Hamilton Insurance (HG) 10-K 27 Feb 25 2024 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Feb. 20, 2025	Jun. 30, 2024
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-41862
Entity Registrant Name	Hamilton Insurance Group, Ltd.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-1153847
Entity Address, Address Line One	Wellesley House North, 1st Floor
Entity Address, Address Line Two	90 Pitts Bay Road
Entity Address, City or Town	Pembroke
Entity Address, Postal Zip Code	HM 08
Entity Address, Country	BM
City Area Code	441
Local Phone Number	405-5200
Title of 12(b) Security	Class B common shares, par value $0.01 per share
Trading Symbol	HG
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Public Float			$ 597.1
Entity Common Stock, Shares Outstanding		64,620,239
Documents Incorporated by Reference	Documents Incorporated by Reference Portions of the registrant’s definitive proxy statement for the 2025 Annual General Meeting of Shareholders are incorporated by reference into Part III of this report. Such Proxy Statement will be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 31, 2024.
Entity Central Index Key	0001593275
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2024
Audit Information [Abstract]
Auditor Firm ID	1277
Auditor Name	Ernst & Young Ltd.
Auditor Location	Hamilton, Bermuda

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Assets
Investments, at fair value	$ 2,874,972	$ 2,260,146
Investments in Two Sigma Funds, at fair value (cost 2024: $805,623; 2023: $770,191)	939,381	851,470
Total investments	3,814,353	3,111,616
Cash and cash equivalents	996,493	794,509
Restricted cash and cash equivalents	104,359	106,351
Premiums receivable	771,707	658,363
Paid losses recoverable	134,406	145,202
Deferred acquisition costs	208,985	156,895
Unpaid losses and loss adjustment expenses recoverable	1,171,040	1,161,077
Receivables for investments sold	74,006	42,419
Prepaid reinsurance	218,921	194,306
Intangible assets	93,121	90,996
Other assets	208,642	209,621
Total assets	7,796,033	6,671,355
Liabilities, non-controlling interest, and shareholders’ equity
Reserve for losses and loss adjustment expenses	3,532,491	3,030,037
Unearned premiums	1,122,277	911,222
Reinsurance balances payable	261,275	272,310
Payable for investments purchased	115,427	66,606
Term loan, net of issuance costs	149,945	149,830
Accounts payable and accrued expenses	185,361	186,887
Payables to related parties	100,420	6,480
Total liabilities	5,467,196	4,623,372
Non-controlling interest – TS Hamilton Fund	128	133
Shareholders' Equity
Common shares:	1,015	1,101
Additional paid-in capital	1,163,609	1,249,817
Accumulated other comprehensive loss	(4,441)	(4,441)
Retained earnings	1,168,526	801,373
Total shareholders' equity	2,328,709	2,047,850
Total liabilities, non-controlling interest, and shareholders’ equity	7,796,033	6,671,355
Investments, amortized cost	2,918,547	2,294,936
Investments in Two Sigma Funds, cost	805,623	770,191
Total fixed maturities
Assets
Investments, at fair value	2,377,862	1,831,268
Shareholders' Equity
Investments, amortized cost	2,422,917	1,867,499
Total short-term investments
Assets
Investments, at fair value	497,110	428,878
Shareholders' Equity
Investments, amortized cost	495,630	427,437
Class A
Shareholders' Equity
Common shares:	178	286
Class B
Shareholders' Equity
Common shares:	643	560
Class C
Shareholders' Equity
Common shares:	$ 194	$ 255

