency. The Company recorded translation gains through earnings of $3.1 million, $6.6 million, and $2.1 million for the years ended September 30, 2024, 2023, and 2022. At September 30, 2024, the Company had net monetary liabilities denominated in Argentine pesos of $2.4 million, compared to net monetary liabilities of $0.2 million at September 30, 2023. The Company held cash and cash equivalents, including amounts in segregation, denominated in Argentine pesos of $3.0 million and $0.8 million as of September 30, 2024 and 2023, respectively. At September 30, 2024 and 2023, the Company had net non-monetary assets denominated in Argentine pesos of $2.7 million and $0.7 million, respectively. Cash and Cash Equivalents The Company considers cash held at banks and all highly liquid investments not held for trading purposes, with original or acquired maturities of 90 days or less, including certificates of deposit and money market mutual funds, to be cash and cash equivalents. Cash and cash equivalents consists of cash, certificates of deposit, and money market mutual funds not deposited with or pledged to clearing organizations, broker-dealers, clearing organizations or counterparties, or segregated under federal or other regulations. Certificates of deposit are stated at cost plus accrued interest, which approximates fair value, and may be withdrawn at any time, at the discretion of the Company. Money market mutual funds are stated at their net asset value. Cash, Securities and Other Assets Segregated under Federal and other Regulations Pursuant to requirements of the Commodity Exchange Act and Commission Regulation 30.7 of the U.S. Commodity Futures Trading Commission (“CFTC”) in the U.S., the Markets in Financial Instruments Implementing Directive 2006/73/EC underpinning the Client Asset (“CASS”) rules in the Financial Conduct Authority (“FCA”) handbook in the United Kingdom (“U.K.”), and the Securities & Futures Act (“SFA”) in Singapore, funds deposited by clients relating to futures and options on futures contracts in regulated commodities must be carried in separate accounts, which are designated as segregated or secured client accounts. Additionally, in accordance with Rule 15c3-3 of the Securities Exchange Act of 1934 (“Rule 15c3-3”), the Company maintains separate accounts for the exclusive benefit of securities clients and proprietary accounts of broker dealers (“PABs”). Rule 15c3-3 requires the Company to maintain special reserve bank accounts (“SRBAs”) for the exclusive benefit of securities clients and PABs. The deposits in segregated client accounts and SRBAs are not commingled with Company funds. Under the FCA’s rules, certain categories of clients may choose to opt-out of segregation. As of September 30, 2024 and 2023, cash, securities, and other assets segregated under federal and other regulations consisted of cash held at banks of approximately $2,789.4 million and $2,420.5 million, respectively, and commodities warehouse receipts of approximately $51.8 million and $5.8 million, respectively (see fair value measurements discussion in Note 3). Collateralized Transactions The Company enters into securities purchased under agreements to resell, securities sold under agreements to repurchase, securities borrowed transactions, and securities loaned transactions primarily to fund principal debt trading, acquire securities to cover short positions, acquire securities for settlement, or meet counterparty needs under matched-booked trading strategies. These transactions are accounted for as collateralized financing transactions and are recorded at their contractual amounts plus accrued interest. In connection with these agreements and transactions, it is the Company’s policy to receive or pledge cash or securities to collateralize such agreements and transactions in accordance with contractual arrangements. The Company monitors the fair value of its collateral on a daily basis, and the Company may require counterparties, or may be required by counterparties, to deposit additional collateral or return collateral pledged. Interest income and interest expense are recognized over the life of the arrangements and are recorded in the Consolidated Income Statements as Interest income or Interest expense , as applicable. The carrying amount of these transactions approximate fair value due to their short-term nature and the level of collateralization. Certain transactions are classified in securities purchased under agreements to resell rather than securities borrowed because the characteristics and circumstances more closely align with this presentation, although the securities’ legal form is securities borrowed. Repurchase and Reverse repurchase agreement netting The Company undertakes certain clearing arrangements and related agreements that meet the criteria for netting under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 210-20, Balance Sheet – Offsetting. Netting occurs within Securities purchased under agreements to resell and Securities sold under agreements to repurchase. More details can be found in Note 12. Deposits with and Receivables from Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties Deposits with broker-dealers, clearing organizations, and counterparties pertain primarily to deposits made to satisfy margin requirements on client and proprietary open futures and options on futures positions and to satisfy the requirements set by clearing exchanges for clearing membership. The Company also deposits margin with various counterparties for over-the-counter (“OTC”) derivative contracts. These deposits are also included in deposits with broker-dealers, clearing organizations, and counterparties. The Company also deposits cash margin with various securities clearing organizations as an ongoing condition of the securities clearing relationships, and these deposits are included in deposits with and receivables from broker-dealers, clearing organizations, and counterparties. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties are reported gross, except where a right of offset exists. As of September 30, 2024 and 2023, the Company had cash and cash equivalents on deposit with or pledged to broker-dealers, clearing organizations, and counterparties of approximately $2,614.2 million and $2,512.9 million, respectively. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also includes guaranty deposits with clearing exchanges. The guaranty deposits are held by the clearing exchanges for use in potential default situations by one or more members of the clearing exchanges. The guaranty deposits may be applied to the Company’s obligations to the clearing exchange, or to the clearing exchange’s obligations to unrelated parties. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also include securities pledged to clearing exchanges. These securities are either pledged to the Company by its clients or represent investments of client funds. It is the Company’s practice to include client-owned securities on its Consolidated Balance Sheets, as the rights to those securities have been transferred to the Company under the terms of the relevant futures trading agreements. Securities pledged primarily include U.S. Treasury obligations, foreign government obligations, and certain ETFs. Securities that are not client-owned, and represent an investment of client funds, are adjusted to fair value with associated changes in unrealized gains or losses recorded in Interest income in the Consolidated Income Statements. For client-owned securities, the change in fair value is offset against the payable to clients with no impact recognized in the Consolidated Income Statements. The total fair value of such client owned and non-client owned securities included within Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net was $2,951.5 million and $4,041.6 million as of September 30, 2024 and 2023, respectively. Management has considered guidance required by ASC 860, Transfers and Servicing as it relates to securities pledged by clients to margin their futures and options on futures trading accounts. Management believes that the transferor surrenders control over those assets because, under the guidance, the transferee relinquishes control of the assets to the Company, among other factors. Under this guidance, the Company reflects the client collateral assets and corresponding liabilities in the Company’s Consolidated Balance Sheets as of September 30, 2024 and 2023. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also includes amounts due from clearing exchanges for unrealized gains and losses associated with clients’ options on futures contracts. See discussion in the Financial Instruments section below for additional information on the Company’s accounting policies for derivative contracts. For client-owned derivative contracts, the fair value is offset against the payable to clients with no impact recognized on the Consolidated Income Statements. The Company maintains client omnibus and proprietary accounts with other clearing organizations. The equity balances in those accounts, along with any margin cash or securities deposited with the clearing organizations are included in deposits with and receivables from broker-dealers, clearing organizations, and counterparties. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also include amounts due from or due to clearing exchanges for daily variation settlements on open futures and options on futures positions. The variation settlements due from or due to clearing exchanges are paid in cash on the following business day. Variation settlements equal the daily settlement of futures contracts and premiums on options on futures contracts. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties further include amounts receivable for securities sold but not yet delivered by the Company on settlement date (“fails-to-deliver”) and net receivables arising from unsettled proprietary trades. Payables to broker-dealers, clearing organizations, and counterparties primarily include amounts payable for securities purchased but not yet received by the Company on settlement date (“fails-to-receive”) and net payables arising from unsettled proprietary trades. Deposits with and receivables from broker-dealers, clearing organizations and counterparties, and payables to broker-dealers, clearing organizations and counterparties also include amounts related to the value of registered broker-dealer clients cross-currency payment transactions related to the Payments segment. These amounts arise due to a clearing period before funds are received and payments are made, which usually is one to two business days. Receivable from and Payables to Clients Receivable from clients, net includes the total of net deficits in individual exchange-traded futures and OTC derivative trading accounts carried by the Company. Client deficits arise from realized and unrealized trading losses on client OTC, futures, options on futures, swaps and forwards and amounts due on cash and margin transactions. Client deficit accounts are reported gross of client accounts that contain net credit or positive balances, except where a right of offset exists. Net deficits in individual futures exchange-traded and OTC derivative trading accounts include both secured and unsecured deficit balances due from clients as of the balance sheet date. Secured deficit amounts are backed by U.S. Treasury obligations and commodity warehouse receipts. These U.S Treasury obligations and commodity warehouse receipts are netted against the secured deficit amounts when conditions necessary for the right to offset exist. Receivable from clients, net also includes the net amounts receivable from securities clients in connection with the settlement of regular-way cash securities, margin loans to clients, and client cash debits. It is the Company’s policy to report margin loans and payables that arise due to positive cash flows in the same client’s accounts on a net basis when the conditions for netting as specified in U.S. GAAP are met. Clients’ securities transactions cleared by the Company are recorded on a settlement date basis, but the Company makes accruals necessary to adjust any uncompleted transactions to a trade date basis for consolidated reporting, under U.S. GAAP. Securities cleared by the Company and pledged to the Company as a condition of custodial clearing arrangements are owned by the clients, including those that collateralize margin or other similar transactions, and are not reflected on the Consolidated Balance Sheets as the Company does not have title to, or beneficial interests, in those assets. The carrying value of the receivables and payables approximates fair value due to their short-term nature. Receivable from clients, net also include amounts receivable from non-broker-dealer clients for securities sold but not yet delivered by the Company on settlement date (“fails-to-deliver”) and net receivables arising from unsettled proprietary trades. Payables to clients represent the total of client accounts with credit or positive balances. Client accounts are used primarily in connection with exchange-traded and OTC commodity, foreign exchange, precious metals, and securities transactions and include gains and losses on open trades as well as securities and cash margin deposits made as required by the Company, the exchange-clearing organizations or other clearing organizations. Client accounts with credit or positive balances are reported gross of client deficit accounts, except where a right of offset exists. Payables to broker-dealers and counterparties also includes amounts payable to non-broker-dealer clients for securities purchased but not yet received by the Company on settlement date (“fails-to-receive”) and net payables arising from unsettled proprietary trades. Receivable from and payables to clients also include amounts related to the value of non-registered broker-dealer clients’ cross-currency payment transactions related to the Payments segment. These amounts arise due to a clearing period before the funds are received and payments are made, which usually is one to two business days. The future collectability of receivable from clients can be impacted by the Company’s collection efforts, client financial stability, and the general economic climate. In determining collectability, the Company considers a number of factors including, but not limited to, historical collection experience, current and forecasted economic and business conditions, internal and external credit risk ratings, collateral terms, payment terms, client financial strength, and aging of the financial asset. The Company adheres to the Current Expected Credit Loss model and, in addition, may use specific-identification in certain circumstances to further inform estimates. The Company may unilaterally close client trading positions in certain circumstances. In addition, to evaluate client margining and collateral requirements, client positions are stress tested regularly and monitored for excessive concentration levels relative to the overall market size. Furthermore, in certain instances, the Company is indemnified and able to charge back introducing broker-dealers for bad debts incurred by their clients. The Company generally writes off an outstanding receivable balance when all economic means of recovery have been exhausted. That determination considers information such as the occurrence of significant changes in the client’s financial position such that the client can no longer pay the obligation, or that the proceeds from collateral will not be sufficient to pay the balance. Notes Receivable Accrual of commodity financing income on any note is discontinued when, in the opinion of management, there is reasonable doubt as to the timely collectability of interest or principal. Nonaccrual notes are returned to an accrual status when, in the opinion of management, the financial position of the borrower indicates there is no longer any reasonable doubt as to the timely payment of principal and interest. The Company records a charge against earnings for notes receivable losses when management believes that the collection of outstanding principal is not probable. Physical Commodities Inventory Inventories of certain agricultural commodities are carried at net realizable value, which approximates fair value less disposal costs. Agricultural commodities inventories have reliable, readily determinable and realizable market prices, relatively predictable and insignificant costs of disposal, and are available for immediate delivery. Changes in the fair values of these agricultural commodities inventories are included as a component of Cost of sales of physical commodities in the Consolidated Income Statements. Inventories of precious metals held by subsidiaries that are not broker-dealers are valued at the lower of cost or net realizable value, using the weighted-average price and first-in first-out costing method. Changes in the values of these inventories are included as a component of Cost of sales of physical commodities in the Consolidated Income Statements. Precious metals inventory held by StoneX Financial Ltd, a U.K. based broker-dealer subsidiary, is measured at fair value, with changes in fair value included as a component of Principal gains, net in the Consolidated Income Statements, in accordance with U.S. GAAP accounting requirements for broker-dealers. Property and Equipment Property and equipment is stated at cost, net of accumulated depreciation and amortization and depreciated using the straight-line method over the estimated useful life. Leasehold improvements are amortized on a straight-line basis over the estimated useful life of the improvement or the term of the lease, whichever is shorter. Expenditures that increase the value or productive capacity of assets are capitalized. When an asset is retired, sold, or otherwise disposed of, the carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in earnings. The Company had no assets held for sale at September 30, 2024 and 2023. The Company accounts for costs incurred to develop its trading platforms and related software in accordance with ASC 350-40, Internal-Use Software, which requires that such technology be capitalized in the application development stage. Costs related to planning, training, administration, and non-value added maintenance are charged to expense as incurred. Capitalized software development costs are amortized over the useful life of the software, which the Company generally estimates at three years. In accordance with ASC 360-10, Property, Plant and Equipment, the Company periodically evaluates the carrying value of long-lived assets when events and circumstances warrant such review. The carrying value of a long-lived asset is considered impaired when the anticipated identifiable undiscounted cash flows from such an asset (or asset group) are less than carrying value. In that event, a loss is recognized in the amount by which the carrying value exceeds fair market value of the long-lived asset. The Company has identified no impairment indicators as of September 30, 2024 and 2023. This standard applies to assets held for use and not to assets held for sale. Acquisitions The Company applies acquisition accounting on the date of acquisition to those transactions meeting the definition of a business under ASC 805. Applying acquisition accounting requires the Company to allocate the purchase consideration to the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed on acquisition date. In determining the fair value of identifiable assets acquired and liabilities assumed, the Company frequently utilizes a third-party valuation specialist. The Company applies certain significant assumptions, estimates, and judgments in determining the fair value of assets acquired and liabilities assumed on acquisition date. These significant assumptions, estimates, and judgments include, but are not limited to, cash flow forecasts, discount rates, client churn rates, royalty rates, and economic lives. Any excess of the purchase consideration over the fair value of the net assets acquired is recorded as goodwill. Alternatively, in an instance where the fair value of the net assets acquired exceeds the purchase consideration, the Company records a bargain purchase gain in the Consolidated Income Statements at the date of acquisition. While the Company uses its best estimates and assumptions as a part of the purchase price allocation to accurately value assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the remeasurement period, which may extend one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill or bargain purchase gain. Upon conclusion of the measurement period or final determination of the fair values of assets acquired and liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the Consolidated Income Statements rather than adjusted through goodwill or bargain purchase gains. The Company includes the post-acquisition results of acquired businesses in the Consolidated Income Statements from the date of acquisition. Acquisition related costs, such as fees for attorneys, accountants, and investment bankers, are expensed as incurred and are not capitalized as part of the purchase price. Goodwill and Identifiable Intangible Assets Goodwill is the cost of acquired companies in excess of the fair value of identifiable net assets at acquisition date. Goodwill is not subject to amortization, but rather is evaluated for impairment at least annually. The Company evaluates its goodwill for impairment during the fourth quarter of its fiscal year or more frequently if indicators of potential impairment exist, in accordance with ASC 350, Intangibles - Goodwill and Other. Goodwill impairment is determined by comparing the estimated fair value of a reporting unit (generally defined as the businesses for which financial information is available and reviewed regularly by management) with its respective carrying value. If the estimated fair value exceeds the carrying value, goodwill at the reporting unit level is not deemed to be impaired. However, if the estimated fair value is below carrying value, further analysis is required to determine the amount of the impairment. In the course of evaluating the potential impairment of goodwill, the Company may perform either a qualitative or a quantitative assessment. The Company’s qualitative assessment of potential impairment may result in the determination that a quantitative impairment analysis is not necessary. Under this elective process, the Company assesses qualitative factors to determine whether the existence of events or circumstances leads the Company to determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If after assessing the totality of events and circumstances, the Company determines it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, then performing a quantitative analysis is not required. However, if the Company concludes otherwise, then the Company performs a quantitative impairment analysis. If the Company either chooses not to perform a qualitative assessment, or the Company chooses to perform a qualitative assessment but is unable to qualitatively conclude that no impairment has occurred, then the Company performs a quantitative evaluation. In the case of a quantitative assessment, the Company estimates the fair value of the reporting unit with which the goodwill that is subject to the quantitative analysis is associated and compares it to the carrying value. If the estimated fair value of a reporting unit is less than its carrying value, the Company estimates the fair value of all assets and liabilities of the reporting unit, including goodwill. If the carrying value of the reporting unit’s goodwill is greater than the estimated fair value, an impairment charge is recognized for the excess. The fair value of the Company’s reporting units exceeded their respective carrying values under the qualitative assessment approach. No goodwill impairment charges were recorded for any of the periods presented, nor were any indicators present. Identifiable intangible assets subject to amortization are amortized using the straight-line method over their estimated period of benefit, ranging from five Financial Instruments Owned and Sold, Not Yet Purchased Financial instruments owned and sold, not yet purchased, at fair value consist of financial instruments carried at fair value, measured on a recurring basis, or amounts that approximate fair value. Related realized and unrealized gains and losses are recognized in current period earnings within Principal gains, net , Interest income , Interest expense , and Cost of sales of physical commodities in the Consolidated Income Statements. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. Th

Earnings per Share

Earnings per Share	12 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share The Company presents basic and diluted earnings per share (“EPS”) using the two-class method which requires all outstanding unvested share-based payment awards that contain rights to non-forfeitable dividends and therefore participate in undistributed earnings with common stockholders be included in computing earnings per share. Under the two-class method, net income is reduced by the amount of dividends declared in the period for each class of common stock and participating security. The remaining undistributed earnings are then allocated to common stock and participating securities, based on their respective rights to receive dividends. Restricted stock awards granted to certain employees and directors contain non-forfeitable rights to dividends at the same rate as common stock, and are considered participating securities. Basic EPS has been computed by dividing net income by the weighted-average number of common shares outstanding. The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below. Year Ended September 30, (in millions, except share amounts) 2024 2023 2022 Numerator: Net income $ 260.8 $ 238.5 $ 207.1 Less: Allocation to participating securities (9.1) (8.1) (6.1) Net income allocated to common stockholders $ 251.7 $ 230.4 $ 201.0 Denominator: Weighted average number of: Common shares outstanding 30,539,237 29,936,000 29,355,605 Dilutive potential common shares outstanding: Share-based awards 1,085,792 993,011 745,706 Diluted shares outstanding 31,625,029 30,929,011 30,101,311 Earnings per share - basic $ 8.24 $ 7.71 $ 6.85 Earnings per share - diluted $ 7.96 $ 7.45 $ 6.67 The dilutive effect of share-based awards is reflected in diluted net income per share by application of the treasury stock method, which includes consideration of unamortized share-based compensation expense. Options to purchase 1,565,788, 371,657 and 677,861 shares of common stock for the years ended September 30, 2024, 2023, and 2022, respectively, were excluded from the calculation of diluted earnings per share because they would have been anti-dilutive.

Assets and Liabilities, at Fair

Assets and Liabilities, at Fair Value	12 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Assets and Liabilities, at Fair Value	Assets and Liabilities, at Fair Value Fair value is defined by U.S. GAAP as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between willing market participants on the measurement date. Fair value is a market-based measure considered from the perspective of a market participant rather than an entity-specific measure. Therefore, even when market assumptions are not readily available, the Company is required to develop a set of assumptions that reflect those that market participants would use in pricing the asset or liability at the measurement date. The Company uses prices and inputs that are current as of the measurement date, including periods of market dislocation. In periods of market dislocation, the observability of prices and inputs may be reduced for many securities. This condition could cause a security to be reclassified to a lower level within the fair value hierarchy. The Company has designed independent price verification controls and periodically performs such controls to ensure the reasonableness of such values. Financial and nonfinancial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). A market is active if there are sufficient transactions on an ongoing basis to provide current pricing information for the asset or liability, pricing information is released publicly, and price quotations do not vary substantially either over time or among market makers. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the reporting entity. The guidance requires the Company to consider counterparty credit risk of all parties of outstanding derivative instruments that would be considered by a market participant in the transfer or settlement of such contracts (exit price). The Company’s exposure to credit risk on derivative financial instruments relates to the portfolio of OTC derivative contracts as all exchange-traded contracts held can be settled on an active market with a credit guaranty from the respective exchange. The Company requires each counterparty to deposit margin collateral for all OTC instruments and is also required to deposit margin collateral with counterparties. The Company has assessed the nature of these deposits and used its discretion to adjust each based on the underlying credit considerations for the counterparty and determined that the collateral deposits minimize the exposure to counterparty credit risk in the evaluation of the fair value of OTC instruments as determined by a market participant. In accordance with ASC 820, Fair Value Measurement, the Company groups its assets and liabilities measured at fair value in three levels based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: Level 1 - Valuation is based upon unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 1 consists of financial assets and liabilities whose fair values are estimated using quoted market prices. Level 2 - Valuation is based upon quoted prices for identical or similar assets or liabilities in markets that are less active, that is, markets in which there are few transactions for the asset or liability that are observable for substantially the full term. Included in Level 2 are those financial assets and liabilities for which fair values are estimated using models or other valuation methodologies. These models are primarily industry-standard models that consider various observable inputs, including time value, yield curve, volatility factors, observable current market and contractual prices for the underlying financial instruments, as well as other relevant economic measures. Level 3 - Valuation is based on prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Level 3 comprises financial assets and liabilities whose fair value is estimated based on internally developed models or methodologies utilizing significant inputs that are not readily observable from objective sources. Level 3 includes contingent liabilities that have been valued using an income approach based upon management developed discounted cash flow projections, which are an unobservable input. Fair value of financial and nonfinancial assets and liabilities that are carried on the Consolidated Balance Sheets at fair value on a recurring basis Cash and cash equivalents reported at fair value on a recurring basis includes certificates of deposit and money market mutual funds, which are stated at cost plus accrued interest, which approximates fair value. Cash, securities and other assets segregated under federal and other regulations reported at fair value on a recurring basis include the value of pledged investments, which may include U.S. Treasury obligations or commodities warehouse receipts. Deposits with and receivables from broker-dealers, clearing organizations and counterparties and payable to clients and broker-dealers, clearing organizations and counterparties includes the fair value of pledged investments, primarily U.S. Treasury obligations and foreign government obligations. These balances also include the fair value of exchange-traded options on futures and OTC forwards, swaps, and options. Financial instruments owned and sold, not yet purchased include the fair value of equity securities, which includes common, preferred, and foreign ordinary shares, American Depository Receipts (“ADRs”), Global Depository Receipts (“GDRs”), and exchange-traded funds (“ETFs”), corporate and municipal bonds, U.S. Treasury obligations, U.S. government agency obligations, foreign government obligations, agency mortgage-backed obligations, asset-backed obligations, derivative financial instruments, commodities warehouse receipts, exchange firm common stock, and investments in managed funds. The fair value of exchange firm common stock is determined by quoted market prices. Cash equivalents, debt and equity securities, commodities warehouse receipts, physical commodities inventory, derivative financial instruments and contingent liabilities are carried at fair value, on a recurring basis, and are classified and disclosed into three levels in the fair value hierarchy. The following section describes the valuation methodologies used by the Company to measure classes of financial instruments at fair value and specifies the level within the fair value hierarchy where various financial instruments are classified. The Company uses quoted prices in active markets, where available, and classifies such instruments within Level 1 of the fair value hierarchy. Examples include U.S. Treasury obligations, foreign government obligations, commodities warehouse receipts, certain equity securities traded in active markets, physical precious metals inventory held by a regulated broker-dealer subsidiary, exchange firm common stock, investments in managed funds, as well as options on futures contracts traded on national exchanges. The fair value of exchange firm common stock is determined by recent sale transactions and is included within Level 1. When instruments are traded in secondary markets and observable prices are not available for substantially the full term, the Company generally relies on internal valuation techniques or prices obtained from third-party pricing services or brokers or a combination thereof, and accordingly, classifies these instruments as Level 2. Examples include corporate and municipal bonds, U.S. government agency obligations, agency-mortgage backed obligations, asset-backed obligations, certain equity securities traded in less active markets, and OTC derivative contracts, which include purchase and sale commitments related to the Company’s agricultural and energy commodities. Certain derivatives without a quoted price in an active market and derivatives executed OTC are valued using internal valuation techniques, including pricing models which utilize significant inputs observable to market participants. The valuation techniques and inputs depend on the type of derivative and the nature of the underlying instrument. The key inputs depend upon the type of derivative and the nature of the underlying instrument and include interest yield curves, foreign exchange rates, commodity prices, volatilities and correlation. These derivative instruments are included within Level 2 of the fair value hierarchy. Physical commodities inventory includes precious metals that are a part of the trading activities of a regulated broker-dealer subsidiary that records these assets at fair value using exchange-quoted prices. Physical commodities inventory also includes agricultural commodities that are a part of the trading activities of a non-broker dealer subsidiary and are recorded at net realizable value using exchange-quoted prices. The fair value of precious metals physical commodities inventory is based upon unadjusted exchange-quoted prices and is, therefore, classified within Level 1 of the fair value hierarchy. The fair value of agricultural physical commodities inventory and related OTC firm sale and purchase commitments are generally based upon exchange-quoted prices, adjusted for basis or differences in local markets, broker or dealer quotations or market transactions in either listed or OTC markets. Exchange-quoted prices are adjusted for location and quality because the exchange-quoted prices for agricultural and energy related products represent contracts that have standardized terms for commodity, quantity, future delivery period, delivery location, and commodity quality or grade. The basis or local market adjustments are observable inputs or have an insignificant impact on the measurement of fair value and, therefore, the agricultural physical commodities inventory as well as the related OTC forward firm sale and purchase commitments have been included within Level 2 of the fair value hierarchy. With the exception of certain derivative instruments where the valuation approach is disclosed above, financial instruments owned and sold are primarily valued using third-party pricing sources. Third-party pricing vendors compile prices from various sources and often apply matrix pricing for similar securities when market-observable transactions for the instruments are not observable for substantially the full term. The Company reviews the pricing methodologies used by third-party pricing vendors in order to evaluate the fair value hierarchy classification of vendor-priced financial instruments and the accuracy of vendor pricing, which typically involves the comparison of primary vendor prices to internal trader prices or secondary vendor prices. When evaluating the propriety of vendor-priced financial instruments using secondary prices, considerations include the range and quality of vendor prices, level of observable transactions for identical and similar instruments, and judgments based upon knowledge of a particular market and asset class. If a primary vendor price does not represent fair value, justification for using a secondary price, including source data used to make the determination, is subject to review and approval by authorized personnel prior to using a secondary price. Financial instruments owned and sold that are valued using third-party pricing vendors are included within either Level 1 or Level 2 of the fair value hierarchy based upon the observability of the inputs used and the level of activity in the market. The fair value estimates presented herein are based on pertinent information related to September 30, 2024 and 2023. Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these consolidated financial statements since that date and current estimates of fair value may differ significantly from the amounts presented herein. The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of September 30, 2024 and 2023 by level in the fair value hierarchy. All fair value measurements were performed on a recurring basis as of September 30, 2024 and 2023. September 30, 2024 (in millions) Level 1 Level 2 Level 3 Netting (1) Total Assets: Certificates of deposit $ 13.9 $ — $ — $ — $ 13.9 Money market mutual funds 35.3 — — — 35.3 Cash and cash equivalents 49.2 — — — 49.2 Commodities warehouse receipts 51.8 — — — 51.8 Securities and other assets segregated under federal and other regulations 51.8 — — — 51.8 U.S. Treasury obligations 2,933.2 — — — 2,933.2 To be announced ("TBA") and forward settling securities — 26.1 — (18.3) 7.8 Foreign government obligations 18.3 — — — 18.3 Derivatives 3,900.1 2,168.2 — (5,740.1) 328.2 Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net 6,851.6 2,194.3 — (5,758.4) 3,287.5 Receivable from clients, net - Derivatives 22.4 506.2 (537.0) (8.4) Equity securities 363.9 15.0 — — 378.9 Corporate and municipal bonds — 322.1 — — 322.1 U.S. Treasury obligations 1,088.6 — — — 1,088.6 U.S. government agency obligations — 531.0 — — 531.0 Foreign government obligations 41.4 — — — 41.4 Agency mortgage-backed obligations — 3,837.2 — — 3,837.2 Asset-backed obligations — 223.5 — — 223.5 Derivatives 0.1 603.2 — (375.2) 228.1 Commodities warehouse receipts 67.8 — — — 67.8 Exchange firm common stock 13.2 — — — 13.2 Cash flow hedges — 9.6 — — 9.6 Mutual funds and other 23.6 — 2.1 — 25.7 Financial instruments owned 1,598.6 5,541.6 2.1 (375.2) 6,767.1 Physical commodities inventory 207.6 169.0 — — 376.6 Total assets at fair value $ 8,781.2 $ 8,411.1 $ 2.1 $ (6,670.6) $ 10,523.8 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 2.3 $ — $ 2.3 Payables to clients - Derivatives 3,577.1 228.9 — (3,540.1) 265.9 TBA and forward settling securities — 24.4 — (22.9) 1.5 Derivatives 378.0 2,356.4 — (2,737.3) (2.9) Payable to broker-dealers, clearing organizations and counterparties 378.0 2,380.8 — (2,760.2) (1.4) Equity securities 219.8 5.0 — — 224.8 Foreign government obligations 41.0 — — — 41.0 Corporate and municipal bonds — 154.6 — — 154.6 U.S. Treasury obligations 2,139.3 — — — 2,139.3 U.S. government agency obligations — 0.2 — — 0.2 Agency mortgage-backed obligations — 23.6 — — 23.6 Asset-backed obligations — 3.9 — — 3.9 Derivatives 8.1 571.0 — (314.3) 264.8 Cash flow hedges — 0.2 — — 0.2 Other — — 0.9 — 0.9 Financial instruments sold, not yet purchased 2,408.2 758.5 0.9 (314.3) 2,853.3 Total liabilities at fair value $ 6,363.3 $ 3,368.2 $ 3.2 $ (6,614.6) $ 3,120.1 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level. September 30, 2023 (in millions) Level 1 Level 2 Level 3 Netting (1) Total Assets: Certificates of deposit $ 8.7 $ — $ — $ — $ 8.7 Money market mutual funds 57.8 — — — 57.8 Cash and cash equivalents 66.5 — — — 66.5 Commodities warehouse receipts 5.8 — — — 5.8 Securities and other assets segregated under federal and other regulations 5.8 — — — 5.8 U.S. Treasury obligations 4,023.8 — — — 4,023.8 TBA and forward settling securities — 73.5 — (31.7) 41.8 Foreign government obligations 17.8 — — — 17.8 Derivatives 5,497.5 1,135.9 — (6,468.5) 164.9 Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net 9,539.1 1,209.4 — (6,500.2) 4,248.3 Receivable from clients, net - Derivatives 61.7 561.3 (630.9) (7.9) Equity securities 324.0 10.3 — — 334.3 Corporate and municipal bonds — 284.2 — — 284.2 U.S. Treasury obligations 531.7 — — — 531.7 U.S. government agency obligations — 451.7 — — 451.7 Foreign government obligations 43.3 — — — 43.3 Agency mortgage-backed obligations — 2,865.8 — — 2,865.8 Asset-backed obligations — 138.8 — — 138.8 Derivatives 0.6 868.1 — (600.2) 268.5 Commodities leases — 16.0 — — 16.0 Commodities warehouse receipts 54.7 — — — 54.7 Exchange firm common stock 12.0 — — — 12.0 Cash flow hedges — 1.7 — — 1.7 Mutual funds and other 39.3 — 2.8 — 42.1 Financial instruments owned 1,005.6 4,636.6 2.8 (600.2) 5,044.8 Physical commodities inventory 240.3 146.2 — — 386.5 Total assets at fair value $ 10,919.0 $ 6,553.5 $ 2.8 $ (7,731.3) $ 9,744.0 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 1.5 $ — $ 1.5 Payables to clients - Derivatives 5,430.7 226.2 — (5,577.1) 79.8 TBA and forward settling securities — 47.5 — (31.4) 16.1 Derivatives 112.2 1,402.0 — (1,520.1) (5.9) Payable to broker-dealers, clearing organizations and counterparties 112.2 1,449.5 — (1,551.5) 10.2 Equity securities 230.6 5.5 — — 236.1 Foreign government obligations 21.5 — — — 21.5 Corporate and municipal bonds — 81.6 — — 81.6 U.S. Treasury obligations 2,409.3 — — — 2,409.3 U.S. government agency obligations — 5.1 — — 5.1 Agency mortgage-backed obligations — 31.7 — — 31.7 Derivatives 2.4 769.2 — (510.4) 261.2 Cash flow hedges — 27.1 — — 27.1 Other — 10.9 1.1 — 12.0 Financial instruments sold, not yet purchased 2,663.8 931.1 1.1 (510.4) 3,085.6 Total liabilities at fair value $ 8,206.7 $ 2,606.8 $ 2.6 $ (7,639.0) $ 3,177.1 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level. Realized and unrealized gains and losses are included in Principal gains, net , Interest income , and Cost of sales of physical commodities in the Consolidated Income Statements. The fair value of an exchange-traded options on futures contract is equal to the unrealized gain or loss on the contract determined by marking the contract to the current settlement price for a like contract on the valuation date of the contract. A settlement price may not be used if the market makes a limit move with respect to a particular options on futures contract or if the contract’s underlying experiences significant price fluctuations after the determination of the settlement price. When a settlement price cannot be used, options on futures contracts will be valued at their fair value as determined in good faith pursuant to procedures adopted by management of the Company. Information on Level 3 Financial Liabilities The acquisition of CDI-Societe Cotonniere De Distribution S.A, as further discussed in Note 20, included a put and call option feature that will be settled in a future period. The future value of these options, which are an asset and liability respectively, is dependent upon certain financial metrics. The preceding table contains the current values in Level 3, within Financial instruments owned and Financial instruments sold, not yet purchased , respectively. The acquisition of Incomm S.A.S., as further discussed in Note 20, included a contingent earn-out. Pursuant to the consideration agreement, the Company is required to make additional future cash payments based on a percentage of the acquired business line’s pre-tax profits and adjusted net revenue. The balance of the earn-out was $0.6 million at September 30, 2024 and is included in Accounts payable and other accrued liabilities in the Consolidated Balance Sheets. The acquisition of Trust Advisory Group, Ltd., as further discussed in Note 20, included a contingent earn-out. Pursuant to the consideration agreement, the Company is required to make an additional future cash payment based on a ratio of the business line’s net revenue. The balance of the earn-out was $1.7 million at September 30, 2024 and is included in Accounts payable and other accrued liabilities in the Consolidated Balance Sheets. Additional Disclosures about the Fair Value of Financial Instruments that are not carried on the Consolidated Balance Sheets at Fair Value Many, but not all, of the financial instruments that the Company holds are recorded at fair value in the Consolidated Balance Sheets. The following represents financial instruments in which the ending balances at September 30, 2024 and 2023 were not carried at fair value in accordance with U.S. GAAP on our Consolidated Balance Sheets: Short-term financial instruments: The carrying values of short-term financial instruments, including cash and cash equivalents, cash segregated under federal and other regulations, securities purchased under agreements to re-sell and securities sold under agreements to re-purchase, and securities borrowed and loaned are recorded at amounts that approximate the fair value of these instruments due to their short-term nature and level of collateralization. These financial instruments generally expose the Company to limited credit risk and have no stated maturities or have short-term maturities and carry interest rates that approximate market rates. Under the fair value hierarchy, cash and cash equivalents and cash segregated under federal and other regulations are classified as Level 1. Securities purchased under agreements to re-sell and securities sold under agreements to re-purchase, and securities borrowed and loaned are classified as Level 2 under the fair value hierarchy as they are generally overnight, or short-term in nature, and are collateralized by common stock, U.S. Treasury obligations, U.S. government agency obligations, agency mortgage-backed obligations, and asset-backed obligations. Receivables and other assets: Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, receivable from clients, net, notes receivables, net and certain other assets are recorded at amounts that approximate fair value due to their short-term nature and are classified as Level 2 under the fair value hierarchy. Payables: Payables to clients and payables to brokers-dealers, clearing organizations, and counterparties are recorded at amounts that approximate fair value due to their short-term nature. They are classified as Level 2 under the fair value hierarchy. Lenders under loans : Payables to lenders under loans carry variable rates of interest and thus approximate fair value and are classified as Level 2 under the fair value hierarchy. Senior secured borrowings, net : Senior secured borrowings, net includes the Company's 7.875% Senior Secured Notes due 2031 (the “Notes due 2031”), as further described in Note 11 with a carrying value of $543.1 million as of September 30, 2024. The carrying value of the Notes due 2031 represent their principal amounts net of unamortized deferred financing costs. As of September 30, 2024, the Notes due 2031 had a fair value of $586.3 million. They were classified as Level 2 under the fair value hierarchy.

