Janus Henderson (JHG) 10-Q31 Oct 242024 Q3 Quarterly reportFinancial data

Company Profile

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
Document And Entity Information - shares	Sep. 30, 2024	Oct. 29, 2024
Document Information [Line Items]
Entity Central Index Key	0001274173
Entity Registrant Name	JANUS HENDERSON GROUP PLC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2024
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-38103
Entity Incorporation, State or Country Code	Y9
Entity Tax Identification Number	98-1376360
Entity Address, Address Line One	201 Bishopsgate
Entity Address, City or Town	London
Entity Address, Country	GB
Entity Address, Postal Zip Code	EC2M3AE
City Area Code	44
Local Phone Number	(0) 20 7818 1818
Title of 12(b) Security	Common Stock, $1.50 Per Share Par Value
Trading Symbol	JHG
Security Exchange Name	NYSE
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		158,994,913

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 1,483.8	$ 1,152.4
Investments	305	334.2
Fees and other receivables	270.7	294
OEIC and unit trust receivables	152.7	94.6
Other current assets	174.1	174.5
Total current assets	3,135.3	2,455.6
Non-current assets:
Property, equipment and software, net	38.8	44.2
Intangible assets, net	2,448.3	2,431.3
Goodwill	1,351.5	1,290.3
Retirement benefit asset, net	93.8	87.6
Other non-current assets	196.1	187.6
Total assets	7,263.8	6,496.6
Current liabilities:
Accounts payable and accrued liabilities	262.3	231.4
Current portion of accrued compensation, benefits and staff costs	285.6	297.9
Current portion of long-term debt	302.4	0
OEIC and unit trust payables	158.9	98.5
Total current liabilities	1,016.4	631
Non-current liabilities:
Accrued compensation, benefits and staff costs	32.7	45
Long-term debt	396.2	304.6
Deferred tax liabilities, net	576.3	570.8
Other non-current liabilities	115.5	89.7
Total liabilities	2,137.1	1,641.1
Commitments and contingencies (See Note 15)
REDEEMABLE NONCONTROLLING INTERESTS	493.5	317.2
EQUITY
Common stock, $1.50 par value; 480,000,000 shares authorized, and 158,553,373 and 163,338,035 shares issued and outstanding as of September 30, 2024, and December 31, 2023, respectively	237.8	245
Additional paid-in capital	3,694.8	3,722.3
Treasury shares, 38,478 and 41,444 shares held at September 30, 2024, and December 31, 2023, respectively	(1)	(1.1)
Accumulated other comprehensive loss, net of tax	(385.2)	(563.6)
Retained earnings	1,086.6	1,135.5
Total shareholders’ equity	4,633	4,538.1
Nonredeemable noncontrolling interests	0.2	0.2
Total equity	4,633.2	4,538.3
Total liabilities, redeemable noncontrolling interests and equity	7,263.8	6,496.6
Variable Interest Entity, Primary Beneficiary [Member]
Current assets:
Cash and cash equivalents	21	15.7
Investments	713	382.4
Other current assets	15	7.8
Current liabilities:
Accounts payable and accrued liabilities	$ 7.2	$ 3.2

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Common stock, par value (in dollars per share)	$ 1.5	$ 1.5
Common stock, shares authorized (in shares)	480,000,000	480,000,000
Common stock, shares issued (in shares)	158,553,373	163,338,035
Common stock, shares outstanding (in shares)	158,553,373	163,338,035
Treasury shares (in shares)	38,478	41,444

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue:
Total revenue	$ 624.8	$ 521	$ 1,764.9	$ 1,533.3
Operating expenses:
Employee compensation and benefits	177	149.2	509.1	437.2
Long-term incentive plans	40.5	32.6	127.3	125.7
Distribution expenses	133.7	116	382.7	342.6
Investment administration	17.7	12.4	42.7	35.1
Marketing	8.3	9.6	26.1	27.7
General, administrative and occupancy	77.4	73.7	212.9	207
Depreciation and amortization	5.5	5.8	15.9	18
Total operating expenses	460.1	399.3	1,316.7	1,193.3
Operating income:	164.7	121.7	448.2	340
Interest expense	(4.5)	(3.2)	(10.8)	(9.5)
Investment gains (losses), net	35	(5.9)	63.9	18.6
Other non-operating income (expense), net	(101.6)	(13.4)	(59.4)	0.7
Income before taxes	93.6	99.2	441.9	349.8
Income tax provision	(43.6)	(13.2)	(117.8)	(67.4)
Net income	50	86	324.1	282.4
Net loss (income) attributable to noncontrolling interests	(22.7)	7.5	(37)	(11.7)
Net income attributable to JHG	$ 27.3	$ 93.5	$ 287.1	$ 270.7
Earnings per share attributable to JHG common shareholders:
Basic (in dollars per share)	$ 0.17	$ 0.56	$ 1.8	$ 1.64
Diluted (in dollars per share)	$ 0.17	$ 0.56	$ 1.8	$ 1.64
Other comprehensive income (loss), net of tax:
Foreign currency translation	$ 108.4	$ (70.7)	$ 88.3	$ 14.3
Reclassification of foreign currency translation to net income	111.9	0	95.4	0
Actuarial gains	0.4	0.5	1.2	0.7
Other comprehensive income (loss), net of tax	220.7	(70.2)	184.9	15
Other comprehensive loss (income) attributable to noncontrolling interests	(7.2)	1	(6.5)	(0.6)
Other comprehensive income (loss) attributable to JHG	213.5	(69.2)	178.4	14.4
Total comprehensive income	270.7	15.8	509	297.4
Total comprehensive loss (income) attributable to noncontrolling interests	(29.9)	8.5	(43.5)	(12.3)
Total comprehensive income attributable to JHG	240.8	24.3	465.5	285.1
Investment Advice [Member]
Revenue:
Total revenue	502.8	434.9	1,435	1,273
Investment Performance [Member]
Revenue:
Total revenue	8.6	(15.8)	2.9	(36.6)
Shareholder Service [Member]
Revenue:
Total revenue	61.4	54.9	177.1	159.7
Product and Service, Other [Member]
Revenue:
Total revenue	$ 52	$ 47	$ 149.9	$ 137.2

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities:
Net income	$ 324.1	$ 282.4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15.9	18
Deferred income taxes	0.3	(5.2)
Stock-based compensation plan expense	51.3	59.8
Reclassification of foreign currency translation to net income	95.4	0
Provision for credit losses and contingent consideration adjustments	0	25.3
Investment gains, net	(63.9)	(18.6)
Other, net	(6.9)	(5.3)
Changes in operating assets and liabilities:
OEIC and unit trust receivables and payables	2.3	(0.5)
Other assets	45.7	49.6
Other accruals and liabilities	(16.9)	(125.4)
Net operating activities	447.3	280.1
Investing activities:
Investments, net	(94.2)	(48.5)
Property, equipment and software	(6.3)	(8.4)
Investments by consolidated seeded investment products, net	(179)	(169.8)
Cash paid on settled seed capital hedges, net	(33.7)	(15.3)
Acquisitions, net of cash acquired	(17.2)	0
Other, net	0.7	(0.1)
Net investing activities	(329.7)	(242.1)
Financing activities:
Purchase of common stock for stock-based compensation plans	(80)	(57.3)
Purchase of common stock for the share buyback program	(155.1)	0
Dividends paid to shareholders	(188.1)	(194)
Issuance of long-term debt	396.2	0
Third-party capital invested into consolidated seeded investment products, net	221.8	174.5
Other, net	(0.3)	1
Net financing activities	194.5	(75.8)
Cash and cash equivalents:
Effect of foreign exchange rate changes	24.6	1.7
Net change	336.7	(36.1)
At beginning of period	1,168.1	1,176.4
At end of period	1,504.8	1,140.3
Supplemental cash flow information:
Cash paid for interest	14.6	14.6
Cash paid for income taxes, net of refunds	95	79.1
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	1,504.8	1,140.3
Consolidated Entity, Excluding VIE [Member]
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	1,483.8	1,121.2
Variable Interest Entity, Primary Beneficiary [Member]
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	$ 21	$ 19.1