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments, amortized cost	$ 2,918,547	$ 2,294,936
Investments in Two Sigma Funds, cost	$ 805,623	$ 770,191
Common stock authorized (in shares)	150,000,000	150,000,000	135,000,000	135,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock issued (in shares)	101,466,997	110,225,103	103,087,859	102,563,042
Common stock outstanding (in shares)	101,466,997	110,225,103	103,087,859	102,563,042
Total fixed maturities
Investments, amortized cost	$ 2,422,917	$ 1,867,499
Total short-term investments
Investments, amortized cost	$ 495,630	$ 427,437
Class A
Common stock authorized (in shares)	26,944,807	28,644,807	53,993,690	53,793,690
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock issued (in shares)	17,820,078	28,644,807	30,520,078	30,320,078
Common stock outstanding (in shares)	17,820,078	28,644,807	30,520,078	30,320,078
Class B
Common stock authorized (in shares)	80,205,911	72,337,352	50,480,684	46,898,612
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock issued (in shares)	64,271,249	56,036,067	42,042,155	37,935,266
Common stock outstanding (in shares)	64,271,249	56,036,067	42,042,155	37,935,266
Class C
Common stock authorized (in shares)	19,375,670	25,544,229	30,525,626	34,307,698
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock issued (in shares)	19,375,670	25,544,229	30,525,626	34,307,698
Common stock outstanding (in shares)	19,375,670	25,544,229	30,525,626	34,307,698

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues
Gross premiums written	$ 2,422,582	$ 1,951,038	$ 1,646,673
Reinsurance premiums ceded	(501,413)	(470,600)	(424,809)
Net premiums written	1,921,169	1,480,438	1,221,864
Net change in unearned premiums	(186,440)	(161,905)	(78,150)
Net premiums earned	1,734,729	1,318,533	1,143,714
Net realized and unrealized gains (losses) on investments	511,407	209,610	93,348
Net investment income (loss)	63,267	30,456	(21,487)
Total net realized and unrealized gains (losses) on investments and net investment income (loss)	574,674	240,066	71,861
Other income (loss)	23,752	18,631	11,316
Net foreign exchange gains (losses)	(3,231)	(6,185)	6,137
Total revenues	2,329,924	1,571,045	1,233,028
Expenses
Losses and loss adjustment expenses	1,010,173	714,603	758,333
Acquisition costs	388,931	309,148	271,189
General and administrative expenses	271,124	259,856	177,682
Impairment of goodwill	0	0	24,082
Amortization of intangible assets	15,520	10,783	12,832
Interest expense	22,616	21,434	15,741
Total expenses	1,708,364	1,315,824	1,259,859
Income (loss) before income tax	621,560	255,221	(26,831)
Income tax expense (benefit)	8,402	(25,066)	3,104
Net income (loss)	613,158	280,287	(29,935)
Net income (loss) attributable to non-controlling interest	212,729	21,560	68,064
Net income (loss) and other comprehensive income (loss) attributable to common shareholders	$ 400,429	$ 258,727	$ (97,999)
Per share data
Basic income (loss) per share attributable to common shareholders	$ 3.81	$ 2.47	$ (0.95)
Diluted income (loss) per share attributable to common shareholders	$ 3.67	$ 2.44	$ (0.95)

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common shares	Additional paid-in capital	Accumulated other comprehensive income (loss)	Retained earnings
Balance, beginning of period at Dec. 31, 2021		$ 1,025	$ 1,110,248		$ 645,769
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common shares		7	308
Repurchases of common shares		(2)	(1,098)		(418)
Share compensation expense			10,784		0
Net income (loss)	$ (29,935)				(29,935)
Net income (loss) attributable to non-controlling interest	(68,064)				(68,064)
Balance, end of period at Dec. 31, 2022	1,664,183	1,030	1,120,242	$ (4,441)	547,352
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common shares		73	82,924
Repurchases of common shares		(2)	(1,896)		(537)
Share compensation expense			48,547		(4,169)
Net income (loss)	280,287				280,287
Net income (loss) attributable to non-controlling interest	(21,560)				(21,560)
Balance, end of period at Dec. 31, 2023	2,047,850	1,101	1,249,817	(4,441)	801,373
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common shares		26	370
Repurchases of common shares		(112)	(116,962)		(33,276)
Share compensation expense			30,384		0
Net income (loss)	613,158				613,158
Net income (loss) attributable to non-controlling interest	(212,729)				(212,729)
Balance, end of period at Dec. 31, 2024	$ 2,328,709	$ 1,015	$ 1,163,609	$ (4,441)	$ 1,168,526