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk	12 Months Ended
	Sep. 30, 2024
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk	Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk The Company is party to certain financial instruments with off-balance sheet risk in the normal course of its business. The Company has sold financial instruments that it does not currently own and will therefore be obliged to purchase such financial instruments at a future date. The Company has recorded these obligations in the consolidated financial statements as of September 30, 2024 at the fair values of the related financial instruments. The Company will incur losses if the fair value of the underlying financial instruments increases subsequent to September 30, 2024. The total Financial instruments sold, not yet purchased, at fair value of $2,853.3 million as of September 30, 2024 includes $264.8 million for derivative contracts not designated as hedges, which represent a liability to the Company based on their fair values as of September 30, 2024. Derivatives The Company utilizes derivative products in its trading capacity as a dealer in order to satisfy client needs and mitigate risk. The Company manages risks from both derivatives and non-derivative cash instruments on a consolidated basis. The risks of derivatives should not be viewed in isolation, but in aggregate with the Company’s other trading activities. The Company’s derivative positions are included in the Consolidating Balance Sheets in Deposits with and receivables from broker-dealers, clearing organizations, and counterparties; Receivable from clients, net; Financial instruments owned , net ; Financial instruments sold, not yet purchased, at fair value; Payables to clients; and Payables to broker-dealers, clearing organizations and counterparties . Listed below are the fair values of the Company’s derivative assets and liabilities as of September 30, 2024 and 2023. Assets represent net unrealized gains and liabilities represent net unrealized losses. September 30, 2024 September 30, 2023 (in millions) Assets (1) Liabilities (1) Assets (1) Liabilities (1) Derivative contracts not accounted for as hedges: Exchange-traded commodity derivatives $ 1,383.1 $ 1,415.7 $ 1,907.0 $ 1,890.3 OTC commodity derivatives 1,967.9 1,924.3 1,523.3 1,456.0 Exchange-traded foreign exchange derivatives 2.0 2.0 4.3 4.3 OTC foreign exchange derivatives 975.2 938.2 497.1 455.3 Exchange-traded interest rate derivatives 720.1 728.1 1,507.6 1,509.8 OTC interest rate derivatives 207.1 207.1 417.6 417.6 Exchange-traded equity index derivatives 1,817.4 1,817.4 2,140.9 2,140.9 OTC equity and indices derivatives 127.4 86.7 127.3 68.5 TBA and forward settling securities 26.1 24.4 73.5 47.5 Total derivative contracts not accounted for as hedges 7,226.3 7,143.9 8,198.6 7,990.2 Derivative contracts designated as hedging instruments: Interest rate swaps — 0.2 — 24.6 Foreign currency forwards 9.6 — 1.7 2.5 Total derivative contracts designated as hedging instruments 9.6 0.2 1.7 27.1 Gross fair value of derivative contracts $ 7,235.9 $ 7,144.1 $ 8,200.3 $ 8,017.3 Impact of netting and collateral (6,670.6) (6,614.6) (7,731.3) (7,639.0) Total fair value included in Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net $ 336.0 $ 206.7 Total fair value included in Receivable from clients, net $ (8.4) $ (7.9) Total fair value included in Financial instruments owned, at fair value $ 237.7 $ 270.2 Total fair value included in Payables to clients $ 265.9 $ 79.8 Total fair value included in Payables to broker-dealers, clearing organizations and counterparties $ (1.4) $ 10.2 Fair value included in Financial instruments sold, not yet purchased, at fair value $ 265.0 $ 288.3 (1) As of September 30, 2024 and 2023, the Company’s derivative contract volume for open positions was approximately 12.2 million and 13.4 million contracts, respectively. The Company’s derivative contracts are principally held in its Institutional, Commercial, and Self-Directed/Retail segments. The Company provides its Institutional segment clients access to exchanges at which they can carry out their trading strategies. The Company assists its Commercial segment clients in protecting the value of their future production by entering into option or forward agreements with them on an OTC basis. The Company also provides its Commercial segment clients with exchange products, including combinations of buying and selling puts and calls. In its Self-Directed/Retail segment, the Company provides its retail clients with access to spot foreign exchange, precious metals trading, as well as contracts for difference (“CFD”) and spread bets, where permitted. The Company mitigates its risk by generally offsetting the client’s transaction simultaneously with one of the Company’s trading counterparties or will offset that transaction with a similar but not identical position on the exchange. The risk mitigation of these offsetting trades is not within the documented hedging designation requirements of the Derivatives and Hedging Topic of the ASC. These derivative contracts are traded along with cash transactions because of the integrated nature of the markets for these products. The Company manages the risks associated with derivatives on an aggregate basis along with the risks associated with its proprietary trading and market-making activities in cash instruments as part of its firm-wide risk management policies. In particular, the risks related to derivative positions may be partially offset by inventory, other derivatives, or cash collateral paid or received. Hedging Activities The Company uses interest rate derivatives, in the form of swaps, to hedge risk related to variability in overnight rates. These hedges are designated cash flow hedges, through which the Company mitigates uncertainty in its interest income by converting floating-rate interest income to fixed-rate interest income. While the swaps mitigate interest rate risk, they do introduce credit risk, which is the possibility that the Company’s trading counterparty fails to meet its obligation. The Company minimizes this risk by entering into its swaps with highly-rated, multi-national institutions. In addition to credit risk, there is market risk associated with the swap positions. The Company’s market risk is limited, because any amounts the Company must pay from having exchanged variable interest will be funded by the variable interest the Company receives on its deposits. These hedges will all mature within approximately 1 year from the end of the current period. The Company also uses foreign currency derivatives, in the form of forward contracts, to hedge risk related to the variability in exchange rates relative to certain of the Company’s non-USD expenditures. These hedges are designated cash flow hedges, through which the Company mitigates variability in exchange rates by exchanging foreign currency for USD at fixed exchange rates at a pre-determined future date, or several cash flows at several pre-determined future dates. While the forward contracts mitigate exchange rate variability risk, they do introduce credit risk, which is the possibility that the Company’s trading counterparty fails to meet its obligation. The Company minimizes this risk by entering into its forward contracts with highly-rated, multi-national institutions. These hedges will all mature within 2 years from the end of the current period. The Company assesses the effectiveness of its hedges at each reporting period to identify any required reclassifications into current earnings. During the year ended September 30, 2024 and 2023, the Company did not designate any portion of its hedges as ineffective and thus did not have any values in current earnings related to ineffective hedges. The fair values of derivative instruments designated for hedging held as of September 30, 2024 and 2023 are as follow: September 30, 2024 September 30, 2023 (in millions) Balance Sheet Location Fair Value Fair Value Asset Derivatives Derivatives designated as hedging instruments: Foreign currency forward contracts Financial instruments owned, net $ 9.6 $ 1.7 Total derivatives designated as hedging instruments $ 9.6 $ 1.7 Derivative assets, net expected to be released from Other comprehensive income into earnings within the next 12 months: Foreign currency forward contracts $ 9.2 $ 1.4 Total expected to be released from Other comprehensive income into earnings $ 9.2 $ 1.4 Liability Derivatives Derivatives designated as hedging instruments: Interest rate contracts Financial instruments sold, not yet purchased $ 0.2 $ 24.6 Foreign currency forward contracts Financial instruments sold, not yet purchased — 2.5 Total derivatives designated as hedging instruments $ 0.2 $ 27.1 Derivative liabilities, net expected to be released from Other comprehensive income into earnings within the next 12 months: Interest rate contracts $ 0.2 $ 20.3 Foreign currency forward contracts — 1.0 Total expected to be released from Other comprehensive income into earnings $ 0.2 $ 21.3 The notional values of derivative instruments designated for hedging held as of September 30, 2024 and 2023 are as follows: September 30, 2024 September 30, 2023 (in millions) Notional Value Notional Value Derivatives designated as hedging instruments: Interest rate contracts $ 500.0 $ 2,000.0 Foreign currency forward contracts: Foreign currency forward contracts to purchase Polish Zloty: Local currency zł 156.1 zł 156.1 USD $ 37.5 $ 34.0 Foreign currency forward contracts to purchase British Pound Sterling: Local currency £ 72.0 £ 168.0 USD $ 88.8 $ 206.9 The Consolidated Income Statement effects of derivative instruments designated for hedging held for the fiscal years ended September 30, 2024 and 2023 are as follows: (in millions) Income Statement Location Year Ended September 30, 2024 Year Ended September 30, 2023 Total amounts in income related to hedges Interest rate contracts Interest income $ (26.7) $ (47.0) Foreign currency forward contracts Compensation and benefits 9.6 2.3 Total derivatives designated as hedging instruments $ (17.1) $ (44.7) Amount of gain reclassified from accumulated other comprehensive income into income as a result of a forecasted transaction that is no longer probable of occurring $ — $ — The accumulated other comprehensive income effects of derivative instruments designated for hedging held for the years ended September 30, 2024 and 2023 are as follow: Amount of Gain Recognized in Other Comprehensive Income on Derivatives, net of tax (in millions) Year Ended September 30, 2024 Year Ended September 30, 2023 Derivatives in Cash Flow Hedging Relationships: Interest rate contracts $ 18.5 $ 18.4 Foreign currency forward contracts 7.2 16.7 Total $ 25.7 $ 35.1 The following table sets forth the Company’s net gains/(losses) related to derivative financial instruments for the periods indicated, in accordance with the Derivatives and Hedging Topic of the ASC. The net gains/(losses) set forth below are included in Principal gains, net and Cost of sales of physical commodities in the Consolidated Income Statements. Year Ended September 30, (in millions) 2024 2023 2022 Commodities $ 383.8 $ 446.5 $ 303.7 Foreign exchange 124.6 269.2 174.4 Interest rate, equities, and indices 100.2 109.0 100.4 TBA and forward settling securities (135.5) 73.0 226.8 Net gains from derivative contracts $ 473.1 $ 897.7 $ 805.3 Credit Risk In the normal course of business, the Company purchases and sells financial instruments, commodities and foreign currencies as either principal or agent on behalf of its clients. If either the client or counterparty fails to perform, the Company may be required to discharge the obligations of the nonperforming party. In such circumstances, the Company may sustain a loss if the fair value of the financial instrument or foreign currency is different from the contract value of the transaction. The majority of the Company’s transactions and, consequently, the concentration of its credit exposure are with commodity exchanges, clients, broker-dealers and other financial institutions. These activities involve both collateralized and uncollateralized arrangements and may result in credit exposure in the event that a counterparty fails to meet its contractual obligations. The Company’s exposure to credit risk can be directly impacted by volatile financial markets, which may impair the ability of counterparties to satisfy their contractual obligations. The Company seeks to control its credit risk through a variety of reporting and control procedures, including establishing credit limits based upon a review of counterparties financial condition and credit ratings. The Company monitors collateral levels on a daily basis for compliance with regulatory and internal guidelines. The Company requests changes in collateral levels as appropriate. The Company is a party to financial instruments in the normal course of its business through client and proprietary trading accounts in exchange-traded and OTC derivative instruments. These instruments are primarily the execution of orders for commodity futures, options on futures and forward foreign currency contracts on behalf of its clients, substantially all of these transactions occur on a margin basis. Such transactions may expose the Company to significant credit risk in the event margin requirements are not sufficient to fully cover losses which clients may incur. The Company controls the risks associated with these transactions by requiring clients to maintain margin deposits in compliance with individual exchange regulations and internal guidelines. The Company monitors required margin levels daily and, therefore, may require clients to deposit additional collateral or reduce positions when necessary. The Company also establishes client credit limits, which are monitored daily. The Company evaluates each client’s creditworthiness on a case by case basis. Clearing, financing, and settlement activities may require the Company to maintain funds with or pledge securities as collateral with other financial institutions. Generally, these exposures to both clients and counterparties are subject to master netting, or client agreements, which reduce the exposure to the Company by permitting receivables and payables with such clients to be offset in the event of a client default. Management believes that the margin deposits held as of September 30, 2024 and 2023 were adequate to minimize the risk of material loss that could be created by positions held at that time. Additionally, the Company monitors collateral fair value on a daily basis and adjusts collateral levels in the event of excess market exposure. Derivative financial instruments involve varying degrees of off-balance sheet market risk whereby changes in the fair values of underlying financial instruments may result in changes in the fair value of the financial instruments in excess of the amounts reflected in the Consolidated Balance Sheets. Exposure to market risk is influenced by a number of factors, including the relationships between the financial instruments and the Company’s positions, as well as the volatility and liquidity in the markets in which the financial instruments are traded. The principal risk components of financial instruments include, among other things, interest rate volatility, the duration of the underlying instruments and changes in commodity pricing and foreign exchange rates. The Company attempts to manage its exposure to market risk through various techniques. Aggregate market limits have been established and market risk measures are routinely monitored against these limits.

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts	12 Months Ended
	Sep. 30, 2024
Receivables [Abstract]
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net; receivable from clients, net; and notes receivable, net include allowances for doubtful accounts, which reflect the Company’s best estimates of probable losses inherent in the accounts. In determining expected credit losses and establishing its allowance for doubtful accounts, the Company considers a number of factors including, but not limited to, historical collection experience, current and forecasted economic and business conditions, internal and external credit risk ratings, collateral terms, payment terms and aging of the financial asset, as well as specific-identification in certain circumstances. The Company continually reviews its allowance for doubtful accounts. The allowance for doubtful accounts related to deposits with and receivables from broker-dealers, clearing organizations, and counterparties was $0.0 million and $0.1 million as of September 30, 2024 and 2023. The allowance for doubtful accounts related to receivable from clients was $51.9 million and $59.8 million as of September 30, 2024 and 2023, respectively. The Company had no allowance for doubtful accounts related to notes receivable as of September 30, 2024 and 2023. Activity in the allowance for doubtful accounts for the years ended September 30, 2024, 2023, and 2022 was as follows: (in millions) 2024 2023 2022 Balance, beginning of year $ 59.9 $ 47.8 $ 39.8 (Recovery) Provision for bad debts (1) (2.4) 12.5 12.4 Allowance charge-offs (6.2) (0.5) (5.6) Other 0.6 0.1 1.2 Balance, end of year $ 51.9 $ 59.9 $ 47.8 (1) An additional $3.0 million, $4.0 million, and $3.4 million is included in bad debt expense for the years ended September 30, 2024, 2023, and 2022, respectively, on the consolidated income statement, which is not included in the allowance.

Physical Commodities Inventory

Physical Commodities Inventory	12 Months Ended
	Sep. 30, 2024
Inventory Disclosure [Abstract]
Physical Commodities Inventory	Physical Commodities Inventory The Company’s inventories consist of finished physical commodities as shown below. September 30, (in millions) 2024 2023 Physical Ag & Energy $ 169.0 $ 146.2 Precious metals - held by broker-dealer subsidiary 207.6 240.3 Precious metals - held by non-broker-dealer subsidiaries 304.5 150.8 Physical commodities inventory $ 681.1 $ 537.3 Physical Ag & Energy consists of agricultural commodity inventories, including corn, soybeans, wheat, dried distillers grain, canola, sorghum, coffee, cocoa, cotton, and various energy commodity inventories. Agricultural inventories have reliable, readily determinable and realizable market prices, have relatively insignificant costs of disposal and are available for immediate delivery. The Company records changes to these values in Cost of sales of physical commodities on the Consolidated Income Statements.

Property and Equipment, net

Property and Equipment, net	12 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment, Net [Abstract]
Property and Equipment, net	Property and Equipment, net Property and equipment is stated at cost, and reported net of accumulated depreciation and amortization on the Consolidated Balance Sheets. Depreciation on property and equipment is generally calculated using the straight-line method over the relevant asset’s estimated useful life. The estimated useful lives of property and equipment range from 3 to 10 years. During the years ended September 30, 2024, 2023, and 2022, depreciation expense was $45.6 million, $36.3 million, and $30.0 million respectively. The Company capitalized $36.1 million and $29.9 million of software development costs during the years ended September 30, 2024 and September 30, 2023. The Company wrote off $4.8 million of fully depreciated property and equipment assets during the fiscal year ended September 30, 2024. A summary of property and equipment, at cost less accumulated depreciation and amortization as of September 30, 2024 and 2023 is as follows: September 30, (in millions) 2024 2023 Property and equipment: Furniture and fixtures $ 21.4 $ 17.5 Software 41.5 38.1 Equipment 57.9 49.9 Leasehold improvements 56.7 47.7 Capitalized software development 113.1 77.0 Total property and equipment 290.6 230.2 Less: accumulated depreciation and amortization (147.5) (106.7) Property and equipment, net $ 143.1 $ 123.5

Goodwill

Goodwill	12 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Goodwill allocated to the Company’s operating segments as of September 30, 2024 and 2023 is as follows: September 30, (in millions) 2024 2023 Commercial $ 33.3 $ 33.7 Institutional 9.8 9.8 Self-Directed/Retail 7.9 5.8 Payments 10.0 10.0 Total Goodwill $ 61.0 $ 59.3 The Company recorded $0.3 million and $0.3 million in foreign exchange translation decline related to Goodwill for the years ended September 30, 2024 and 2023, respectively. The Company recorded additional goodwill of $2.0 million during the year ended September 30, 2024 within the Self-Directed/Retail reportable segment related to the initial purchase price allocation for the acquisition of Trust Advisory Group, Ltd. (“TAG”), as further discussed in Note 20.

Intangible Assets

Intangible Assets	12 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets The Company recorded $3.6 million of customer list assets and wrote off $27.8 million of fully amortized intangible assets during the fiscal year ended September 30, 2024. The Company recorded $8.5 million of customer list assets and $0.4 million of trade name assets related to the acquisition of CDI during the fiscal year ended September 30, 2023. The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows (in millions): September 30, 2024 September 30, 2023 Gross Accumulated Net Amount Gross Accumulated Net Amount Intangible assets subject to amortization: Trade/domain names $ 4.1 $ (3.2) $ 0.9 $ 4.1 $ (2.4) $ 1.7 Software programs/platforms 4.9 (4.1) 0.8 28.5 (26.9) 1.6 Client base 37.7 (25.6) 12.1 38.3 (24.1) 14.2 Total intangible assets subject to amortization 46.7 (32.9) 13.8 70.9 (53.4) 17.5 Intangible assets not subject to amortization Website domains 2.1 — 2.1 1.9 — 1.9 Business licenses 3.7 — 3.7 3.7 — 3.7 Total intangible assets not subject to amortization 5.8 — 5.8 5.6 — 5.6 Total intangible assets $ 52.5 $ (32.9) $ 19.6 $ 76.5 $ (53.4) $ 23.1 Amortization expense related to intangible assets was $7.5 million, $14.7 million, and $14.4 million for the years ended September 30, 2024, 2023, and 2022, respectively. As of September 30, 2024, estimated future amortization expense was as follows: (in millions) Fiscal 2025 $ 4.1 Fiscal 2026 3.1 Fiscal 2027 2.4 Fiscal 2028 1.5 Fiscal 2029 and thereafter 2.7 $ 13.8

Leases

Leases	12 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Leases	Leases The Company leases office space under non-cancelable operating leases with third parties as of September 30, 2024. Leases with an initial term of twelve months or less are not recorded on the Consolidated Balance Sheets and the Company recognizes lease expense for these leases on a straight-line basis over the lease term. Certain office space leases include one or more options to renew, with renewal terms that can extend the lease term from three As the office space leases do not provide an implicit rate, the Company applies a collateralized incremental borrowing rate based on information available at lease commencement date in determining the present value of lease payments. For office space leases executed by subsidiaries, including foreign subsidiaries, the Company has applied its incremental borrowing rate. The Company believes this is a reasonable approach as its subsidiaries either do not have their own treasury functions or the credit facilities available to its subsidiaries do not permit financing of right-of-use assets. Additionally, in certain instances, the parent company provides a guaranty of the lease payments to the lessor under office space leases executed by its subsidiaries. The Company believes that pricing subsidiary leases is more significantly influenced by the credit standing of the parent company than that of its subsidiaries. Certain office space leases contain variable lease payments related to fair market rent adjustments and local inflation index measures. The Company estimates variable lease payments based upon information available at lease commencement date in determining the present value of lease payments. The Company has elected to not separate lease components from nonlease components for all office space leases. The Company does not have any financing leases as of September 30, 2024. Operating lease expense is recognized on a straight-line basis over the lease term and is reported within Occupancy and equipment rental on the Consolidated Income Statements. As of September 30, 2024 and 2023, the Company recorded operating lease right-of-use assets of $157.0 million and $122.1 million, respectively, and operating lease liabilities of $195.9 million and $149.3 million, respectively. The following table presents operating lease costs and other related information as of and for the fiscal year ended September 30, 2024 and 2023 (in millions, except as stated): Year Ended September 30, 2024 2023 Operating lease costs (1)(2) $ 42.9 $ 28.0 Supplemental cash flow information and non-cash activity: Cash paid for amounts included in the measurement of operating lease liabilities $ 25.8 $ 18.4 Right-of-use assets obtained in exchange for operating lease liabilities $ 56.4 $ 14.3 Lease term and discount rate information: Weighted average remaining lease term (years) 8.6 9.8 Weighted average discount rate 5.0 % 4.5 % (1) Includes short-term leases and variable lease costs, which are immaterial. (2) Elements of operating lease costs are included as components of Cost of sales of physical commodities and Occupancy and equipment rental in the Consolidated Income Statements. The maturities of the lease liabilities are as follows as of September 30, 2024 (in millions): 2025 $ 29.3 2026 30.5 2027 31.1 2028 29.3 2029 24.2 After 2029 95.5 Total lease payments 239.9 Less: interest 44.0 Present value of lease liabilities $ 195.9

Credit Facilities

Credit Facilities	12 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Credit Facilities	Credit Facilities Committed Credit Facilities The Company and its subsidiaries have committed credit facilities under which they may borrow up to $1,205.0 million, subject to the terms and conditions for these facilities. The amounts outstanding under these credit facilities carry variable rates of interest, thus approximating fair value. The committed credit facilities have covenant requirements that generally relate to various leverage, debt to net worth, fixed charge, tangible net worth, excess net capital, or profitability measures, as agreed for each. The Company and its subsidiaries were in compliance with all relevant covenants as of September 30, 2024. Uncommitted Credit Facilities The Company has access to certain uncommitted financing agreements that support its ordinary course securities and commodities business activities. The agreements are subject to certain borrowing terms and conditions. Notes Payable to Bank The Company has notes payable to bank related to financing certain equipment which secures the notes. Senior Secured Notes On March 1, 2024, the Company issued $550 million in aggregate principal amount of its 7.875% Notes due 2031 at the offering price of 100% of the aggregate principal amount. The Notes due 2031 are fully and unconditionally guaranteed, jointly and severally, on a senior secured second lien basis by each of the Company’s existing and future subsidiaries that guarantee indebtedness under the Company’s senior secured revolving credit facility and certain other senior indebtedness. Interest related to these notes is payable twice annually, in arrears. The Company incurred debt issuance costs of $7.7 million, which are being amortized over the term of the Notes due 2031 under the effective interest method. On June 17, 2024 , the Company used part of the proceeds from its Notes due 2031 to extinguish its 8.625% Senior Secured Notes due 2025 (the “Notes due 2025”) when $363.0 million that the Company had previously deposited into an irrevocable trust as part of an in-substance defeasance was remitted to the note holders to redeem the notes and pay interest due up to that date. In accordance with ASC 470-50 “Debt - Modifications and Extinguishments”, the transactions noted above were determined to be an extinguishment of the Notes due 2025 and an issuance of new debt. As a result, the Company recorded a loss on the extinguishment of debt in the amount of $3.7 million included in Interest expense on corporate funding on the Consolidated Income Statements for the year ended September 30, 2024, of which $2.4 million represented the write off of deferred financing costs and $1.3 million represented the write off of original issue discount. The following table sets forth a listing of credit facilities, the current committed amounts as of the report date on the facilities, and outstanding (in millions, except for percentages): Amounts Outstanding Borrower Security Renewal or Interest Rate at September 30, 2024 Total Commitment September 30, 2024 September 30, Committed Credit Facilities Senior StoneX Group Inc. Committed Credit Facility (1) April 21, 2026 Base rate - 9.00% SOFR - 6.95% 500.0 161.0 (5) 150.0 StoneX Financial Inc. None October 28, 2025 10.00 % 250.0 (7) — (5) — StoneX Commodity Solutions LLC Certain assets July 29, 2025 Base rate - 8.5% SOFR - 7.54% 325.0 66.0 (5) 103.0 StoneX Financial Ltd None October 9, 2025 7.47 % 115.0 (6) — (5) 25.0 StoneX Financial Pte. Ltd. None September 5, 2025 7.46 % 15.0 — (5) — $ 1,205.0 $ 227.0 $ 278.0 Uncommitted Credit Facilities Various Various Various 104.9 (5) 55.5 Notes payable to bank Certain equipment December 1, 2025 Index rate plus 2.35% 6.9 (5) 7.5 Senior Secured Notes due 2031 (2) March 1, 2031 7.875 % 543.1 (4) — Senior Secured Notes due 2025 (2) June 15, 2025 8.625 % — (3) 342.1 Total outstanding borrowings $ 881.9 $ 683.1 (1) The StoneX Group Inc. senior committed credit facility is a revolving facility secured by substantially all of the assets of StoneX Group Inc. and certain subsidiaries identified in the credit facility agreement as obligors, and pledged equity of certain subsidiaries identified in the credit facility as limited guarantors. (2) The Notes and the related guarantees are secured by liens on substantially all of the Company’s and the guarantors’ assets, subject to certain customary and other exceptions and permitted liens. The liens on the assets that secure the Notes and the related guarantees are contractually subordinated to the liens on the assets that secure the Company’s and the guarantors’ existing and future first lien secured indebtedness, including indebtedness under the Company’s senior committed credit facility. (3) Included in Senior secured borrowings, net on the Consolidated Balance Sheets. Amounts outstanding under the Notes due 2025 are reported net of unamortized original issue discount and unamortized deferred financing costs of $5.8 million as of September 30, 2023. The Notes due 2025 were extinguished as of June 30, 2024. (4) Included in Senior secured borrowings, net on the Consolidated Balance Sheets . Amounts outstanding under the Notes due 2031 are reported net of unamortized deferred financing costs of $6.9 million . (5) Included in Lenders under loans on the Consolidated Balance Sheets. (6) The facility was amended on October 9, 2024 to extend the maturity date to October 9, 2025. The facility was amended on October 31, 2024 to increase the amount available from $100 million to $115 million. (7) The facility was amended on October 29, 2024 to extend the maturity date to October 28, 2025 , and to increase the amount available from $190.0 million to $250.0 million. As reflected above, $340.0 million of the Company’s committed credit facilities are scheduled to expire during the upcoming fiscal year. The Company intends to renew or replace all of its facilities as they expire over time, and based on the Company’s liquidity position and capital structure, the Company believes it will be able to do so.

Securities and Commodity Financ

Securities and Commodity Financing Transactions	12 Months Ended
	Sep. 30, 2024
Broker-Dealer [Abstract]
Securities and Commodity Financing Transactions	Securities and Commodity Financing Transactions The Company’s repurchase agreements and securities borrowing and lending arrangements are generally recorded at cost in the Consolidated Balance Sheets, which is a reasonable approximation of their fair values due to their short-term nature. Secured borrowing and lending arrangements are entered into to obtain collateral necessary to effect settlement, finance inventory positions, meet customer needs or re-lend as part of our dealer operations. The fair value of securities loaned and borrowed is monitored daily compared with the related payable or receivable, and additional collateral or returning excess collateral is requested, as appropriate. These arrangements may serve to limit credit risk resulting from our transactions with our counterparties. Financial instruments are pledged as collateral under repurchase agreements, securities lending agreements and other secured arrangements, including clearing arrangements. Agreements with counterparties generally contain contractual provisions allowing counterparties the right to sell or repledge collateral. Either the Company or its counterparties may require additional collateral. All collateral is held by the Company or a custodian. The following tables set forth the carrying value of repurchase agreements, and securities lending agreements by remaining contractual maturity (in millions): September 30, 2024 Overnight and Open Less than 30 Days 30-90 Days Over 90 Days Total Securities sold under agreements to repurchase $ 15,260.8 $ 585.4 $ 631.0 $ 50.7 $ 16,527.9 Securities loaned 1,615.9 — — — 1,615.9 Gross amount of secured financing $ 16,876.7 $ 585.4 $ 631.0 $ 50.7 $ 18,143.8 September 30, 2023 Overnight and Open Less than 30 Days 30-90 Days Over 90 Days Total Securities sold under agreements to repurchase $ 8,300.0 $ 786.8 $ 107.0 $ 2.6 $ 9,196.4 Securities loaned 1,117.3 — — — 1,117.3 Gross amount of secured financing $ 9,417.3 $ 786.8 $ 107.0 $ 2.6 $ 10,313.7 Offsetting of Collateralized Transactions The following table sets forth the carrying value of repurchase agreements and securities lending agreements by class of collateral pledged (in millions): September 30, Securities sold under agreements to repurchase 2024 2023 U.S. Treasury obligations $ 9,673.7 $ 3,696.1 U.S. government agency obligations and municipal bonds 652.0 542.2 Asset-based obligations 136.1 102.9 Agency mortgage-backed obligations 5,079.6 4,371.6 Foreign government obligations 649.6 148.1 Corporate bonds 336.9 335.5 Total securities sold under agreement to repurchase $ 16,527.9 $ 9,196.4 Securities loaned Equity securities $ 1,615.9 $ 1,117.3 Total securities loaned 1,615.9 1,117.3 Gross amount of secured financing $ 18,143.8 $ 10,313.7 The following tables provide the netting of securities purchased under agreements to resell, securities sold under agreements to repurchase, securities borrowed and securities loaned as of the periods indicated (in millions): September 30, 2024 Offsetting of collateralized transactions: Gross Amounts Recognized Amounts Offset in the Consolidated Balance Sheet Net Amounts Presented in the Consolidated Balance Sheet Securities purchased under agreements to resell $ 13,148.1 $ (7,946.6) $ 5,201.5 Securities borrowed $ 1,662.3 $ — $ 1,662.3 Securities sold under agreements to repurchase $ 16,527.9 $ (7,946.6) $ 8,581.3 Securities loaned $ 1,615.9 $ — $ 1,615.9 September 30, 2023 Offsetting of collateralized transactions: Gross Amounts Recognized Amounts Offset in the Consolidated Balance Sheet Net Amounts Presented in the Consolidated Balance Sheet Securities purchased under agreements to resell $ 7,649.3 $ (4,669.8) $ 2,979.5 Securities borrowed $ 1,129.1 $ — $ 1,129.1 Securities sold under agreements to repurchase $ 9,196.4 $ (4,669.8) $ 4,526.6 Securities loaned $ 1,117.3 $ — $ 1,117.3 The Company pledges securities owned as collateral in both tri-party and bilateral arrangements. Pledged securities under tri-party arrangements may not be repledged or sold by the Company’s counterparties, whereas bilaterally pledged securities may be. The approximate fair value of pledged securities that can be sold or repledged by the Company’s counterparties has been parenthetically disclosed on the Consolidated Balance Sheets. The Company receives securities as collateral under reverse repurchase agreements, securities borrowed agreements, and margin securities held on behalf of counterparties. This collateral is used by the Company to cover financial instruments sold, not yet purchased; to obtain financing in the form of repurchase agreements; and to meet counterparties’ needs under lending arrangement and matched-booked trading strategies. Additional securities collateral is obtained as necessary to ensure such transactions are adequately collateralized. In many instances, the Company is permitted by contract to repledge the securities received as collateral, which may include pledges to cover collateral requirements for tri-party repurchase agreements. The following table sets forth the fair value, which approximates carrying value because of the short term nature, of collateral pledged, received and repledged (in millions): September 30, 2024 September 30, 2023 Securities pledged or repledged to cover collateral requirements for tri-party arrangements $ 6,777.9 $ 4,726.6 Securities received as collateral that may be repledged $ 20,126.8 $ 9,180.1 Securities received as collateral that may be repledged covering securities sold short $ 2,408.3 $ 2,461.1 Repledged securities borrowed and client securities held under custodial clearing arrangements to collateralize securities loaned agreements $ 1,533.3 $ 1,097.3