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes In Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2022	165.7
Balance at Dec. 31, 2022	$ 248.5	$ 3,706.6	$ (8.3)	$ (647.7)	$ 1,060.7	$ 2.8	$ 4,362.6
Net income	0	0	0	0	270.7	0	270.7
Other comprehensive income	0	0	0	14.4	0	0	14.4
Reclassification of foreign currency translation to net income							0
Dividends paid to shareholders	0	0	0	0	(194)	0	(194)
Purchase of common stock for stock-based compensation plans	0	56.5	0.8	0	0	0	57.3
Purchase of common stock for stock-based compensation plans	0	(56.5)	(0.8)	0	0	0	(57.3)
Vesting of stock-based compensation plans	0	(8)	8	0	0	0	0
Stock-based compensation plan expense	0	59.8	0	0	0	0	59.8
Proceeds from stock-based compensation plans	$ 0	2.5	0	0	0	0	2.5
Balance (in shares) at Sep. 30, 2023	165.7
Balance at Sep. 30, 2023	$ 248.5	3,704.4	(1.1)	(633.3)	1,137.4	2.8	4,458.7
Balance (in shares) at Jun. 30, 2023	165.7
Balance at Jun. 30, 2023	$ 248.5	3,687.1	(1.1)	(564.1)	1,108.6	2.8	4,481.8
Net income	0	0	0	0	93.5	0	93.5
Other comprehensive income	0	0	0	(69.2)	0	0	(69.2)
Reclassification of foreign currency translation to net income							0
Dividends paid to shareholders	0	0	0	0	(64.7)	0	(64.7)
Purchase of common stock for stock-based compensation plans	0		0.3	0	0	0	0.2
Purchase of common stock for stock-based compensation plans	0		(0.3)	0	0	0	(0.2)
Vesting of stock-based compensation plans	0	(0.3)	0.3	0	0	0	0
Stock-based compensation plan expense	0	16.9	0	0	0	0	16.9
Proceeds from stock-based compensation plans	$ 0	0.2	0	0	0	0	0.2
Purchase of common stock for stock-based compensation plans		0.5
Balance (in shares) at Sep. 30, 2023	165.7
Balance at Sep. 30, 2023	$ 248.5	3,704.4	(1.1)	(633.3)	1,137.4	2.8	4,458.7
Balance (in shares) at Dec. 31, 2023	163.3
Balance at Dec. 31, 2023	$ 245	3,722.3	(1.1)	(563.6)	1,135.5	0.2	4,538.3
Net income	0	0	0	0	287.1	0	287.1
Other comprehensive income	0	0	0	83	0	0	83
Reclassification of foreign currency translation to net income	0	0	0	95.4	0	0	95.4
Dividends paid to shareholders	$ 0		0	0	(188.1)	0	(188.1)
Dividends paid to shareholders		0
Purchase of common stock for the share buyback program (in shares)	(4.7)
Purchase of common stock for the share buyback program	$ (7.2)	0	0	0	(147.9)	0	(155.1)
Purchase of common stock for stock-based compensation plans	0	79.1	0.9	0	0	0	80
Purchase of common stock for stock-based compensation plans	0	(79.1)	(0.9)	0	0	0	(80)
Vesting of stock-based compensation plans	0	(1.1)	1	0	0	0	(0.1)
Stock-based compensation plan expense	0	51.3	0	0	0	0	51.3
Proceeds from stock-based compensation plans	$ 0	1.4	0	0	0	0	1.4
Dividends paid to shareholders		0
Balance (in shares) at Sep. 30, 2024	158.6
Balance at Sep. 30, 2024	$ 237.8	3,694.8	(1)	(385.2)	1,086.6	0.2	4,633.2
Balance (in shares) at Jun. 30, 2024	159.6
Balance at Jun. 30, 2024	$ 239.5	3,675.4	(1.1)	(598.7)	1,159.5	0.2	4,474.8
Net income	0	0	0	0	27.3	0	27.3
Other comprehensive income	0	0	0	101.6	0	0	101.6
Reclassification of foreign currency translation to net income	0	0	0	111.9	0	0	111.9
Dividends paid to shareholders	$ 0		0	0	(62.2)	0	(62.3)
Dividends paid to shareholders		(0.1)
Purchase of common stock for the share buyback program (in shares)	(1)
Purchase of common stock for the share buyback program	$ (1.7)	0	0	0	(38)	0	(39.7)
Purchase of common stock for stock-based compensation plans	0	0.6	0.2	0	0	0	0.4
Purchase of common stock for stock-based compensation plans	0	(0.6)	(0.2)	0	0	0	(0.4)
Vesting of stock-based compensation plans	0	(0.4)	0.3	0	0	0	(0.1)
Stock-based compensation plan expense	0	18.1	0	0	0	0	18.1
Proceeds from stock-based compensation plans	$ 0	1.2	0	0	0	0	1.2
Dividends paid to shareholders		0.1
Balance (in shares) at Sep. 30, 2024	158.6
Balance at Sep. 30, 2024	$ 237.8	$ 3,694.8	$ (1)	$ (385.2)	$ 1,086.6	$ 0.2	$ 4,633.2

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes In Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Dividends paid (in dollars per share)	$ 0.39	$ 0.39	$ 1.17	$ 1.17

Note 1 - Basis of Presentation

Note 1 - Basis of Presentation	9 Months Ended
Note 1 - Basis of Presentation	Sep. 30, 2024
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	Note 1 Basis of Presentation Basis of Presentation In the opinion of management of Janus Henderson Group plc (“JHG,” “the Company,” “we,” “us,” “our” and similar terms), the accompanying unaudited condensed consolidated financial statements contain all normal recurring adjustments necessary to fairly state our financial position, results of operations and cash flows in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Such financial statements have been prepared in accordance with the instructions to Form 10 not 10 December 31, 2023 Recent Accounting Pronouncements In November 2023, 2023 07, 280 2023 07 January 1, 2024, January 1, 2025. not In December 2023, 2023 09, 740 2023 09 January 1, 2025. not

Note 2 - Acquisitions

Note 2 - Acquisitions	9 Months Ended
Note 2 - Acquisitions	Sep. 30, 2024
Notes to Financial Statements
Business Combination Disclosure [Text Block]	Note 2 Acquisitions Victory Park Capital Advisors, LLC On October 1, 2024, two 2027. In addition to our acquisition of VPC, we expect to close our acquisition of a 55% voting equity interest in Triumph Capital Markets Holdco, LP, which represents VPC's broker-dealer business, in the fourth 2024. Tabula Investment Management On July 1, 2024, not not NBK Capital Partners On September 19, 2024, not

Note 3 - Consolidation

Note 3 - Consolidation	9 Months Ended
Note 3 - Consolidation	Sep. 30, 2024
Notes to Financial Statements
Variable Interest Entities Voting Rights Entities Consolidation Disclosure [Text Block]	Note 3 Consolidation Variable Interest Entities Consolidated Variable Interest Entities Our consolidated variable interest entities (“VIEs”) as of September 30, 2024 December 31, 2023 not may not, third no Unconsolidated Variable Interest Entities The following table presents the carrying value of investments included in our Condensed Consolidated Balance Sheets pertaining to unconsolidated VIEs as of September 30, 2024 December 31, 2023 September 30, December 31, 2024 2023 Unconsolidated VIEs $ 16.5 $ 17.2 Our total exposure to unconsolidated VIEs represents the value of our economic ownership interest in the investments. Voting Rights Entities Consolidated Voting Rights Entities The following table presents the balances related to consolidated voting rights entities (“VREs”) that were recorded in our Condensed Consolidated Balance Sheets, including our net interest in these products, as of September 30, 2024 December 31, 2023 September 30, December 31, 2024 2023 Investments $ 119.8 $ 242.9 Cash and cash equivalents 44.0 6.5 Other current assets 1.7 21.6 Accounts payable and accrued liabilities (1.0 ) (1.1 ) Total $ 164.5 $ 269.9 Redeemable noncontrolling interests in consolidated VREs (19.2 ) (100.9 ) JHG’s net interest in consolidated VREs $ 145.3 $ 169.0 Third-party assets held in consolidated VREs are not may not, third no Our total exposure to consolidated VREs represents the value of our economic ownership interest in these seeded investment products. Unconsolidated Voting Rights Entities The following table presents the carrying value of investments included in our Condensed Consolidated Balance Sheets pertaining to unconsolidated VREs as of September 30, 2024 December 31, 2023 September 30, December 31, 2024 2023 Unconsolidated VREs $ 85.4 $ 9.9 Our total exposure to unconsolidated VREs represents the value of our economic ownership interest in the investments.

Note 4 - Investments

Note 4 - Investments	9 Months Ended
Note 4 - Investments	Sep. 30, 2024
Notes to Financial Statements
Investment [Text Block]	Note 4 Investments Our investments as of September 30, 2024 December 31, 2023 September 30, December 31, 2024 2023 Current investments: Seeded investment products: Consolidated VIEs $ 713.0 $ 382.4 Consolidated VREs 119.8 242.9 Unconsolidated VIEs and VREs 101.9 27.1 Separately managed accounts 46.1 44.1 Total seeded investment products 980.8 696.5 Investments related to deferred compensation plans 31.9 12.0 Other investments 5.3 8.1 Total current investments $ 1,018.0 $ 716.6 Non-current investments: Equity method investments 24.2 29.5 Total investments $ 1,042.2 $ 746.1 Investment Gains (Losses), Net Investment gains (losses), net in our Condensed Consolidated Statements of Comprehensive Income included the following for the three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Seeded investment products and seed hedges, net $ 10.8 $ 2.5 $ 27.3 $ 17.5 Third-party ownership interests in seeded investment products 22.7 (7.5 ) 37.0 11.7 Equity method investments (1.0 ) (0.8 ) (4.5 ) (12.3 ) Other 2.5 (0.1 ) 4.1 1.7 Investment gains (losses), net $ 35.0 $ (5.9 ) $ 63.9 $ 18.6 Net unrealized gains (losses), excluding noncontrolling interests, on seeded investment products and associated derivative instruments still held at period end for the nine September 30, 2024 2023 September 30, 2024 2023 Unrealized gains (losses), net $ 61.9 $ (12.8 ) Gains and losses attributable to third not Equity Method Investments Our equity method investments include a 49% interest in Privacore Capital and a 20% Cash Flows Cash flows related to our investments for the nine September 30, 2024 2023 Nine months ended September 30, 2024 2023 Purchases Sales, Purchases Sales, and settlements and Net and settlements and Net settlements maturities cash flow settlements maturities cash flow Investments by consolidated seeded investment products $ (230.2 ) $ 51.2 $ (179.0 ) $ (179.9 ) $ 10.1 $ (169.8 ) Investments (178.1 ) 83.9 (94.2 ) (150.1 ) 101.6 (48.5 )