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Certain conditions may exist as of the date the financial statements are issued, which may result in a loss to the Company but which will only be resolved when one or more future events occur or fail to occur. The Company assesses such contingent liabilities, and such assessment inherently involves an exercise of judgment. In assessing loss contingencies related to legal and regulatory proceedings that are pending against the Company or unasserted claims that may result in such proceedings, the Company’s legal counsel evaluates the perceived merits of any legal or regulatory proceedings or unasserted claims as well as the perceived merits of the amount of relief sought or expected to be sought therein. If the assessment of a contingency indicates that it is probable that a material loss has been incurred at the date of the financial statements and the amount of the liability can be estimated, then the estimated liability would be accrued in the Company’s financial statements. If the assessment indicates that a potentially material loss contingency is not probable, but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability, together with an estimate of the range of possible loss if determinable and material, would be disclosed. Neither accrual nor disclosure is required for loss contingencies that are deemed remote. The Company accrues legal fees related to contingent liabilities as they are incurred. Legal Proceedings From time to time and in the ordinary course of business, the Company is involved in various legal actions and proceedings, including tort claims, contractual disputes, employment matters and workers’ compensation claims. The Company carries insurance that provides protection against certain types of claims, up to the limits of the respective policy. Additionally, the Company is subject to extensive regulation and supervision by U.S. federal and international governmental agencies and various self-regulatory organizations. The Company and its advisors periodically engage with such regulatory agencies and organizations, in the context of examinations or otherwise, to respond to inquiries, informational requests, and investigations. From time to time, such engagements result in regulatory complaints or other matters, the resolution of which can include fines and other remediation. On November 13, 2023, BTIG filed a civil complaint (the “BTIG complaint”) against the Company and StoneX Financial Inc. in San Francisco Superior Court (CGC-23-610525) seeking monetary damages and injunctive relief for, among other things, alleged theft of purported trade secrets by former BTIG employees later employed at StoneX. The proceedings have moved to FINRA Arbitration and the court action is stayed. The Company intends to vigorously defend itself. The Company subsequently received from the U.S. Department of Justice (the “DOJ”) and the SEC subpoenas that the Company believes are related to conduct alleged in the BTIG complaint, and the Company is cooperating with these agencies. The ultimate outcomes of the BTIG complaint and the DOJ and SEC subpoenas cannot presently be determined. As of September 30, 2024 and 2023, the Consolidated Balance Sheets include loss contingency accruals, recorded during and prior to these years then ended, which are not material, individually or in the aggregate, to the Company’s financial position or liquidity. Management does not currently believe exposure from loss contingencies in excess of the amounts accrued, and in addition to the possible losses discussed below, to be material to the Company’s earnings, financial position or liquidity. Contingencies The Company had receivables, net of collections and other allowable deductions, of $10.0 million as of September 30, 2024, due from account holders in connection with the liquidation of their accounts in accordance with StoneX Financial Inc.’s client agreements and obligations under market regulation standards after the balances in the accounts fell below required maintenance margin levels and into deficit balances. The allowance against these uncollected balances was $3.8 million as of September 30, 2024. The Company is pursuing collection of the outstanding balances through arbitration proceedings against the account holders. The Company will consider developments in these proceedings, and any other relevant matters, in determining whether any changes in the allowance against the uncollected balances are required. In these and other arbitration proceedings, clients are seeking damages from StoneX Financial Inc. relating to the trading losses in their accounts. During the fiscal year ended September 30, 2024, the Company favorably resolved several of these arbitration claims through arbitration decisions and privately negotiated settlements. All of the arbitration panels that issued decisions during the year awarded StoneX Financial Inc. the full amount of the uncollected balances. As noted, several of the arbitrations were resolved through privately negotiated settlement, pursuant to which the account holders agreed to pay some or all of their outstanding deficit balances. The Company intends to continue vigorously pursuing claims through arbitration and settling cases in what the Company determines to be appropriate circumstances. The ultimate outcome of remaining arbitrations cannot presently be determined. Depending on future collections and the outcomes of arbitration proceedings, any provisions for bad debts and actual losses may or may not be material to the Company’s financial results. However, the Company believes that the likelihood of a material adverse outcome is remote, and does not currently believe that any potential losses related to this matter would impact its ability to comply with its ongoing liquidity, capital, and regulatory requirements. Contractual Commitments Post-Acquisition Commitment Subsequent to the Gain Capital Holdings, Inc (“Gain”) acquisition date of July 30, 2020 (“the Gain acquisition date”), certain holders of Gain common stock outstanding at the Gain acquisition date who did not vote to approve the merger (“Dissenting Holders”, and the shares held by such Dissenting Holders, the “Dissenting Shares”) purportedly demanded appraisal rights pursuant to Section 262 of the Delaware General Corporation Law in the Court of Chancery of the State of Delaware. The Company has reached a settlement with the Dissenting Holders, pending the Court’s approval. As of September 30, 2024, the Company has a payable amount of $31.1 million due to the Dissenting Holders, included in Accounts Payable and Other Accrued Liabilities , for which funds have been placed in escrow, and are included in Other Assets in the Consolidated Balance Shee ts. This amount is included in the less than one year purchase commitments amount shown below. Purchase Commitments The Company determines an estimate of contractual purchase commitments in the ordinary course of business primarily for the purchase of precious metals and agricultural and energy commodities. Unpriced contract commitments have been estimated using September 30, 2024 fair values. Purchase commitments and other obligations as of September 30, 2024 for less than one year, one to three years, three to five years, and after five years were $57,592.2 million, $810.0 million, $78.5 million, and $126.2 million respectively. The purchase commitments for less than one year will be offset by corresponding sales commitments of $56,275.9 million. Exchange Member Guaranties The Company is a member of various exchanges that trade and clear futures and option contracts. The Company is also a member of and provides guaranties to securities clearinghouses and exchanges in connection with client trading activities. Associated with its memberships, the Company may be required to pay a proportionate share of the financial obligations of another member who may default on its obligations to the exchanges. While the rules governing different exchange memberships vary, in general the Company’s guaranty obligations would arise only if the exchange had previously exhausted its resources. In addition, any such guaranty obligation would be apportioned among the other non-defaulting members of the exchange. Any potential contingent liability under these arrangements is not quantifiable and could exceed the cash and securities posted to the clearinghouse as collateral. The Company has not recorded any contingent liability in the consolidated financial statements for these agreements and believes that any potential requirement to make payments under these agreements is remote. Self-Insurance The Company self-insures its medical and dental claims costs up to a stop loss amount, for eligible participating employees and retirees, and for qualified dependents, subject to deductibles and limitations. Liabilities are recognized based on claims filed and an estimate of claims incurred but not reported. The Company has purchased stop-loss coverage to limit its exposure on a per claim basis and in aggregate in the event that aggregated actual claims would exceed 120% of the actuarial estimate. The Company is insured for covered costs in excess of these limits. Although the ultimate outcome of these matters may exceed the amounts recorded and additional losses may be incurred, the Company does not believe that any additional potential exposure for such liabilities will have a material adverse effect on the Company’s consolidated financial position or results of operations. As of September 30, 2024 and 2023, the Company had $2.2 million and $1.9 million, respectively, accrued for self-insured medical and dental claims included in Accounts payable and other liabilities in the Consolidated Balance Sheets.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss, Net	12 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Accumulated Other Comprehensive Loss, Net	Accumulated Other Comprehensive Loss, Net Comprehensive income consists of net income and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net income. Other comprehensive loss and income includes gains and losses on cash flow hedges, net actuarial gains and losses from defined benefit pension plans, and gains and losses on foreign currency translations. The following table summarizes the changes in accumulated other comprehensive loss for the years ended September 30, 2024, 2023, and 2022. (in millions) Foreign Currency Translation Adjustment Pension Benefits Adjustment Cash Flow Hedge Accumulated Other Comprehensive Loss, net Balances as of September 30, 2021 $ (22.7) $ (2.4) $ — $ (25.1) Other comprehensive loss net of tax (11.7) (0.3) (53.5) (65.5) Balances as of September 30, 2022 $ (34.4) $ (2.7) $ (53.5) $ (90.6) Other comprehensive income net of tax 3.2 0.5 35.1 38.8 Balances as of September 30, 2023 $ (31.2) $ (2.2) $ (18.4) $ (51.8) Other comprehensive income/(loss) net of tax (0.1) 1.0 25.7 26.6 Balances as of September 30, 2024 $ (31.3) $ (1.2) $ 7.3 $ (25.2)

Revenue from Contracts with Cli

Revenue from Contracts with Clients	12 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Clients	Revenue from Contracts with Clients The Company’s revenues from contracts with clients subject to FASB ASC 606, Revenue from Contracts with Customers (“Topic 606”) represent approxim ately 2.2%, 5.7%, and 5.5% of the Company’s total revenues for the years ended September 30, 2024, 2023, and 2022, respectively. Revenues within the scope of Topic 606 are presented within Commission and clearing fees , Consulting, management, and account fees , and Sales of physical commodities , on the Consolidated Income Statements. Revenues that are not within the scope of Topic 606 are presented within Sales of physical commodities , Principal gains, net , and Interest income on the Consolidated Income Statements. The following table represents a disaggregation of the Company’s total revenues separated between revenues from contracts with clients and other sources of revenue for the periods indicated (in millions): Year Ended September 30, 2024 2023 2022 Revenues from contracts with clients: Commission and clearing fees: Sales-based: Exchange-traded futures and options $ 226.1 $ 214.1 $ 210.7 OTC derivative brokerage 11.3 14.5 16.8 Equities and fixed income 65.9 57.8 62.9 Mutual funds 3.1 3.0 4.1 Insurance and annuity products 11.0 9.2 9.3 Other — 3.4 3.1 Total sales-based commission 317.4 302.0 306.9 Trailing: Mutual funds 12.7 12.4 14.1 Insurance and annuity products 15.2 14.2 16.0 Total trailing commission 27.9 26.6 30.1 Clearing fees 180.2 153.3 153.2 Trade conversion fees 13.1 8.5 11.5 Other 9.4 8.0 6.2 Total commission and clearing fees 548.0 498.4 507.9 Consulting, management, and account fees: Underwriting fees 0.4 0.7 0.5 Asset management fees 50.9 45.1 43.9 Advisory and consulting fees 38.2 35.0 30.9 Sweep program fees 44.4 48.6 13.1 Client account fees 19.8 15.9 16.0 Other 13.5 13.7 6.9 Total consulting, management, and account fees 167.2 159.0 111.3 Sales of physical commodities: Precious metals sales under ASC Topic 606 1,500.7 2,836.0 2,988.3 Total revenues from contracts with clients $ 2,215.9 $ 3,493.4 $ 3,607.5 Method of revenue recognition: Point-in-time $ 2,054.5 $ 3,338.1 $ 3,489.5 Time elapsed 161.4 155.3 118.0 Total revenues from contracts with clients 2,215.9 3,493.4 3,607.5 Other sources of revenues Physical precious metals under ASC Topic 815 91,241.1 50,979.5 57,404.3 Physical agricultural and energy products 3,844.4 4,315.7 3,660.0 Principal gains, net 1,189.6 1,079.9 1,145.2 Interest income 1,396.8 987.6 219.0 Total revenues $ 99,887.8 $ 60,856.1 $ 66,036.0 The substantial majority of the Company’s performance obligations for revenues from contracts with clients are satisfied at a point in time and are typically collected from clients by debiting client trading accounts with the Company. Commission and clearing fee revenue and consulting, management, and account fees revenue are primarily related to the Commercial, Institutional and Self-Directed/Retail reportable segments. Principal gains, net are contributed by all of the Company’s reportable segments. Interest income is primarily related to the Commercial and Institutional reportable segments. Precious metals trading and agricultural and energy product trading revenues are primarily related to the Commercial reportable segment. Precious metals retail sales revenues are primarily related to the Self-Directed/Retail reportable segment. Commission and Clearing Fees Commission revenue represents sales and brokerage commissions generated by internal brokers, introducing broker-dealers, or registered investment advisors of introducing-broker dealers for their clients’ trading activity in futures, options on futures, OTC derivatives, fixed income securities, equity securities, mutual funds, and annuities. The Company views the selling, distribution, and marketing, or any combination thereof, of mutual funds and insurance and annuity products to clients on the Company’s registered investment advisor (“RIA”) platform as a single performance obligation to the product sponsors. The Company is the principal for commission revenue, as it is responsible for executing client purchases and sales, and maintaining relationships with product sponsors for trailing commissions. Introducing broker dealers and registered investment advisors assist the Company in performing its obligations. Accordingly, total commission revenues are reported on a gross basis. The Company primarily generates commission revenue on exchange-traded derivatives, OTC derivatives, and securities. Exchange-traded and OTC derivative commissions are recognized at a point in time on the trade date when the client, either directly or through the use of an internal broker or introducing broker, requests the clearance and execution of a trade. Securities commissions are either sale-based commissions that are recognized at a point in time on the trade date or trailing commission that are recognized over time as earned. Sales-based securities commissions are typically a flat fee per security transaction and in certain instances are based on a percentage of the trade date transaction value. Trailing commission revenue is generally based on a percentage of the periodic fair value of clients’ investment holdings in trail-eligible assets, and is recognized over the period during which services, such as on-going support, are performed. As trailing commission revenue is based on the fair value of clients’ investment holdings in trail-eligible assets. This variable consideration is constrained until the fair value of trail-eligible assets is determinable. Clearing fees generally represent transaction based fees charged by the various exchanges and clearing organizations at which the Company or one of its clearing brokers is a member for the privilege of executing and clearing trades through them. Clearing fees are generally passed through to the clients’ accounts and are reported gross as the Company maintains control over the clearing and execution services provided, maintains relationships with the exchanges or clearing brokers, and has ultimate discretion in whether the fees are passed through to the clients and the rates at which they are passed through. As clearing fees are transactional based revenues they are recognized at a point in time on the trade date along with the related commission revenue when the client requests the clearance and execution of a trade. Trade Conversion Fees Trade conversion fees include revenue earned from converting foreign ordinary equities into an American Depository Receipt (“ADR”) or Global Depository Receipt (“GDR”) and fees earned from converting an ADR or GDR into foreign ordinary equities on behalf of clients. Trade conversion revenue is recognized at a point in time on the trade date. Underwriting Fees Revenues from investment banking consists of revenues earned from underwriting fixed income securities, primarily municipal and asset-backed securities, and are recognized in revenues upon completion of the underlying transaction, which is generally the trade date, based upon the terms of the assignment as the performance obligation is to successfully broker a specific transaction. Asset Management Fees The Company earns asset management fees on Company sponsored and managed mutual funds and on the advisory accounts of independent registered investment advisors on the Company’s platform. The Company provides ongoing investment advice and acts as a custodian, providing brokerage and execution services on transactions, and performs administrative services for these accounts. This series of performance obligations transfers control of the services to the client over time as the services are performed. This revenue is recognized ratably over time to match the continued delivery of the performance obligations to the client over the life of the contract. The asset management revenue generated is based on a percentage of the market value of the eligible assets in the clients’ accounts. As such, the consideration for this revenue is variable and this variable consideration is constrained until the market value of eligible assets in the clients’ accounts is determinable. Advisory and Consulting Fees Advisory and consulting fees are primarily related to risk management consulting fees which are billed and recognized as revenue on a monthly basis when risk management services are provided. Risk management consulting contracts are generally for a minimum term of six months and then continue from month to month, but may be terminated at any time after the original six months by either party upon providing written notice. Advisory and consulting fees are not variable based on client trading activities. This revenue is generally recognized ratably over time to match the continued delivery of the performance obligation to the client over the life of the contract. Sweep Program Fees The Company earns fees generated in lieu of interest income from a multi-bank sweep program with unaffiliated banks and money market funds. Pursuant to contractual arrangements with clients and their introducing-brokers, available cash balances in client accounts are swept into either Federal Deposit Insurance Corporation (“FDIC”) insured cash accounts at unaffiliated banks or unaffiliated money market funds for which the Company earns a portion of the income generated by the client balances for administration and recordkeeping. The fees generated by the Company’s multi-bank sweep program are reported net of the balances remitted to the introducing-brokers and the clients of introducing-brokers. These fees are paid and recognized over time to match the continued delivery of the administration and recordkeeping performance obligations to the life of the contract. The fees earned under this program are generally based upon the type of sweep account, prevailing interest rates, and the amount of client balances invested. Client Account Fees Client account fees represent fees earned for custodial, recordkeeping, and administrative functions performed for client accounts. These functions include statement delivery fees, account transfer fees, safekeeping fees, errors and omission insurance fees, platform fees, and other fees. Client account fees that are transactional based, such as account transfer fees, are recognized at a point in time when the related performance obligation is satisfied. Client account fees that are related to ongoing services, such as statement delivery fees and errors and omission insurance fees, are recognized over time. Client account fees that relate to ongoing services are typically billed to clients’ accounts on a monthly or quarterly basis. Precious Metals Sales Under ASC Topic 606 The Company principally generates revenue from sale of bullion coins and small bars of precious metal via its websites. Revenues from the sale of physical precious metals are recognized when control of the inventory is transferred within the meaning of Topic 606. This revenue source primarily executes its contracts on a spot basis at agreed upon rates and amounts, which further aligns with Topic 606. Physical Precious Metals Under ASC 815 The Company principally generates revenue from trading physical precious metals on an OTC basis. Revenues from the sale of physical precious metals are recorded on a trade date basis and generally settle on an unallocated basis. Substantially all of the Company’s sales of precious metals are conducted using sales contracts that meet the definition of derivative instruments in accordance with ASC 815, Derivatives and Hedging (“Topic 815”). The contracts underlying the Company’s commitment to deliver precious metals are referred to as fixed price forward commodity contracts because the price of the commodity is fixed at the time the order is placed. Although the contracts typically are executed on a spot basis and settle on unallocated account, the client has the option to request delivery of the precious metals, the option to net settle out of the position by executing an offsetting trade, or the option to roll the transaction to a subsequent maturity date. Thus, the sales contracts contain embedded option derivatives that would be subject to the guidance in Topic 815. As the contracts are subject to the guidance in Topic 815, the fixed price derivative sales contracts are outside the scope of Topic 606. The Company recognizes revenue when control of the inventory is transferred within the meaning of Topic 606. Physical precious metals trading revenue generated by registered broker-dealer subsidiaries is presented on a net basis and included as a component of Principal gains, net in the Consolidated Income Statements, in accordance with U.S GAAP for broker-dealers. Revenues from the sale of physical precious metals originating from non-broker-dealer subsidiaries is reported gross in the Consolidated Income Statements. Physical Agricultural and Energy Products The Company principally generates revenue from merchandising and originating physical agricultural and energy commodities from forward firm sales commitments accounted for in accordance with Topic 815. The fixed and provisionally-priced derivative sales contracts that result in physical delivery are outside the scope of Topic 606. The Company recognizes revenue when control of the inventory is transferred within the meaning of Topic 606. Principal Gains, Net Principal gains, net includes revenues on financial transactions or contracts for which the Company acts as principal. This revenue is reported on a net basis and is primarily outside the scope of ASC 606. Principal gains, net includes margins generated from OTC derivative trades, equities, fixed income, precious metals with derivative characteristics, and foreign exchange executed with clients and other counterparties and are recognized on a trade-date basis. Principal gains, net, also includes realized and unrealized gains and losses derived principally from market making activities in OTC derivatives, equities, fixed income, and foreign exchange. Net dealer inventory and investment gains are recognized on a trade-date basis and include realized gains or losses and changes in unrealized gains or losses on investments at fair value. Principal gains, net also includes dividend income on long equity positions and dividend expense on short equity positions, which are recognized on the ex-dividend date. The following table indicates the relevant income and expense: Year Ended September 30, (in millions) 2024 2023 2022 Dividend income on long equity positions $ 192.3 $ 32.0 $ 142.3 Dividend expense on short equity positions 191.2 33.3 134.0 Dividend income/(loss) net of dividend expense reported within Principal Gains, net $ 1.1 $ (1.3) $ 8.3 Interest Income Interest income is generated from client funds deposited with the Company to satisfy margin required by third-party banks, exchange-clearing organizations, or other FCMs. Interest income is also generated from investing client funds in allowable securities, primarily U.S. Treasury obligations and from trading fixed income securities that the Company holds in its market-making businesses. Interest income also includes interest generated from collateralized transactions, including securities borrowed and securities purchased under agreements to resell, and from extending margin loans to clients. Interest income is recognized on an accrual basis and is not within the scope of Topic 606. Remaining Performance Obligations Remaining performance obligations are services that the firm has committed to perform in the future in connection with its contracts with clients. The Company’s remaining performance obligations are generally related to its risk management consulting and asset management contracts with clients. Revenues associated with remaining performance obligations related to these contracts with clients are not material to the overall consolidated results of the Company. Similar to the above, risk management consulting contracts are generally for a minimum term of six months and then continue from month to month, but may be terminated at any time after the original six months by either party upon providing written notice. Asset management contracts may be terminated by the client at any time. For the Company’s asset management activities, where fees are calculated based on a percentage of the market value of eligible assets in client’s accounts, future revenue associated with remaining performance obligations cannot be determined as such fees are subject to fluctuations in the market value of eligible assets in clients’ accounts. Practical Expedients The Company has applied Topic 606’s practical expedient that permits for the non-disclosure of the value of performance obligations for (i) contracts with an original expected length or one year or less and (ii) contracts for which the Company recognizes revenue at the amount to which is has the right to invoice for services performed.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation The 2022 Omnibus Incentive Compensation Plan (the “Omnibus Plan”), authorizes the Company to issue up to 3.5 million shares in connection with the grants of stock options and restricted stock, and 0.4 million shares are available for issuance as of September 30, 2024. Share-based compensation expense is included in Compensation and benefits in the Consolidated Income Statements and totaled $37.2 million, $28.0 million and $17.8 million for the years ended September 30, 2024, 2023, and 2022, respectively. Stock Options The Company sponsors the Omnibus Plan for its directors, officers, employees and consultants. Shares underlying awards that expire or are canceled generally become available for issuance again under the Omnibus Plan. The Company settles stock option exercises with newly issued shares of common stock. Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions: Year Ended September 30, 2024 2023 2022 Expected stock price volatility 38 % 42 % 39 % Expected dividend yield — % — % — % Risk free interest rate 2.21 % 1.60 % 1.54 % Average expected life (in years) 6.32 4.25 5.21 Expected stock price volatility rates are primarily based on historical volatility. The Company has not paid dividends in the past and does not currently expect to do so in the future. Risk free interest rates are based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option or award. The average expected life represents the estimated period of time that options or awards granted are expected to be outstanding, based on the Company’s historical share option exercise experience for similar option grants. The weighted average fair value of options issued during the years ended September 30, 2024, 2023, and 2022 was $26.77, $22.14, and $15.21, respectively. The following is a summary of stock option activity for the year ended September 30, 2024: Number of Weighted Weighted Weighted Aggregate Balances as of September 30, 2023 1,763,788 $ 35.65 $ 10.56 3.80 $ 51.1 Granted 1,627,150 $ 65.37 $ 26.77 Exercised (237,613) $ 32.89 $ 9.07 Forfeited (89,432) $ 36.50 $ 10.65 Expired (2,320) $ 40.88 $ 14.69 Balances as of September 30, 2024 3,061,573 $ 51.63 $ 19.28 5.06 $ 92.6 Exercisable at September 30, 2024 721,635 $ 34.58 $ 10.05 2.68 $ 34.1 The total compensation cost not yet recognized for non-vested awards of $43.1 million as of September 30, 2024 has a weighted-average period of 3.01 years over which the compensation expense is expected to be recognized. The total intrinsic value of options exercised during the years ended September 30, 2024, 2023, and 2022 was $9.8 million, $4.2 million and $39.0 million, respectively. The options outstanding as of September 30, 2024 broken down by exercise price are as follows: Exercise Price Number of Options Outstanding Weighted Average Exercise Price Weighted Average Remaining Term $ 25.00 - $ 30.00 810,000 $ 30.00 2.18 $ 35.00 - $ 40.00 234,020 $ 39.10 2.31 $ 40.00 - $ 45.00 289,212 $ 41.36 4.60 $ 45.00 - $ 75.00 1,728,341 $ 65.18 6.86 3,061,573 $ 51.63 5.06 Restricted Stock The Company grants restricted stock under the Omnibus Plan to its directors, officers, and employees. Restricted stock awards that expire or are canceled generally become available for issuance again under the Omnibus Plan. The Company utilizes newly issued shares of common stock to make restricted stock grants. The following is a summary of restricted stock activity through September 30, 2024: Number of Weighted Weighted Aggregate Balances as of September 30, 2023 1,026,642 $ 54.10 1.24 $ 66.5 Granted 477,096 $ 68.10 Vested (494,568) $ 51.30 Forfeited (1,582) $ 54.79 Balances as of September 30, 2024 1,007,588 $ 62.10 1.13 $ 82.5 The total compensation cost not yet recognized of $43.9 million as of September 30, 2024 has a weighted-average period of 1.13 years over which the compensation expense is expected to be recognized. Compensation expense is amortized on a straight-line basis over the vesting period. Restricted stock grants are included in the Company’s total issued and outstanding common shares.

Retirement Plans

Retirement Plans	12 Months Ended
	Sep. 30, 2024
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans Defined Benefit Retirement Plans The Company has a frozen qualified defined benefit pension plan (the “Qualified Plan”) and a nonqualified defined benefit pension plan (the “Nonqualified Plan”), and recognizes their funded status, measured as the difference between the fair value of the plan assets and the projected benefit obligation, in Other assets or Accounts payable and other accrued liabilities in the Consolidated Balance Sheets, depending on the funded status of each plan. The Qualified Plan assets, which are managed in a third-party trust, primarily consist of a diversified blend of approximately 90% debt securities and 10% equity investments and had a total fair value of $32.3 million and $29.6 million as of September 30, 2024 and 2023, respectively. All Qualified Plan assets fall within Level 2 of the fair value hierarchy. The benefit obligation associated with the Qualified Plan will vary over time only as a result of changes in market interest rates, the life expectancy of the plan participants, and benefit payments, since the accrual of benefits was suspended when the Qualified Plan was frozen in 2006. The benefit obligation was $25.9 million and $24.6 million and the discount rate assumption used in the measurement of this obligation was 4.90% and 5.80% as of September 30, 2024 and 2023, respectively. Related to the Qualified Plan, the Company’s net pension obligation was in a funded status of $6.4 million and $5.0 million as of September 30, 2024 and 2023, respectively. The Nonqualified Plan assets had a total fair value of less than $0.1 million as of September 30, 2024 and 2023. The benefit obligation associated with the Nonqualified Plan will vary over time only as a result of changes in market interest rates, the life expectancy of the plan participants, and benefit payments. There are no active participants in the Nonqualified plan. The benefit obligation was $1.1 million and $1.1 million as of September 30, 2024 and 2023, respectively. Related to the Nonqualified Plan, the Company’s unfunded pension obligation was $1.1 million and $1.1 million as of September 30, 2024 and 2023, respectively. The Company recognized a net periodic cost of $0.1 million and $0.3 million for the years ended September 30, 2024 and 2023, respectively, and a net periodic benefit of $0.1 million for the year ended September 30, 2022. The expected long-term return on plan assets assumption was 4.65% for 2024. The Company made contributions of $0.1 million to the plans in the years ended September 30, 2024 and 2023. The Company complies with minimum funding requirements. The estimated undiscounted future benefit payments are expected to be $2.0 million in 2025, $2.0 million in 2026, $2.0 million in 2027, $2.1 million in 2028, $2.1 million in 2029, and $9.4 million in 2030 through 2034. Defined Contribution Retirement Plans The Company offers participation in the StoneX Group Inc. 401(k) Plan (“401(k) Plan”), a defined contribution plan providing retirement benefits to all domestic full-time non-temporary employees who have reached 21 years of age. Employees may contribute from 1% to 80% of their annual compensation to the 401(k) Plan, limited to a maximum annual amount as set periodically by the Internal Revenue Service. For each participant’s eligible elective deferral contribution to the 401(k) Plan, the Company makes matching contributions to the 401(k) Plan in amounts equal to 100% on the first 3% of employee contributions and 50% on the next 4% of employee contributions, up to 7% of employee compensation. Employees are fully vested in both employee and matching employer contributions immediately. U.K. based employees of StoneX Group are eligible to participate in a defined contribution pension plan. The Company contributes double the employee’s contribution up to 10% of total base salary for this plan. For this plan, employees are 100% vested in both the employee and employer contributions at all times. For fiscal years ended September 30, 2024, 2023, and 2022, the Company’s contributions to these defined contribution plans were $23.3 million, $19.2 million and $16.9 million, respectively.

Other Expenses

Other Expenses	12 Months Ended
	Sep. 30, 2024
Other Expenses [Abstract]
Other Expenses	Other Expenses Other expenses consisted of the following, for the periods indicated. Year Ended September 30, (in millions) 2024 2023 2022 Non-income taxes $ 12.8 $ 16.8 $ 13.5 Insurance 11.8 11.1 10.8 Employee related expenses 7.3 10.1 9.6 Other direct business expenses 15.1 14.8 10.0 Membership fees 3.7 3.4 3.3 Director and public company expenses 2.1 2.3 1.8 Office expenses 2.4 1.9 1.7 Other expenses 9.9 6.0 9.9 Total other expenses $ 65.1 $ 66.4 $ 60.6

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Inflation Reduction Act In August 2022, the Inflation Reduction Act of 2022 (“Act”) was signed into U.S. law. Under the Act, there is a new 15% corporate minimum tax and a new 1% excise tax on stock repurchases that are effective after December 31, 2022. Further, the Act includes provisions related to climate change, energy, and health care. These provisions are not expected to have a material impact on the Company’s consolidated financial statements. Income tax expense/(benefit) for the years ended September 30, 2024, 2023, and 2022 was allocated as follows: Year Ended September 30, (in millions) 2024 2023 2022 Income tax expense attributable to income from operations $ 93.3 $ 84.5 $ 70.1 Taxes allocated to stockholders’ equity, related to pension liabilities 0.3 0.2 (0.1) Taxes allocated to stockholders’ equity, related to hedge accounting 8.1 11.1 (17.0) Total income tax expense $ 101.7 $ 95.8 $ 53.0 The components of income tax expense/(benefit) attributable to income from operations were as follows: Year Ended September 30, (in millions) 2024 2023 2022 Current taxes: U.S. federal $ 26.4 $ 15.8 $ 8.2 U.S. state and local 5.9 3.9 3.6 Australia 0.2 2.2 2.8 Brazil 18.2 16.0 12.6 Germany 4.2 4.5 8.9 Singapore 7.7 4.9 2.0 Switzerland — 2.6 — United Kingdom 34.5 30.9 29.2 Other international 6.7 6.1 3.1 Total current taxes 103.8 86.9 70.4 Deferred taxes: U.S. federal 1.7 (1.1) 3.4 U.S. state and local 0.5 — (0.1) Australia (0.1) 0.1 (0.2) Brazil (3.6) — (0.8) Germany (0.4) — — Switzerland (1.2) 0.4 — United Kingdom (7.2) (1.4) (2.7) Other international (0.2) (0.4) 0.1 Total deferred taxes (10.5) (2.4) (0.3) Income tax expense $ 93.3 $ 84.5 $ 70.1 U.S. and international components of income from operations, before tax, were as follows: Year Ended September 30, (in millions) 2024 2023 2022 U.S. $ 97.8 $ 135.1 $ 50.0 Australia 0.5 7.4 8.7 Brazil 37.8 35.3 25.3 Germany 12.1 13.3 27.8 Singapore 55.1 38.1 19.4 Switzerland (2.3) 22.5 — United Kingdom 121.3 77.7 104.8 Other international 31.8 (6.4) 41.2 Income from operations, before tax $ 354.1 $ 323.0 $ 277.2 Items accounting for the difference between income taxes computed at the federal statutory rate and income tax expense were as follows: Year Ended September 30, 2024 2023 2022 Federal statutory rate effect of: 21.0 % 21.0 % 21.0 % U.S. State and local income taxes 1.4 % 1.0 % 1.0 % Foreign earnings and losses taxed at different rates 2.6 % 1.1 % 1.1 % Change in valuation allowance — % (0.4) % 0.9 % U.K. bank tax 0.2 % 0.3 % 2.6 % U.S. permanent items (0.4) % 0.2 % 0.2 % Non-deductible compensation 0.8 % 2.0 % 0.7 % Foreign permanent items (1.4) % 0.4 % (2.8) % U.S. bargain purchase gain — % (1.4) % — % GILTI 2.0 % 2.0 % 0.6 % Unrecognized tax benefits 0.1 % — % — % Effective rate 26.3 % 26.2 % 25.3 % The components of deferred income tax assets and liabilities were as follows: (in millions) September 30, 2024 September 30, 2023 Deferred tax assets: Share-based compensation $ 12.2 $ 7.4 Deferred compensation 5.4 5.4 Net operating loss carryforwards 19.6 17.2 Intangible assets 1.3 3.8 Bad debt reserve 7.2 9.6 Hedging — 5.9 Foreign tax credit carryforwards 1.2 0.6 Other compensation 7.5 7.8 Pension 2.5 3.6 Right of use assets 30.1 20.1 Property and equipment 3.4 — Other 1.6 1.1 Total gross deferred tax assets 92.0 82.5 Less valuation allowance (15.5) (12.4) Deferred tax assets 76.5 70.1 Deferred income tax liabilities: Unrealized gain on securities 3.1 2.8 Prepaid expenses 2.5 5.0 Property and equipment — 1.6 Right of use liabilities 26.7 17.2 Mark to market on inventory 3.8 4.8 Other deferred liabilities 0.5 1.4 Hedging 2.2 — Deferred income tax liabilities 38.8 32.8 Deferred income taxes, net $ 37.7 $ 37.3 Deferred income tax balances reflect the effects of temporary differences between the carrying amounts of assets and liabilities and their tax bases and are stated at enacted tax rates expected to be in effect when taxes are actually paid or recovered. As of September 30, 2024 and 2023, the Company has net operating loss carryforwards for U.S. federal, state, local, and fore ign income tax purposes of $5.3 million and $5.4 million, net of valuation allowances, respectively, which are available to offset future taxable income in these jurisdictions. The state and local net operating loss carryforwards of $4.2 million, net of valuation allowance, begin to expire after September 2024. The Company also has $0.7 million, net of valuation allowances, of federal net operating loss carryforwards, which consist of a portion that will expire in tax years ending 2031 through 2036, and are limited by Internal Revenue Code (“IRC”) Section 382. The remaining portion of the federal net operating loss carryforwards do not expire, but cannot be utilized until after 2037 and are also limited by IRC Section 382. As of September 30, 2024, the Company has $0.4 million, net of valuation allowance, of foreign net operating loss carryforwards primarily in Brazil, Columbia, Ireland, Germany, and Switzerland, which have various carryforward periods. The valuation allowance for deferred tax assets as of September 30, 2024 was $15.5 million. The net change in the total valuation allowance for the year ended September 30, 2024 was an increase of $3.1 million. The increase was related to the increase in foreign net operating loss carryforwards and increases related to foreign tax credits. The valuation allowances as of September 30, 2024 and 2023 were primarily related to U.S. state and local and foreign net operating loss carryforwards that, in the judgment of management, are not more likely than not to be realized. T he Company does not intend to distribute earnings of its foreign subsidiaries in a taxable manner, and therefore intends to limit distributions to earnings previously taxed in the U.S., or earnings that would qualify for the 100 percent dividends received deduction, and earnings that would not result in any significant foreign taxes. The Company repatriated $100.0 million and $35.5 million during the years ended September 30, 2024 and 2023, respectively, of earnings previously taxed in the U.S. resulting in no significant incremental taxes. Therefore, the Company has not recognized a deferred tax liability on its investment in foreign subsidiaries. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authority, based upon the technical merits of the position. The tax benefit recognized in the consolidated financial statements from such a position is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Year Ended September 30, (in millions) 2024 2023 2022 Balance, beginning of year $ — $ — $ — Gross increases for tax positions related to current year — — — Gross increases for tax positions related to prior years 0.3 — — Gross decreases for tax positions of prior years — — — Settlements — — — Lapse of statute of limitations — — — Balance, end of year $ 0.3 $ — $ — The Company had $0.3 million of unrecognized tax benefits as of September 30, 2024 that, if recognized, would affect the effective tax rate. The Company had a de minimis balance of unrecognized tax benefits as of September 30, 2023 and 2022 that, if recognized, would affect the effective tax rate. Accrued interest and penalties are included in the related tax liability line in the Consolidated Balance Sheets. The Company had $0.1 million and $0.0 million accrued interest and penalties included in the Consolidated Balance Sheets as of September 30, 2024 and 2023, respectively. The Company recognizes accrued interest and penalties related to income taxes as a component of income tax expense. The Company had $0.1 million of interest, net of federal benefit, and penalties recognized as a component of income tax expense during the year ended September 30, 2024 and a de minimis amount during the years ended September 30, 2023 and 2022.