Note 5 - Derivative Instruments

Note 5 - Derivative Instruments	9 Months Ended
Note 5 - Derivative Instruments	Sep. 30, 2024
Notes to Financial Statements
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Note 5 Derivative Instruments Derivative Instruments Used to Hedge Seeded Investment Products We maintain an economic hedge program that uses derivative instruments to mitigate against market exposure of certain seeded investments by using index and commodity futures (“futures”), total return swaps and credit default swaps. Certain foreign currency exposures associated with our seeded investment products are also hedged by using foreign currency forward contracts. We were party to the following derivative instruments as of September 30, 2024 December 31, 2023 Notional value September 30, 2024 December 31, 2023 Futures $ 545.4 $ 1,018.0 Credit default swaps 129.3 199.7 Total return swaps 74.7 51.8 Foreign currency forward contracts 273.5 176.2 The derivative instruments are not three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Futures $ (16.6 ) $ 9.1 $ (22.4 ) $ 6.0 Credit default swaps (1.0 ) 0.8 (2.5 ) (1.7 ) Total return swaps (3.4 ) 5.2 (9.3 ) (6.5 ) Foreign currency forward contracts and swaps 9.7 (2.5 ) 10.6 6.3 Total gains (losses) from derivative instruments $ (11.3 ) $ 12.6 $ (23.6 ) $ 4.1 Derivative assets and liabilities are generally recognized on a gross basis and included in other current assets or in accounts payable and accrued liabilities in our Condensed Consolidated Balance Sheets. The derivative assets and liabilities as of September 30, 2024 December 31, 2023 Fair value September 30, 2024 December 31, 2023 Derivative assets $ 2.8 $ 1.8 Derivative liabilities 11.3 16.7 In addition to using derivative instruments to mitigate against market exposure of certain seeded investments, we also engage in short sales of securities to mitigate against market exposure of certain seed investments. As of September 30, 2024 December 31, 2023 not Derivative Instruments Used in Consolidated Seeded Investment Products Certain of our consolidated seeded investment products use derivative instruments to contribute to the achievement of defined investment objectives. These derivative instruments are classified within other current assets or in accounts payable and accrued liabilities in our Condensed Consolidated Balance Sheets. Gains and losses on these derivative instruments are classified within investment gains (losses), net in our Condensed Consolidated Statements of Comprehensive Income. Our consolidated seeded investment products were party to the following derivative instruments as of September 30, 2024 December 31, 2023 Notional value September 30, 2024 December 31, 2023 Futures $ 183.4 $ 1,555.1 Credit default swaps 5.3 13.2 Foreign currency forward contracts and swaps 199.0 135.3 Other 4.3 5.5 As of September 30, 2024 December 31, 2023 Derivative Instruments Foreign Currency Hedging Program We maintain a foreign currency hedging program to take reasonable measures to minimize the income statement effects of foreign currency remeasurement of monetary balance sheet accounts. The program uses foreign currency forward contracts and swaps to achieve its objectives, and it is considered an economic hedge for accounting purposes. The notional value of the foreign currency forward contracts and swaps as of September 30, 2024 December 31, 2023 Notional value September 30, 2024 December 31, 2023 Foreign currency forward contracts and swaps $ 56.2 $ 65.3 The derivative assets and liabilities are generally recognized on a gross basis and included in other current assets or in accounts payable and accrued liabilities in our Condensed Consolidated Balance Sheets. As of September 30, 2024 December 31, 2023 Changes in fair value of the derivatives are recognized in other non-operating income (expense), net in our Condensed Consolidated Statements of Comprehensive Income. Foreign currency remeasurement is also recognized in other non-operating income (expense), net in our Condensed Consolidated Statements of Comprehensive Income. For the three nine September 30, 2024 2023

Note 6 - Fair Value Measurement

Note 6 - Fair Value Measurements	9 Months Ended
Note 6 - Fair Value Measurements	Sep. 30, 2024
Notes to Financial Statements
Fair Value Disclosures [Text Block]	Note 6 Fair Value Measurements The following table presents assets and liabilities reflected in the financial statements or disclosed in the notes to the financial statements at fair value on a recurring basis as of September 30, 2024 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 1,110.7 $ — $ — $ 1,110.7 Current investments: Consolidated VIEs 441.3 271.7 — 713.0 Other investments 260.6 32.6 11.8 305.0 Total current investments 701.9 304.3 11.8 1,018.0 Other — 4.6 2.0 6.6 Total assets $ 1,812.6 $ 308.9 $ 13.8 $ 2,135.3 Liabilities: Seed hedge derivatives $ — $ 11.3 $ — $ 11.3 Securities sold, not yet purchased 33.0 — — 33.0 Long-term debt (1) — 698.0 — 698.0 Deferred bonuses — — 100.7 100.7 Other — 1.2 4.6 5.8 Total liabilities $ 33.0 $ 710.5 $ 105.3 $ 848.8 ( 1 Carried at amortized cost in our Condensed Consolidated Balance Sheets and disclosed in this table at fair value. The following table presents assets and liabilities reflected in the financial statements or disclosed in the notes to the financial statements at fair value on a recurring basis as of December 31, 2023 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 894.4 $ — $ — $ 894.4 Current investments: Consolidated VIEs 317.6 64.7 0.1 382.4 Other investments 212.2 122.0 — 334.2 Total current investments 529.8 186.7 0.1 716.6 Other — 8.5 1.0 9.5 Total assets $ 1,424.2 $ 195.2 $ 1.1 $ 1,620.5 Liabilities: Long-term debt (1) $ — $ 298.0 $ — $ 298.0 Deferred bonuses — — 117.6 117.6 Other 1.7 18.6 — 20.3 Total liabilities $ 1.7 $ 316.6 $ 117.6 $ 435.9 ( 1 Carried at amortized cost in our Condensed Consolidated Balance Sheets and disclosed in this table at fair value. Level 1 Our Level 1 Level 2 Our Level 2 2 Level 3 Investments As of September 30, 2024 December 31, 2023 3 Deferred Bonuses Deferred bonuses represent liabilities to employees over the vesting period that will be settled by investments in our products or cash. Upon vesting, employees receive the value of the investment product selected by the participant, adjusted for gains or losses attributable to the product. The significant unobservable inputs used to value the liabilities are investment designations and vesting periods. Changes in Fair Value Changes in fair value of our Level 3 three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Beginning of period fair value $ 4.0 $ 16.6 $ 1.1 $ 18.3 Settlement of contingent consideration — — — (0.2 ) Fair value adjustments (2.0 ) (11.7 ) 0.2 (13.1 ) Transfers from (to) Level 1, net — (4.8 ) 0.7 (4.6 ) Purchases (sales) of securities, net 11.8 0.1 11.8 (0.2 ) End of period fair value $ 13.8 $ 0.2 $ 13.8 $ 0.2 Changes in fair value of our Level 3 three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Beginning of period fair value $ 76.3 $ 78.2 $ 117.6 $ 46.5 Fair value adjustments 3.9 (0.7 ) 11.6 1.9 Vesting of deferred bonuses 0.1 (0.2 ) (84.2 ) (34.5 ) Amortization of deferred bonuses 18.4 15.9 53.9 41.8 Foreign currency translation 2.2 (1.1 ) 2.0 0.6 Additions 4.4 — 4.4 35.8 End of period fair value $ 105.3 $ 92.1 $ 105.3 $ 92.1 Nonrecurring Fair Value Measurements Nonrecurring Level 3 3.