Acquisitions

Acquisitions	12 Months Ended
	Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Acquisitions	Acquisitions The Company’s consolidated financial statements include the operating results and cash flows of the acquired businesses from the dates of acquisition. Acquisitions in Fiscal 2024 Trust Advisory Group, Ltd. On September 20, 2024, the Company’s subsidiary StoneX Advisors Inc. executed a sale and purchase agreement to acquire all of the outstanding shares of Trust Advisory Group, Ltd. (“TAG”), a Massachusetts corporation. . This transaction was effective on the closing date of September 20, 2024. The purchase price consists of $1.5 million of cash consideration paid at closing, plus an estimated $1.0 million hold-back due to be paid on or before February 15, 2025 and a contingent earn-out valued at approximately $1.7 million due within 90 days after March 31, 2026. The business activities of TAG have been assigned to the Company’s Self-Directed/Retail reportable segment. The acquisition generated $2.0 million of Goodwill and $2.1 million of intangible assets. Acquisitions in Fiscal 2023 Cotton Distributors Inc. On October 31, 2022, the Company’s wholly owned subsidiary, StoneX Netherlands B.V., acquired CDI-Societe Cotonniere De Distribution S.A (“CDI”), based in Switzerland. CDI operates a global cotton merchant business with clients and producers in Brazil and West Africa as well as buyers throughout Asia. The purchase price is approximately $42.7 million, which is based on CDI’s estimated acquisition date tangible book value as defined by the terms of the purchase agreement and based on Swiss accounting practices, and an earn-out payment due to the seller. The earn-out value was determined by CDI’s performance with respect to certain contracts entered into before the acquisition date and settling after the closing date. During the year ended September 30, 2023, CDI contributed $36.9 million of Net operating revenue and $18.6 million of Net income . The gain on acquisition was principally due to the fair value of commodity forward purchases and sales contracts and fair value of identified intangible assets acquired exceeding the consideration paid for these assets. (in millions) Fair Value Cash and cash equivalents $ 8.2 Deposits with and receivables from broker-dealers, clearing organizations, and counterparties 7.7 Receivable from clients, net 51.9 Financial instruments owned, at fair value 45.7 Deferred income taxes, net (3.3) Property and equipment, net 0.1 Physical commodities inventory, net 22.5 Other assets 6.7 Total fair value of tangible assets acquired 139.5 Accounts payable and other accrued liabilities 40.0 Financial instruments sold, not yet purchased, at fair value 28.3 Payables to lenders under loans 10.1 Payables to broker-dealers, clearing organizations, and counterparties 0.4 Payables to clients 2.6 Income taxes payable 0.8 Total fair value of liabilities assumed 82.2 Fair value of tangible net assets acquired $ 57.3 Identifiable intangible assets acquired Client relationships $ 4.7 Supplier relationships 3.7 Trade name 0.4 Non-compete 0.1 Total fair value of intangible assets acquired 8.9 Fair value of identifiable net assets acquired 66.2 Total merger consideration 42.7 Gain on acquisition $ 23.5 Incomm S.A.S. On February 3, 2023, the Company’s subsidiary StoneX Commodity Solutions LLC executed a sale and purchase agreement to acquire all of the outstanding shares of Incomm S.A.S. (“Incomm”), a company duly incorporated and in existence according with the laws of Colombia. This transaction was effective on the closing date of February 3, 2023. Incomm was established to support the import of grain and feed products for Colombian clients, and is a proven resource in management of customs clearing, inventory management at destination ports and providing non-recourse trade finance for destination buyers via local Colombian banks. The purchase price consists of $0.2 million of cash consideration and also includes a contingent earn-out valued at approximately $1.3 million with annual payments over the four years following the acquisition. The contingent earn-out payments are variable in nature, as they equal a percentage of the acquired business line’s pre-tax profits, as defined in the purchase agreement. The business activities of Incomm will be assigned to the Company’s Commercial reportable segment. The acquisition generated $1.3 million of Goodwill.

Regulatory Requirements and Sub

Regulatory Requirements and Subsidiary Dividend Restrictions	12 Months Ended
	Sep. 30, 2024
Capital and Other Regulatory Requirements [Abstract]
Regulatory Requirements and Subsidiary Dividend Restrictions	Regulatory Requirements and Subsidiary Dividend Restrictions The Company’s subsidiary StoneX Financial Inc. is registered as a broker dealer and member of the Financial Industry Regulatory Authority (“FINRA”) subject to the SEC Uniform Net Capital Rule 15c3-1, which requires the maintenance of minimum net capital. StoneX Financial Inc. is also a futures commission merchant registered with the CFTC and subject to the net capital requirements of the CFTC Regulation 1.17. Under the more restrictive of these rules, StoneX Financial Inc. is required to maintain “adjusted net capital”, equivalent to the greater of $1.5 million or 8% of client and non-client risk maintenance margin requirements on all positions, as defined in such rules, regulations, and requirements. Adjusted net capital and the related net capital requirement may fluctuate on a daily basis. StoneX Financial Inc., along with certain regulated affiliates, including GAIN Capital Group, LLC and others, has a restriction on dividends. For StoneX Financial Inc. withdrawn excess capital cannot reduce excess capital, after haircuts and charges, to an amount less than 120% of the greatest minimum requirement. The Company’s subsidiary, GAIN Capital Group, LLC, is subject to regulation by the CFTC and NFA and is required to maintain specific levels of regulatory capital. As a futures commission merchant and retail foreign exchange dealer, GAIN Capital Group, LLC is required to maintain adjusted net capital of the greater of $1.0 million or 8% of customer and non-customer risk maintenance margin, or $20.0 million plus 5.0% of the amount of retail customer liabilities over $10.0 million, plus 10% of all liabilities owed to eligible contract participant counterparties acting as a dealer that are not an affiliate. Swap dealers are subject to a comprehensive regulatory regime with new obligations for the swaps activities for which they are registered, including adherence to risk management policies, supervisory procedures, trade record and real time reporting requirements, as well as rules for minimum capital requirements which became effective October 6, 2021. Our subsidiary, StoneX Markets LLC, is a CFTC registered swap dealer, and under these capital rules, StoneX Markets LLC is subject to a minimum regulatory capital requirement of $20.0 million. StoneX Financial Inc. as a registered securities carrying broker dealer is also subject to Rule 15c3-3 of the Securities Exchange Act of 1934 (“Rule 15c3-3”), which requires the Company to maintain separate accounts for the benefit of securities clients and proprietary accounts of broker dealers (“PABs”). These client protection rules require the Company to maintain special reserve bank accounts (“SRBAs”) for the exclusive benefit of securities clients and PABs. As of September 30, 2024, StoneX Financial Inc. prepared reserve computations for the client accounts and PAB accounts in accordance with the customer reserve computation guidelines set forth in Rule 15c3-3. Based upon these computations, excess of total credits over debits was $87.7 million as of September 30, 2024. The Company held $30.8 million in customer SRBAs as of September 30, 2024, and made additional deposits of $55.1 million on October 2, 2024. The total PAB credits over total PAB debits was $7.7 million as of September 30, 2024 and the PAB reserve requirement was $7.7 million as of September 30, 2024. The Company held $12.5 million in the PAB SRBA as of September 30, 2024, and withdrew $3.8 million on October 2, 2024. Pursuant to the requirements of the Commodity Exchange Act, funds deposited by clients of StoneX Financial Inc. supporting trading of futures and options on futures on a U.S. commodities exchange must be carried in separate accounts which are designated as segregated client accounts. Pursuant to the requirements of the CFTC, funds deposited by clients of StoneX Financial Inc. related to trading futures and options on futures traded on, or subject to the rules of a foreign board of trade, must be carried in separate accounts in, which are designated as secured clients’ accounts. As of September 30, 2024, StoneX Financial Inc. had client segregated and client secured funds of $5,762.6 million and $262.5 million, respectively, compared to a minimum regulatory requirement of $5,690.4 million and $250.5 million, respectively. The Company’s subsidiary StoneX Financial Ltd is regulated by the Financial Conduct Authority (“FCA”), the regulator of the financial services industry in the U.K. The regulations impose regulatory capital, as well as conduct of business, governance, and other requirements. The conduct of business rules include those that govern the treatment of client money and other assets which, under certain circumstances, for certain classes of client, must be segregated from the firm’s own assets. As of September 30, 2024, StoneX Financial Ltd had client segregated funds of $1,292.2 million, compared to a minimum regulatory requirement of $1,230.1 million. StoneX Financial Pte. Ltd. is regulated by the Monetary Authority of Singapore (“MAS”) and operates as an approved holder of a Capital Market Services and a Payments Service License. StoneX Financial Pte. Ltd. is subject to the requirements of MAS pursuant to the Securities and Futures Act and the Payments Services Act 2019. The regulations include those that govern the treatment of client money and other assets which under certain circumstances must be segregated from the firm’s own assets. As of September 30, 2024, StoneX Financial Pte. Ltd. had client segregated funds of $973.6 million compared to a minimum regulatory requirement of $958.4 million. The following table details the Company’s subsidiaries with a minimum regulatory net capital requirement in excess of $10.0 million as well as the actual regulatory capital of the subsidiary as of September 30, 2024 (in millions): Subsidiary Regulatory Authority Actual Minimum StoneX Financial Inc. SEC and CFTC $ 435.7 $ 243.5 StoneX Financial Ltd FCA $ 433.8 $ 358.0 GAIN Capital Group, LLC CFTC and NFA $ 57.1 $ 29.7 StoneX Financial Pte. Ltd. MAS $ 100.6 $ 22.3 StoneX Markets LLC CFTC and NFA $ 237.9 $ 134.3

Segment and Geographic Informat

Segment and Geographic Information	12 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Segment and Geographic Information	Segment and Geographic Information The Company's operating segments are principally based on the nature of the clients we serve (commercial, institutional, and self-directed/retail), and a fourth operating segment, its payments business. The Company manages its business in this manner due to its large global footprint, in which it has more than 4,500 employees allowing it to serve clients in more than 180 countries. The Company’s business activities are managed as operating segments and organized into reportable segments as follows: • Commercial • Institutional • Self-Directed/Retail • Payments Commercial The Company offers commercial clients a comprehensive array of products and services, including risk management and hedging services, execution and clearing of exchange-traded and OTC products, voice brokerage, market intelligence and physical commodity trading, marketing, procurement, logistics and price management services. The ability to provide these high-value-added products and services, differentiates the Company from its competitors and maximizes the opportunity to retain clients. Institutional The Company provides institutional clients with a complete suite of equity trading services to help them find liquidity with best execution, consistent liquidity across a robust array of fixed income products, competitive and efficient clearing and execution in all major futures and securities exchanges globally as well as prime brokerage in equities and major foreign currency pairs and swap transactions. In addition, the Company originates, structures and place debt instruments in the international and domestic capital markets. These instruments include asset-backed securities (primarily in Argentina) and domestic municipal securities. Self-Directed/Retail The Company provides self-directed/retail clients around the world access to over 18,000 global financial markets, including spot foreign exchange ("forex"), both financial trading and physical investment in precious metals, as well as CFDs, which are investment products with returns linked to the performance of underlying assets. In addition, its independent wealth management business offers a comprehensive product suite to self-directed/retail investors in the United States. Payments The Company provides customized payment, technology and treasury services to banks and commercial businesses as well as charities and non-governmental organizations and government organizations. The Company provides transparent pricing and offers payments services in more than 180 countries and 140 currencies, which it believes is more than any other payments solution provider. ******** The total revenues reported combine gross revenues from physical contracts for subsidiaries that are not broker-dealers and net revenues for all other businesses. In order to reflect the way that the Company’s management views the results, the table below also reflects the segment contribution to Operating revenues , which is shown on the face of the Consolidated Income Statements and which is calculated by deducting physical commodities cost of sales from total revenues. Segment data includes the profitability measure of net contribution by segment. Net contribution is one of the key measures used by management to assess the performance of each segment and for decisions regarding the allocation of the Company’s resources. Net contribution is calculated as revenue less direct cost of sales, transaction-based clearing expenses, variable compensation, introducing broker commissions, and interest expense. Variable compensation paid to risk management consultants/traders generally represents a fixed percentage of revenues generated, and in some cases, revenues generated less transaction-based clearing expenses, base salaries and an overhead allocation. Segment data also includes segment income which is calculated as net contribution less non-variable direct expenses of the segment. These non-variable direct expenses include trader base compensation and benefits, operational employee compensation and benefits, communication and data services, business development, professional fees, bad debt expense and other direct expenses. Inter-segment revenues, expenses, receivables and payables are eliminated upon consolidation. Total revenues, operating revenues and net operating revenues shown as “Corporate” primarily consist of interest income from its centralized corporate treasury function. In the normal course of operations, the Company operates a centralized corporate treasury function in which it may sweep excess cash from certain subsidiaries, where permitted within regulatory limitations, in exchange for a short-term interest bearing intercompany payable, or provide excess cash to subsidiaries in exchange for a short-term interest bearing intercompany receivable in lieu of the subsidiary borrowing on external credit facilities. The intercompany receivables and payables are eliminated during consolidation; however, this practice may impact reported total assets between segments. Net costs not allocated to operating segments include costs and expenses of certain shared services such as information technology, accounting and treasury, credit and risk, legal and compliance, and human resources and other activities. Information for the reportable segments is shown in accordance with the Segment Reporting Topic of the ASC as follows: Year Ended September 30, (in millions) 2024 2023 2022 Total revenues: Commercial $ 97,278.3 $ 58,249.2 $ 63,743.2 Institutional 1,962.1 1,513.6 831.8 Self-Directed/Retail 440.2 888.5 1,304.2 Payments 209.6 212.6 172.0 Corporate 46.9 31.7 7.8 Eliminations (49.3) (39.5) (23.0) Total $ 99,887.8 $ 60,856.1 $ 66,036.0 Operating revenues: Commercial $ 871.9 $ 862.7 $ 692.1 Institutional 1,962.1 1,513.6 831.8 Self-Directed/Retail 395.0 333.0 426.7 Payments 209.6 212.6 172.0 Corporate 46.9 31.7 7.8 Eliminations (49.3) (39.5) (23.0) Total $ 3,436.2 $ 2,914.1 $ 2,107.4 Net operating revenues (loss): Commercial $ 715.9 $ 721.3 $ 586.5 Institutional 630.4 532.0 483.5 Self-Directed/Retail 286.1 227.3 302.9 Payments 199.5 203.3 162.5 Corporate (64.7) (62.9) (59.5) Total $ 1,767.2 $ 1,621.0 $ 1,475.9 Net contribution: (Revenues less cost of sales of physical commodities, transaction-based clearing expenses, variable compensation, introducing broker commissions and interest expense) Commercial $ 541.8 $ 544.9 $ 415.3 Institutional 430.3 351.5 295.1 Self-Directed/Retail 267.0 212.7 280.3 Payments 162.5 164.5 131.2 Total $ 1,401.6 $ 1,273.6 $ 1,121.9 Segment income: (Net contribution less non-variable direct segment costs) Commercial $ 387.7 $ 390.7 $ 288.3 Institutional 266.0 217.9 174.6 Self-Directed/Retail 119.3 45.8 115.4 Payments 112.6 109.1 97.4 Total $ 885.6 $ 763.5 $ 675.7 Reconciliation of segment income to income before tax: Segment income $ 885.6 $ 763.5 $ 675.7 Net operating loss within Corporate (64.7) (62.9) (59.5) Overhead costs and expenses (466.8) (400.9) (339.0) Gain on acquisitions and other gains, net within Corporate — 23.3 — Income before tax $ 354.1 $ 323.0 $ 277.2 (in millions) As of September 30, 2024 As of September 30, 2023 As of September 30, 2022 Total assets: Commercial $ 5,387.0 $ 4,676.3 $ 5,931.0 Institutional 19,492.9 15,059.3 11,687.1 Self-Directed/Retail 1,024.1 1,014.2 971.2 Payments 438.8 376.6 524.0 Corporate 1,123.5 812.3 746.3 Total $ 27,466.3 $ 21,938.7 $ 19,859.6 Information regarding revenues and operating revenues for the ended September 30, 2024, 2023, and 2022, and information regarding long-lived assets (defined as property, equipment, leasehold improvements and software) as of September 30, 2024, 2023, and 2022 in geographic areas were as follows: Year Ended September 30, (in millions) 2024 2023 2022 Total revenues: United States $ 6,026.3 $ 6,017.4 $ 5,102.3 Europe 2,358.8 3,498.9 3,440.2 South America 455.0 271.4 87.2 Middle East and Asia 91,015.0 51,023.6 57,395.5 Other 32.7 44.8 10.8 Total $ 99,887.8 $ 60,856.1 $ 66,036.0 Operating revenues: United States $ 2,507.0 $ 2,120.4 $ 1,448.2 Europe 594.8 494.3 474.6 South America 141.8 127.0 87.2 Middle East and Asia 159.9 127.6 86.6 Other 32.7 44.8 10.8 Total $ 3,436.2 $ 2,914.1 $ 2,107.4 (in millions) As of September 30, 2024 As of September 30, 2023 As of September 30, 2022 Long-lived assets, as defined: United States $ 76.2 $ 76.0 $ 67.9 Europe 54.2 40.7 41.1 South America 5.6 4.4 2.9 Middle East and Asia 7.1 2.4 1.0 Other — — — Total $ 143.1 $ 123.5 $ 112.9

Condensed Financial Information

Condensed Financial Information of Parent Company Only Disclosure	12 Months Ended
	Sep. 30, 2024
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure	Schedule I StoneX Group Inc. Condensed Balance Sheets Parent Company Only (in millions) September 30, 2024 September 30, ASSETS Cash and cash equivalents $ 22.1 $ 2.1 Receivable from subsidiaries, net 7.9 — Deposits with and receivables from subsidiary broker-dealer, net 2.0 77.0 Notes receivable, net — 5.0 Income taxes receivable 135.9 132.1 Investment in subsidiaries (1) 1,390.1 1,325.3 Financial instruments owned, at fair value 9.6 7.6 Deferred tax assets 2.3 7.2 Property and equipment, net 61.2 66.3 Operating right of use assets 62.2 65.5 Other assets 39.8 35.6 Total assets $ 1,733.1 $ 1,723.7 LIABILITIES AND EQUITY Liabilities: Accounts payable and other accrued liabilities $ 78.1 $ 135.7 Operating lease liabilities 88.6 91.1 Payable to subsidiaries, net — 288.3 Payable to lenders under loans 167.9 157.5 Senior secured borrowings, net 543.1 342.1 Financial instruments sold, not yet purchased, at fair value 0.2 27.0 Total liabilities 877.9 1,041.7 Equity: StoneX Group Inc. (Parent Company Only) stockholders’ equity: Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding — — Common stock, $0.01 par value. Authorized 200,000,000 shares; 35,785,432 issued and 31,874,447 outstanding at September 30, 2024 and 35,105,852 issued and 31,194,867 outstanding at September 30, 2023 0.4 0.4 Common stock in treasury, at cost - 3,910,985 shares at September 30, 2024 and 2023 (69.3) (69.3) Additional paid-in capital 414.3 371.7 Retained earnings (1) 502.7 397.9 Accumulated other comprehensive loss, net 7.1 (18.7) Total StoneX Group Inc. (Parent Company Only) stockholders’ equity 855.2 682.0 Total liabilities and equity $ 1,733.1 $ 1,723.7 (1) Within the Condensed Balance Sheets and Condensed Statements of Operations of StoneX Group Inc. - Parent Company Only, the Company has accounted for its investment in wholly owned subsidiaries using the cost method of accounting. Under this method, the Company’s share of the earnings or losses of such subsidiaries is not included in the Condensed Balance Sheet or Condensed Statements of Operations. If the accounting for its investment in wholly owned subsidiaries was presented under the equity method of accounting, investment in subsidiaries and retained earnings would each increase by $886.2 million as of September 30, 2024, and $730.2 million, as of September 30, 2023, respectively. Schedule I StoneX Group Inc. Condensed Statements of Operations Parent Company Only Year Ended September 30, (in millions) 2024 2023 2022 Revenues: Management fees from affiliates $ 274.2 $ 328.7 $ 109.9 Trading gains (losses), net (0.6) 1.8 (2.8) Consulting fees — 0.2 0.1 Interest income 9.3 3.3 2.2 Dividend income from subsidiaries (1) 272.8 281.1 124.4 Total revenues 555.7 615.1 233.8 Interest expense 92.2 83.1 60.9 Net revenues 463.5 532.0 172.9 Non-interest expenses: Compensation and benefits 137.3 137.9 113.7 Trade systems and market information 9.5 10.2 6.5 Occupancy and equipment rental 10.7 9.3 8.4 Selling and marketing 5.5 2.2 4.9 Professional fees 13.2 12.7 11.9 Travel and business development 3.3 3.1 2.3 Non-trading technology and support 49.4 37.4 30.6 Depreciation and amortization 16.6 13.7 11.0 Communications 2.9 3.4 1.8 Management services fees to affiliates 140.4 188.4 4.3 Other 16.5 12.1 12.4 Total non-interest expenses 405.3 430.4 207.8 Gain on acquisitions and other gains, net 7.0 2.1 — Income (loss) before tax 65.2 103.7 (34.9) Income tax benefit 39.6 45.4 45.0 Net income $ 104.8 $ 149.1 $ 10.1 (1) W ithin the Condensed Balance Sheets and Condensed Statements of Operations of StoneX Group Inc. - Parent Company Only, the Company has accounted for its investment in wholly owned subsidiaries using the cost method of accounting. Under this method, the Company’s share of the earnings or losses of such subsidiaries is not included in the Condensed Balance Sheet or Condensed Statements of Operations. If the accounting for its investment in wholly owned subsidiaries was presented under the equity method of accounting, total revenues would also include subsidiary earnings of $156.0 million , $89.4 million, and $197.0 million for the years ended September 30, 2024, 2023, and 2022, respectively. Schedule I StoneX Group Inc. Condensed Statements of Cash Flows Parent Company Only Year Ended September 30, (in millions) 2024 2023 2022 Cash flows from operating activities: Net income $ 104.8 $ 149.1 $ 10.1 Adjustments to reconcile net income to net cash (used in)/provided by operating activities: Depreciation and amortization 16.6 13.7 11.0 Amortization of operating right of use assets 5.7 5.8 6.1 Deferred income taxes (3.2) (3.6) 4.7 Amortization and extinguishment of debt issuance costs 3.8 3.9 3.2 Loss on extinguishment of debt 3.7 — — Amortization of share-based compensation expense 33.6 26.2 16.5 Dividends (48.1) (12.7) (9.6) Changes in operating assets and liabilities: Receivables from subsidiaries, net (7.9) — — Payable to subsidiaries, net (245.1) 11.0 113.6 Receivable from clients, net — 0.2 0.2 Deposits with and receivables from subsidiary broker-dealer, net 75.0 12.1 (89.1) Notes receivable, net — — 1.1 Income taxes receivable (3.9) (76.6) 8.2 Financial instruments owned, at fair value 5.9 (0.8) (5.1) Other assets (5.1) (5.7) (7.3) Accounts payable and other accrued liabilities (34.8) 45.8 12.0 Operating lease liabilities (4.9) (4.5) (1.7) Financial instruments sold, not yet purchased, at fair value 0.1 (3.1) 2.1 Net cash (used in)/provided by operating activities (103.8) 160.8 76.0 Cash flows from investing activities: Capital contribution to affiliates (56.3) (40.0) (180.8) Collection of notes receivable 5.0 — — Purchase of property and equipment and internally developed software (11.5) (17.9) (17.8) Net cash used in investing activities (62.8) (57.9) (198.6) Cash flows from financing activities: Net change in lenders under loans with maturities 90 days or less 10.4 (110.6) 259.5 Repayments of senior secured term loan — — (170.3) Repayments of senior secured notes (347.9) — — Proceeds from issuance of senior secured notes 550.0 — — Deferred payments on acquisitions (23.6) — (1.9) Debt issuance costs (7.7) — — Exercise of stock options 5.4 3.7 6.7 Net cash provided by/(used in) financing activities 186.6 (106.9) 94.0 Net increase/(decrease) in cash and cash equivalents 20.0 (4.0) (28.6) Cash and cash equivalents at beginning of period 2.1 6.1 34.7 Cash and cash equivalents at end of period $ 22.1 $ 2.1 $ 6.1 Supplemental disclosure of cash flow information: Cash paid for interest $ 26.5 $ 15.3 $ 34.9 Income taxes paid, net of cash refunds $ 21.3 $ 34.9 $ 2.6

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net income	$ 260.8	$ 238.5	$ 207.1

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Sep. 30, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Description of Business and S_2