Note 7 - Goodwill and Intangibl

Note 7 - Goodwill and Intangible Assets	9 Months Ended
Note 7 - Goodwill and Intangible Assets	Sep. 30, 2024
Notes to Financial Statements
Goodwill and Intangible Assets Disclosure [Text Block]	Note 7 Goodwill and Intangible Assets The following tables present activity in our intangible assets and goodwill balances during the nine September 30, 2024 2023 Foreign December 31, currency September 30, 2023 Amortization Additions translation 2024 Indefinite-lived intangible assets: Investment management agreements $ 2,064.8 $ — $ — $ 17.3 $ 2,082.1 Trademarks 360.0 — — — 360.0 Definite-lived intangible assets: Client relationships 68.6 — — 2.3 70.9 Accumulated amortization (62.1 ) (0.3 ) — (2.3 ) (64.7 ) Net intangible assets $ 2,431.3 $ (0.3 ) $ — $ 17.3 $ 2,448.3 Goodwill $ 1,290.3 $ — $ 24.8 $ 36.4 $ 1,351.5 Foreign December 31, currency September 30, 2022 Amortization translation 2023 Indefinite-lived intangible assets: Investment management agreements $ 2,046.5 $ — $ 3.1 $ 2,049.6 Trademarks 360.0 — — 360.0 Definite-lived intangible assets: Client relationships 68.9 — (0.7 ) 68.2 Accumulated amortization (60.7 ) (1.5 ) 0.3 (61.9 ) Net intangible assets $ 2,414.7 $ (1.5 ) $ 2.7 $ 2,415.9 Goodwill $ 1,253.1 $ — $ 6.7 $ 1,259.8

Note 8 - Debt

Note 8 - Debt	9 Months Ended
Note 8 - Debt	Sep. 30, 2024
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 8 Debt Our debt as of September 30, 2024 December 31, 2023 Carrying value September 30, 2024 December 31, 2023 Current: 4.875% Senior Notes due 2025 $ 302.4 $ — Non-current: 4.875% Senior Notes due 2025 $ — $ 304.6 5.450% Senior Notes due 2034 396.2 — 4.875% 2025 The 4.875% Senior Notes due 2025 “2025 September 30, 2024 February 1 August 1 August 1, 2025. 2025 September 30, 2024 2025 JHG’s wholly-owned subsidiary, Janus Henderson US (Holdings) Inc., has decided to redeem its 2025 November 7, 2024, May 30, 2017. 2025 5.450% 2034 On September 10, 2024, 2034 “2034 2034 September 30, 2024 March 10 September 10 September 10, 2034. 2034 September 30, 2024 2034 Credit Facility On June 30, 2023, June 30, 2028, two one first second first June 30, 2029. may 3.00x September 30, 2024

Note 9 - Income Taxes

Note 9 - Income Taxes	9 Months Ended
Note 9 - Income Taxes	Sep. 30, 2024
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 9 Income Taxes Our effective tax rates for the three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Effective tax rate 46.6 % 13.2 % 26.6 % 19.3 % The effective tax rate for the three nine September 30, 2024 2023, As of September 30, 2024 12 The Organisation for Economic Co-operation and Development has a framework to implement a global minimum corporate tax of 15% 2” 2 January 1, 2024, January 1, 2025. June 20, 2023, No. 2 2023 15%. December 31, 2023. 2, 2. September 30, 2024 2 not

Note 10 - Noncontrolling Intere

Note 10 - Noncontrolling Interests	9 Months Ended
Note 10 - Noncontrolling Interests	Sep. 30, 2024
Notes to Financial Statements
Noncontrolling Interest Disclosure [Text Block]	Note 10 Noncontrolling Interests Redeemable Noncontrolling Interests Redeemable noncontrolling interests as of September 30, 2024 December 31, 2023 September 30, December 31, 2024 2023 Consolidated seeded investment products $ 493.5 $ 317.2 Consolidated Seeded Investment Products Noncontrolling interests in consolidated seeded investment products are classified as redeemable noncontrolling interests when there is an obligation to repurchase units at the investor’s request. Redeemable noncontrolling interests in consolidated seeded investment products may third The following table presents the movement in redeemable noncontrolling interests in consolidated seeded investment products for the three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Opening balance $ 346.7 $ 389.8 $ 317.2 $ 233.9 Changes in market value 22.7 (7.5 ) 37.0 11.7 Changes in ownership 116.9 (135.4 ) 132.8 0.8 Foreign currency translation 7.2 (1.0 ) 6.5 (0.5 ) Closing balance $ 493.5 $ 245.9 $ 493.5 $ 245.9

Note 11 - Long-Term Incentive C

Note 11 - Long-Term Incentive Compensation	9 Months Ended
Note 11 - Long-Term Incentive Compensation	Sep. 30, 2024
Notes to Financial Statements
Share-Based Payment Arrangement [Text Block]	Note 11 Long-Term Incentive Compensation The following table presents restricted stock and mutual fund awards granted during the three nine September 30, 2024 Three months ended Nine months ended September 30, September 30, 2024 2024 Restricted stock $ 5.8 $ 62.7 Mutual fund awards 0.1 67.2 Total $ 5.9 $ 129.9 Restricted stock and mutual fund awards generally vest and will be recognized using a graded vesting method over a three

Note 12 - Retirement Benefit Pl

Note 12 - Retirement Benefit Plans	9 Months Ended
Note 12 - Retirement Benefit Plans	Sep. 30, 2024
Notes to Financial Statements
Retirement Benefits [Text Block]	Note 12 Retirement Benefit Plans We operate defined contribution retirement benefit plans and defined benefit pension plans. Our primary defined benefit pension plan is the defined benefit section of the Janus Henderson Group UK Pension Scheme (“JHGPS”). Net Periodic Benefit Cost The components of net periodic benefit cost in respect of defined benefit plans for the three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Interest cost $ (6.9 ) $ (7.0 ) $ (20.4 ) $ (20.7 ) Amortization of prior service cost (0.1 ) (0.1 ) (0.3 ) (0.3 ) Amortization of net gain (0.3 ) (0.4 ) (0.9 ) (0.4 ) Expected return on plan assets 6.9 6.9 20.3 20.3 Net periodic benefit cost $ (0.4 ) $ (0.6 ) $ (1.3 ) $ (1.1 )

Note 13 - Accumulated Other Com

Note 13 - Accumulated Other Comprehensive Loss	9 Months Ended
Note 13 - Accumulated Other Comprehensive Loss	Sep. 30, 2024
Notes to Financial Statements
Comprehensive Income (Loss) Note [Text Block]	Note 13 Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss, net of tax for the three nine September 30, 2024 2023 Three months ended September 30, 2024 2023 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (514.8 ) $ (83.9 ) $ (598.7 ) $ (493.9 ) $ (70.2 ) $ (564.1 ) Other comprehensive income (loss) 108.4 — 108.4 (67.9 ) — (67.9 ) Reclassifications to net income (1) 111.9 0.4 112.3 (2.8 ) 0.5 (2.3 ) Total other comprehensive income (loss) 220.3 0.4 220.7 (70.7 ) 0.5 (70.2 ) Less: other comprehensive loss (income) attributable to noncontrolling interests (7.2 ) — (7.2 ) 1.0 — 1.0 Ending balance $ (301.7 ) $ (83.5 ) $ (385.2 ) $ (563.6 ) $ (69.7 ) $ (633.3 ) Nine months ended September 30, 2024 2023 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (478.9 ) $ (84.7 ) $ (563.6 ) $ (577.3 ) $ (70.4 ) $ (647.7 ) Other comprehensive income 88.3 — 88.3 15.0 — 15.0 Reclassifications to net income (1) 95.4 1.2 96.6 (0.7 ) 0.7 — Total other comprehensive income 183.7 1.2 184.9 14.3 0.7 15.0 Less: other comprehensive income attributable to noncontrolling interests (6.5 ) — (6.5 ) (0.6 ) — (0.6 ) Ending balance $ (301.7 ) $ (83.5 ) $ (385.2 ) $ (563.6 ) $ (69.7 ) $ (633.3 ) ( 1 The components of other comprehensive income (loss), net of tax for the three nine September 30, 2024 2023 Three months ended September 30, 2024 2023 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 109.8 $ (1.4 ) $ 108.4 $ (68.8 ) $ 0.9 $ (67.9 ) Reclassifications to net income (1) 112.3 — 112.3 (2.3 ) — (2.3 ) Total other comprehensive income (loss) $ 222.1 $ (1.4 ) $ 220.7 $ (71.1 ) $ 0.9 $ (70.2 ) Nine months ended September 30, 2024 2023 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 87.0 $ 1.3 $ 88.3 $ 11.5 $ 3.5 $ 15.0 Reclassifications to net income (1) 96.6 — 96.6 — — — Total other comprehensive income $ 183.6 $ 1.3 $ 184.9 $ 11.5 $ 3.5 $ 15.0 ( 1

Note 14 - Earnings and Dividend

Note 14 - Earnings and Dividends Per Share	9 Months Ended
Note 14 - Earnings and Dividends Per Share	Sep. 30, 2024
Notes to Financial Statements
Earnings and Dividends Per Share [Text Block]	Note 14 Earnings and Dividends Per Share Earnings Per Share The following is a summary of the earnings per share calculation for the three nine September 30, 2024 2023 Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Net income attributable to JHG $ 27.3 $ 93.5 $ 287.1 $ 270.7 Allocation of earnings to participating stock-based awards (0.7 ) (2.8 ) (6.8 ) (7.8 ) Net income attributable to JHG common shareholders $ 26.6 $ 90.7 $ 280.3 $ 262.9 Weighted-average common shares outstanding — basic 154.4 160.8 155.8 160.5 Dilutive effect of nonparticipating stock-based awards 0.3 0.1 0.2 0.2 Weighted-average common shares outstanding — diluted 154.7 160.9 156.0 160.7 Earnings per share: Basic $ 0.17 $ 0.56 $ 1.80 $ 1.64 Diluted $ 0.17 $ 0.56 $ 1.80 $ 1.64 Dividends Per Share The payment of cash dividends is within the discretion of our Board of Directors and depends on many factors, including, but not The following is a summary of cash dividends declared and paid during the nine September 30, 2024 Dividend Date Dividends paid Date per share declared (in US$ millions) paid $ 0.39 January 31, 2024 $ 63.2 February 28, 2024 $ 0.39 May 1, 2024 $ 62.6 May 29, 2024 $ 0.39 July 31, 2024 $ 62.3 August 28, 2024 On October 30, 2024 third 2024 November 27, 2024 November 11, 2024