Description of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Consolidation	The accompanying 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.
Basis of Presentation	In the Consolidated Income Statements, total revenues reported combine gross revenues for the physical commodities business and metals business and net revenues for all other businesses, including metals transacted by broker-dealer subsidiaries. The subtotal Operating revenues in the Consolidated Income Statements is physical commodities cost of sales deducted from total revenues. The subtotal Net operating revenues in the Consolidated Income Statements is operating revenues less transaction-based clearing expenses, introducing broker commissions, and interest expense. Transaction-based clearing expenses are variable expenses paid to executing brokers, exchanges, clearing organizations, and banks, typically related to transactional volumes. Introducing broker commissions include commission paid to 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, certain non-variable expenses, as well as variable and non-variable expenses related to both operational and administrative employees.
Use of Estimates	Use of Estimates Preparing consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires that management make estimates and assumptions affecting the reported amounts of assets and liabilities, disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenue and expense during the reporting period. The most significant of these estimates and assumptions in the current year relate to fair value measurements for financial instruments, revenue recognition, valuation of inventories, acquisition valuation, 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.
Foreign Currency Translation	Foreign Currency Translation The Company’s consolidated financial statements are reported in U.S. dollars. The Company’s subsidiaries maintain their records either in U.S. dollars or, as appropriate, the currencies of the countries in which they operate. The method of translating local currency financial information into U.S. dollars depends on whether the economy in which the foreign subsidiary operates has been designated as highly inflationary. Economies with a three-year cumulative inflation rate of more than 100% are considered highly inflationary. Assets and liabilities of foreign subsidiaries in non-highly inflationary economies are translated into U.S. dollars using rates of exchange at the balance sheet date. Translation adjustments are recorded in other comprehensive income (loss). Revenues and expense are translated at rates of exchange in effect at relevant times during the year. Transaction gains and losses related to changes in currency rates are recorded in earnings. Foreign subsidiaries that operate in highly inflationary countries use the U.S. dollar as their functional currency. Local currency monetary assets and liabilities are remeasured into U.S. dollars using rates of exchange as of each balance sheet date, with remeasurement adjustments and other transaction gains and losses recognized in earnings. Nonmonetary assets and liabilities do not fluctuate with changes in the local currency exchange rates to the dollar as the translated amounts for nonmonetary assets and liabilities at the end of the accounting period in which the economy becomes highly inflationary becomes the accounting basis for those assets and liabilities in the period of change and subsequent periods. Revenues and expenses are translated at rates of exchange in effect at relevant times during the year.
Cash and Cash Equivalents	Cash and Cash Equivalents
Cash, Securities and Other Assets Segregated under Federal and other Regulations	Cash, Securities and Other Assets Segregated under Federal and other Regulations
Collateralized Transactions	Collateralized Transactions The Company enters into securities purchased under agreements to resell, securities sold under agreements to repurchase, securities borrowed transactions, and securities loaned transactions primarily to fund principal debt trading, acquire securities to cover short positions, acquire securities for settlement, or meet counterparty needs under matched-booked trading strategies. These transactions are accounted for as collateralized financing transactions and are recorded at their contractual amounts plus accrued interest. In connection with these agreements and transactions, it is the Company’s policy to receive or pledge cash or securities to collateralize such agreements and transactions in accordance with contractual arrangements. The Company monitors the fair value of its collateral on a daily basis, and the Company may require counterparties, or may be required by counterparties, to deposit additional collateral or return collateral pledged. Interest income and interest expense are recognized over the life of the arrangements and are recorded in the Consolidated Income Statements as Interest income or Interest expense , as applicable. The carrying amount of these transactions approximate fair value due to their short-term nature and the level of collateralization. Certain transactions are classified in securities purchased under agreements to resell rather than securities borrowed because the characteristics and circumstances more closely align with this presentation, although the securities’ legal form is securities borrowed.
Repurchase and Reverse repurchase agreement netting	Repurchase and Reverse repurchase agreement netting
Deposits with and Receivables from Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties	Deposits with and Receivables from Broker-dealers, Clearing Organizations and Counterparties, and Payables to Broker-dealers, Clearing Organizations and Counterparties Deposits with broker-dealers, clearing organizations, and counterparties pertain primarily to deposits made to satisfy margin requirements on client and proprietary open futures and options on futures positions and to satisfy the requirements set by clearing exchanges for clearing membership. The Company also deposits margin with various counterparties for over-the-counter (“OTC”) derivative contracts. These deposits are also included in deposits with broker-dealers, clearing organizations, and counterparties. The Company also deposits cash margin with various securities clearing organizations as an ongoing condition of the securities clearing relationships, and these deposits are included in deposits with and receivables from broker-dealers, clearing organizations, and counterparties. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties are reported gross, except where a right of offset exists. As of September 30, 2024 and 2023, the Company had cash and cash equivalents on deposit with or pledged to broker-dealers, clearing organizations, and counterparties of approximately $2,614.2 million and $2,512.9 million, respectively. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also includes guaranty deposits with clearing exchanges. The guaranty deposits are held by the clearing exchanges for use in potential default situations by one or more members of the clearing exchanges. The guaranty deposits may be applied to the Company’s obligations to the clearing exchange, or to the clearing exchange’s obligations to unrelated parties. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also include securities pledged to clearing exchanges. These securities are either pledged to the Company by its clients or represent investments of client funds. It is the Company’s practice to include client-owned securities on its Consolidated Balance Sheets, as the rights to those securities have been transferred to the Company under the terms of the relevant futures trading agreements. Securities pledged primarily include U.S. Treasury obligations, foreign government obligations, and certain ETFs. Securities that are not client-owned, and represent an investment of client funds, are adjusted to fair value with associated changes in unrealized gains or losses recorded in Interest income in the Consolidated Income Statements. For client-owned securities, the change in fair value is offset against the payable to clients with no impact recognized in the Consolidated Income Statements. The total fair value of such client owned and non-client owned securities included within Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net was $2,951.5 million and $4,041.6 million as of September 30, 2024 and 2023, respectively. Management has considered guidance required by ASC 860, Transfers and Servicing as it relates to securities pledged by clients to margin their futures and options on futures trading accounts. Management believes that the transferor surrenders control over those assets because, under the guidance, the transferee relinquishes control of the assets to the Company, among other factors. Under this guidance, the Company reflects the client collateral assets and corresponding liabilities in the Company’s Consolidated Balance Sheets as of September 30, 2024 and 2023. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also includes amounts due from clearing exchanges for unrealized gains and losses associated with clients’ options on futures contracts. See discussion in the Financial Instruments section below for additional information on the Company’s accounting policies for derivative contracts. For client-owned derivative contracts, the fair value is offset against the payable to clients with no impact recognized on the Consolidated Income Statements. The Company maintains client omnibus and proprietary accounts with other clearing organizations. The equity balances in those accounts, along with any margin cash or securities deposited with the clearing organizations are included in deposits with and receivables from broker-dealers, clearing organizations, and counterparties. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties also include amounts due from or due to clearing exchanges for daily variation settlements on open futures and options on futures positions. The variation settlements due from or due to clearing exchanges are paid in cash on the following business day. Variation settlements equal the daily settlement of futures contracts and premiums on options on futures contracts. Deposits with and receivables from broker-dealers, clearing organizations, and counterparties further include amounts receivable for securities sold but not yet delivered by the Company on settlement date (“fails-to-deliver”) and net receivables arising from unsettled proprietary trades. Payables to broker-dealers, clearing organizations, and counterparties primarily include amounts payable for securities purchased but not yet received by the Company on settlement date (“fails-to-receive”) and net payables arising from unsettled proprietary trades. Deposits with and receivables from broker-dealers, clearing organizations and counterparties, and payables to broker-dealers, clearing organizations and counterparties also include amounts related to the value of registered broker-dealer clients cross-currency payment transactions related to the Payments segment. These amounts arise due to a clearing period before funds are received and payments are made, which usually is one to two business days.
Receivable from and Payables to Clients	Receivable from and Payables to Clients Receivable from clients, net includes the total of net deficits in individual exchange-traded futures and OTC derivative trading accounts carried by the Company. Client deficits arise from realized and unrealized trading losses on client OTC, futures, options on futures, swaps and forwards and amounts due on cash and margin transactions. Client deficit accounts are reported gross of client accounts that contain net credit or positive balances, except where a right of offset exists. Net deficits in individual futures exchange-traded and OTC derivative trading accounts include both secured and unsecured deficit balances due from clients as of the balance sheet date. Secured deficit amounts are backed by U.S. Treasury obligations and commodity warehouse receipts. These U.S Treasury obligations and commodity warehouse receipts are netted against the secured deficit amounts when conditions necessary for the right to offset exist. Receivable from clients, net also includes the net amounts receivable from securities clients in connection with the settlement of regular-way cash securities, margin loans to clients, and client cash debits. It is the Company’s policy to report margin loans and payables that arise due to positive cash flows in the same client’s accounts on a net basis when the conditions for netting as specified in U.S. GAAP are met. Clients’ securities transactions cleared by the Company are recorded on a settlement date basis, but the Company makes accruals necessary to adjust any uncompleted transactions to a trade date basis for consolidated reporting, under U.S. GAAP. Securities cleared by the Company and pledged to the Company as a condition of custodial clearing arrangements are owned by the clients, including those that collateralize margin or other similar transactions, and are not reflected on the Consolidated Balance Sheets as the Company does not have title to, or beneficial interests, in those assets. The carrying value of the receivables and payables approximates fair value due to their short-term nature. Receivable from clients, net also include amounts receivable from non-broker-dealer clients for securities sold but not yet delivered by the Company on settlement date (“fails-to-deliver”) and net receivables arising from unsettled proprietary trades. Payables to clients represent the total of client accounts with credit or positive balances. Client accounts are used primarily in connection with exchange-traded and OTC commodity, foreign exchange, precious metals, and securities transactions and include gains and losses on open trades as well as securities and cash margin deposits made as required by the Company, the exchange-clearing organizations or other clearing organizations. Client accounts with credit or positive balances are reported gross of client deficit accounts, except where a right of offset exists. Payables to broker-dealers and counterparties also includes amounts payable to non-broker-dealer clients for securities purchased but not yet received by the Company on settlement date (“fails-to-receive”) and net payables arising from unsettled proprietary trades. Receivable from and payables to clients also include amounts related to the value of non-registered broker-dealer clients’ cross-currency payment transactions related to the Payments segment. These amounts arise due to a clearing period before the funds are received and payments are made, which usually is one to two business days. The future collectability of receivable from clients can be impacted by the Company’s collection efforts, client financial stability, and the general economic climate. In determining collectability, the Company considers a number of factors including, but not limited to, historical collection experience, current and forecasted economic and business conditions, internal and external credit risk ratings, collateral terms, payment terms, client financial strength, and aging of the financial asset. The Company adheres to the Current Expected Credit Loss model and, in addition, may use specific-identification in certain circumstances to further inform estimates. The Company may unilaterally close client trading positions in certain circumstances. In addition, to evaluate client margining and collateral requirements, client positions are stress tested regularly and monitored for excessive concentration levels relative to the overall market size. Furthermore, in certain instances, the Company is indemnified and able to charge back introducing broker-dealers for bad debts incurred by their clients. The Company generally writes off an outstanding receivable balance when all economic means of recovery have been exhausted. That determination considers information such as the occurrence of significant changes in the client’s financial position such that the client can no longer pay the obligation, or that the proceeds from collateral will not be sufficient to pay the balance.
Notes Receivable	Notes Receivable Accrual of commodity financing income on any note is discontinued when, in the opinion of management, there is reasonable doubt as to the timely collectability of interest or principal. Nonaccrual notes are returned to an accrual status when, in the opinion of management, the financial position of the borrower indicates there is no longer any reasonable doubt as to the timely payment of principal and interest. The Company records a charge against earnings for notes receivable losses when management believes that the collection of outstanding principal is not probable.
Physical Commodities Inventory	Physical Commodities Inventory Inventories of certain agricultural commodities are carried at net realizable value, which approximates fair value less disposal costs. Agricultural commodities inventories have reliable, readily determinable and realizable market prices, relatively predictable and insignificant costs of disposal, and are available for immediate delivery. Changes in the fair values of these agricultural commodities inventories are included as a component of Cost of sales of physical commodities in the Consolidated Income Statements. Inventories of precious metals held by subsidiaries that are not broker-dealers are valued at the lower of cost or net realizable value, using the weighted-average price and first-in first-out costing method. Changes in the values of these inventories are included as a component of Cost of sales of physical commodities in the Consolidated Income Statements. Precious metals inventory held by StoneX Financial Ltd, a U.K. based broker-dealer subsidiary, is measured at fair value, with changes in fair value included as a component of Principal gains, net
Property and Equipment	Property and Equipment Property and equipment is stated at cost, net of accumulated depreciation and amortization and depreciated using the straight-line method over the estimated useful life. Leasehold improvements are amortized on a straight-line basis over the estimated useful life of the improvement or the term of the lease, whichever is shorter. Expenditures that increase the value or productive capacity of assets are capitalized. When an asset is retired, sold, or otherwise disposed of, the carrying amount and related accumulated depreciation are removed from the accounts and any gain or loss is included in earnings. The Company had no assets held for sale at September 30, 2024 and 2023. The Company accounts for costs incurred to develop its trading platforms and related software in accordance with ASC 350-40, Internal-Use Software, which requires that such technology be capitalized in the application development stage. Costs related to planning, training, administration, and non-value added maintenance are charged to expense as incurred. Capitalized software development costs are amortized over the useful life of the software, which the Company generally estimates at three years.
Acquisitions and Contingent Consideration	Acquisitions The Company applies acquisition accounting on the date of acquisition to those transactions meeting the definition of a business under ASC 805. Applying acquisition accounting requires the Company to allocate the purchase consideration to the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed on acquisition date. In determining the fair value of identifiable assets acquired and liabilities assumed, the Company frequently utilizes a third-party valuation specialist. The Company applies certain significant assumptions, estimates, and judgments in determining the fair value of assets acquired and liabilities assumed on acquisition date. These significant assumptions, estimates, and judgments include, but are not limited to, cash flow forecasts, discount rates, client churn rates, royalty rates, and economic lives. Any excess of the purchase consideration over the fair value of the net assets acquired is recorded as goodwill. Alternatively, in an instance where the fair value of the net assets acquired exceeds the purchase consideration, the Company records a bargain purchase gain in the Consolidated Income Statements at the date of acquisition. While the Company uses its best estimates and assumptions as a part of the purchase price allocation to accurately value assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the remeasurement period, which may extend one year from the acquisition date, the Company may record adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill or bargain purchase gain. Upon conclusion of the measurement period or final determination of the fair values of assets acquired and liabilities assumed, whichever comes first, any subsequent adjustments are recorded to Contingent Consideration For acquisitions which include contingent consideration as a component of the purchase price, the Company estimates and records the fair value of the contingent consideration at the acquisition date. Additionally, each reporting period, the Company estimates changes in the fair value of contingent consideration, and any change in fair value is recognized in the Consolidated Income Statements. Estimating contingent consideration fair value incorporates assumptions regarding future operating results, discount rates, and probabilities assigned to various potential operating results scenarios.
Goodwill and Identifiable Intangible Assets	Goodwill and Identifiable Intangible Assets Goodwill is the cost of acquired companies in excess of the fair value of identifiable net assets at acquisition date. Goodwill is not subject to amortization, but rather is evaluated for impairment at least annually. The Company evaluates its goodwill for impairment during the fourth quarter of its fiscal year or more frequently if indicators of potential impairment exist, in accordance with ASC 350, Intangibles - Goodwill and Other. Goodwill impairment is determined by comparing the estimated fair value of a reporting unit (generally defined as the businesses for which financial information is available and reviewed regularly by management) with its respective carrying value. If the estimated fair value exceeds the carrying value, goodwill at the reporting unit level is not deemed to be impaired. However, if the estimated fair value is below carrying value, further analysis is required to determine the amount of the impairment. In the course of evaluating the potential impairment of goodwill, the Company may perform either a qualitative or a quantitative assessment. The Company’s qualitative assessment of potential impairment may result in the determination that a quantitative impairment analysis is not necessary. Under this elective process, the Company assesses qualitative factors to determine whether the existence of events or circumstances leads the Company to determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If after assessing the totality of events and circumstances, the Company determines it is more likely than not that the fair value of a reporting unit is greater than its carrying amount, then performing a quantitative analysis is not required. However, if the Company concludes otherwise, then the Company performs a quantitative impairment analysis. If the Company either chooses not to perform a qualitative assessment, or the Company chooses to perform a qualitative assessment but is unable to qualitatively conclude that no impairment has occurred, then the Company performs a quantitative evaluation. In the case of a quantitative assessment, the Company estimates the fair value of the reporting unit with which the goodwill that is subject to the quantitative analysis is associated and compares it to the carrying value. If the estimated fair value of a reporting unit is less than its carrying value, the Company estimates the fair value of all assets and liabilities of the reporting unit, including goodwill. If the carrying value of the reporting unit’s goodwill is greater than the estimated fair value, an impairment charge is recognized for the excess. The fair value of the Company’s reporting units exceeded their respective carrying values under the qualitative assessment approach. No goodwill impairment charges were recorded for any of the periods presented, nor were any indicators present. Identifiable intangible assets subject to amortization are amortized using the straight-line method over their estimated period of benefit, ranging from five
Financial Instruments Owned and Sold, Not Yet Purchased	Financial Instruments Owned and Sold, Not Yet Purchased Financial instruments owned and sold, not yet purchased, at fair value consist of financial instruments carried at fair value, measured on a recurring basis, or amounts that approximate fair value. Related realized and unrealized gains and losses are recognized in current period earnings within Principal gains, net , Interest income , Interest expense , and Cost of sales of physical commodities in the Consolidated Income Statements. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. The Company has entered into certain mortgages and other loans that will eventually be securitized. The Company has elected the fair value option, under ASC 825, because this election aligns mark to market recognition of these assets with the rest of the Company’s portfolio of similar assets. Changes to the value of these assets are recorded to Principal gains, net in the Consolidated Income Statements. Financial instruments owned and sold, not yet purchased comprise primarily the financial instruments held by the Company’s broker-dealer subsidiaries and the Company’s OTC derivative swap dealer. Financial instruments owned and financial instruments sold, not yet purchased, includes trading securities that the Company holds as a principal. The Company has not classified any financial instruments owned or sold, not yet purchased, as available-for-sale or held-to-maturity. Financial instruments owned and sold, not yet purchased includes derivative instruments that the Company holds as a principal which are primarily transacted on an OTC basis. As a derivatives dealer, the Company utilizes these instruments to manage exposures to foreign currency, commodity price and interest rate risks for the Company and its clients. The Company’s objectives for holding derivatives include reducing, eliminating, and efficiently managing the economic impact of these exposures as effectively as possible. The Company’s derivative instruments also include forward purchase and sale commitments for the physical delivery of agricultural and energy related commodities in a future period. Contracts for the sale of agricultural and energy commodities generally do not extend beyond one year, while contracts to purchase agricultural and energy commodities generally relate to the current or future crop year. Derivative instruments are measured at fair value on a recurring basis. For derivatives for which the Company does not elect hedge accounting, realized and unrealized gains and losses from the changes in fair value of derivative instruments are recognized immediately in current period earnings. Realized and unrealized gains and losses from the derivative instruments in which the Company acts as a dealer are included within Principal gains, net on the Consolidated Income Statements. Realized and unrealized gains and losses on firm purchase and sale commitments are included within Cost of sales of physical commodities on the Consolidated Income Statements. To reduce credit exposure on the derivative instruments for which the Company acts as a dealer, the Company may enter into a master netting arrangement that allows for settlement of all derivative transactions with each counterparty. In addition, the credit support annex that accompanies master netting arrangements allows parties to the master netting agreement to mitigate their credit risk by requiring the party which is out of the money to post collateral. The Company accepts collateral in the form of cash or other marketable securities. Where permitted, the Company elects to net-by-counterparty certain derivative instruments entered into under a legally enforceable master netting agreement and, therefore, the fair value of those derivative instruments are netted by counterparty in the Consolidated Balance Sheets. As the Company elects to net-by-counterparty the fair value of such derivative instruments, the Company also nets-by-counterparty cash collateral exchanged as part of those derivative instruments. The Company also brokers foreign exchange forwards, options and cash, or spot, transactions between clients and external counterparties. A portion of the contracts are arranged on an offsetting basis, limiting the Company’s risk to performance of the two offsetting parties. The offsetting nature of the contracts eliminates the effects of market fluctuations on the Company’s operating results. Due to the Company’s role as a principal participating in both sides of these contracts, the amounts are presented gross on the Consolidated Balance Sheets at their respective fair values, net of offsetting assets and liabilities. The Company holds proprietary positions in its foreign exchange line of business. On a limited basis, the Company’s foreign exchange trade desk will accept a client transaction and will offset that transaction with a similar but not identical position with a counterparty. These unmatched transactions are intended to be short-term in nature and are often conducted to facilitate the most effective transaction for the Company’s client. These spot and forward contracts are accounted for as free-standing derivatives and reported in the Consolidated Balance Sheets at their fair values.
Derivative instruments and hedging activities	Derivative instruments and hedging activities The Company executes interest rate swaps and foreign currency hedges to lessen the impacts of changes to interest rates and currency exchange rates, respectively, as well as benefit from favorable conditions. The Company recognizes all derivative instruments as either assets or liabilities at fair value. For all of the Company’s derivative positions that are designated and qualify as part of a cash flow hedging relationship, the effective portion of the gain or loss on the derivatives is reported as a component of other comprehensive income and reclassified into earnings in the same period or periods during which the hedged transactions affect earnings. Gains and losses on derivatives representing any ineffective component of the hedge are recognized in current earnings. All of the Company’s cash flow hedges have been deemed effective as of September 30, 2024 for both accounting and tax purposes. The Company has elected hedge accounting for both U.S. GAAP and tax purposes. The Company maintains formal documentation through a periodic memo and accounting analysis that cover what is being hedged, how it is being hedged, hedge effectiveness, the nature of the risk being hedged, among other required analyses. Company policy further includes a quarterly probability analysis covering hedge effectiveness.
Exchange and Clearing Organization Memberships	Exchange and Clearing Organization Memberships The Company or its affiliates are required to hold certain exchange and clearing organization memberships and pledges them for clearing purposes, in order to provide the right to process trades directly with the respective venues. Exchange memberships include seats on the Chicago Board of Trade (“CBOT”), the Minneapolis Grain Exchange, the New York Mercantile Exchange (“NYMEX”), the Commodity Exchange, Inc. (“COMEX”) Division of the New York Mercantile Exchange, Mercado de Valores de Buenos Aires S.A. (“MERVAL”), the Chicago Mercantile Exchange (“CME”) Growth and Emerging Markets, InterContinental Exchange, Inc. (“ICE”) Futures US, and the London Metal Exchange (“LME”). Exchange firm and clearing organization common stock include shares of CME Group, Inc., ICE, LME Holdings Limited, and the Depository Trust & Clearing Corporation (“DTCC”). Exchange and clearing organization memberships required in order to conduct business through the respective venues are recorded at cost and are included in Other assets on the Consolidated Balance Sheets. Equity investments in exchange firm common stock not required in order to conduct business on the exchanges are classified as trading securities included within Financial instruments owned, at fair value on the Consolidated Balance Sheets and recorded at fair value, with unrealized gains and losses recorded as a component of Principal gains, net on the Consolidated Income Statements. The fair value of exchange firm common stock not required in order to conduct business on the exchanges is determined from quoted market prices. Exchange memberships that represent both (a) an ownership interest and the right to conduct business in the respective venues and are held for operating purposes, or (b) an ownership interest, which must be held by the Company to conduct business in the respective venues are accounted for as an ownership interest at cost with appropriate consideration for other-than-temporary impairment. Alternatively, exchange memberships, or seats, that only represent the right to conduct business on an exchange, but not an ownership interest in the exchange, are accounted for as intangible assets at cost with potential impairment determined under Accounting Standards Codification 350-30- Intangibles - Goodwill and Other . As of and during the year ended September 30, 2024, there were no indicators of impairment that would suggest that the carrying value of exchange memberships that don’t represent an ownership interest are impaired, primarily based upon projections of future cash flows and earnings attributable to access these respective venues.
Commodity Financing	Commodity Financing The Company also participates in commodity repurchase transactions that are accounted for as commodity inventory and purchases and sales of physical commodities as opposed to secured borrowings. The repurchase price under these arrangements is not fixed at the time of execution and, therefore, does not meet all the criteria to be accounted for as product financing arrangements.
Lenders Under Loans and Senior Secured Borrowings	Lenders Under Loans Senior Secured Borrowings
Revenue Recognition	Revenue Recognition The Company accounts for revenue earned from contracts with clients for services such as the execution, clearing, brokering, and custody of futures and options on futures contracts, OTC derivatives, and securities, investment management, and underwriting services under FASB ASC 606, Revenue from Contracts with Customers (“Topic 606”). Revenues for these services are recognized when the performance obligations related to the underlying transaction are completed. Only when goods or services are transferred to clients are revenues recognized and the amount reflects the consideration that the Company expects to be entitled to in exchange for those goods or services. Revenues are analyzed to determine whether the Company is the principal (i.e. reports revenue on a gross basis) or agent (i.e., reports revenues on a net basis) in the contract. Principal or agent designations depend primarily on the control an entity has over the good or service before control is transferred to a client. The indicators of which party exercises control include primary responsibility over performance obligations, inventory risk before the good or service is transferred, and discretion in establishing the price.
Cost of Sales of Physical Commodities	Cost of Sales of Physical Commodities Cost of sales of physical commodities include finished commodity or raw material and processing costs along with operating costs relating to the receipt, storage and delivery of physical commodities. Cost of sales of physical commodities also includes changes in the fair value of agricultural commodity inventories held for sale and adjustments for related forward purchase and sale commitments and exchange-traded futures and options contracts. Cost of sales of physical commodities further includes lower of cost or net realizable value for energy commodities and certain precious metals. The Company’s cost of sales of physical commodities and the related impact on inventory are valued using various methods, including average costing and specific identification, in different geographies and for different business lines.
Interest Expense	Interest Expense Interest expense is recognized on an accrual basis. Interest expense is incurred on outstanding balances on the Company’s credit facilities. Interest expense is also incurred on fixed income securities sold, not yet purchased, that the Company holds in its market-marking businesses. Interest expense is also incurred from collateralized transactions, including securities loaned and securities sold under agreements to repurchase.
Transaction-Based Clearing Expenses	Transaction-Based Clearing Expenses Clearing fees and related expenses include primarily variable expenses for clearing and settlement services, including fees the Company pays to executing brokers, exchanges, clearing organizations and banks. These fees are based on transaction volume and recorded as expense on trade date. Clearing fees are passed on to clients and are presented gross in the consolidated statements of income as the Company acts as a principal for these transactions.
Introducing Broker Commissions	Introducing Broker Commissions Introducing broker commissions are amounts paid to non-employee individuals or organizations that maintain relationships with clients and introduce them to the Company. Introducing brokers accept exchange-based futures and options orders from those clients, while the Company directly provides all account, transaction and margining services, including accepting money, securities and property from the clients. Introducing brokers bring clients to the Company’s OTC, physical commodity and payment businesses as well. Introducing broker commissions are determined monthly and settled regularly.
Compensation and Benefits	Compensation and Benefits Compensation and benefits consists primarily of salaries, incentive compensation, share-based compensation, variable compensation, including commissions, related payroll taxes and employee benefits. The Company classifies employees as either front office, operational or administrative personnel, which includes executive officers. Variable compensation paid to front office personnel generally represents a fixed percentage of revenues generated, and in some cases, revenues produced less direct costs and an overhead allocation. The Company accrues commission expense on a trade-date basis. The Company accounts for share-based compensation from option and restricted stock awards in accordance with the guidance in ASC 718-10, Compensation - Stock Compensation. The cost of employee services received in exchange for a share-based award is generally measured based on the grant-date fair value of the award. Share-based employee awards that require future service are amortized over the relevant service period. Forfeitures are accounted for as they occur in determining share-based employee compensation expense. For awards granted, compensation cost is recognized on a straight-line basis over the vesting period for the entire award.
Selling and Marketing	Selling and Marketing The Company generally expenses Selling and marketing costs as incurred. The Company’s policy includes expensing commercial media development costs as incurred, rather than deferring them until the related commercial airs. The Company expenses air time, such as television air-time, as used.
Income Taxes	Income Taxes
Additional Paid-In Capital	Additional Paid-In Capital The Company’s additional paid-in capital (“APIC”) consists of stockholder contributions that are in excess of par value of common stock, also including amounts related to stock options exercises and share-based compensation.
Comprehensive Income	Comprehensive Income Comprehensive income consists of net income and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net income. Other comprehensive income (loss) includes net actuarial gains and losses from defined benefit pension plans, the unrealized gains and losses from the Company’s cash flow hedges, as well as and gains and losses on foreign currency translations.
Accounting Standards Adopted	Accounting Standards Adopted The Company did not adopt any new accounting standards during the fiscal years ended September 30, 2024 and 2023.
Earnings per Share	The Company presents basic and diluted earnings per share (“EPS”) using the two-class method which requires all outstanding unvested share-based payment awards that contain rights to non-forfeitable dividends and therefore participate in undistributed earnings with common stockholders be included in computing earnings per share. Under the two-class method, net income is reduced by the amount of dividends declared in the period for each class of common stock and participating security. The remaining undistributed earnings are then allocated to common stock and participating securities, based on their respective rights to receive dividends. Restricted stock awards granted to certain employees and directors contain non-forfeitable rights to dividends at the same rate as common stock, and are considered participating securities. Basic EPS has been computed by dividing net income by the weighted-average number of common shares outstanding.

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	The following is a reconciliation of the numerator and denominator of the diluted net income per share computations for the periods presented below. Year Ended September 30, (in millions, except share amounts) 2024 2023 2022 Numerator: Net income $ 260.8 $ 238.5 $ 207.1 Less: Allocation to participating securities (9.1) (8.1) (6.1) Net income allocated to common stockholders $ 251.7 $ 230.4 $ 201.0 Denominator: Weighted average number of: Common shares outstanding 30,539,237 29,936,000 29,355,605 Dilutive potential common shares outstanding: Share-based awards 1,085,792 993,011 745,706 Diluted shares outstanding 31,625,029 30,929,011 30,101,311 Earnings per share - basic $ 8.24 $ 7.71 $ 6.85 Earnings per share - diluted $ 7.96 $ 7.45 $ 6.67

Assets and Liabilities, at Fa_2

Assets and Liabilities, at Fair Value (Tables)	12 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial and Non-Financial Assets and Liabilities Accounted at Fair Value on a Recurring Basis	The following tables set forth the Company’s financial and nonfinancial assets and liabilities accounted for at fair value, on a recurring basis, as of September 30, 2024 and 2023 by level in the fair value hierarchy. All fair value measurements were performed on a recurring basis as of September 30, 2024 and 2023. September 30, 2024 (in millions) Level 1 Level 2 Level 3 Netting (1) Total Assets: Certificates of deposit $ 13.9 $ — $ — $ — $ 13.9 Money market mutual funds 35.3 — — — 35.3 Cash and cash equivalents 49.2 — — — 49.2 Commodities warehouse receipts 51.8 — — — 51.8 Securities and other assets segregated under federal and other regulations 51.8 — — — 51.8 U.S. Treasury obligations 2,933.2 — — — 2,933.2 To be announced ("TBA") and forward settling securities — 26.1 — (18.3) 7.8 Foreign government obligations 18.3 — — — 18.3 Derivatives 3,900.1 2,168.2 — (5,740.1) 328.2 Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net 6,851.6 2,194.3 — (5,758.4) 3,287.5 Receivable from clients, net - Derivatives 22.4 506.2 (537.0) (8.4) Equity securities 363.9 15.0 — — 378.9 Corporate and municipal bonds — 322.1 — — 322.1 U.S. Treasury obligations 1,088.6 — — — 1,088.6 U.S. government agency obligations — 531.0 — — 531.0 Foreign government obligations 41.4 — — — 41.4 Agency mortgage-backed obligations — 3,837.2 — — 3,837.2 Asset-backed obligations — 223.5 — — 223.5 Derivatives 0.1 603.2 — (375.2) 228.1 Commodities warehouse receipts 67.8 — — — 67.8 Exchange firm common stock 13.2 — — — 13.2 Cash flow hedges — 9.6 — — 9.6 Mutual funds and other 23.6 — 2.1 — 25.7 Financial instruments owned 1,598.6 5,541.6 2.1 (375.2) 6,767.1 Physical commodities inventory 207.6 169.0 — — 376.6 Total assets at fair value $ 8,781.2 $ 8,411.1 $ 2.1 $ (6,670.6) $ 10,523.8 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 2.3 $ — $ 2.3 Payables to clients - Derivatives 3,577.1 228.9 — (3,540.1) 265.9 TBA and forward settling securities — 24.4 — (22.9) 1.5 Derivatives 378.0 2,356.4 — (2,737.3) (2.9) Payable to broker-dealers, clearing organizations and counterparties 378.0 2,380.8 — (2,760.2) (1.4) Equity securities 219.8 5.0 — — 224.8 Foreign government obligations 41.0 — — — 41.0 Corporate and municipal bonds — 154.6 — — 154.6 U.S. Treasury obligations 2,139.3 — — — 2,139.3 U.S. government agency obligations — 0.2 — — 0.2 Agency mortgage-backed obligations — 23.6 — — 23.6 Asset-backed obligations — 3.9 — — 3.9 Derivatives 8.1 571.0 — (314.3) 264.8 Cash flow hedges — 0.2 — — 0.2 Other — — 0.9 — 0.9 Financial instruments sold, not yet purchased 2,408.2 758.5 0.9 (314.3) 2,853.3 Total liabilities at fair value $ 6,363.3 $ 3,368.2 $ 3.2 $ (6,614.6) $ 3,120.1 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level. September 30, 2023 (in millions) Level 1 Level 2 Level 3 Netting (1) Total Assets: Certificates of deposit $ 8.7 $ — $ — $ — $ 8.7 Money market mutual funds 57.8 — — — 57.8 Cash and cash equivalents 66.5 — — — 66.5 Commodities warehouse receipts 5.8 — — — 5.8 Securities and other assets segregated under federal and other regulations 5.8 — — — 5.8 U.S. Treasury obligations 4,023.8 — — — 4,023.8 TBA and forward settling securities — 73.5 — (31.7) 41.8 Foreign government obligations 17.8 — — — 17.8 Derivatives 5,497.5 1,135.9 — (6,468.5) 164.9 Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net 9,539.1 1,209.4 — (6,500.2) 4,248.3 Receivable from clients, net - Derivatives 61.7 561.3 (630.9) (7.9) Equity securities 324.0 10.3 — — 334.3 Corporate and municipal bonds — 284.2 — — 284.2 U.S. Treasury obligations 531.7 — — — 531.7 U.S. government agency obligations — 451.7 — — 451.7 Foreign government obligations 43.3 — — — 43.3 Agency mortgage-backed obligations — 2,865.8 — — 2,865.8 Asset-backed obligations — 138.8 — — 138.8 Derivatives 0.6 868.1 — (600.2) 268.5 Commodities leases — 16.0 — — 16.0 Commodities warehouse receipts 54.7 — — — 54.7 Exchange firm common stock 12.0 — — — 12.0 Cash flow hedges — 1.7 — — 1.7 Mutual funds and other 39.3 — 2.8 — 42.1 Financial instruments owned 1,005.6 4,636.6 2.8 (600.2) 5,044.8 Physical commodities inventory 240.3 146.2 — — 386.5 Total assets at fair value $ 10,919.0 $ 6,553.5 $ 2.8 $ (7,731.3) $ 9,744.0 Liabilities: Accounts payable and other accrued liabilities - contingent liabilities $ — $ — $ 1.5 $ — $ 1.5 Payables to clients - Derivatives 5,430.7 226.2 — (5,577.1) 79.8 TBA and forward settling securities — 47.5 — (31.4) 16.1 Derivatives 112.2 1,402.0 — (1,520.1) (5.9) Payable to broker-dealers, clearing organizations and counterparties 112.2 1,449.5 — (1,551.5) 10.2 Equity securities 230.6 5.5 — — 236.1 Foreign government obligations 21.5 — — — 21.5 Corporate and municipal bonds — 81.6 — — 81.6 U.S. Treasury obligations 2,409.3 — — — 2,409.3 U.S. government agency obligations — 5.1 — — 5.1 Agency mortgage-backed obligations — 31.7 — — 31.7 Derivatives 2.4 769.2 — (510.4) 261.2 Cash flow hedges — 27.1 — — 27.1 Other — 10.9 1.1 — 12.0 Financial instruments sold, not yet purchased 2,663.8 931.1 1.1 (510.4) 3,085.6 Total liabilities at fair value $ 8,206.7 $ 2,606.8 $ 2.6 $ (7,639.0) $ 3,177.1 (1) Represents cash collateral and the impact of netting across the levels of the fair value hierarchy. Netting among positions classified within the same level are included in that level.

Financial Instruments with Of_2

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk (Tables)	12 Months Ended
	Sep. 30, 2024
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Schedule of Derivative Assets and Liabilities	Listed below are the fair values of the Company’s derivative assets and liabilities as of September 30, 2024 and 2023. Assets represent net unrealized gains and liabilities represent net unrealized losses. September 30, 2024 September 30, 2023 (in millions) Assets (1) Liabilities (1) Assets (1) Liabilities (1) Derivative contracts not accounted for as hedges: Exchange-traded commodity derivatives $ 1,383.1 $ 1,415.7 $ 1,907.0 $ 1,890.3 OTC commodity derivatives 1,967.9 1,924.3 1,523.3 1,456.0 Exchange-traded foreign exchange derivatives 2.0 2.0 4.3 4.3 OTC foreign exchange derivatives 975.2 938.2 497.1 455.3 Exchange-traded interest rate derivatives 720.1 728.1 1,507.6 1,509.8 OTC interest rate derivatives 207.1 207.1 417.6 417.6 Exchange-traded equity index derivatives 1,817.4 1,817.4 2,140.9 2,140.9 OTC equity and indices derivatives 127.4 86.7 127.3 68.5 TBA and forward settling securities 26.1 24.4 73.5 47.5 Total derivative contracts not accounted for as hedges 7,226.3 7,143.9 8,198.6 7,990.2 Derivative contracts designated as hedging instruments: Interest rate swaps — 0.2 — 24.6 Foreign currency forwards 9.6 — 1.7 2.5 Total derivative contracts designated as hedging instruments 9.6 0.2 1.7 27.1 Gross fair value of derivative contracts $ 7,235.9 $ 7,144.1 $ 8,200.3 $ 8,017.3 Impact of netting and collateral (6,670.6) (6,614.6) (7,731.3) (7,639.0) Total fair value included in Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net $ 336.0 $ 206.7 Total fair value included in Receivable from clients, net $ (8.4) $ (7.9) Total fair value included in Financial instruments owned, at fair value $ 237.7 $ 270.2 Total fair value included in Payables to clients $ 265.9 $ 79.8 Total fair value included in Payables to broker-dealers, clearing organizations and counterparties $ (1.4) $ 10.2 Fair value included in Financial instruments sold, not yet purchased, at fair value $ 265.0 $ 288.3 (1) As of September 30, 2024 and 2023, the Company’s derivative contract volume for open positions was approximately 12.2 million and 13.4 million contracts, respectively.
Schedule of Fair Value of Derivative Instruments Designated for Hedging	The fair values of derivative instruments designated for hedging held as of September 30, 2024 and 2023 are as follow: September 30, 2024 September 30, 2023 (in millions) Balance Sheet Location Fair Value Fair Value Asset Derivatives Derivatives designated as hedging instruments: Foreign currency forward contracts Financial instruments owned, net $ 9.6 $ 1.7 Total derivatives designated as hedging instruments $ 9.6 $ 1.7 Derivative assets, net expected to be released from Other comprehensive income into earnings within the next 12 months: Foreign currency forward contracts $ 9.2 $ 1.4 Total expected to be released from Other comprehensive income into earnings $ 9.2 $ 1.4 Liability Derivatives Derivatives designated as hedging instruments: Interest rate contracts Financial instruments sold, not yet purchased $ 0.2 $ 24.6 Foreign currency forward contracts Financial instruments sold, not yet purchased — 2.5 Total derivatives designated as hedging instruments $ 0.2 $ 27.1 Derivative liabilities, net expected to be released from Other comprehensive income into earnings within the next 12 months: Interest rate contracts $ 0.2 $ 20.3 Foreign currency forward contracts — 1.0 Total expected to be released from Other comprehensive income into earnings $ 0.2 $ 21.3
Schedule of Notional Values of Derivative Instruments Designated for Hedging Held	The notional values of derivative instruments designated for hedging held as of September 30, 2024 and 2023 are as follows: September 30, 2024 September 30, 2023 (in millions) Notional Value Notional Value Derivatives designated as hedging instruments: Interest rate contracts $ 500.0 $ 2,000.0 Foreign currency forward contracts: Foreign currency forward contracts to purchase Polish Zloty: Local currency zł 156.1 zł 156.1 USD $ 37.5 $ 34.0 Foreign currency forward contracts to purchase British Pound Sterling: Local currency £ 72.0 £ 168.0 USD $ 88.8 $ 206.9
Schedule of Effects of Derivative Instruments Designated for Hedging Held and Net Gains/(Losses) from Derivative Contracts	The Consolidated Income Statement effects of derivative instruments designated for hedging held for the fiscal years ended September 30, 2024 and 2023 are as follows: (in millions) Income Statement Location Year Ended September 30, 2024 Year Ended September 30, 2023 Total amounts in income related to hedges Interest rate contracts Interest income $ (26.7) $ (47.0) Foreign currency forward contracts Compensation and benefits 9.6 2.3 Total derivatives designated as hedging instruments $ (17.1) $ (44.7) Amount of gain reclassified from accumulated other comprehensive income into income as a result of a forecasted transaction that is no longer probable of occurring $ — $ — The following table sets forth the Company’s net gains/(losses) related to derivative financial instruments for the periods indicated, in accordance with the Derivatives and Hedging Topic of the ASC. The net gains/(losses) set forth below are included in Principal gains, net and Cost of sales of physical commodities in the Consolidated Income Statements. Year Ended September 30, (in millions) 2024 2023 2022 Commodities $ 383.8 $ 446.5 $ 303.7 Foreign exchange 124.6 269.2 174.4 Interest rate, equities, and indices 100.2 109.0 100.4 TBA and forward settling securities (135.5) 73.0 226.8 Net gains from derivative contracts $ 473.1 $ 897.7 $ 805.3
Schedule of Accumulated Other Comprehensive Income Effects of Derivative Instruments Designated for Hedging Held	The accumulated other comprehensive income effects of derivative instruments designated for hedging held for the years ended September 30, 2024 and 2023 are as follow: Amount of Gain Recognized in Other Comprehensive Income on Derivatives, net of tax (in millions) Year Ended September 30, 2024 Year Ended September 30, 2023 Derivatives in Cash Flow Hedging Relationships: Interest rate contracts $ 18.5 $ 18.4 Foreign currency forward contracts 7.2 16.7 Total $ 25.7 $ 35.1

Allowance for Doubtful Accoun_2

Allowance for Doubtful Accounts (Tables)	12 Months Ended
	Sep. 30, 2024
Receivables [Abstract]
Schedule of Activity of Allowance for Doubtful Accounts	Activity in the allowance for doubtful accounts for the years ended September 30, 2024, 2023, and 2022 was as follows: (in millions) 2024 2023 2022 Balance, beginning of year $ 59.9 $ 47.8 $ 39.8 (Recovery) Provision for bad debts (1) (2.4) 12.5 12.4 Allowance charge-offs (6.2) (0.5) (5.6) Other 0.6 0.1 1.2 Balance, end of year $ 51.9 $ 59.9 $ 47.8 (1) An additional $3.0 million, $4.0 million, and $3.4 million is included in bad debt expense for the years ended September 30, 2024, 2023, and 2022, respectively, on the consolidated income statement, which is not included in the allowance.

Physical Commodities Inventory

Physical Commodities Inventory (Tables)	12 Months Ended
	Sep. 30, 2024
Inventory Disclosure [Abstract]
Schedule of Physical Commodities Inventory	The Company’s inventories consist of finished physical commodities as shown below. September 30, (in millions) 2024 2023 Physical Ag & Energy $ 169.0 $ 146.2 Precious metals - held by broker-dealer subsidiary 207.6 240.3 Precious metals - held by non-broker-dealer subsidiaries 304.5 150.8 Physical commodities inventory $ 681.1 $ 537.3

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment, Net [Abstract]
Schedule of Property and Equipment, Net	A summary of property and equipment, at cost less accumulated depreciation and amortization as of September 30, 2024 and 2023 is as follows: September 30, (in millions) 2024 2023 Property and equipment: Furniture and fixtures $ 21.4 $ 17.5 Software 41.5 38.1 Equipment 57.9 49.9 Leasehold improvements 56.7 47.7 Capitalized software development 113.1 77.0 Total property and equipment 290.6 230.2 Less: accumulated depreciation and amortization (147.5) (106.7) Property and equipment, net $ 143.1 $ 123.5

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill Allocated to Operating Segments	Goodwill allocated to the Company’s operating segments as of September 30, 2024 and 2023 is as follows: September 30, (in millions) 2024 2023 Commercial $ 33.3 $ 33.7 Institutional 9.8 9.8 Self-Directed/Retail 7.9 5.8 Payments 10.0 10.0 Total Goodwill $ 61.0 $ 59.3

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Gross and Net Carrying Values of Intangible Assets	The gross and net carrying values of intangible assets as of the balance sheet dates, by major intangible asset class are as follows (in millions): September 30, 2024 September 30, 2023 Gross Accumulated Net Amount Gross Accumulated Net Amount Intangible assets subject to amortization: Trade/domain names $ 4.1 $ (3.2) $ 0.9 $ 4.1 $ (2.4) $ 1.7 Software programs/platforms 4.9 (4.1) 0.8 28.5 (26.9) 1.6 Client base 37.7 (25.6) 12.1 38.3 (24.1) 14.2 Total intangible assets subject to amortization 46.7 (32.9) 13.8 70.9 (53.4) 17.5 Intangible assets not subject to amortization Website domains 2.1 — 2.1 1.9 — 1.9 Business licenses 3.7 — 3.7 3.7 — 3.7 Total intangible assets not subject to amortization 5.8 — 5.8 5.6 — 5.6 Total intangible assets $ 52.5 $ (32.9) $ 19.6 $ 76.5 $ (53.4) $ 23.1
Schedule of Expected Amortization Expense	As of September 30, 2024, estimated future amortization expense was as follows: (in millions) Fiscal 2025 $ 4.1 Fiscal 2026 3.1 Fiscal 2027 2.4 Fiscal 2028 1.5 Fiscal 2029 and thereafter 2.7 $ 13.8

Leases (Tables)

Leases (Tables)	12 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Schedule of Operating Lease Costs and Other Related Information	The following table presents operating lease costs and other related information as of and for the fiscal year ended September 30, 2024 and 2023 (in millions, except as stated): Year Ended September 30, 2024 2023 Operating lease costs (1)(2) $ 42.9 $ 28.0 Supplemental cash flow information and non-cash activity: Cash paid for amounts included in the measurement of operating lease liabilities $ 25.8 $ 18.4 Right-of-use assets obtained in exchange for operating lease liabilities $ 56.4 $ 14.3 Lease term and discount rate information: Weighted average remaining lease term (years) 8.6 9.8 Weighted average discount rate 5.0 % 4.5 % (1) Includes short-term leases and variable lease costs, which are immaterial. (2) Elements of operating lease costs are included as components of Cost of sales of physical commodities and Occupancy and equipment rental in the Consolidated Income Statements.
Schedule of Maturities of Lease Liabilities	The maturities of the lease liabilities are as follows as of September 30, 2024 (in millions): 2025 $ 29.3 2026 30.5 2027 31.1 2028 29.3 2029 24.2 After 2029 95.5 Total lease payments 239.9 Less: interest 44.0 Present value of lease liabilities $ 195.9

Credit Facilities (Tables)

Credit Facilities (Tables)	12 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Schedule of Debt	The following table sets forth a listing of credit facilities, the current committed amounts as of the report date on the facilities, and outstanding (in millions, except for percentages): Amounts Outstanding Borrower Security Renewal or Interest Rate at September 30, 2024 Total Commitment September 30, 2024 September 30, Committed Credit Facilities Senior StoneX Group Inc. Committed Credit Facility (1) April 21, 2026 Base rate - 9.00% SOFR - 6.95% 500.0 161.0 (5) 150.0 StoneX Financial Inc. None October 28, 2025 10.00 % 250.0 (7) — (5) — StoneX Commodity Solutions LLC Certain assets July 29, 2025 Base rate - 8.5% SOFR - 7.54% 325.0 66.0 (5) 103.0 StoneX Financial Ltd None October 9, 2025 7.47 % 115.0 (6) — (5) 25.0 StoneX Financial Pte. Ltd. None September 5, 2025 7.46 % 15.0 — (5) — $ 1,205.0 $ 227.0 $ 278.0 Uncommitted Credit Facilities Various Various Various 104.9 (5) 55.5 Notes payable to bank Certain equipment December 1, 2025 Index rate plus 2.35% 6.9 (5) 7.5 Senior Secured Notes due 2031 (2) March 1, 2031 7.875 % 543.1 (4) — Senior Secured Notes due 2025 (2) June 15, 2025 8.625 % — (3) 342.1 Total outstanding borrowings $ 881.9 $ 683.1 (1) The StoneX Group Inc. senior committed credit facility is a revolving facility secured by substantially all of the assets of StoneX Group Inc. and certain subsidiaries identified in the credit facility agreement as obligors, and pledged equity of certain subsidiaries identified in the credit facility as limited guarantors. (2) The Notes and the related guarantees are secured by liens on substantially all of the Company’s and the guarantors’ assets, subject to certain customary and other exceptions and permitted liens. The liens on the assets that secure the Notes and the related guarantees are contractually subordinated to the liens on the assets that secure the Company’s and the guarantors’ existing and future first lien secured indebtedness, including indebtedness under the Company’s senior committed credit facility. (3) Included in Senior secured borrowings, net on the Consolidated Balance Sheets. Amounts outstanding under the Notes due 2025 are reported net of unamortized original issue discount and unamortized deferred financing costs of $5.8 million as of September 30, 2023. The Notes due 2025 were extinguished as of June 30, 2024. (4) Included in Senior secured borrowings, net on the Consolidated Balance Sheets . Amounts outstanding under the Notes due 2031 are reported net of unamortized deferred financing costs of $6.9 million . (5) Included in Lenders under loans on the Consolidated Balance Sheets. (6) The facility was amended on October 9, 2024 to extend the maturity date to October 9, 2025. The facility was amended on October 31, 2024 to increase the amount available from $100 million to $115 million. (7) The facility was amended on October 29, 2024 to extend the maturity date to October 28, 2025 , and to increase the amount available from $190.0 million to $250.0 million.

Securities and Commodity Fina_2

Securities and Commodity Financing Transactions (Tables)	12 Months Ended
	Sep. 30, 2024
Broker-Dealer [Abstract]
Schedule of Carrying Value of Repurchase Agreements, and Securities Lending Agreements by Remaining Contractual Maturity	The following tables set forth the carrying value of repurchase agreements, and securities lending agreements by remaining contractual maturity (in millions): September 30, 2024 Overnight and Open Less than 30 Days 30-90 Days Over 90 Days Total Securities sold under agreements to repurchase $ 15,260.8 $ 585.4 $ 631.0 $ 50.7 $ 16,527.9 Securities loaned 1,615.9 — — — 1,615.9 Gross amount of secured financing $ 16,876.7 $ 585.4 $ 631.0 $ 50.7 $ 18,143.8 September 30, 2023 Overnight and Open Less than 30 Days 30-90 Days Over 90 Days Total Securities sold under agreements to repurchase $ 8,300.0 $ 786.8 $ 107.0 $ 2.6 $ 9,196.4 Securities loaned 1,117.3 — — — 1,117.3 Gross amount of secured financing $ 9,417.3 $ 786.8 $ 107.0 $ 2.6 $ 10,313.7
Schedule of Carrying Value of Repurchase Agreements and Securities Lending Agreements by Class of Collateral Pledged and Netting of Securities Purchased Under Agreements	The following table sets forth the carrying value of repurchase agreements and securities lending agreements by class of collateral pledged (in millions): September 30, Securities sold under agreements to repurchase 2024 2023 U.S. Treasury obligations $ 9,673.7 $ 3,696.1 U.S. government agency obligations and municipal bonds 652.0 542.2 Asset-based obligations 136.1 102.9 Agency mortgage-backed obligations 5,079.6 4,371.6 Foreign government obligations 649.6 148.1 Corporate bonds 336.9 335.5 Total securities sold under agreement to repurchase $ 16,527.9 $ 9,196.4 Securities loaned Equity securities $ 1,615.9 $ 1,117.3 Total securities loaned 1,615.9 1,117.3 Gross amount of secured financing $ 18,143.8 $ 10,313.7 The following tables provide the netting of securities purchased under agreements to resell, securities sold under agreements to repurchase, securities borrowed and securities loaned as of the periods indicated (in millions): September 30, 2024 Offsetting of collateralized transactions: Gross Amounts Recognized Amounts Offset in the Consolidated Balance Sheet Net Amounts Presented in the Consolidated Balance Sheet Securities purchased under agreements to resell $ 13,148.1 $ (7,946.6) $ 5,201.5 Securities borrowed $ 1,662.3 $ — $ 1,662.3 Securities sold under agreements to repurchase $ 16,527.9 $ (7,946.6) $ 8,581.3 Securities loaned $ 1,615.9 $ — $ 1,615.9 September 30, 2023 Offsetting of collateralized transactions: Gross Amounts Recognized Amounts Offset in the Consolidated Balance Sheet Net Amounts Presented in the Consolidated Balance Sheet Securities purchased under agreements to resell $ 7,649.3 $ (4,669.8) $ 2,979.5 Securities borrowed $ 1,129.1 $ — $ 1,129.1 Securities sold under agreements to repurchase $ 9,196.4 $ (4,669.8) $ 4,526.6 Securities loaned $ 1,117.3 $ — $ 1,117.3
Schedule of Carrying Value of Collateral Pledged, Received and Repledged	The following table sets forth the fair value, which approximates carrying value because of the short term nature, of collateral pledged, received and repledged (in millions): September 30, 2024 September 30, 2023 Securities pledged or repledged to cover collateral requirements for tri-party arrangements $ 6,777.9 $ 4,726.6 Securities received as collateral that may be repledged $ 20,126.8 $ 9,180.1 Securities received as collateral that may be repledged covering securities sold short $ 2,408.3 $ 2,461.1 Repledged securities borrowed and client securities held under custodial clearing arrangements to collateralize securities loaned agreements $ 1,533.3 $ 1,097.3

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss, Net (Tables)	12 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Loss	The following table summarizes the changes in accumulated other comprehensive loss for the years ended September 30, 2024, 2023, and 2022. (in millions) Foreign Currency Translation Adjustment Pension Benefits Adjustment Cash Flow Hedge Accumulated Other Comprehensive Loss, net Balances as of September 30, 2021 $ (22.7) $ (2.4) $ — $ (25.1) Other comprehensive loss net of tax (11.7) (0.3) (53.5) (65.5) Balances as of September 30, 2022 $ (34.4) $ (2.7) $ (53.5) $ (90.6) Other comprehensive income net of tax 3.2 0.5 35.1 38.8 Balances as of September 30, 2023 $ (31.2) $ (2.2) $ (18.4) $ (51.8) Other comprehensive income/(loss) net of tax (0.1) 1.0 25.7 26.6 Balances as of September 30, 2024 $ (31.3) $ (1.2) $ 7.3 $ (25.2)

Revenue from Contracts with C_2

Revenue from Contracts with Clients (Tables)	12 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table represents a disaggregation of the Company’s total revenues separated between revenues from contracts with clients and other sources of revenue for the periods indicated (in millions): Year Ended September 30, 2024 2023 2022 Revenues from contracts with clients: Commission and clearing fees: Sales-based: Exchange-traded futures and options $ 226.1 $ 214.1 $ 210.7 OTC derivative brokerage 11.3 14.5 16.8 Equities and fixed income 65.9 57.8 62.9 Mutual funds 3.1 3.0 4.1 Insurance and annuity products 11.0 9.2 9.3 Other — 3.4 3.1 Total sales-based commission 317.4 302.0 306.9 Trailing: Mutual funds 12.7 12.4 14.1 Insurance and annuity products 15.2 14.2 16.0 Total trailing commission 27.9 26.6 30.1 Clearing fees 180.2 153.3 153.2 Trade conversion fees 13.1 8.5 11.5 Other 9.4 8.0 6.2 Total commission and clearing fees 548.0 498.4 507.9 Consulting, management, and account fees: Underwriting fees 0.4 0.7 0.5 Asset management fees 50.9 45.1 43.9 Advisory and consulting fees 38.2 35.0 30.9 Sweep program fees 44.4 48.6 13.1 Client account fees 19.8 15.9 16.0 Other 13.5 13.7 6.9 Total consulting, management, and account fees 167.2 159.0 111.3 Sales of physical commodities: Precious metals sales under ASC Topic 606 1,500.7 2,836.0 2,988.3 Total revenues from contracts with clients $ 2,215.9 $ 3,493.4 $ 3,607.5 Method of revenue recognition: Point-in-time $ 2,054.5 $ 3,338.1 $ 3,489.5 Time elapsed 161.4 155.3 118.0 Total revenues from contracts with clients 2,215.9 3,493.4 3,607.5 Other sources of revenues Physical precious metals under ASC Topic 815 91,241.1 50,979.5 57,404.3 Physical agricultural and energy products 3,844.4 4,315.7 3,660.0 Principal gains, net 1,189.6 1,079.9 1,145.2 Interest income 1,396.8 987.6 219.0 Total revenues $ 99,887.8 $ 60,856.1 $ 66,036.0
Schedule of Income and Expense	The following table indicates the relevant income and expense: Year Ended September 30, (in millions) 2024 2023 2022 Dividend income on long equity positions $ 192.3 $ 32.0 $ 142.3 Dividend expense on short equity positions 191.2 33.3 134.0 Dividend income/(loss) net of dividend expense reported within Principal Gains, net $ 1.1 $ (1.3) $ 8.3

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Fair Value Estimated at Grant Date Based on Black-Scholes-Merton Option-Pricing Model Using Weighted-Average Assumptions	Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions: Year Ended September 30, 2024 2023 2022 Expected stock price volatility 38 % 42 % 39 % Expected dividend yield — % — % — % Risk free interest rate 2.21 % 1.60 % 1.54 % Average expected life (in years) 6.32 4.25 5.21
Schedule of Stock Option Activity	The following is a summary of stock option activity for the year ended September 30, 2024: Number of Weighted Weighted Weighted Aggregate Balances as of September 30, 2023 1,763,788 $ 35.65 $ 10.56 3.80 $ 51.1 Granted 1,627,150 $ 65.37 $ 26.77 Exercised (237,613) $ 32.89 $ 9.07 Forfeited (89,432) $ 36.50 $ 10.65 Expired (2,320) $ 40.88 $ 14.69 Balances as of September 30, 2024 3,061,573 $ 51.63 $ 19.28 5.06 $ 92.6 Exercisable at September 30, 2024 721,635 $ 34.58 $ 10.05 2.68 $ 34.1
Schedule of Options Outstanding Broken Down by Exercise Price	The options outstanding as of September 30, 2024 broken down by exercise price are as follows: Exercise Price Number of Options Outstanding Weighted Average Exercise Price Weighted Average Remaining Term $ 25.00 - $ 30.00 810,000 $ 30.00 2.18 $ 35.00 - $ 40.00 234,020 $ 39.10 2.31 $ 40.00 - $ 45.00 289,212 $ 41.36 4.60 $ 45.00 - $ 75.00 1,728,341 $ 65.18 6.86 3,061,573 $ 51.63 5.06
Schedule of Restricted Stock Units Activity	The following is a summary of restricted stock activity through September 30, 2024: Number of Weighted Weighted Aggregate Balances as of September 30, 2023 1,026,642 $ 54.10 1.24 $ 66.5 Granted 477,096 $ 68.10 Vested (494,568) $ 51.30 Forfeited (1,582) $ 54.79 Balances as of September 30, 2024 1,007,588 $ 62.10 1.13 $ 82.5

Other Expenses (Tables)

Other Expenses (Tables)	12 Months Ended
	Sep. 30, 2024
Other Expenses [Abstract]
Schedule of Other Expenses	Other expenses consisted of the following, for the periods indicated. Year Ended September 30, (in millions) 2024 2023 2022 Non-income taxes $ 12.8 $ 16.8 $ 13.5 Insurance 11.8 11.1 10.8 Employee related expenses 7.3 10.1 9.6 Other direct business expenses 15.1 14.8 10.0 Membership fees 3.7 3.4 3.3 Director and public company expenses 2.1 2.3 1.8 Office expenses 2.4 1.9 1.7 Other expenses 9.9 6.0 9.9 Total other expenses $ 65.1 $ 66.4 $ 60.6

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense/(Benefit) and Components of Income Tax Expense/(Benefit) Attributable to Income from Operations	Income tax expense/(benefit) for the years ended September 30, 2024, 2023, and 2022 was allocated as follows: Year Ended September 30, (in millions) 2024 2023 2022 Income tax expense attributable to income from operations $ 93.3 $ 84.5 $ 70.1 Taxes allocated to stockholders’ equity, related to pension liabilities 0.3 0.2 (0.1) Taxes allocated to stockholders’ equity, related to hedge accounting 8.1 11.1 (17.0) Total income tax expense $ 101.7 $ 95.8 $ 53.0 The components of income tax expense/(benefit) attributable to income from operations were as follows: Year Ended September 30, (in millions) 2024 2023 2022 Current taxes: U.S. federal $ 26.4 $ 15.8 $ 8.2 U.S. state and local 5.9 3.9 3.6 Australia 0.2 2.2 2.8 Brazil 18.2 16.0 12.6 Germany 4.2 4.5 8.9 Singapore 7.7 4.9 2.0 Switzerland — 2.6 — United Kingdom 34.5 30.9 29.2 Other international 6.7 6.1 3.1 Total current taxes 103.8 86.9 70.4 Deferred taxes: U.S. federal 1.7 (1.1) 3.4 U.S. state and local 0.5 — (0.1) Australia (0.1) 0.1 (0.2) Brazil (3.6) — (0.8) Germany (0.4) — — Switzerland (1.2) 0.4 — United Kingdom (7.2) (1.4) (2.7) Other international (0.2) (0.4) 0.1 Total deferred taxes (10.5) (2.4) (0.3) Income tax expense $ 93.3 $ 84.5 $ 70.1
Schedule of Components of Income from Operations, Before Tax	U.S. and international components of income from operations, before tax, were as follows: Year Ended September 30, (in millions) 2024 2023 2022 U.S. $ 97.8 $ 135.1 $ 50.0 Australia 0.5 7.4 8.7 Brazil 37.8 35.3 25.3 Germany 12.1 13.3 27.8 Singapore 55.1 38.1 19.4 Switzerland (2.3) 22.5 — United Kingdom 121.3 77.7 104.8 Other international 31.8 (6.4) 41.2 Income from operations, before tax $ 354.1 $ 323.0 $ 277.2
Schedule of Effective Income Tax Rate Reconciliation	Items accounting for the difference between income taxes computed at the federal statutory rate and income tax expense were as follows: Year Ended September 30, 2024 2023 2022 Federal statutory rate effect of: 21.0 % 21.0 % 21.0 % U.S. State and local income taxes 1.4 % 1.0 % 1.0 % Foreign earnings and losses taxed at different rates 2.6 % 1.1 % 1.1 % Change in valuation allowance — % (0.4) % 0.9 % U.K. bank tax 0.2 % 0.3 % 2.6 % U.S. permanent items (0.4) % 0.2 % 0.2 % Non-deductible compensation 0.8 % 2.0 % 0.7 % Foreign permanent items (1.4) % 0.4 % (2.8) % U.S. bargain purchase gain — % (1.4) % — % GILTI 2.0 % 2.0 % 0.6 % Unrecognized tax benefits 0.1 % — % — % Effective rate 26.3 % 26.2 % 25.3 %
Schedule of Components of Deferred Income Tax Assets and Liabilities	The components of deferred income tax assets and liabilities were as follows: (in millions) September 30, 2024 September 30, 2023 Deferred tax assets: Share-based compensation $ 12.2 $ 7.4 Deferred compensation 5.4 5.4 Net operating loss carryforwards 19.6 17.2 Intangible assets 1.3 3.8 Bad debt reserve 7.2 9.6 Hedging — 5.9 Foreign tax credit carryforwards 1.2 0.6 Other compensation 7.5 7.8 Pension 2.5 3.6 Right of use assets 30.1 20.1 Property and equipment 3.4 — Other 1.6 1.1 Total gross deferred tax assets 92.0 82.5 Less valuation allowance (15.5) (12.4) Deferred tax assets 76.5 70.1 Deferred income tax liabilities: Unrealized gain on securities 3.1 2.8 Prepaid expenses 2.5 5.0 Property and equipment — 1.6 Right of use liabilities 26.7 17.2 Mark to market on inventory 3.8 4.8 Other deferred liabilities 0.5 1.4 Hedging 2.2 — Deferred income tax liabilities 38.8 32.8 Deferred income taxes, net $ 37.7 $ 37.3
Schedule of Roll Forward of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Year Ended September 30, (in millions) 2024 2023 2022 Balance, beginning of year $ — $ — $ — Gross increases for tax positions related to current year — — — Gross increases for tax positions related to prior years 0.3 — — Gross decreases for tax positions of prior years — — — Settlements — — — Lapse of statute of limitations — — — Balance, end of year $ 0.3 $ — $ —

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Schedule of Aggregate Merger Consideration	(in millions) Fair Value Cash and cash equivalents $ 8.2 Deposits with and receivables from broker-dealers, clearing organizations, and counterparties 7.7 Receivable from clients, net 51.9 Financial instruments owned, at fair value 45.7 Deferred income taxes, net (3.3) Property and equipment, net 0.1 Physical commodities inventory, net 22.5 Other assets 6.7 Total fair value of tangible assets acquired 139.5 Accounts payable and other accrued liabilities 40.0 Financial instruments sold, not yet purchased, at fair value 28.3 Payables to lenders under loans 10.1 Payables to broker-dealers, clearing organizations, and counterparties 0.4 Payables to clients 2.6 Income taxes payable 0.8 Total fair value of liabilities assumed 82.2 Fair value of tangible net assets acquired $ 57.3 Identifiable intangible assets acquired Client relationships $ 4.7 Supplier relationships 3.7 Trade name 0.4 Non-compete 0.1 Total fair value of intangible assets acquired 8.9 Fair value of identifiable net assets acquired 66.2 Total merger consideration 42.7 Gain on acquisition $ 23.5

Regulatory Requirements and S_2

Regulatory Requirements and Subsidiary Dividend Restrictions (Tables)	12 Months Ended
	Sep. 30, 2024
Capital and Other Regulatory Requirements [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following table details the Company’s subsidiaries with a minimum regulatory net capital requirement in excess of $10.0 million as well as the actual regulatory capital of the subsidiary as of September 30, 2024 (in millions): Subsidiary Regulatory Authority Actual Minimum StoneX Financial Inc. SEC and CFTC $ 435.7 $ 243.5 StoneX Financial Ltd FCA $ 433.8 $ 358.0 GAIN Capital Group, LLC CFTC and NFA $ 57.1 $ 29.7 StoneX Financial Pte. Ltd. MAS $ 100.6 $ 22.3 StoneX Markets LLC CFTC and NFA $ 237.9 $ 134.3

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	12 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	Information for the reportable segments is shown in accordance with the Segment Reporting Topic of the ASC as follows: Year Ended September 30, (in millions) 2024 2023 2022 Total revenues: Commercial $ 97,278.3 $ 58,249.2 $ 63,743.2 Institutional 1,962.1 1,513.6 831.8 Self-Directed/Retail 440.2 888.5 1,304.2 Payments 209.6 212.6 172.0 Corporate 46.9 31.7 7.8 Eliminations (49.3) (39.5) (23.0) Total $ 99,887.8 $ 60,856.1 $ 66,036.0 Operating revenues: Commercial $ 871.9 $ 862.7 $ 692.1 Institutional 1,962.1 1,513.6 831.8 Self-Directed/Retail 395.0 333.0 426.7 Payments 209.6 212.6 172.0 Corporate 46.9 31.7 7.8 Eliminations (49.3) (39.5) (23.0) Total $ 3,436.2 $ 2,914.1 $ 2,107.4 Net operating revenues (loss): Commercial $ 715.9 $ 721.3 $ 586.5 Institutional 630.4 532.0 483.5 Self-Directed/Retail 286.1 227.3 302.9 Payments 199.5 203.3 162.5 Corporate (64.7) (62.9) (59.5) Total $ 1,767.2 $ 1,621.0 $ 1,475.9 Net contribution: (Revenues less cost of sales of physical commodities, transaction-based clearing expenses, variable compensation, introducing broker commissions and interest expense) Commercial $ 541.8 $ 544.9 $ 415.3 Institutional 430.3 351.5 295.1 Self-Directed/Retail 267.0 212.7 280.3 Payments 162.5 164.5 131.2 Total $ 1,401.6 $ 1,273.6 $ 1,121.9 Segment income: (Net contribution less non-variable direct segment costs) Commercial $ 387.7 $ 390.7 $ 288.3 Institutional 266.0 217.9 174.6 Self-Directed/Retail 119.3 45.8 115.4 Payments 112.6 109.1 97.4 Total $ 885.6 $ 763.5 $ 675.7 Reconciliation of segment income to income before tax: Segment income $ 885.6 $ 763.5 $ 675.7 Net operating loss within Corporate (64.7) (62.9) (59.5) Overhead costs and expenses (466.8) (400.9) (339.0) Gain on acquisitions and other gains, net within Corporate — 23.3 — Income before tax $ 354.1 $ 323.0 $ 277.2 (in millions) As of September 30, 2024 As of September 30, 2023 As of September 30, 2022 Total assets: Commercial $ 5,387.0 $ 4,676.3 $ 5,931.0 Institutional 19,492.9 15,059.3 11,687.1 Self-Directed/Retail 1,024.1 1,014.2 971.2 Payments 438.8 376.6 524.0 Corporate 1,123.5 812.3 746.3 Total $ 27,466.3 $ 21,938.7 $ 19,859.6
Schedule of Revenue Long-Lived Assets, by Geographical Areas	Information regarding revenues and operating revenues for the ended September 30, 2024, 2023, and 2022, and information regarding long-lived assets (defined as property, equipment, leasehold improvements and software) as of September 30, 2024, 2023, and 2022 in geographic areas were as follows: Year Ended September 30, (in millions) 2024 2023 2022 Total revenues: United States $ 6,026.3 $ 6,017.4 $ 5,102.3 Europe 2,358.8 3,498.9 3,440.2 South America 455.0 271.4 87.2 Middle East and Asia 91,015.0 51,023.6 57,395.5 Other 32.7 44.8 10.8 Total $ 99,887.8 $ 60,856.1 $ 66,036.0 Operating revenues: United States $ 2,507.0 $ 2,120.4 $ 1,448.2 Europe 594.8 494.3 474.6 South America 141.8 127.0 87.2 Middle East and Asia 159.9 127.6 86.6 Other 32.7 44.8 10.8 Total $ 3,436.2 $ 2,914.1 $ 2,107.4 (in millions) As of September 30, 2024 As of September 30, 2023 As of September 30, 2022 Long-lived assets, as defined: United States $ 76.2 $ 76.0 $ 67.9 Europe 54.2 40.7 41.1 South America 5.6 4.4 2.9 Middle East and Asia 7.1 2.4 1.0 Other — — — Total $ 143.1 $ 123.5 $ 112.9

Description of Business and S_3

Description of Business and Significant Accounting Policies (Details) $ / shares in Units, client in Thousands		12 Months Ended
	Nov. 07, 2023	Sep. 30, 2024 USD ($) client country $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares	Sep. 30, 2022 USD ($)
Number of countries in which entity operates (more than) | country		180
Number of commercial, institutional and global payment clients (more than) | client		54
Number of self-directed/retail clients (more than) | client		400
Net liabilities denominated in argentine pesos		$ 2,400,000	$ 200,000
Cash denominated in argentine pesos (less than)		3,000,000	800,000
Net nonmonetary denominated in argentine pesos		2,700,000	700,000
Cash held at banks and money market funds - segregated		2,789,400,000	2,420,500,000
Commodities warehouse receipts		51,800,000	5,800,000
Cash and cash equivalents - deposits and receivables		2,614,200,000	2,512,900,000
US government securities and other securities - deposits and receivables		$ 2,951,500,000	4,041,600,000
Acquired finite-lived intangible asset, weighted average useful life		1 year
Goodwill impairment charges		$ 0	0	$ 0
Intangible assets impairment charges		$ 0	$ 0	0
Preferred stock, authorized (in shares) | shares		1,000,000	1,000,000
Preferred stock, par value (in dollar per share) | $ / shares		$ 0.01	$ 0.01
Preferred stock, outstanding (in shares) | shares		0	0
Stock split, conversion ratio	1.5
Common stock, par value (in dollar per share) | $ / shares		$ 0.01	$ 0.01
Minimum
Property plant and equipment, useful life		3 years
Identifiable intangible assets amortization period		5 years
Maximum
Property plant and equipment, useful life		10 years
Identifiable intangible assets amortization period		20 years
Capitalized software development
Property plant and equipment, useful life		3 years
Argentina
Translation gains		$ 3,100,000	$ 6,600,000	$ 2,100,000
Argentina | Revenue Benchmark | Geographic Concentration Risk
Percentage of operating revenues (as a percent)		1%
Self-Directed/Retail
Number of countries in which entity operates (more than) | country		180

Earnings per Share - Schedule o

Earnings per Share - Schedule of Calculation of Numerator and Denominator in Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Net income	$ 260.8	$ 238.5	$ 207.1
Less: Allocation to participating securities	(9.1)	(8.1)	(6.1)
Net income allocated to common stockholders, basic	251.7	230.4	201
Net income allocated to common stockholders, diluted	$ 251.7	$ 230.4	$ 201
Denominator:
Common shares outstanding (in shares)	30,539,237	29,936,000	29,355,605
Dilutive potential common shares outstanding:
Share-based awards (in shares)	1,085,792	993,011	745,706
Diluted shares outstanding (in shares)	31,625,029	30,929,011	30,101,311
Earnings per share:
Earnings per share - basic (in dollar per share)	$ 8.24	$ 7.71	$ 6.85
Earnings per share - diluted (in dollar per share)	$ 7.96	$ 7.45	$ 6.67

Earnings per Share - Narrative

Earnings per Share - Narrative (Details) - shares	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Antidilutive securities (in shares)	1,565,788	371,657	677,861