Note 15 - Commitments and Conti

Note 15 - Commitments and Contingencies	9 Months Ended
Note 15 - Commitments and Contingencies	Sep. 30, 2024
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	Note 15 Commitments and Contingencies Commitments and contingencies may Litigation and Other Regulatory Matters We are periodically involved in various legal proceedings and other regulatory matters. Sandra Schissler v. Janus Henderson US (Holdings) Inc., Janus Henderson Advisory Committee, and John and Jane Does 1 30 On September 9, 2022, Schissler v. Janus Henderson US (Holdings) Inc., et al. 401 September 9, 2016. January 10, 2023, November 23, 2022, two September 9, 2016, September 9, 2022, February 9, 2023, March 13, 2023, March 28, 2023. September 7, 2023, September 21, 2023, October 12, 2023. January 22, 2024,

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Insider Trading Arr Line Items
Rule 10b5-1 Arrangement Adopted [Flag]	false
Non-Rule 10b5-1 Arrangement Adopted [Flag]	false
Rule 10b5-1 Arrangement Terminated [Flag]	false
Non-Rule 10b5-1 Arrangement Terminated [Flag]	false

Significant Accounting Policies

Significant Accounting Policies (Policies)	9 Months Ended
Significant Accounting Policies (Policies)	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation In the opinion of management of Janus Henderson Group plc (“JHG,” “the Company,” “we,” “us,” “our” and similar terms), the accompanying unaudited condensed consolidated financial statements contain all normal recurring adjustments necessary to fairly state our financial position, results of operations and cash flows in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Such financial statements have been prepared in accordance with the instructions to Form 10 not 10 December 31, 2023
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In November 2023, 2023 07, 280 2023 07 January 1, 2024, January 1, 2025. not In December 2023, 2023 09, 740 2023 09 January 1, 2025. not

Note 3 - Consolidation (Tables)

Note 3 - Consolidation (Tables)	9 Months Ended
Note 3 - Consolidation (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Variable Interest Entities [Table Text Block]	September 30, December 31, 2024 2023 Unconsolidated VIEs $ 16.5 $ 17.2
Consolidated Voting Right Entities VRE [Table Text Block]	September 30, December 31, 2024 2023 Investments $ 119.8 $ 242.9 Cash and cash equivalents 44.0 6.5 Other current assets 1.7 21.6 Accounts payable and accrued liabilities (1.0 ) (1.1 ) Total $ 164.5 $ 269.9 Redeemable noncontrolling interests in consolidated VREs (19.2 ) (100.9 ) JHG’s net interest in consolidated VREs $ 145.3 $ 169.0
Unconsolidated Voting Right Entities VRE [Table Text Block]	September 30, December 31, 2024 2023 Unconsolidated VREs $ 85.4 $ 9.9

Note 4 - Investments (Tables)

Note 4 - Investments (Tables)	9 Months Ended
Note 4 - Investments (Tables)	Sep. 30, 2024
Notes Tables
Investment [Table Text Block]	September 30, December 31, 2024 2023 Current investments: Seeded investment products: Consolidated VIEs $ 713.0 $ 382.4 Consolidated VREs 119.8 242.9 Unconsolidated VIEs and VREs 101.9 27.1 Separately managed accounts 46.1 44.1 Total seeded investment products 980.8 696.5 Investments related to deferred compensation plans 31.9 12.0 Other investments 5.3 8.1 Total current investments $ 1,018.0 $ 716.6 Non-current investments: Equity method investments 24.2 29.5 Total investments $ 1,042.2 $ 746.1
Gain (Loss) on Securities [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Seeded investment products and seed hedges, net $ 10.8 $ 2.5 $ 27.3 $ 17.5 Third-party ownership interests in seeded investment products 22.7 (7.5 ) 37.0 11.7 Equity method investments (1.0 ) (0.8 ) (4.5 ) (12.3 ) Other 2.5 (0.1 ) 4.1 1.7 Investment gains (losses), net $ 35.0 $ (5.9 ) $ 63.9 $ 18.6
Unrealized Gain (Loss) on Investments [Table Text Block]	September 30, 2024 2023 Unrealized gains (losses), net $ 61.9 $ (12.8 )
Cash Flows Related to Investment Securities and Other Assets [Table Text Block]	Nine months ended September 30, 2024 2023 Purchases Sales, Purchases Sales, and settlements and Net and settlements and Net settlements maturities cash flow settlements maturities cash flow Investments by consolidated seeded investment products $ (230.2 ) $ 51.2 $ (179.0 ) $ (179.9 ) $ 10.1 $ (169.8 ) Investments (178.1 ) 83.9 (94.2 ) (150.1 ) 101.6 (48.5 )

Note 5 - Derivative Instrumen_2

Note 5 - Derivative Instruments (Tables)	9 Months Ended
Note 5 - Derivative Instruments (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	Notional value September 30, 2024 December 31, 2023 Futures $ 545.4 $ 1,018.0 Credit default swaps 129.3 199.7 Total return swaps 74.7 51.8 Foreign currency forward contracts 273.5 176.2 Notional value September 30, 2024 December 31, 2023 Futures $ 183.4 $ 1,555.1 Credit default swaps 5.3 13.2 Foreign currency forward contracts and swaps 199.0 135.3 Other 4.3 5.5 Notional value September 30, 2024 December 31, 2023 Foreign currency forward contracts and swaps $ 56.2 $ 65.3
Derivative Instruments, Gain (Loss) [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Futures $ (16.6 ) $ 9.1 $ (22.4 ) $ 6.0 Credit default swaps (1.0 ) 0.8 (2.5 ) (1.7 ) Total return swaps (3.4 ) 5.2 (9.3 ) (6.5 ) Foreign currency forward contracts and swaps 9.7 (2.5 ) 10.6 6.3 Total gains (losses) from derivative instruments $ (11.3 ) $ 12.6 $ (23.6 ) $ 4.1
Schedule of Derivative Instruments [Table Text Block]	Fair value September 30, 2024 December 31, 2023 Derivative assets $ 2.8 $ 1.8 Derivative liabilities 11.3 16.7

Note 6 - Fair Value Measureme_2

Note 6 - Fair Value Measurements (Tables)	9 Months Ended
Note 6 - Fair Value Measurements (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 1,110.7 $ — $ — $ 1,110.7 Current investments: Consolidated VIEs 441.3 271.7 — 713.0 Other investments 260.6 32.6 11.8 305.0 Total current investments 701.9 304.3 11.8 1,018.0 Other — 4.6 2.0 6.6 Total assets $ 1,812.6 $ 308.9 $ 13.8 $ 2,135.3 Liabilities: Seed hedge derivatives $ — $ 11.3 $ — $ 11.3 Securities sold, not yet purchased 33.0 — — 33.0 Long-term debt (1) — 698.0 — 698.0 Deferred bonuses — — 100.7 100.7 Other — 1.2 4.6 5.8 Total liabilities $ 33.0 $ 710.5 $ 105.3 $ 848.8 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 894.4 $ — $ — $ 894.4 Current investments: Consolidated VIEs 317.6 64.7 0.1 382.4 Other investments 212.2 122.0 — 334.2 Total current investments 529.8 186.7 0.1 716.6 Other — 8.5 1.0 9.5 Total assets $ 1,424.2 $ 195.2 $ 1.1 $ 1,620.5 Liabilities: Long-term debt (1) $ — $ 298.0 $ — $ 298.0 Deferred bonuses — — 117.6 117.6 Other 1.7 18.6 — 20.3 Total liabilities $ 1.7 $ 316.6 $ 117.6 $ 435.9
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Beginning of period fair value $ 4.0 $ 16.6 $ 1.1 $ 18.3 Settlement of contingent consideration — — — (0.2 ) Fair value adjustments (2.0 ) (11.7 ) 0.2 (13.1 ) Transfers from (to) Level 1, net — (4.8 ) 0.7 (4.6 ) Purchases (sales) of securities, net 11.8 0.1 11.8 (0.2 ) End of period fair value $ 13.8 $ 0.2 $ 13.8 $ 0.2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Beginning of period fair value $ 76.3 $ 78.2 $ 117.6 $ 46.5 Fair value adjustments 3.9 (0.7 ) 11.6 1.9 Vesting of deferred bonuses 0.1 (0.2 ) (84.2 ) (34.5 ) Amortization of deferred bonuses 18.4 15.9 53.9 41.8 Foreign currency translation 2.2 (1.1 ) 2.0 0.6 Additions 4.4 — 4.4 35.8 End of period fair value $ 105.3 $ 92.1 $ 105.3 $ 92.1

Note 7 - Goodwill and Intangi_2

Note 7 - Goodwill and Intangible Assets (Tables)	9 Months Ended
Note 7 - Goodwill and Intangible Assets (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Intangible Assets and Goodwill [Table Text Block]	Foreign December 31, currency September 30, 2023 Amortization Additions translation 2024 Indefinite-lived intangible assets: Investment management agreements $ 2,064.8 $ — $ — $ 17.3 $ 2,082.1 Trademarks 360.0 — — — 360.0 Definite-lived intangible assets: Client relationships 68.6 — — 2.3 70.9 Accumulated amortization (62.1 ) (0.3 ) — (2.3 ) (64.7 ) Net intangible assets $ 2,431.3 $ (0.3 ) $ — $ 17.3 $ 2,448.3 Goodwill $ 1,290.3 $ — $ 24.8 $ 36.4 $ 1,351.5 Foreign December 31, currency September 30, 2022 Amortization translation 2023 Indefinite-lived intangible assets: Investment management agreements $ 2,046.5 $ — $ 3.1 $ 2,049.6 Trademarks 360.0 — — 360.0 Definite-lived intangible assets: Client relationships 68.9 — (0.7 ) 68.2 Accumulated amortization (60.7 ) (1.5 ) 0.3 (61.9 ) Net intangible assets $ 2,414.7 $ (1.5 ) $ 2.7 $ 2,415.9 Goodwill $ 1,253.1 $ — $ 6.7 $ 1,259.8

Note 8 - Debt (Tables)

Note 8 - Debt (Tables)	9 Months Ended
Note 8 - Debt (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Long-Term Debt Instruments [Table Text Block]	Carrying value September 30, 2024 December 31, 2023 Current: 4.875% Senior Notes due 2025 $ 302.4 $ — Non-current: 4.875% Senior Notes due 2025 $ — $ 304.6 5.450% Senior Notes due 2034 396.2 —

Note 9 - Income Taxes (Tables)

Note 9 - Income Taxes (Tables)	9 Months Ended
Note 9 - Income Taxes (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Effective tax rate 46.6 % 13.2 % 26.6 % 19.3 %

Note 10 - Noncontrolling Inte_2

Note 10 - Noncontrolling Interests (Tables)	9 Months Ended
Note 10 - Noncontrolling Interests (Tables)	Sep. 30, 2024
Notes Tables
Redeemable Noncontrolling Interest [Table Text Block]	September 30, December 31, 2024 2023 Consolidated seeded investment products $ 493.5 $ 317.2
Noncontrolling Interest Increase (Decrease) [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Opening balance $ 346.7 $ 389.8 $ 317.2 $ 233.9 Changes in market value 22.7 (7.5 ) 37.0 11.7 Changes in ownership 116.9 (135.4 ) 132.8 0.8 Foreign currency translation 7.2 (1.0 ) 6.5 (0.5 ) Closing balance $ 493.5 $ 245.9 $ 493.5 $ 245.9

Note 11 - Long-Term Incentive_2

Note 11 - Long-Term Incentive Compensation (Tables)	9 Months Ended
Note 11 - Long-Term Incentive Compensation (Tables)	Sep. 30, 2024
Notes Tables
Share-Based Payment Arrangement, Activity [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2024 Restricted stock $ 5.8 $ 62.7 Mutual fund awards 0.1 67.2 Total $ 5.9 $ 129.9

Note 12 - Retirement Benefit _2

Note 12 - Retirement Benefit Plans (Tables)	9 Months Ended
Note 12 - Retirement Benefit Plans (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Net Benefit Costs [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Interest cost $ (6.9 ) $ (7.0 ) $ (20.4 ) $ (20.7 ) Amortization of prior service cost (0.1 ) (0.1 ) (0.3 ) (0.3 ) Amortization of net gain (0.3 ) (0.4 ) (0.9 ) (0.4 ) Expected return on plan assets 6.9 6.9 20.3 20.3 Net periodic benefit cost $ (0.4 ) $ (0.6 ) $ (1.3 ) $ (1.1 )

Note 13 - Accumulated Other C_2

Note 13 - Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
Note 13 - Accumulated Other Comprehensive Loss (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Three months ended September 30, 2024 2023 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (514.8 ) $ (83.9 ) $ (598.7 ) $ (493.9 ) $ (70.2 ) $ (564.1 ) Other comprehensive income (loss) 108.4 — 108.4 (67.9 ) — (67.9 ) Reclassifications to net income (1) 111.9 0.4 112.3 (2.8 ) 0.5 (2.3 ) Total other comprehensive income (loss) 220.3 0.4 220.7 (70.7 ) 0.5 (70.2 ) Less: other comprehensive loss (income) attributable to noncontrolling interests (7.2 ) — (7.2 ) 1.0 — 1.0 Ending balance $ (301.7 ) $ (83.5 ) $ (385.2 ) $ (563.6 ) $ (69.7 ) $ (633.3 ) Nine months ended September 30, 2024 2023 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (478.9 ) $ (84.7 ) $ (563.6 ) $ (577.3 ) $ (70.4 ) $ (647.7 ) Other comprehensive income 88.3 — 88.3 15.0 — 15.0 Reclassifications to net income (1) 95.4 1.2 96.6 (0.7 ) 0.7 — Total other comprehensive income 183.7 1.2 184.9 14.3 0.7 15.0 Less: other comprehensive income attributable to noncontrolling interests (6.5 ) — (6.5 ) (0.6 ) — (0.6 ) Ending balance $ (301.7 ) $ (83.5 ) $ (385.2 ) $ (563.6 ) $ (69.7 ) $ (633.3 )
Comprehensive Income (Loss) [Table Text Block]	Three months ended September 30, 2024 2023 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 109.8 $ (1.4 ) $ 108.4 $ (68.8 ) $ 0.9 $ (67.9 ) Reclassifications to net income (1) 112.3 — 112.3 (2.3 ) — (2.3 ) Total other comprehensive income (loss) $ 222.1 $ (1.4 ) $ 220.7 $ (71.1 ) $ 0.9 $ (70.2 ) Nine months ended September 30, 2024 2023 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 87.0 $ 1.3 $ 88.3 $ 11.5 $ 3.5 $ 15.0 Reclassifications to net income (1) 96.6 — 96.6 — — — Total other comprehensive income $ 183.6 $ 1.3 $ 184.9 $ 11.5 $ 3.5 $ 15.0

Note 14 - Earnings and Divide_2

Note 14 - Earnings and Dividends Per Share (Tables)	9 Months Ended
Note 14 - Earnings and Dividends Per Share (Tables)	Sep. 30, 2024
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Net income attributable to JHG $ 27.3 $ 93.5 $ 287.1 $ 270.7 Allocation of earnings to participating stock-based awards (0.7 ) (2.8 ) (6.8 ) (7.8 ) Net income attributable to JHG common shareholders $ 26.6 $ 90.7 $ 280.3 $ 262.9 Weighted-average common shares outstanding — basic 154.4 160.8 155.8 160.5 Dilutive effect of nonparticipating stock-based awards 0.3 0.1 0.2 0.2 Weighted-average common shares outstanding — diluted 154.7 160.9 156.0 160.7 Earnings per share: Basic $ 0.17 $ 0.56 $ 1.80 $ 1.64 Diluted $ 0.17 $ 0.56 $ 1.80 $ 1.64
Dividends Declared [Table Text Block]	Dividend Date Dividends paid Date per share declared (in US$ millions) paid $ 0.39 January 31, 2024 $ 63.2 February 28, 2024 $ 0.39 May 1, 2024 $ 62.6 May 29, 2024 $ 0.39 July 31, 2024 $ 62.3 August 28, 2024

Note 2 - Acquisitions (Details

Note 2 - Acquisitions (Details Textual) - USD ($) $ in Millions	Oct. 01, 2024	Dec. 31, 2024	Sep. 19, 2024	Jul. 01, 2024	Jun. 30, 2024
Tabula Investment Management [Member]
Subsidiary, Ownership Percentage, Noncontrolling Owner					1.20%
Victory Park Capital Advisors (V P C) [Member] \| Subsequent Event [Member]
Business Acquisition, Percentage of Voting Interests Acquired	55%
Business Combination, Consideration Transferred	$ 99
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	824,000
Triumph Capital Markets Holdco [Member] \| Forecast [Member]
Business Acquisition, Percentage of Voting Interests Acquired		55%
Tabula Investment Management [Member]
Business Acquisition, Percentage of Voting Interests Acquired				98.80%
N B K Capital Partners [Member]
Business Acquisition, Percentage of Voting Interests Acquired			100%

Note 3 - Consolidation - VIEs (

Note 3 - Consolidation - VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Variable Interest Entity, Primary Beneficiary [Member]
Unconsolidated VIEs	$ 16.5	$ 17.2

Note 3 - Consolidation - VREs (

Note 3 - Consolidation - VREs (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Investments	$ 305	$ 334.2
Cash and cash equivalents	1,483.8	1,152.4
Other current assets	174.1	174.5
Accounts payable and accrued liabilities	(262.3)	(231.4)
Variable Rights Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Investments	119.8	242.9
Cash and cash equivalents	44	6.5
Other current assets	1.7	21.6
Accounts payable and accrued liabilities	(1)	(1.1)
Total	164.5	269.9
Redeemable noncontrolling interests in consolidated VREs	(19.2)	(100.9)
JHG’s net interest in consolidated VREs	$ 145.3	$ 169