Assets and Liabilities, at Fa_3

Assets and Liabilities, at Fair Value - Schedule of Financial and Non-Financial Assets and Liabilities Accounted at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 51.8	$ 5.8
Securities and other assets segregated under federal and other regulations	2,841.2	2,426.3
Financial instruments owned	6,767.1	5,044.8
Physical commodities inventory	681.1	537.3
Accounts payable and other accrued liabilities	522.1	533
Financial instruments sold, not yet purchased, at fair value	2,853.3	3,085.6
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	49.2	66.5
Securities and other assets segregated under federal and other regulations	51.8	5.8
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	3,287.5	4,248.3
Receivable from clients, net - Derivatives	(8.4)	(7.9)
Financial instruments owned	6,767.1	5,044.8
Total assets at fair value	10,523.8	9,744
Payables to clients - Derivatives	265.9	79.8
Financial instruments sold, not yet purchased, at fair value	2,853.3	3,085.6
Total liabilities at fair value	3,120.1	3,177.1
Fair Value, Measurements, Recurring | Accounts payable and other accrued liabilities - contingent liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	2.3	1.5
Fair Value, Measurements, Recurring | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	1.5	16.1
Fair Value, Measurements, Recurring | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	(2.9)	(5.9)
Fair Value, Measurements, Recurring | Payable to broker-dealers, clearing organizations and counterparties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	(1.4)	10.2
Fair Value, Measurements, Recurring | Physical commodities inventory
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical commodities inventory	376.6	386.5
Fair Value, Measurements, Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	378.9	334.3
Financial instruments sold, not yet purchased, at fair value	224.8	236.1
Fair Value, Measurements, Recurring | Corporate and municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	322.1	284.2
Financial instruments sold, not yet purchased, at fair value	154.6	81.6
Fair Value, Measurements, Recurring | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	1,088.6	531.7
Financial instruments sold, not yet purchased, at fair value	2,139.3	2,409.3
Fair Value, Measurements, Recurring | U.S. government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	531	451.7
Financial instruments sold, not yet purchased, at fair value	0.2	5.1
Fair Value, Measurements, Recurring | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	41.4	43.3
Financial instruments sold, not yet purchased, at fair value	41	21.5
Fair Value, Measurements, Recurring | Agency mortgage-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	3,837.2	2,865.8
Financial instruments sold, not yet purchased, at fair value	23.6	31.7
Fair Value, Measurements, Recurring | Asset-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	223.5	138.8
Financial instruments sold, not yet purchased, at fair value	3.9
Fair Value, Measurements, Recurring | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	228.1	268.5
Financial instruments sold, not yet purchased, at fair value	264.8	261.2
Fair Value, Measurements, Recurring | Commodities leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned		16
Fair Value, Measurements, Recurring | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	67.8	54.7
Fair Value, Measurements, Recurring | Exchange firm common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	13.2	12
Fair Value, Measurements, Recurring | Cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	9.6	1.7
Financial instruments sold, not yet purchased, at fair value	0.2	27.1
Fair Value, Measurements, Recurring | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	25.7	42.1
Fair Value, Measurements, Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments sold, not yet purchased, at fair value	0.9	12
Fair Value, Measurements, Recurring | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	7.8	41.8
Fair Value, Measurements, Recurring | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	18.3	17.8
Fair Value, Measurements, Recurring | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	2,933.2	4,023.8
Fair Value, Measurements, Recurring | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	328.2	164.9
Fair Value, Measurements, Recurring | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities and other assets segregated under federal and other regulations	51.8	5.8
Fair Value, Measurements, Recurring | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	13.9	8.7
Fair Value, Measurements, Recurring | Money market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	35.3	57.8
Fair Value, Measurements, Recurring | Netting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Securities and other assets segregated under federal and other regulations	0	0
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	(5,758.4)	(6,500.2)
Receivable from clients, net - Derivatives	(537)	(630.9)
Financial instruments owned	(375.2)	(600.2)
Total assets at fair value	(6,670.6)	(7,731.3)
Payables to clients - Derivatives	(3,540.1)	(5,577.1)
Financial instruments sold, not yet purchased, at fair value	(314.3)	(510.4)
Total liabilities at fair value	(6,614.6)	(7,639)
Fair Value, Measurements, Recurring | Netting | Accounts payable and other accrued liabilities - contingent liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring | Netting | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	(22.9)	(31.4)
Fair Value, Measurements, Recurring | Netting | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	(2,737.3)	(1,520.1)
Fair Value, Measurements, Recurring | Netting | Payable to broker-dealers, clearing organizations and counterparties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	(2,760.2)	(1,551.5)
Fair Value, Measurements, Recurring | Netting | Physical commodities inventory
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical commodities inventory	0	0
Fair Value, Measurements, Recurring | Netting | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | Corporate and municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | U.S. government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | Agency mortgage-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | Asset-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0
Fair Value, Measurements, Recurring | Netting | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	(375.2)	(600.2)
Financial instruments sold, not yet purchased, at fair value	(314.3)	(510.4)
Fair Value, Measurements, Recurring | Netting | Commodities leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned		0
Fair Value, Measurements, Recurring | Netting | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Netting | Exchange firm common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Netting | Cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Netting | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Netting | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	(18.3)	(31.7)
Fair Value, Measurements, Recurring | Netting | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Netting | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Netting | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	(5,740.1)	(6,468.5)
Fair Value, Measurements, Recurring | Netting | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring | Netting | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Fair Value, Measurements, Recurring | Netting | Money market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	49.2	66.5
Securities and other assets segregated under federal and other regulations	51.8	5.8
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	6,851.6	9,539.1
Receivable from clients, net - Derivatives	22.4	61.7
Financial instruments owned	1,598.6	1,005.6
Total assets at fair value	8,781.2	10,919
Payables to clients - Derivatives	3,577.1	5,430.7
Financial instruments sold, not yet purchased, at fair value	2,408.2	2,663.8
Total liabilities at fair value	6,363.3	8,206.7
Fair Value, Measurements, Recurring | Level 1 | Accounts payable and other accrued liabilities - contingent liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	0	0
Fair Value, Measurements, Recurring | Level 1 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	378	112.2
Fair Value, Measurements, Recurring | Level 1 | Payable to broker-dealers, clearing organizations and counterparties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	378	112.2
Fair Value, Measurements, Recurring | Level 1 | Physical commodities inventory
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical commodities inventory	207.6	240.3
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	363.9	324
Financial instruments sold, not yet purchased, at fair value	219.8	230.6
Fair Value, Measurements, Recurring | Level 1 | Corporate and municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	1,088.6	531.7
Financial instruments sold, not yet purchased, at fair value	2,139.3	2,409.3
Fair Value, Measurements, Recurring | Level 1 | U.S. government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	41.4	43.3
Financial instruments sold, not yet purchased, at fair value	41	21.5
Fair Value, Measurements, Recurring | Level 1 | Agency mortgage-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 1 | Asset-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0
Fair Value, Measurements, Recurring | Level 1 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0.1	0.6
Financial instruments sold, not yet purchased, at fair value	8.1	2.4
Fair Value, Measurements, Recurring | Level 1 | Commodities leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned		0
Fair Value, Measurements, Recurring | Level 1 | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	67.8	54.7
Fair Value, Measurements, Recurring | Level 1 | Exchange firm common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	13.2	12
Fair Value, Measurements, Recurring | Level 1 | Cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 1 | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	23.6	39.3
Fair Value, Measurements, Recurring | Level 1 | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 1 | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	18.3	17.8
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	2,933.2	4,023.8
Fair Value, Measurements, Recurring | Level 1 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	3,900.1	5,497.5
Fair Value, Measurements, Recurring | Level 1 | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities and other assets segregated under federal and other regulations	51.8	5.8
Fair Value, Measurements, Recurring | Level 1 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	13.9	8.7
Fair Value, Measurements, Recurring | Level 1 | Money market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	35.3	57.8
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Securities and other assets segregated under federal and other regulations	0	0
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	2,194.3	1,209.4
Receivable from clients, net - Derivatives	506.2	561.3
Financial instruments owned	5,541.6	4,636.6
Total assets at fair value	8,411.1	6,553.5
Payables to clients - Derivatives	228.9	226.2
Financial instruments sold, not yet purchased, at fair value	758.5	931.1
Total liabilities at fair value	3,368.2	2,606.8
Fair Value, Measurements, Recurring | Level 2 | Accounts payable and other accrued liabilities - contingent liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	0	0
Fair Value, Measurements, Recurring | Level 2 | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	24.4	47.5
Fair Value, Measurements, Recurring | Level 2 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	2,356.4	1,402
Fair Value, Measurements, Recurring | Level 2 | Payable to broker-dealers, clearing organizations and counterparties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	2,380.8	1,449.5
Fair Value, Measurements, Recurring | Level 2 | Physical commodities inventory
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical commodities inventory	169	146.2
Fair Value, Measurements, Recurring | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	15	10.3
Financial instruments sold, not yet purchased, at fair value	5	5.5
Fair Value, Measurements, Recurring | Level 2 | Corporate and municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	322.1	284.2
Financial instruments sold, not yet purchased, at fair value	154.6	81.6
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	531	451.7
Financial instruments sold, not yet purchased, at fair value	0.2	5.1
Fair Value, Measurements, Recurring | Level 2 | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2 | Agency mortgage-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	3,837.2	2,865.8
Financial instruments sold, not yet purchased, at fair value	23.6	31.7
Fair Value, Measurements, Recurring | Level 2 | Asset-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	223.5	138.8
Financial instruments sold, not yet purchased, at fair value	3.9
Fair Value, Measurements, Recurring | Level 2 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	603.2	868.1
Financial instruments sold, not yet purchased, at fair value	571	769.2
Fair Value, Measurements, Recurring | Level 2 | Commodities leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned		16
Fair Value, Measurements, Recurring | Level 2 | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Level 2 | Exchange firm common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Level 2 | Cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	9.6	1.7
Financial instruments sold, not yet purchased, at fair value	0.2	27.1
Fair Value, Measurements, Recurring | Level 2 | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Level 2 | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments sold, not yet purchased, at fair value	0	10.9
Fair Value, Measurements, Recurring | Level 2 | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	26.1	73.5
Fair Value, Measurements, Recurring | Level 2 | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 2 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	2,168.2	1,135.9
Fair Value, Measurements, Recurring | Level 2 | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring | Level 2 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Fair Value, Measurements, Recurring | Level 2 | Money market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Securities and other assets segregated under federal and other regulations	0	0
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Receivable from clients, net - Derivatives
Financial instruments owned	2.1	2.8
Total assets at fair value	2.1	2.8
Payables to clients - Derivatives	0	0
Financial instruments sold, not yet purchased, at fair value	0.9	1.1
Total liabilities at fair value	3.2	2.6
Fair Value, Measurements, Recurring | Level 3 | Accounts payable and other accrued liabilities - contingent liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts payable and other accrued liabilities	2.3	1.5
Fair Value, Measurements, Recurring | Level 3 | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	0	0
Fair Value, Measurements, Recurring | Level 3 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	0	0
Fair Value, Measurements, Recurring | Level 3 | Payable to broker-dealers, clearing organizations and counterparties
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable to broker-dealers, clearing organizations and counterparties	0	0
Fair Value, Measurements, Recurring | Level 3 | Physical commodities inventory
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Physical commodities inventory	0	0
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate and municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. government agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Agency mortgage-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Asset-backed obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0
Fair Value, Measurements, Recurring | Level 3 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Commodities leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned		0
Fair Value, Measurements, Recurring | Level 3 | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Level 3 | Exchange firm common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Fair Value, Measurements, Recurring | Level 3 | Cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	0	0
Financial instruments sold, not yet purchased, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3 | Mutual funds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments owned	2.1	2.8
Fair Value, Measurements, Recurring | Level 3 | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments sold, not yet purchased, at fair value	0.9	1.1
Fair Value, Measurements, Recurring | Level 3 | TBA and forward settling securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 3 | Foreign government obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 3 | Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits with and receivables from broker-dealers, clearing organizations and counterparties, net	0	0
Fair Value, Measurements, Recurring | Level 3 | Commodities warehouse receipts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities and other assets segregated under federal and other regulations	0	0
Fair Value, Measurements, Recurring | Level 3 | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Fair Value, Measurements, Recurring | Level 3 | Money market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 0	$ 0

Assets and Liabilities, at Fa_4

Assets and Liabilities, at Fair Value - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Mar. 01, 2024	Sep. 30, 2023
Senior Secured Notes due 2031
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	$ 543.1		$ 0
Senior Secured Notes due 2031 | Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate (as a percent)	7.875%	7.875%
Senior Secured Notes due 2031 | Senior Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	$ 586.3
Income S.A.S
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration	0.6
Trust Advisory Group, Ltd
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration	$ 1.7

Financial Instruments with Of_3

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Derivatives, Fair Value [Line Items]
Financial instruments sold, not yet purchased, at fair value	$ 2,853.3	$ 3,085.6
Interest rate contracts
Derivatives, Fair Value [Line Items]
Maximum length of time hedged in cash flow hedge	1 year
Foreign currency forwards
Derivatives, Fair Value [Line Items]
Maximum length of time hedged in cash flow hedge	2 years
Fair Value, Measurements, Recurring
Derivatives, Fair Value [Line Items]
Financial instruments sold, not yet purchased, at fair value	$ 2,853.3	3,085.6
Fair Value, Measurements, Recurring | Derivatives
Derivatives, Fair Value [Line Items]
Financial instruments sold, not yet purchased, at fair value	264.8	$ 261.2
Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument | Derivatives
Derivatives, Fair Value [Line Items]
Financial instruments sold, not yet purchased, at fair value	$ 264.8

Financial Instruments with Of_4

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Schedule of Derivative Assets and Liabilities (Details) contract in Millions, $ in Millions	Sep. 30, 2024 USD ($) contract	Sep. 30, 2023 USD ($) contract
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	$ 7,235.9	$ 8,200.3
Derivative liability, fair value, gross liability	7,144.1	8,017.3
Impact of netting and collateral asset	(6,670.6)	(7,731.3)
Impact of netting and collateral liability	$ (6,614.6)	$ (7,639)
Derivative, number of instruments held | contract	12.2	13.4
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	$ 7,226.3	$ 8,198.6
Derivative liability, fair value, gross liability	7,143.9	7,990.2
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	9.6	1.7
Derivative liability, fair value, gross liability	0.2	27.1
Total fair value included in Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net
Derivatives, Fair Value [Line Items]
Derivative, fair value, net	336	206.7
Total fair value included in Receivable from clients, net
Derivatives, Fair Value [Line Items]
Derivative, fair value, net	(8.4)	(7.9)
Total fair value included in Financial instruments owned, at fair value
Derivatives, Fair Value [Line Items]
Derivative, fair value, net	237.7	270.2
Total fair value included in Payables to clients
Derivatives, Fair Value [Line Items]
Derivative, fair value, net	265.9	79.8
Total fair value included in Payables to broker-dealers, clearing organizations and counterparties
Derivatives, Fair Value [Line Items]
Derivative, fair value, net	(1.4)	10.2
Fair value included in Financial instruments sold, not yet purchased, at fair value
Derivatives, Fair Value [Line Items]
Derivative, fair value, net	265	288.3
Exchange-traded commodity derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	1,383.1	1,907
Derivative liability, fair value, gross liability	1,415.7	1,890.3
OTC commodity derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	1,967.9	1,523.3
Derivative liability, fair value, gross liability	1,924.3	1,456
Exchange-traded foreign exchange derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	2	4.3
Derivative liability, fair value, gross liability	2	4.3
OTC foreign exchange derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	975.2	497.1
Derivative liability, fair value, gross liability	938.2	455.3
Exchange-traded interest rate derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	720.1	1,507.6
Derivative liability, fair value, gross liability	728.1	1,509.8
OTC interest rate derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	207.1	417.6
Derivative liability, fair value, gross liability	207.1	417.6
OTC interest rate derivatives | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, gross liability	0.2	24.6
Exchange-traded equity index derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	1,817.4	2,140.9
Derivative liability, fair value, gross liability	1,817.4	2,140.9
OTC equity and indices derivatives | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	127.4	127.3
Derivative liability, fair value, gross liability	86.7	68.5
TBA and forward settling securities | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	26.1	73.5
Derivative liability, fair value, gross liability	24.4	47.5
Interest rate swaps | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	0	0
Derivative liability, fair value, gross liability	0.2	24.6
Foreign currency forwards | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	9.6	1.7
Derivative liability, fair value, gross liability	$ 0	$ 2.5

Financial Instruments with Of_5

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Schedule of Fair Value of Derivative Instruments Designated for Hedging (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 7,235.9	$ 8,200.3
Liability Derivatives	7,144.1	8,017.3
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives	9.6	1.7
Derivative assets, net expected to be released from Other comprehensive income into earnings within the next 12 months:	9.2	1.4
Liability Derivatives	0.2	27.1
Derivative liabilities, net expected to be released from Other comprehensive income into earnings within the next 12 months:	0.2	21.3
Designated as Hedging Instrument | Foreign currency forwards
Derivatives, Fair Value [Line Items]
Asset Derivatives	9.6	1.7
Derivative assets, net expected to be released from Other comprehensive income into earnings within the next 12 months:	9.2	1.4
Liability Derivatives	0	2.5
Derivative liabilities, net expected to be released from Other comprehensive income into earnings within the next 12 months:	0	1
Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Liability Derivatives	0.2	24.6
Derivative liabilities, net expected to be released from Other comprehensive income into earnings within the next 12 months:	$ 0.2	$ 20.3

Financial Instruments with Of_6

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Schedule of Notional Values of Derivative Instruments Designated for Hedging Held (Details) - Designated as Hedging Instrument £ in Millions, zł in Millions, $ in Millions	Sep. 30, 2024 USD ($)	Sep. 30, 2024 PLN (zł)	Sep. 30, 2024 GBP (£)	Sep. 30, 2023 USD ($)	Sep. 30, 2023 PLN (zł)	Sep. 30, 2023 GBP (£)
Interest rate contracts
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Derivative, notional amount	$ 500			$ 2,000
Foreign currency forwards | Polish Zloty
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Derivative, notional amount	37.5	zł 156.1		34	zł 156.1
Foreign currency forwards | British Pound Sterling
Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items]
Derivative, notional amount	$ 88.8		£ 72	$ 206.9		£ 168

Financial Instruments with Of_7

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Schedule of Effects of Derivative Instruments Designated for Hedging Held (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivatives designated as hedging instruments	$ (17.1)	$ (44.7)
Amount of gain reclassified from accumulated other comprehensive income into income as a result of a forecasted transaction that is no longer probable of occurring	0	0
Interest rate contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivatives designated as hedging instruments	100.2	109	$ 100.4
Interest rate contracts | Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivatives designated as hedging instruments	(26.7)	(47)
Foreign currency forwards | Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivatives designated as hedging instruments	$ 9.6	$ 2.3

Financial Instruments with Of_8

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Schedule of Accumulated Other Comprehensive Income Effects of Derivative Instruments Designated for Hedging Held (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain Recognized in Other Comprehensive Income on Derivatives, net of tax	$ 25.7	$ 35.1
Interest rate contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain Recognized in Other Comprehensive Income on Derivatives, net of tax	18.5	18.4
Foreign currency forwards
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain Recognized in Other Comprehensive Income on Derivatives, net of tax	$ 7.2	$ 16.7

Financial Instruments with Of_9

Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Schedule of Net Gains/(Losses) from Derivative Contracts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk [Abstract]
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales of physical commodities, Total revenues	Cost of sales of physical commodities, Total revenues	Cost of sales of physical commodities, Total revenues
Net gains from derivative contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net	$ 473.1	$ 897.7	$ 805.3
Commodities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net	383.8	446.5	303.7
Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net	124.6	269.2	174.4
Interest rate, equities, and indices
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net	100.2	109	100.4
TBA and forward settling securities
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net	$ (135.5)	$ 73	$ 226.8

Allowance for Doubtful Accoun_3

Allowance for Doubtful Accounts - Narrative (Details) - USD ($)	Sep. 30, 2024	Sep. 30, 2023
Receivables [Abstract]
Allowance for doubtful accounts, deposits with and receivables from broker-dealers, clearings organizations, and counterparties	$ 0	$ 100,000
Allowance for doubtful accounts receivable	51,900,000	59,800,000
Allowance for doubtful accounts	$ 0	$ 0

Allowance for Doubtful Accoun_4

Allowance for Doubtful Accounts - Schedule of Activity of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance, beginning of year	$ 59.9	$ 47.8	$ 39.8
(Recovery) provision for bad debts	(2.4)	12.5	12.4
Allowance charge-offs	(6.2)	(0.5)	(5.6)
Other	0.6	0.1	1.2
Balance, end of year	51.9	59.9	47.8
Bad debt expense not included in allowance	$ 3	$ 4	$ 3.4

Physical Commodities Inventor_2

Physical Commodities Inventory (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Inventory [Line Items]
Physical Ag & Energy	$ 169	$ 146.2
Precious metals - held by broker-dealer subsidiary	376.6	386.5
Physical commodities inventory	681.1	537.3
Physical Commodities Inventory - Precious Metals
Inventory [Line Items]
Precious metals - held by broker-dealer subsidiary	207.6	240.3
Precious metals - held by non-broker-dealer subsidiaries	$ 304.5	$ 150.8

Property and Equipment, net - N

Property and Equipment, net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 45.6	$ 36.3	$ 30
Capitalized computer software, additions	36.1	$ 29.9
Write off of property and equipment assets	$ 4.8
Minimum
Property, Plant and Equipment [Line Items]
Property plant and equipment, useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Property plant and equipment, useful life	10 years

Property and Equipment, net - S

Property and Equipment, net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 290.6	$ 230.2
Less: accumulated depreciation and amortization	(147.5)	(106.7)
Property and equipment, net	143.1	123.5
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	21.4	17.5
Software
Property, Plant and Equipment [Line Items]
Total property and equipment	41.5	38.1
Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	57.9	49.9
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	56.7	47.7
Capitalized software development
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 113.1	$ 77

Goodwill - Schedule of Goodwill

Goodwill - Schedule of Goodwill Allocated to Operating Segments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Goodwill [Line Items]
Goodwill	$ 61	$ 59.3
Commercial
Goodwill [Line Items]
Goodwill	33.3	33.7
Institutional
Goodwill [Line Items]
Goodwill	9.8	9.8
Self-Directed/Retail
Goodwill [Line Items]
Goodwill	7.9	5.8
Payments
Goodwill [Line Items]
Goodwill	$ 10	$ 10

Goodwill - Narrative (Details)

Goodwill - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Goodwill [Line Items]
Goodwill, foreign exchange translation, decline	$ 0.3	$ 0.3
Trust Advisory Group, Ltd
Goodwill [Line Items]
Additional goodwill from acquisition	$ 2

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Acquired Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets, finite-lived	$ 27.8
Impairment of intangible assets, finite-lived Extensible Enumeration	amortized intangible assets
Amortization of intangible assets	$ 7.5	$ 14.7	$ 14.4
Client base
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 3.6
Client base | CDI
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		8.5
Trade/domain names | CDI
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 0.4

Intangible Assets - Schedule of

Intangible Assets - Schedule of Gross and Net Carrying Values of Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross amount	$ 46.7	$ 70.9
Finite-lived intangible assets, accumulated amortization	(32.9)	(53.4)
Finite-lived intangible assets, net amount	13.8	17.5
Indefinite-lived intangible assets	5.8	5.6
Intangible assets, gross amount	52.5	76.5
Total intangible assets, net amount	19.6	23.1
Website domains
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	2.1	1.9
Business licenses
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	3.7	3.7
Trade/domain names
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived trade/domain names, gross amount	4.1	4.1
Finite-lived intangible assets, accumulated amortization	(3.2)	(2.4)
Finite-lived intangible assets, net amount	0.9	1.7
Software programs/platforms
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived software programs/platforms, gross amount	4.9	28.5
Finite-lived intangible assets, accumulated amortization	(4.1)	(26.9)
Finite-lived intangible assets, net amount	0.8	1.6
Client base
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived customer base, gross amount	37.7	38.3
Finite-lived intangible assets, accumulated amortization	(25.6)	(24.1)
Finite-lived intangible assets, net amount	$ 12.1	$ 14.2

Intangible Assets - Schedule _2

Intangible Assets - Schedule of Expected Amortization Expense (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Fiscal 2025	$ 4.1
Fiscal 2026	3.1
Fiscal 2027	2.4
Fiscal 2028	1.5
Fiscal 2029 and thereafter	2.7
Finite-lived intangible assets, net amount	$ 13.8	$ 17.5

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	12 Months Ended
	Sep. 30, 2024 USD ($) option	Sep. 30, 2023 USD ($)
Lessee, Lease, Description [Line Items]
Number of options to renew (or more) | option	1
Termination period	2 years
Operating right of use assets	$ 157	$ 122.1
Operating lease liabilities	$ 195.9	$ 149.3
Building | Minimum
Lessee, Lease, Description [Line Items]
Renewal term	3 years
Building | Maximum
Lessee, Lease, Description [Line Items]
Renewal term	10 years

Leases - Schedule of Operating

Leases - Schedule of Operating Lease Costs and Other Related Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Leases [Abstract]
Operating lease costs	$ 42.9	$ 28
Cash paid for amounts included in the measurement of operating lease liabilities	25.8	18.4
Right-of-use assets obtained in exchange for operating lease liabilities	$ 56.4	$ 14.3
Weighted average remaining lease term (years)	8 years 7 months 6 days	9 years 9 months 18 days
Weighted average discount rate (as a percent)	5%	4.50%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Leases [Abstract]
2025	$ 29.3
2026	30.5
2027	31.1
2028	29.3
2029	24.2
After 2029	95.5
Total lease payments	239.9
Less: interest	44
Present value of lease liabilities	$ 195.9	$ 149.3

Credit Facilities - Narrative (

Credit Facilities - Narrative (Details) - USD ($)		12 Months Ended
	Jun. 17, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Mar. 01, 2024
Line of Credit Facility [Line Items]
Loss on extinguishment of debt		$ 3,700,000	$ 0	$ 0
Senior Notes
Line of Credit Facility [Line Items]
Loss on extinguishment of debt		3,700,000
Deferred debt issuance cost, writeoff		2,400,000
Deferred financing costs		$ 1,300,000
Senior Secured Notes due 2031 | Senior Notes
Line of Credit Facility [Line Items]
Debt instrument, face amount					$ 550,000,000
Stated interest rate (as a percent)		7.875%			7.875%
Discount rate at issuance of face value (as a percent)					100%
Debt issuance costs, gross					$ 7,700,000
Senior Secured Notes due 2025 | Senior Notes
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	8.625%	8.625%
Repayments of long-term debt	$ 363,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility borrowing		$ 1,205,000,000
Line of credit facility, current borrowing capacity		$ 340,000,000

Credit Facilities - Schedule of

Credit Facilities - Schedule of Debt (Details) - USD ($)	12 Months Ended
	Sep. 30, 2024	Oct. 31, 2024	Oct. 30, 2024	Oct. 29, 2024	Oct. 28, 2024	Jun. 17, 2024	Mar. 01, 2024	Sep. 30, 2023
Line of Credit Facility [Line Items]
Lenders under loans	$ 338,800,000							$ 341,000,000
Uncommitted Credit Facilities	104,900,000							55,500,000
Notes payable to bank	6,900,000							7,500,000
Total outstanding borrowings	$ 881,900,000							683,100,000
Notes payable to bank
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	2.35%
Senior Secured Notes due 2031
Line of Credit Facility [Line Items]
Senior notes	$ 543,100,000							0
Senior Secured Notes due 2031 | Senior notes
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	7.875%						7.875%
Debt instrument, unamortized discount (premium) and debt issuance costs, net	$ 6,900,000
Senior Secured Notes due 2025
Line of Credit Facility [Line Items]
Senior notes	$ 0							342,100,000
Senior Secured Notes due 2025 | Senior notes
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	8.625%					8.625%
Debt instrument, unamortized discount (premium) and debt issuance costs, net								5,800,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility borrowing	$ 1,205,000,000
Lenders under loans	227,000,000							278,000,000
Revolving Credit Facility | Senior StoneX Group Inc. Committed Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility borrowing	500,000,000
Lenders under loans	$ 161,000,000							150,000,000
Revolving Credit Facility | Senior StoneX Group Inc. Committed Credit Facility | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	9%
Revolving Credit Facility | Senior StoneX Group Inc. Committed Credit Facility | SOFR
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	6.95%
Revolving Credit Facility | StoneX Financial Inc.
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	10%
Line of credit facility borrowing	$ 250,000,000
Lenders under loans	0							0
Revolving Credit Facility | StoneX Commodity Solutions LLC
Line of Credit Facility [Line Items]
Line of credit facility borrowing	325,000,000
Lenders under loans	$ 66,000,000							103,000,000
Revolving Credit Facility | StoneX Commodity Solutions LLC | Subsequent Event
Line of Credit Facility [Line Items]
Line of credit facility borrowing				$ 250,000,000	$ 190,000,000
Revolving Credit Facility | StoneX Commodity Solutions LLC | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	8.50%
Revolving Credit Facility | StoneX Commodity Solutions LLC | SOFR
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	7.54%
Revolving Credit Facility | StoneX Financial Ltd
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	7.47%
Line of credit facility borrowing	$ 115,000,000
Lenders under loans	$ 0							25,000,000
Revolving Credit Facility | StoneX Financial Ltd | Subsequent Event
Line of Credit Facility [Line Items]
Line of credit facility borrowing		$ 115,000,000	$ 100,000,000
Revolving Credit Facility | StoneX Financial Pte. Ltd.
Line of Credit Facility [Line Items]
Stated interest rate (as a percent)	7.46%
Line of credit facility borrowing	$ 15,000,000
Lenders under loans	$ 0							$ 0

Securities and Commodity Fina_3

Securities and Commodity Financing Transactions - Schedule of Carrying Value of Repurchase Agreements, and Securities Lending Agreements by Remaining Contractual Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 16,527.9	$ 9,196.4
Securities loaned	1,615.9	1,117.3
Gross amount of secured financing	18,143.8	10,313.7
Overnight and Open
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	15,260.8	8,300
Securities loaned	1,615.9	1,117.3
Gross amount of secured financing	16,876.7	9,417.3
Less than 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	585.4	786.8
Securities loaned	0	0
Gross amount of secured financing	585.4	786.8
30-90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	631	107
Securities loaned	0	0
Gross amount of secured financing	631	107
Over 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	50.7	2.6
Securities loaned	0	0
Gross amount of secured financing	$ 50.7	$ 2.6

Securities and Commodity Fina_4

Securities and Commodity Financing Transactions - Schedule of Carrying Value of Repurchase Agreements and Securities Lending Agreements by Class of Collateral Pledged (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 16,527.9	$ 9,196.4
Securities loaned	1,615.9	1,117.3
Gross amount of secured financing	18,143.8	10,313.7
U.S. Treasury obligations
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	9,673.7	3,696.1
U.S. government agency obligations and municipal bonds
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	652	542.2
Asset-based obligations
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	136.1	102.9
Agency mortgage-backed obligations
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	5,079.6	4,371.6
Foreign government obligations
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	649.6	148.1
Corporate bonds
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	336.9	335.5
Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities loaned	$ 1,615.9	$ 1,117.3

Securities and Commodity Fina_5

Securities and Commodity Financing Transactions - Schedule of Netting of Securities Purchased Under Agreements (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Broker-Dealer [Abstract]
Securities purchased under agreements to resell, gross	$ 13,148.1	$ 7,649.3
Securities purchased under agreements to resell, offset	(7,946.6)	(4,669.8)
Securities purchased under agreements to resell, net	5,201.5	2,979.5
Securities borrowed, gross	1,662.3	1,129.1
Securities borrowed, net	1,662.3	1,129.1
Securities sold under agreements to repurchase, gross	16,527.9	9,196.4
Securities sold under agreements to repurchase, offset	(7,946.6)	(4,669.8)
Securities sold under agreements to repurchase, net	8,581.3	4,526.6
Securities loaned, gross	1,615.9	1,117.3
Securities loaned, net	$ 1,615.9	$ 1,117.3

Securities and Commodity Fina_6

Securities and Commodity Financing Transactions - Schedule of Fair Value of Collateral Pledged, Received and Repledged (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged or repledged to cover collateral requirements for tri-party arrangements	$ 6,767.1	$ 5,044.8
Securities received as collateral that may be repledged	20,126.8	9,180.1
Securities received as collateral that may be repledged covering securities sold short	2,408.3	2,461.1
Asset Pledged as Collateral with Right
Assets Sold under Agreements to Repurchase [Line Items]
Repledged securities borrowed and client securities held under custodial clearing arrangements to collateralize securities loaned agreements	1,533.3	1,097.3
Tri-Party Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged or repledged to cover collateral requirements for tri-party arrangements	$ 6,777.9	$ 4,726.6

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Loss Contingencies [Line Items]
Loss contingency, range of possible loss, portion not accrued	$ 10
Loss contingency accrual	3.8
Purchase obligation, due in next twelve months	57,592.2
Purchase obligation, due in second and third year	810
Purchase obligation, due in fourth and fifth year	78.5
Purchase obligation, due after fifth year	126.2
Purchase obligation, due in next twelve months	$ 56,275.9
Percentage of stop loss actual estimated claims (as a percent)	120%
Self insurance reserve and dental claims	$ 2.2	$ 1.9
Gain Capital Holdings Inc
Loss Contingencies [Line Items]
Loss contingency accrual, current	$ 31.1

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,379.1	$ 1,070.1	$ 904
Other comprehensive income/(loss) net of tax	26.6	38.8	(65.5)
Ending balance	1,709.1	1,379.1	1,070.1
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(31.2)	(34.4)	(22.7)
Other comprehensive income/(loss) net of tax	(0.1)	3.2	(11.7)
Ending balance	(31.3)	(31.2)	(34.4)
Pension Benefits Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2.2)	(2.7)	(2.4)
Other comprehensive income/(loss) net of tax	1	0.5	(0.3)
Ending balance	(1.2)	(2.2)	(2.7)
Cash Flow Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18.4)	(53.5)	0
Other comprehensive income/(loss) net of tax	25.7	35.1	(53.5)
Ending balance	7.3	(18.4)	(53.5)
Accumulated Other Comprehensive Loss, net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(51.8)	(90.6)	(25.1)
Other comprehensive income/(loss) net of tax	26.6	38.8	(65.5)
Ending balance	$ (25.2)	$ (51.8)	$ (90.6)

Revenue from Contracts with C_3

Revenue from Contracts with Clients - Narrative (Details)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Term of risk management consulting contracts	6 months
Clients | Revenue from Contract with Customer Benchmark | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	2.20%	5.70%	5.50%

Revenue from Contracts with C_4

Revenue from Contracts with Clients - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 2,215.9	$ 3,493.4	$ 3,607.5
Principal gains, net	1,189.6	1,079.9	1,145.2
Interest income	1,396.8	987.6	219
Total revenues	99,887.8	60,856.1	66,036
Point-in-time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2,054.5	3,338.1	3,489.5
Time elapsed
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	161.4	155.3	118
Total commission and clearing fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	548	498.4	507.9
Total revenues	548	498.4	507.9
Total sales-based commission
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	317.4	302	306.9
Exchange-traded futures and options
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	226.1	214.1	210.7
OTC derivative brokerage
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	11.3	14.5	16.8
Equities and fixed income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	65.9	57.8	62.9
Mutual funds
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	3.1	3	4.1
Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	11	9.2	9.3
Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	3.4	3.1
Total trailing commission
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	27.9	26.6	30.1
Mutual funds
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	12.7	12.4	14.1
Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	15.2	14.2	16
Clearing fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	180.2	153.3	153.2
Trade conversion fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	13.1	8.5	11.5
Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	9.4	8	6.2
Total consulting, management, and account fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	167.2	159	111.3
Total revenues	167.2	159	111.3
Underwriting fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0.4	0.7	0.5
Asset management fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	50.9	45.1	43.9
Advisory and consulting fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	38.2	35	30.9
Sweep program fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	44.4	48.6	13.1
Client account fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	19.8	15.9	16
Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	13.5	13.7	6.9
Precious metals sales under ASC Topic 606
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,500.7	2,836	2,988.3
Physical precious metals under ASC Topic 815
Disaggregation of Revenue [Line Items]
Sales of physical commodities	91,241.1	50,979.5	57,404.3
Physical agricultural and energy products
Disaggregation of Revenue [Line Items]
Sales of physical commodities	$ 3,844.4	$ 4,315.7	$ 3,660

Revenue from Contracts with C_5

Revenue from Contracts with Clients - Schedule of Income and Expense (Details) - Equity Positions - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Dividend income/(loss) net of dividend expense reported within Principal Gains, net	$ 1.1	$ (1.3)	$ 8.3
Long
Disaggregation of Revenue [Line Items]
Dividend income/(loss) net of dividend expense reported within Principal Gains, net	192.3	32	142.3
Short
Disaggregation of Revenue [Line Items]
Dividend income/(loss) net of dividend expense reported within Principal Gains, net	$ (191.2)	$ (33.3)	$ (134)

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)	3.5
Stock options authorized (in shares)	0.4
Allocated share-based compensation expense	$ 37.2	$ 28	$ 17.8
Weighted average grant date fair value, granted (in dollar per share)	$ 26.77	$ 22.14	$ 15.21
Employee service share-based compensation, non vested awards, total compensation cost not yet recognized, stock options	$ 43.1
Employee service share-based compensation, non vested awards, total compensation cost not yet recognized, period for recognition	3 years 3 days
Share-based compensation arrangement by share-based payment award, options, exercises in period, total intrinsic value	$ 9.8	$ 4.2	$ 39
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized	$ 43.9
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized, period for recognition, restricted stock	1 year 1 month 17 days

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Fair Value Estimated at Grant Date Based on Black-Scholes-Merton Option-Pricing Model Using Weighted-Average Assumptions (Details)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Expected stock price volatility	38%	42%	39%
Expected dividend yield	0%	0%	0%
Risk free interest rate	2.21%	1.60%	1.54%
Average expected life (in years)	6 years 3 months 25 days	4 years 3 months	5 years 2 months 15 days

Share-Based Compensation - Sc_2

Share-Based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Number of Options Outstanding
Number of options outstanding, beginning (in shares)	1,763,788
Number of options outstanding, granted (in shares)	1,627,150
Number of options outstanding, exercised (in shares)	(237,613)
Number of options outstanding, forfeited (in shares)	(89,432)
Number of options outstanding, expired (in shares)	(2,320)
Number of options outstanding, ending (in shares)	3,061,573	1,763,788
Number of options outstanding, exercisable (in shares)	721,635
Weighted Average  Exercise Price
Weighted average exercise price, beginning (in dollar per share)	$ 35.65
Weighted average  exercise price, granted (in dollar per share)	65.37
Weighted average  exercise price, exercised (in dollar per share)	32.89
Weighted average  exercise price, forfeited (in dollar per share)	36.50
Weighted average  exercise price, expired (in dollar per share)	40.88
Weighted average exercise price, ending (in dollar per share)	51.63	$ 35.65
Weighted average  exercise price, exercisable (in dollar per share)	34.58
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning (in dollar per share)	10.56
Weighted average grant date fair value, granted (in dollar per share)	26.77	22.14	$ 15.21
Weighted average grant date fair value, exercised (in dollar per share)	9.07
Weighted average grant date fair value, forfeited (in dollar per share)	10.65
Weighted average grant date fair value, expired (in dollar per share)	14.69
Weighted average grant date fair value, ending (in dollar per share)	19.28	$ 10.56
Weighted average grant date fair value, exercisable (in dollar per share)	$ 10.05
Stock Option Activity, Additional Disclosures
Weighted average remaining term	5 years 21 days	3 years 9 months 18 days
Weighted average remaining term, exercisable	2 years 8 months 4 days
Aggregate intrinsic value	$ 92.6	$ 51.1
Aggregate intrinsic value, exercisable	$ 34.1