Note 3 - Consolidation - Uncons

Note 3 - Consolidation - Unconsolidated VREs (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Unconsolidated VREs [Member]
JHG’s net interest in consolidated VREs	$ 85.4	$ 9.9

Note 4 - Investments (Details T

Note 4 - Investments (Details Textual)	Sep. 30, 2024
Privacore [Member]
Equity Method Investment, Ownership Percentage	49%

Note 4 - Investments - General

Note 4 - Investments - General Disclosure (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Seeded investment products	$ 980.8	$ 696.5
Estimated Fair Value	1,042.2	746.1
Equity method investments	24.2	29.5
Unconsolidated VIEs and VREs [Member]
Seeded investment products	101.9	27.1
Separately Managed Accounts [Member]
Seeded investment products	46.1	44.1
Investments Related to Deferred Compensation Plans [Member]
Estimated Fair Value	31.9	12
Other Security Investments [Member]
Estimated Fair Value	5.3	8.1
Current Investments [Member]
Estimated Fair Value	1,018	716.6
Variable Interest Entity, Primary Beneficiary [Member]
Seeded investment products	713	382.4
Voting Rights Entity, Primary Beneficiary Aggregated Disclosure [Member]
Seeded investment products	$ 119.8	$ 242.9

Note 4 - Investments - Investme

Note 4 - Investments - Investment Gains (Losses), Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Investment gains (losses), net	$ 35	$ (5.9)	$ 63.9	$ 18.6
Seeded Investment Products and Hedges, Net [Member]
Investment gains (losses), net	10.8	2.5	27.3	17.5
Third-party Ownership Interests in Seeded Investment Products [Member]
Investment gains (losses), net	22.7	(7.5)	37	11.7
Equity Method Investments [Member]
Investment gains (losses), net	(1)	(0.8)	(4.5)	(12.3)
Other Security Investments [Member]
Investment gains (losses), net	$ 2.5	$ (0.1)	$ 4.1	$ 1.7

Note 4 - Investments - Unrealiz

Note 4 - Investments - Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Unrealized gains (losses), net	$ 61.9	$ (12.8)

Note 4 - Investments - Cash Flo

Note 4 - Investments - Cash Flows (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Investments, net	$ (94.2)	$ (48.5)
Seeded Investment Products [Member]
Purchases and settlements	(230.2)	(179.9)
Sales, settlements and maturities	51.2	10.1
Investments, net	(179)	(169.8)
Securities Investment [Member]
Purchases and settlements	(178.1)	(150.1)
Sales, settlements and maturities	83.9	101.6
Investments, net	$ (94.2)	$ (48.5)

Note 5 - Derivative Instrumen_3

Note 5 - Derivative Instruments (Details Textual) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts	$ 33	$ 1.7

Note 5 - Derivative Instrumen_4

Note 5 - Derivative Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Futures [Member]
Notional value of derivative	$ 545.4	$ 1,018
Futures [Member] \| Seeded Investment Products [Member]
Notional value of derivative	183.4	1,555.1
Credit Default Swaps [Member]
Notional value of derivative	129.3	199.7
Credit Default Swaps [Member] \| Seeded Investment Products [Member]
Notional value of derivative	5.3	13.2
Foreign Currency, Forward Contracts and Swaps [Member]
Notional value of derivative	273.5	176.2
Foreign Currency, Forward Contracts and Swaps [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member]
Notional value of derivative	56.2	65.3
Foreign Currency, Forward Contracts and Swaps [Member] \| Seeded Investment Products [Member]
Notional value of derivative	199	135.3
Other [Member] \| Seeded Investment Products [Member]
Notional value of derivative	4.3	5.5
Total Return Swaps [Member]
Notional value of derivative	$ 74.7	$ 51.8

Note 5 - Derivative Instrumen_5

Note 5 - Derivative Instruments - Change in Fair Value of Derivatives (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Gain (losses) from derivative instruments	$ (11.3)	$ 12.6	$ (23.6)	$ 4.1
Futures [Member]
Gain (losses) from derivative instruments	(16.6)	9.1	(22.4)	6
Credit Default Swaps [Member]
Gain (losses) from derivative instruments	(1)	0.8	(2.5)	(1.7)
Total Return Swaps [Member]
Gain (losses) from derivative instruments	(3.4)	5.2	(9.3)	(6.5)
Foreign Currency, Forward Contracts and Swaps [Member]
Gain (losses) from derivative instruments	$ 9.7	$ (2.5)	$ 10.6	$ 6.3

Note 5 - Derivative Instrumen_6

Note 5 - Derivative Instruments - Derivative Assets and Liabilities (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Derivative assets	$ 2.8	$ 1.8
Derivative liabilities	$ 11.3	$ 16.7

Note 6 - Fair Value Measureme_3

Note 6 - Fair Value Measurements - Level of Fair Value (Details) - USD ($) $ in Millions		Sep. 30, 2024	Dec. 31, 2023
Total investment securities		$ 305	$ 334.2
Securities sold, not yet purchased		33	1.7
Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities		713	382.4
Fair Value, Recurring [Member]
Cash equivalents		1,110.7	894.4
Total investment securities		1,018	716.6
Other		6.6
Total assets		2,135.3	1,620.5
Securities sold, not yet purchased		33
Long-term debt	[1]	698	298
Other		5.8	20.3
Total liabilities		848.8	435.9
Other		5.8	20.3
Fair Value, Recurring [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Other			9.5
Fair Value, Recurring [Member] \| Seed Hedge Derivatives [Member]
Seed hedge derivatives		11.3
Fair Value, Recurring [Member] \| Deferred Bonuses Hedge [Member]
Seed hedge derivatives		100.7	117.6
Fair Value, Recurring [Member] \| Other Investment Securities [Member]
Total investment securities		305	334.2
Fair Value, Recurring [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities		713	382.4
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash equivalents		1,110.7	894.4
Total investment securities		701.9	529.8
Other		0
Total assets		1,812.6	1,424.2
Securities sold, not yet purchased		33
Long-term debt	[1]	0	0
Other		0	1.7
Total liabilities		33	1.7
Other		0	1.7
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Other			0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Seed Hedge Derivatives [Member]
Seed hedge derivatives		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Deferred Bonuses Hedge [Member]
Seed hedge derivatives		0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Other Investment Securities [Member]
Total investment securities		260.6	212.2
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities		441.3	317.6
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash equivalents		0	0
Total investment securities		304.3	186.7
Other		4.6
Total assets		308.9	195.2
Securities sold, not yet purchased		0
Long-term debt	[1]	698	298
Other		1.2	18.6
Total liabilities		710.5	316.6
Other		1.2	18.6
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Other			8.5
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Seed Hedge Derivatives [Member]
Seed hedge derivatives		11.3
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Deferred Bonuses Hedge [Member]
Seed hedge derivatives		0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Other Investment Securities [Member]
Total investment securities		32.6	122
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities		271.7	64.7
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash equivalents		0	0
Total investment securities		11.8	0.1
Other		2
Total assets		13.8	1.1
Securities sold, not yet purchased		0
Long-term debt	[1]	0	0
Other		4.6	0
Total liabilities		105.3	117.6
Other		4.6	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivatives Used in Consolidated Seeded Investment Products [Member]
Other			1
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Seed Hedge Derivatives [Member]
Seed hedge derivatives		0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Deferred Bonuses Hedge [Member]
Seed hedge derivatives		100.7	117.6
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Other Investment Securities [Member]
Total investment securities		11.8	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities		$ 0	$ 0.1

[1]Carried at amortized cost in our Condensed Consolidated Balance Sheets and disclosed in this table at fair value.

Note 6 - Fair Value Measureme_4

Note 6 - Fair Value Measurements - Changes in Level 3 Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Beginning of period fair value	$ 4	$ 16.6	$ 1.1	$ 18.3
Settlement of contingent consideration	0	0	0	(0.2)
Fair value adjustments	(2)	(11.7)	0.2	(13.1)
Transfers from (to) Level 1, net	0	(4.8)	0.7	(4.6)
Purchases (sales) of securities, net	11.8	0.1	11.8	(0.2)
End of period fair value	$ 13.8	$ 0.2	$ 13.8	$ 0.2

Note 6 - Fair Value Measureme_5

Note 6 - Fair Value Measurements - Changes in Level 3 Liabilities (Details) - Deferred Bonuses [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Beginning of period fair value	$ 76.3	$ 78.2	$ 117.6	$ 46.5
Fair value adjustments	3.9	(0.7)	11.6	1.9
Vesting of deferred bonuses	0.1	(0.2)	(84.2)	(34.5)
Amortization of deferred bonuses	18.4	15.9	53.9	41.8
Foreign currency translation	2.2	(1.1)	2	0.6
Additions	4.4	0	4.4	35.8
End of period fair value	$ 105.3	$ 92.1	$ 105.3	$ 92.1

Note 7 - Goodwill and Intangi_3

Note 7 - Goodwill and Intangible Assets - Intangible Assets and Goodwill (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Intangible assets, amortization	$ (0.3)	$ (1.5)
Accumulated amortization, balance	(62.1)	(60.7)
Foreign currency translation, accumulated amortization	(2.3)	(0.3)
Accumulated amortization, balance	(64.7)	(61.9)
Net intangible assets, balance	2,431.3	2,414.7
Foreign currency translation, Net intangible assets	17.3	2.7
Net intangible assets, balance	2,448.3	2,415.9
Goodwill, balance	1,290.3	1,253.1
Goodwill, addition	24.8
Foreign currency translation, Goodwill	36.4	6.7
Goodwill, balance	1,351.5	1,259.8
Foreign currency translation, accumulated amortization	2.3	0.3
Client Relationships [Member]
Balance	68.6	68.9
Intangible assets, amortization	0	0
Foreign currency translation, definite-lived intangible assets	2.3	(0.7)
Balance	70.9	68.2
Foreign currency translation, definite-lived intangible assets	2.3	(0.7)
Investment Management Agreements [Member]
Balance	2,064.8	2,046.5
Foreign currency translation, indefinite-lived intangible assets	17.3	3.1
Balance	2,082.1	2,049.6
Foreign currency translation	17.3	3.1
Trademarks [Member]
Balance	360	360
Foreign currency translation, indefinite-lived intangible assets	0	0
Balance	360	360
Foreign currency translation	$ 0	$ 0

Note 8 - Debt (Details Textual)

Note 8 - Debt (Details Textual) $ in Thousands	6 Months Ended
Note 8 - Debt (Details Textual) $ in Thousands	Jun. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 10, 2024 USD ($)
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 200,000
Line of Credit Facility, Option for Additional Capacity, Additional Borrowing Capacity	$ 50,000
Line of Credit Facility, Covenant Terms Financing Leverage Ratio, Upper Range Limit	3
Long-Term Line of Credit, Total		$ 0
Senior Notes, 4.876 Percent, Due 2025 [Member]
Debt Instrument, Interest Rate, Stated Percentage		4.875%
Debt Instrument, Face Amount		$ 300,000
Debt Instrument, Unamortized Premium		$ 2,400
Senior Notes, 5.450 Percent, Due 2034 [Member]
Debt Instrument, Interest Rate, Stated Percentage		5.45%	5.45%
Debt Instrument, Face Amount		$ 400,000	$ 400,000
Debt Instrument, Unamortized Discount		$ 3,800

Note 8 - Debt - Schedule of Deb

Note 8 - Debt - Schedule of Debt (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Long term debt, current	$ 302.4	$ 0
Long term debt, non-current	396.2	304.6
Senior Notes, 4.876 Percent, Due 2025 [Member]
Long term debt, current	302.4	0
Long term debt, non-current	0	304.6
Senior Notes, 5.450 Percent, Due 2034 [Member]
Long term debt, non-current	$ 396.2	$ 0

Note 9 - Income Taxes (Details

Note 9 - Income Taxes (Details Textual) $ in Millions	Sep. 30, 2024 USD ($)
Unrecognized Tax Benefits	$ 26
Maximum [Member]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 6.5

Note 9 - Income Taxes - Schedul

Note 9 - Income Taxes - Schedule of Effective Income Tax Rate (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Effective tax rate	46.60%	13.20%	26.60%	19.30%

Note 10 - Noncontrolling Inte_3

Note 10 - Noncontrolling Interests - Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Consolidated seeded investment products	$ 493.5	$ 346.7	$ 317.2	$ 245.9	$ 389.8	$ 233.9
Consolidated Entity, Excluding VIE [Member]
Consolidated seeded investment products	$ 493.5		$ 317.2

Note 10 - Noncontrolling Inte_4

Note 10 - Noncontrolling Interests - Schedule of Changes in Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Opening balance	$ 346.7	$ 389.8	$ 317.2	$ 233.9
Changes in market value	22.7	(7.5)	37	11.7
Changes in ownership	116.9	(135.4)	132.8	0.8
Foreign currency translation	7.2	(1)	6.5	(0.5)
Closing balance	$ 493.5	$ 245.9	$ 493.5	$ 245.9

Note 11 - Long-Term Incentive_3

Note 11 - Long-Term Incentive Compensation - Award Activity (Details) - shares shares in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024
Awards granted (in shares)	5.9	129.9
Restricted Stock [Member]
Awards granted (in shares)	5.8	62.7
Mutual Fund Awards [Member]
Awards granted (in shares)	0.1	67.2

Note 12 - Retirement Benefit _3

Note 12 - Retirement Benefit Plans - Actuarial Gains (Losses), Benefit Cost, Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Interest cost	$ (6.9)	$ (7)	$ (20.4)	$ (20.7)
Amortization of prior service cost	(0.1)	(0.1)	(0.3)	(0.3)
Amortization of net gain	(0.3)	(0.4)	(0.9)	(0.4)
Expected return on plan assets	6.9	6.9	20.3	20.3
Net periodic benefit cost	$ (0.4)	$ (0.6)	$ (1.3)	$ (1.1)

Note 13 - Accumulated Other C_3

Note 13 - Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Balance		$ 4,474.8	$ 4,481.8	$ 4,538.3	$ 4,362.6
Total other comprehensive income (loss)		220.7	(70.2)	184.9	15
Less: other comprehensive loss (income) attributable to noncontrolling interests		7.2	(1)	6.5	0.6
Balance		4,633.2	4,458.7	4,633.2	4,458.7
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Balance		(514.8)	(493.9)	(478.9)	(577.3)
Other comprehensive income (loss)		108.4	(67.9)	88.3	15
Reclassifications to net income(1)	[1]	111.9	(2.8)	95.4	(0.7)
Total other comprehensive income (loss)		220.3	(70.7)	183.7	14.3
Less: other comprehensive loss (income) attributable to noncontrolling interests		(7.2)	1	(6.5)	(0.6)
Balance		(301.7)	(563.6)	(301.7)	(563.6)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Balance		(83.9)	(70.2)	(84.7)	(70.4)
Other comprehensive income (loss)		0	0	0	0
Reclassifications to net income(1)	[1]	0.4	0.5	1.2	0.7
Total other comprehensive income (loss)		0.4	0.5	1.2	0.7
Less: other comprehensive loss (income) attributable to noncontrolling interests		0	0	0	0
Balance		(83.5)	(69.7)	(83.5)	(69.7)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Balance		(598.7)	(564.1)	(563.6)	(647.7)
Other comprehensive income (loss)		108.4	(67.9)	88.3	15
Reclassifications to net income(1)	[1]	112.3	(2.3)	96.6	0
Total other comprehensive income (loss)		220.7	(70.2)	184.9	15
Less: other comprehensive loss (income) attributable to noncontrolling interests		(7.2)	1	(6.5)	(0.6)
Balance		$ (385.2)	$ (633.3)	$ (385.2)	$ (633.3)

[1]Reclassifications to net income are primarily related to the release of accumulated foreign currency translation reserves during the period in which a JHG entity liquidated.

Note 13 - Accumulated Other C_4

Note 13 - Accumulated Other Comprehensive Loss - Schedule of Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Total other comprehensive loss, pre tax	$ 222.1	$ (71.1)	$ 183.6	$ 11.5
Total other comprehensive loss, tax	(1.4)	0.9	1.3	3.5
Total other comprehensive loss, net	220.7	(70.2)	184.9	15
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Total other comprehensive loss, pre tax	109.8	(68.8)	87	11.5
Total other comprehensive loss, tax	(1.4)	0.9	1.3	3.5
Total other comprehensive loss, net	108.4	(67.9)	88.3	15
Reclassification to Net Income [Member]
Total other comprehensive loss, pre tax	112.3	(2.3)	96.6	0
Total other comprehensive loss, tax	0	0	0	0
Total other comprehensive loss, net	$ 112.3	$ (2.3)	$ 96.6	$ 0

Note 14 - Earnings and Divide_3

Note 14 - Earnings and Dividends Per Share (Details Textual) - $ / shares		3 Months Ended
	Oct. 30, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.39	$ 0.39	$ 0.39
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.39

Note 14 - Earnings and Divide_4

Note 14 - Earnings and Dividends Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net income attributable to JHG	$ 27.3	$ 93.5	$ 287.1	$ 270.7
Allocation of earnings to participating stock-based awards	(0.7)	(2.8)	(6.8)	(7.8)
Net income attributable to JHG common shareholders	$ 26.6	$ 90.7	$ 280.3	$ 262.9
Weighted-average common shares outstanding — basic (in shares)	154.4	160.8	155.8	160.5
Dilutive effect of nonparticipating stock-based awards (in shares)	0.3	0.1	0.2	0.2
Weighted-average common shares outstanding — diluted (in shares)	154.7	160.9	156	160.7
Basic (in dollars per share)	$ 0.17	$ 0.56	$ 1.8	$ 1.64
Diluted (in dollars per share)	$ 0.17	$ 0.56	$ 1.8	$ 1.64

Note 14 - Earnings and Divide_5

Note 14 - Earnings and Dividends Per Share - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2024	Sep. 30, 2023
Dividend per share (in dollars per share)	$ 0.39	$ 0.39	$ 0.39
Dividends paid	$ 62.3	$ 62.6	$ 63.2	$ 188.1	$ 194