Share-Based Compensation - Sc_3

Share-Based Compensation - Schedule of Options Outstanding Broken Down by Exercise Price (Details)	12 Months Ended
	Sep. 30, 2024 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of outstanding options (in shares) | shares	3,061,573
Weighted average exercise price (in dollars per share)	$ 51.63
Weighted Average Remaining Term (in Years)	5 years 21 days
$25.00 - $30.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 25
Exercise price range, upper range limit (in dollars per share)	$ 30
Number of outstanding options (in shares) | shares	810,000
Weighted average exercise price (in dollars per share)	$ 30
Weighted Average Remaining Term (in Years)	2 years 2 months 4 days
$35.00 - $40.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 35
Exercise price range, upper range limit (in dollars per share)	$ 40
Number of outstanding options (in shares) | shares	234,020
Weighted average exercise price (in dollars per share)	$ 39.10
Weighted Average Remaining Term (in Years)	2 years 3 months 21 days
$40.00 - $45.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 40
Exercise price range, upper range limit (in dollars per share)	$ 45
Number of outstanding options (in shares) | shares	289,212
Weighted average exercise price (in dollars per share)	$ 41.36
Weighted Average Remaining Term (in Years)	4 years 7 months 6 days
$45.00 - $75.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 45
Exercise price range, upper range limit (in dollars per share)	$ 75
Number of outstanding options (in shares) | shares	1,728,341
Weighted average exercise price (in dollars per share)	$ 65.18
Weighted Average Remaining Term (in Years)	6 years 10 months 9 days

Share-Based Compensation - Sc_4

Share-Based Compensation - Schedule of Restricted Stock Units Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Number of Shares Outstanding
Number of shares outstanding, beginning (in shares)	1,026,642
Number of shares outstanding, granted (in shares)	477,096
Number of shares outstanding, vested (in shares)	(494,568)
Number of shares outstanding, forfeited (in shares)	(1,582)
Number of shares outstanding, ending (in shares)	1,007,588	1,026,642
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning (in dollar per share)	$ 54.10
Weighted average grant date fair value, granted (in dollar per share)	68.10
Weighted average grant date fair value, vested (in dollar per share)	51.30
Weighted average grant date fair value, forfeited (in dollar per share)	54.79
Weighted average grant date fair value, ending (in dollars per share)	$ 62.10	$ 54.10
Stock Option Activity, Additional Disclosures
Weighted Average Remaining Term (in years)	1 year 1 month 17 days	1 year 2 months 26 days
Aggregate intrinsic value	$ 82.5	$ 66.5

Retirement Plans - Defined Bene

Retirement Plans - Defined Benefit Retirement Plans - Narrative (Details) $ in Millions	12 Months Ended
	Sep. 30, 2024 USD ($) participant	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (benefit)	$ 0.1	$ 0.3	$ (0.1)
Expected long-term return (as a percent)	4.65%
Defined benefit plan contributions	$ 0.1	0.1
Defined benefit plan, expected future benefit payment, year one	2
Defined benefit plan, expected future benefit payment, year two	2
Defined benefit plan, expected future benefit payment, year three	2
Defined benefit plan, expected future benefit payment, year four	2.1
Defined benefit plan, expected future benefit payment, year five	2.1
Defined benefit plan, expected future benefit payment, five fiscal years thereafter	9.4
Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	32.3	29.6
Defined benefit plan, benefit obligation	$ 25.9	$ 24.6
Defined benefit plan, assumptions used calculating benefit obligation, discount rate (as a percent)	4.90%	5.80%
Defined benefit plan, funded (unfunded) status of plan	$ 6.4	$ 5
Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, benefit obligation	1.1	1.1
Defined benefit plan, funded (unfunded) status of plan	$ (1.1)	(1.1)
Defined contribution plan, number of active participants | participant	0
Nonqualified Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 0.1	$ 0.1
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage (as a percent)	90%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage (as a percent)	10%

Retirement Plans - Defined Cont

Retirement Plans - Defined Contribution Retirement Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer discretionary contribution amount	$ 23.3	$ 19.2	$ 16.9
United States | 401k Plan | First Matching Contributions
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of employees' gross pay (as a percent)	100%
Defined contribution plan, employers matching contribution, annual vesting percentage (as a percent)	3%
United States | 401k Plan | Second Matching Contributions
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of employees' gross pay (as a percent)	50%
Defined contribution plan, employers matching contribution, annual vesting percentage (as a percent)	4%
United Kingdom
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employers matching contribution, annual vesting percentage (as a percent)	100%
Minimum | United States | 401k Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, annual contributions per employee, percent (as a percent)	1%
Maximum | United States | 401k Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, annual contributions per employee, percent (as a percent)	80%
Defined contribution plan, employers matching contribution, annual vesting percentage (as a percent)	7%
Maximum | United Kingdom
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of employees' gross pay (as a percent)	10%

Other Expenses (Details)

Other Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Other Expenses [Abstract]
Non-income taxes	$ 12.8	$ 16.8	$ 13.5
Insurance	11.8	11.1	10.8
Employee related expenses	7.3	10.1	9.6
Other direct business expenses	15.1	14.8	10
Membership fees	3.7	3.4	3.3
Director and public company expenses	2.1	2.3	1.8
Office expenses	2.4	1.9	1.7
Other expenses	9.9	6	9.9
Total other expenses	$ 65.1	$ 66.4	$ 60.6

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense/(Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income tax expense attributable to income from operations	$ 93.3	$ 84.5	$ 70.1
Taxes allocated to stockholders’ equity, related to pension liabilities	0.3	0.2	(0.1)
Taxes allocated to stockholders’ equity, related to hedge accounting	8.1	11.1	(17)
Total income tax expense	$ 101.7	$ 95.8	$ 53

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense/(Benefit) Attributable to Income from Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Current taxes:
U.S. federal	$ 26.4	$ 15.8	$ 8.2
U.S. state and local	5.9	3.9	3.6
Total current taxes	103.8	86.9	70.4
Deferred taxes:
U.S. federal	1.7	(1.1)	3.4
U.S. state and local	0.5	0	(0.1)
Total deferred taxes	(10.5)	(2.4)	(0.3)
Income tax expense	93.3	84.5	70.1
Australia
Current taxes:
Foreign tax expense	0.2	2.2	2.8
Deferred taxes:
Other international	(0.1)	0.1	(0.2)
Brazil
Current taxes:
Foreign tax expense	18.2	16	12.6
Deferred taxes:
Other international	(3.6)	0	(0.8)
Germany
Current taxes:
Foreign tax expense	4.2	4.5	8.9
Deferred taxes:
Other international	(0.4)	0	0
Singapore
Current taxes:
Foreign tax expense	7.7	4.9	2
Switzerland
Current taxes:
Foreign tax expense	0	2.6	0
Deferred taxes:
Other international	(1.2)	0.4	0
United Kingdom
Current taxes:
Foreign tax expense	34.5	30.9	29.2
Deferred taxes:
Other international	(7.2)	(1.4)	(2.7)
Other international
Current taxes:
Foreign tax expense	6.7	6.1	3.1
Deferred taxes:
Other international	$ (0.2)	$ (0.4)	$ 0.1

Income Taxes - Schedule of Co_2

Income Taxes - Schedule of Components of Income from Operations, Before Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Operating Loss Carryforwards [Line Items]
U.S.	$ 97.8	$ 135.1	$ 50
Income before tax	354.1	323	277.2
Australia
Operating Loss Carryforwards [Line Items]
Non-U.S.	0.5	7.4	8.7
Brazil
Operating Loss Carryforwards [Line Items]
Non-U.S.	37.8	35.3	25.3
Germany
Operating Loss Carryforwards [Line Items]
Non-U.S.	12.1	13.3	27.8
Singapore
Operating Loss Carryforwards [Line Items]
Non-U.S.	55.1	38.1	19.4
Switzerland
Operating Loss Carryforwards [Line Items]
Non-U.S.	(2.3)	22.5	0
United Kingdom
Operating Loss Carryforwards [Line Items]
Non-U.S.	121.3	77.7	104.8
Other international
Operating Loss Carryforwards [Line Items]
Non-U.S.	$ 31.8	$ (6.4)	$ 41.2

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Federal statutory rate effect of:	21%	21%	21%
U.S. State and local income taxes	1.40%	1%	1%
Foreign earnings and losses taxed at different rates	2.60%	1.10%	1.10%
Change in valuation allowance	0%	(0.40%)	0.90%
U.K. bank tax	0.002	0.003	0.026
U.S. permanent items	(0.004)	0.002	0.002
Non-deductible compensation	0.80%	2%	0.70%
Foreign permanent items	(1.40%)	0.40%	(2.80%)
U.S. bargain purchase gain	0%	(1.40%)	0%
GILTI	2%	2%	0.60%
Unrecognized tax benefits	0.10%	0%	0%
Effective rate	26.30%	26.20%	25.30%

Income Taxes - Schedule of Co_3

Income Taxes - Schedule of Components of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Deferred tax assets:
Share-based compensation	$ 12.2	$ 7.4
Deferred compensation	5.4	5.4
Net operating loss carryforwards	19.6	17.2
Intangible assets	1.3	3.8
Bad debt reserve	7.2	9.6
Hedging	0	5.9
Foreign tax credit carryforwards	1.2	0.6
Other compensation	7.5	7.8
Pension	2.5	3.6
Right of use assets	30.1	20.1
Property and equipment	3.4	0
Other	1.6	1.1
Total gross deferred tax assets	92	82.5
Less valuation allowance	(15.5)	(12.4)
Deferred tax assets	76.5	70.1
Deferred income tax liabilities:
Unrealized gain on securities	3.1	2.8
Prepaid expenses	2.5	5
Property and equipment	0	1.6
Right of use liabilities	26.7	17.2
Mark to market on inventory	3.8	4.8
Other deferred liabilities	0.5	1.4
Hedging	2.2	0
Deferred income tax liabilities	38.8	32.8
Deferred income taxes, net	$ 37.7	$ 37.3

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Operating loss carryforwards	$ 5.3	$ 5.4
State and local net operating loss carryforwards of net of valuation allowance	4.2
Federal operating loss carryforwards, net of valuation allowances	0.7
Foreign operating loss carryforwards, net of valuation allowances	0.4
Valuation allowance	15.5	12.4
Increase in total valuation allowance	3.1
Foreign earnings repatriated	100	35.5
Unrecognized tax benefits that would impact effective tax rate	0.3	0	$ 0
Unrecognized tax benefits, income tax penalties and interest accrued	0.1	0
Income tax examination, penalties and interest expense	$ 0.1	$ 0	$ 0

Income Taxes - Schedule of Roll

Income Taxes - Schedule of Roll Forward of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Unrecognized Tax Benefits [Roll Forward]
Balance, beginning of year	$ 0	$ 0	$ 0
Gross increases for tax positions related to current year	0	0	0
Gross increases for tax positions related to prior years	0.3	0	0
Gross decreases for tax positions of prior years	0	0	0
Settlements	0	0	0
Lapse of statute of limitations	0	0	0
Balance, end of year	$ 0.3	$ 0	$ 0

Acquisitions - Trust Advisory G

Acquisitions - Trust Advisory Group, Ltd. - Narrative (Details) - USD ($) $ in Millions	Sep. 20, 2024	Sep. 30, 2024	Sep. 30, 2023
Business Acquisition [Line Items]
Purchase price allocated to goodwill		$ 61	$ 59.3
Trust Advisory Group, Ltd
Business Acquisition [Line Items]
Purchase price	$ 1.5
Holdback amount	1
Fair value of contingent consideration, current	$ 1.7
Contingent consideration, liability term	90 days
Purchase price allocated to goodwill	$ 2
Purchase price allocated to intangible assets	$ 2.1

Acquisitions - Cotton Distribut

Acquisitions - Cotton Distributors Inc. - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 31, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Business Acquisition [Line Items]
Net operating revenues		$ 1,767.2	$ 1,621	$ 1,475.9
Net income		$ 260.8	238.5	$ 207.1
Cotton Distributors Inc.
Business Acquisition [Line Items]
Purchase price	$ 42.7
Net operating revenues			36.9
Net income			$ 18.6

Acquisitions - Cotton Distrib_2

Acquisitions - Cotton Distributors Inc. - Schedule of Aggregate Merger Consideration (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 31, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Business Acquisition [Line Items]
Gain on acquisition		$ 0	$ 23.5	$ 0
Cotton Distributors Inc.
Business Acquisition [Line Items]
Cash and cash equivalents	$ 8.2
Deposits with and receivables from broker-dealers, clearing organizations, and counterparties	7.7
Receivable from clients, net	51.9
Financial instruments owned, at fair value	45.7
Deferred income taxes, net	(3.3)
Property and equipment, net	0.1
Physical commodities inventory, net	22.5
Other assets	6.7
Total fair value of tangible assets acquired	139.5
Accounts payable and other accrued liabilities	40
Financial instruments sold, not yet purchased, at fair value	28.3
Payables to lenders under loans	10.1
Payables to broker-dealers, clearing organizations, and counterparties	0.4
Payables to clients	2.6
Income taxes payable	0.8
Total fair value of liabilities assumed	82.2
Fair value of tangible net assets acquired	57.3
Total fair value of intangible assets acquired	8.9
Fair value of identifiable net assets acquired	66.2
Total merger consideration	42.7
Gain on acquisition	23.5
Cotton Distributors Inc. | Client relationships
Business Acquisition [Line Items]
Total fair value of intangible assets acquired	4.7
Cotton Distributors Inc. | Supplier relationships
Business Acquisition [Line Items]
Total fair value of intangible assets acquired	3.7
Cotton Distributors Inc. | Trade name
Business Acquisition [Line Items]
Total fair value of intangible assets acquired	0.4
Cotton Distributors Inc. | Non-compete
Business Acquisition [Line Items]
Total fair value of intangible assets acquired	$ 0.1

Acquisitions - Incomm S.A.S. -

Acquisitions - Incomm S.A.S. - Narrative (Details) - USD ($) $ in Millions	Feb. 03, 2023	Sep. 30, 2024	Sep. 30, 2023
Business Acquisition [Line Items]
Purchase price allocated to goodwill		$ 61	$ 59.3
Incomm S.A.S..
Business Acquisition [Line Items]
Purchase price	$ 0.2
Fair value of contingent consideration	$ 1.3
Contingent consideration, liability term	4 years
Purchase price allocated to goodwill	$ 1.3

Regulatory Requirements and S_3

Regulatory Requirements and Subsidiary Dividend Restrictions - Narrative (Details)	12 Months Ended
	Sep. 30, 2024 USD ($)
Capital and Other Regulatory Requirements [Line Items]
Adjusted net capital	$ 10,000,000
StoneX Financial Inc.
Capital and Other Regulatory Requirements [Line Items]
Adjusted net capital	$ 1,500,000
Adjusted net capital of percentage (as a percent)	8%
Broker-dealer, minimum net capital required, dividend withdrawal threshold, percent (as a percent)	120%
Net capital under commodity exchange act computation	$ 435,700,000
Required net capital under commodity exchange act	243,500,000
GAIN Capital Group, LLC
Capital and Other Regulatory Requirements [Line Items]
Net capital under commodity exchange act computation	57,100,000
Required net capital under commodity exchange act	29,700,000
GAIN Capital Group, LLC | Customer and Non-Customer Risk Maintenance Margin
Capital and Other Regulatory Requirements [Line Items]
Adjusted net capital	$ 1,000,000
Adjusted net capital of percentage (as a percent)	8%
GAIN Capital Group, LLC | Retail Customer Liabilities
Capital and Other Regulatory Requirements [Line Items]
Net capital under commodity exchange act computation	$ 20,000,000
Percentage of net capital under commodity exchange act computation (as a percent)	5%
GAIN Capital Group, LLC | Liabilities Owed to Counterparties
Capital and Other Regulatory Requirements [Line Items]
Required net capital under commodity exchange act	$ 10,000,000
Percentage of required net capital under commodity exchange act (as a percent)	10%
StoneX Markets LLC
Capital and Other Regulatory Requirements [Line Items]
Net capital under commodity exchange act computation	$ 237,900,000
Required net capital under commodity exchange act	134,300,000
Minimum regulatory capital requirement	$ 20,000,000

Regulatory Requirements and S_4

Regulatory Requirements and Subsidiary Dividend Restrictions - Customer Reserve Requirements - Narrative (Details) - USD ($) $ in Millions	Oct. 02, 2024	Sep. 30, 2024
Capital and Other Regulatory Requirements [Line Items]
Cash reserve deposit required		$ 87.7
Customer SRBA
Capital and Other Regulatory Requirements [Line Items]
Cash reserve deposit required		30.8
Customer SRBA | Subsequent Event
Capital and Other Regulatory Requirements [Line Items]
Cash reserve deposit made	$ 55.1
PAB
Capital and Other Regulatory Requirements [Line Items]
Cash reserve deposit required		7.7
PAB Reserve Requirement
Capital and Other Regulatory Requirements [Line Items]
Cash reserve deposit required		7.7
PAB SRBA
Capital and Other Regulatory Requirements [Line Items]
Cash reserve deposit required		$ 12.5
PAB SRBA | Subsequent Event
Capital and Other Regulatory Requirements [Line Items]
Cash reserve withdrawal	$ (3.8)

Regulatory Requirements and S_5

Regulatory Requirements and Subsidiary Dividend Restrictions - Regulatory Capital Requirements - Narrative (Details) $ in Millions	Sep. 30, 2024 USD ($)
StoneX Financial Inc.
Capital and Other Regulatory Requirements [Line Items]
Cash and securities segregated under commodity exchange act regulation	$ 5,762.6
Secured funds	262.5
Minimum regulatory requirement	5,690.4
Secured funds required under commodity exchange act	250.5
StoneX Financial Ltd
Capital and Other Regulatory Requirements [Line Items]
Cash and securities segregated under commodity exchange act regulation	1,292.2
Minimum regulatory requirement	1,230.1
StoneX Financial Pte. Ltd.
Capital and Other Regulatory Requirements [Line Items]
Cash and securities segregated under commodity exchange act regulation	973.6
Minimum regulatory requirement	$ 958.4

Regulatory Requirements and S_6

Regulatory Requirements and Subsidiary Dividend Restrictions - Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations (Details)	Sep. 30, 2024 USD ($)
Capital and Other Regulatory Requirements [Abstract]
Adjusted net capital	$ 10,000,000
StoneX Financial Inc.
Capital and Other Regulatory Requirements [Abstract]
Adjusted net capital	1,500,000
Capital and Other Regulatory Requirements [Line Items]
Actual	435,700,000
Minimum Requirement	243,500,000
StoneX Financial Ltd
Capital and Other Regulatory Requirements [Line Items]
Actual	433,800,000
Minimum Requirement	358,000,000
GAIN Capital Group, LLC
Capital and Other Regulatory Requirements [Line Items]
Actual	57,100,000
Minimum Requirement	29,700,000
StoneX Financial Pte. Ltd.
Capital and Other Regulatory Requirements [Line Items]
Actual	100,600,000
Minimum Requirement	22,300,000
StoneX Markets LLC
Capital and Other Regulatory Requirements [Line Items]
Actual	237,900,000
Minimum Requirement	$ 134,300,000

Segment and Geographic Inform_3

Segment and Geographic Information - Narrative (Details) market in Thousands	12 Months Ended
	Sep. 30, 2024 employee currency market country
Segment Reporting Information [Line Items]
Number of employees (more than) | employee	4,500
Number of countries in which entity operates (more than)	180
Self-Directed/Retail
Segment Reporting Information [Line Items]
Number of countries in which entity operates (more than)	180
Number of global financial markets (more than) | market	18
Payments
Segment Reporting Information [Line Items]
Number of countries in which entity operates (more than)	180
Number of different types of foreign currencies (more than) | currency	140

Segment and Geographic Inform_4

Segment and Geographic Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 99,887.8	$ 60,856.1	$ 66,036
Operating revenues	3,436.2	2,914.1	2,107.4
Net operating revenues (loss)	1,767.2	1,621	1,475.9
Net contribution	1,401.6	1,273.6	1,121.9
Segment income	885.6	763.5	675.7
Net operating loss within Corporate	(64.7)	(62.9)	(59.5)
Overhead costs and expenses	(466.8)	(400.9)	(339)
Gain on acquisitions and other gains, net within Corporate	0	23.3	0
Income before tax	354.1	323	277.2
Assets	27,466.3	21,938.7	19,859.6
Corporate
Segment Reporting Information [Line Items]
Total revenues	46.9	31.7	7.8
Operating revenues	46.9	31.7	7.8
Net operating revenues (loss)	(64.7)	(62.9)	(59.5)
Assets	1,123.5	812.3	746.3
Eliminations
Segment Reporting Information [Line Items]
Total revenues	(49.3)	(39.5)	(23)
Operating revenues	(49.3)	(39.5)	(23)
Commercial
Segment Reporting Information [Line Items]
Net contribution	541.8	544.9	415.3
Segment income	387.7	390.7	288.3
Commercial | Operating Segments
Segment Reporting Information [Line Items]
Total revenues	97,278.3	58,249.2	63,743.2
Operating revenues	871.9	862.7	692.1
Net operating revenues (loss)	715.9	721.3	586.5
Assets	5,387	4,676.3	5,931
Institutional
Segment Reporting Information [Line Items]
Net contribution	430.3	351.5	295.1
Segment income	266	217.9	174.6
Institutional | Operating Segments
Segment Reporting Information [Line Items]
Total revenues	1,962.1	1,513.6	831.8
Operating revenues	1,962.1	1,513.6	831.8
Net operating revenues (loss)	630.4	532	483.5
Assets	19,492.9	15,059.3	11,687.1
Self-Directed/Retail
Segment Reporting Information [Line Items]
Net contribution	267	212.7	280.3
Segment income	119.3	45.8	115.4
Self-Directed/Retail | Operating Segments
Segment Reporting Information [Line Items]
Total revenues	440.2	888.5	1,304.2
Operating revenues	395	333	426.7
Net operating revenues (loss)	286.1	227.3	302.9
Assets	1,024.1	1,014.2	971.2
Payments
Segment Reporting Information [Line Items]
Net contribution	162.5	164.5	131.2
Segment income	112.6	109.1	97.4
Payments | Operating Segments
Segment Reporting Information [Line Items]
Total revenues	209.6	212.6	172
Operating revenues	209.6	212.6	172
Net operating revenues (loss)	199.5	203.3	162.5
Assets	$ 438.8	$ 376.6	$ 524

Segment and Geographic Inform_5

Segment and Geographic Information - Schedule of Revenue Long-Lived Assets, by Geographical Areas (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Total revenues	$ 99,887.8	$ 60,856.1	$ 66,036
Operating revenues	3,436.2	2,914.1	2,107.4
Long-lived assets	143.1	123.5	112.9
United States
Total revenues	6,026.3	6,017.4	5,102.3
Operating revenues	2,507	2,120.4	1,448.2
Long-lived assets	76.2	76	67.9
Europe
Total revenues	2,358.8	3,498.9	3,440.2
Operating revenues	594.8	494.3	474.6
Long-lived assets	54.2	40.7	41.1
South America
Total revenues	455	271.4	87.2
Operating revenues	141.8	127	87.2
Long-lived assets	5.6	4.4	2.9
Middle East and Asia
Total revenues	91,015	51,023.6	57,395.5
Operating revenues	159.9	127.6	86.6
Long-lived assets	7.1	2.4	1
Other
Total revenues	32.7	44.8	10.8
Operating revenues	32.7	44.8	10.8
Long-lived assets	$ 0	$ 0	$ 0

Condensed Financial Informati_2

Condensed Financial Information of Parent Company Only Disclosure - Condensed Balance Sheets (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
ASSETS
Cash and cash equivalents	$ 1,269	$ 1,108.3	$ 1,108.5
Deposits with and receivables from subsidiary broker-dealer, net	7,283.2	7,443.8
Notes receivable, net	0	5.2
Income taxes receivable	19.3	25.1
Financial instruments owned	6,767.1	5,044.8
Deferred tax assets	46.3	45.4
Property and equipment, net	143.1	123.5
Operating right of use assets	157	122.1
Other assets	301.5	182.8
Total assets	27,466.3	21,938.7	19,859.6
Liabilities:
Accounts payable and other accrued liabilities	522.1	533
Operating lease liabilities	195.9	149.3
Payable to lenders under loans	338.8	341
Senior secured borrowings, net	543.1	342.1
Financial instruments sold, not yet purchased, at fair value	2,853.3	3,085.6
Total liabilities	25,757.2	20,559.6
StoneX Group Inc. (Parent Company Only) stockholders’ equity:
Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.01 par value. Authorized 200,000,000 shares; 35,785,432 issued and 31,874,447 outstanding at September 30, 2024 and 35,105,852 issued and 31,194,867 outstanding at September 30, 2023	0.4	0.4
Common stock in treasury, at cost - 3,910,985 shares at September 30, 2024 and 2023	(69.3)	(69.3)
Additional paid-in capital	414.3	371.7
Retained earnings	1,388.9	1,128.1
Accumulated other comprehensive loss, net	(25.2)	(51.8)
Total equity	1,709.1	1,379.1	$ 1,070.1	$ 904
Total liabilities and stockholders' equity	27,466.3	21,938.7
StoneX Group
ASSETS
Cash and cash equivalents	22.1	2.1
Receivable from subsidiaries, net	7.9	0
Deposits with and receivables from subsidiary broker-dealer, net	2	77
Notes receivable, net	0	5
Income taxes receivable	135.9	132.1
Investment in subsidiaries	1,390.1	1,325.3
Financial instruments owned	9.6	7.6
Deferred tax assets	2.3	7.2
Property and equipment, net	61.2	66.3
Operating right of use assets	62.2	65.5
Other assets	39.8	35.6
Total assets	1,733.1	1,723.7
Liabilities:
Accounts payable and other accrued liabilities	78.1	135.7
Operating lease liabilities	88.6	91.1
Payable to subsidiaries, net	0	288.3
Payable to lenders under loans	167.9	157.5
Senior secured borrowings, net	543.1	342.1
Financial instruments sold, not yet purchased, at fair value	0.2	27
Total liabilities	877.9	1,041.7
StoneX Group Inc. (Parent Company Only) stockholders’ equity:
Preferred stock, $0.01 par value. Authorized 1,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.01 par value. Authorized 200,000,000 shares; 35,785,432 issued and 31,874,447 outstanding at September 30, 2024 and 35,105,852 issued and 31,194,867 outstanding at September 30, 2023	0.4	0.4
Common stock in treasury, at cost - 3,910,985 shares at September 30, 2024 and 2023	(69.3)	(69.3)
Additional paid-in capital	414.3	371.7
Retained earnings	502.7	397.9
Accumulated other comprehensive loss, net	7.1	(18.7)
Total equity	855.2	682
Total liabilities and stockholders' equity	1,733.1	1,723.7
Adjustment to investment in subsidiaries for equity method accounting	$ 886.2	$ 730.2

Condensed Financial Informati_3

Condensed Financial Information of Parent Company Only Disclosure - Condensed Balance Sheets (Share Information) (Details) - $ / shares	Sep. 30, 2024	Sep. 30, 2023
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred stock, par value (in dollar per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollar per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	35,785,432	35,105,852
Common stock, outstanding (in shares)	31,874,447	31,194,867
Treasury stock, shares (in shares)	3,910,985	3,910,985
StoneX Group
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred stock, par value (in dollar per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollar per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (in shares)	35,785,432	35,105,852
Common stock, outstanding (in shares)	31,874,447	31,194,867
Treasury stock, shares (in shares)	3,910,985	3,910,985

Condensed Financial Informati_4

Condensed Financial Information of Parent Company Only Disclosure - Condensed Statements of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Condensed Income Statements, Captions [Line Items]
Total revenues	$ 99,887.8	$ 60,856.1	$ 66,036
Interest expense	1,115.7	802.2	135.5
Net operating revenues	1,767.2	1,621	1,475.9
Non-interest expenses:
Compensation and benefits	942.4	868.6	794.8
Trade systems and market information	79.1	74	66.2
Occupancy and equipment rental	49	40.4	36.1
Selling and marketing	52.6	54	55.3
Professional fees	69.7	57	54.3
Travel and business development	28.4	24.8	16.9
Non-trading technology and support	73.4	61.6	52.4
Depreciation and amortization	53.1	51	44.4
Communications	8.5	9.1	8.3
Other	65.1	66.4	60.6
Total compensation and other expenses	1,421.9	1,323.4	1,205.1
Gain on acquisitions and other gains, net	8.8	25.4	6.4
Income before tax	354.1	323	277.2
Income tax benefit	(93.3)	(84.5)	(70.1)
Net income	260.8	238.5	207.1
Interest income
Condensed Income Statements, Captions [Line Items]
Total revenues	1,396.8	987.6	219
StoneX Group
Condensed Income Statements, Captions [Line Items]
Total revenues	555.7	615.1	233.8
Interest expense	92.2	83.1	60.9
Net operating revenues	463.5	532	172.9
Non-interest expenses:
Compensation and benefits	137.3	137.9	113.7
Trade systems and market information	9.5	10.2	6.5
Occupancy and equipment rental	10.7	9.3	8.4
Selling and marketing	5.5	2.2	4.9
Professional fees	13.2	12.7	11.9
Travel and business development	3.3	3.1	2.3
Non-trading technology and support	49.4	37.4	30.6
Depreciation and amortization	16.6	13.7	11
Communications	2.9	3.4	1.8
Management services fees to affiliates	140.4	188.4	4.3
Other	16.5	12.1	12.4
Total compensation and other expenses	405.3	430.4	207.8
Gain on acquisitions and other gains, net	7	2.1	0
Income before tax	65.2	103.7	(34.9)
Income tax benefit	39.6	45.4	45
Net income	104.8	149.1	10.1
Investment in subsidiaries for equity method accounting, earnings (loss)	156	89.4	197
StoneX Group | Management fees from affiliates
Condensed Income Statements, Captions [Line Items]
Total revenues	274.2	328.7	109.9
StoneX Group | Trading gains (losses), net
Condensed Income Statements, Captions [Line Items]
Total revenues	(0.6)	1.8	(2.8)
StoneX Group | Consulting fees
Condensed Income Statements, Captions [Line Items]
Total revenues	0	0.2	0.1
StoneX Group | Interest income
Condensed Income Statements, Captions [Line Items]
Total revenues	9.3	3.3	2.2
StoneX Group | Dividend income from subsidiaries
Condensed Income Statements, Captions [Line Items]
Total revenues	$ 272.8	$ 281.1	$ 124.4

Condensed Financial Informati_5

Condensed Financial Information of Parent Company Only Disclosure - Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net income	$ 260.8	$ 238.5	$ 207.1
Adjustments to reconcile net income to net cash (used in)/provided by operating activities:
Depreciation and amortization	53.1	51	44.4
Amortization of operating right of use assets	21.5	14	15.9
Deferred income taxes	(10.5)	(2.4)	(0.3)
Amortization and extinguishment of debt issuance costs	5.4	5.8	4.5
Loss on extinguishment of debt	3.7	0	0
Amortization of share-based compensation expense	37.2	28	17.8
Changes in operating assets and liabilities:
Receivable from clients, net	(330.3)	(80.5)	(119.7)
Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net	262.5	(595.6)	(2,174.3)
Notes receivable, net	0.2	(0.1)	1
Income taxes receivable	7.2	(13.4)	10.4
Financial instruments owned, at fair value	(1,714.4)	(857.9)	187.3
Other assets	(119.8)	(60.4)	(9.8)
Accounts payable and other accrued liabilities	(5.3)	82.5	101.4
Operating lease liabilities	(9.8)	(8)	(16)
Financial instruments sold, not yet purchased, at fair value	(205.4)	658.4	627.8
Net cash provided by/(used in) operating activities	506.9	(23.7)	(229.5)
Cash flows from investing activities:
Collection of notes receivable	5	0	0
Purchase of property and equipment and internally developed software	(65.2)	(46.9)	(49.5)
Net cash used in investing activities	(63.7)	(53)	(49.5)
Cash flows from financing activities:
Net change in lenders under loans with maturities 90 days or less	(2.2)	(119.3)	211.5
Repayments of senior secured term loan	0	0	(170.3)
Repayment of senior secured notes	(347.9)	0	(0.5)
Proceeds from issuance of senior secured notes	550	0	0
Deferred payments on acquisitions	(9.6)	(18.7)	(3)
Debt issuance costs	(7.7)	0	0
Exercise of stock options	7.7	3.7	6.7
Net cash provided by/(used in) financing activities	188	(169.3)	65.8
Net increase/(decrease) in cash, segregated cash, cash equivalents, and segregated cash equivalents	630.9	(243.4)	(224.4)
Cash, segregated cash, cash equivalents, and segregated cash equivalents at beginning of period	6,041.7	6,285.1	6,509.5
Cash, segregated cash, cash equivalents, and segregated cash equivalents at end of period	6,672.6	6,041.7	6,285.1
Supplemental disclosure of cash flow information:
Cash paid for interest	1,230.2	786.5	149.2
Income taxes paid, net of cash refunds	117.8	71	56.3
StoneX Group
Cash flows from operating activities:
Net income	104.8	149.1	10.1
Adjustments to reconcile net income to net cash (used in)/provided by operating activities:
Depreciation and amortization	16.6	13.7	11
Amortization of operating right of use assets	5.7	5.8	6.1
Deferred income taxes	(3.2)	(3.6)	4.7
Amortization and extinguishment of debt issuance costs	3.8	3.9	3.2
Loss on extinguishment of debt	3.7	0	0
Amortization of share-based compensation expense	33.6	26.2	16.5
Dividends	(48.1)	(12.7)	(9.6)
Changes in operating assets and liabilities:
Receivables from subsidiaries, net	(7.9)	0	0
Payable to subsidiaries, net	(245.1)	11	113.6
Receivable from clients, net	0	0.2	0.2
Deposits with and receivables from broker-dealers, clearing organizations, and counterparties, net	75	12.1	(89.1)
Notes receivable, net	0	0	1.1
Income taxes receivable	(3.9)	(76.6)	8.2
Financial instruments owned, at fair value	5.9	(0.8)	(5.1)
Other assets	(5.1)	(5.7)	(7.3)
Accounts payable and other accrued liabilities	(34.8)	45.8	12
Operating lease liabilities	(4.9)	(4.5)	(1.7)
Financial instruments sold, not yet purchased, at fair value	0.1	(3.1)	2.1
Net cash provided by/(used in) operating activities	(103.8)	160.8	76
Cash flows from investing activities:
Capital contribution to affiliates	(56.3)	(40)	(180.8)
Collection of notes receivable	5	0	0
Purchase of property and equipment and internally developed software	(11.5)	(17.9)	(17.8)
Net cash used in investing activities	(62.8)	(57.9)	(198.6)
Cash flows from financing activities:
Net change in lenders under loans with maturities 90 days or less	10.4	(110.6)	259.5
Repayments of senior secured term loan	0	0	(170.3)
Repayment of senior secured notes	(347.9)	0	0
Proceeds from issuance of senior secured notes	550	0	0
Deferred payments on acquisitions	(23.6)	0	(1.9)
Debt issuance costs	(7.7)	0	0
Exercise of stock options	5.4	3.7	6.7
Net cash provided by/(used in) financing activities	186.6	(106.9)	94
Net increase/(decrease) in cash, segregated cash, cash equivalents, and segregated cash equivalents	20	(4)	(28.6)
Cash, segregated cash, cash equivalents, and segregated cash equivalents at beginning of period	2.1	6.1	34.7
Cash, segregated cash, cash equivalents, and segregated cash equivalents at end of period	22.1	2.1	6.1
Supplemental disclosure of cash flow information:
Cash paid for interest	26.5	15.3	34.9
Income taxes paid, net of cash refunds	$ 21.3	$ 34.9	$ 2.6