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities
Net income (loss)	$ 613,158	$ 280,287	$ (29,935)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	16,466	12,410	14,994
Share compensation expense	30,384	44,378	10,784
Net realized (gains) losses on investments	(468,068)	(84,513)	(258,653)
Change in net unrealized (gains) losses on investments	(43,339)	(125,097)	165,305
Impairment of goodwill	0	0	24,082
Other items	3,831	(6,529)	12,494
Change in:
Premiums receivable	(113,344)	(135,693)	(60,397)
Paid losses recoverable	10,796	(54,547)	(11,408)
Deferred acquisition costs	(52,090)	(41,748)	(16,323)
Prepaid reinsurance	(24,615)	(29,993)	(11,764)
Unpaid losses and loss adjustment expenses recoverable	(9,963)	16,786	(65,320)
Other assets	1,158	(42,669)	(41,894)
Reserve for losses and loss adjustment expenses	502,454	173,762	440,784
Unearned premiums	211,055	193,034	96,733
Reinsurance balances payable	(11,035)	27,990	(42,476)
Accounts payable and accrued expenses and other	92,455	55,297	(36,079)
Net cash provided by (used in) operating activities	759,303	283,155	190,927
Investing activities
Proceeds from redemptions from Two Sigma Funds	2,874,348	2,591,705	2,592,289
Contributions to Two Sigma Funds	(2,481,159)	(2,554,888)	(2,464,902)
Purchases of fixed maturity investments	(1,929,974)	(1,221,576)	(705,144)
Proceeds from sales, redemptions and maturity of fixed maturity investments	1,381,128	688,978	420,702
Purchases of short-term investments	(1,831,596)	(1,506,241)	(1,551,834)
Proceeds from sales of short-term investments	1,804,670	1,389,409	1,843,007
Change in receivables for investments sold	(31,587)	(42,048)	(345)
Change in payables for investments purchased	48,821	18,511	12,920
Other	(18,811)	(15,938)	(13,591)
Net cash provided by (used in) investing activities	(184,160)	(652,088)	133,102
Financing activities
Issuance of common shares	26	73	7
Repurchases of common shares	(150,350)	(2,435)	(1,518)
Contribution of additional paid-in capital	370	82,924	308
Term loan, net of issuance costs	0	0	(345)
Withdrawal of non-controlling interest	(212,734)	(21,546)	(68,069)
Net cash provided by (used in) financing activities	(362,688)	59,016	(69,617)
Effect of exchange rate changes on cash and cash equivalents and restricted cash and cash equivalents	(12,463)	3,574	(11,335)
Net increase (decrease) in cash and cash equivalents and restricted cash and cash equivalents	199,992	(306,343)	243,077
Cash and cash equivalents and restricted cash and cash equivalents, beginning of period	900,860	1,207,203	964,126
Cash and cash equivalents and restricted cash and cash equivalents, end of period	1,100,852	900,860	1,207,203
Net income taxes paid	10,662	4,211	9,971
Interest paid	$ 22,419	$ 21,608	$ 15,655

Organization

Organization	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Hamilton Insurance Group, Ltd. ("Hamilton Group", the "Group" or the "Company"), the ultimate group holding company, was incorporated on September 4, 2013, under the laws of Bermuda. On November 14, 2023, the Company consummated an initial public offering ("IPO") of its Class B common shares, which are listed on the NYSE. Our Bermuda operations are led by Hamilton Re, Ltd. ("Hamilton Re"), a registered Class 4 insurer incorporated in Bermuda. Hamilton Re writes property, casualty, and specialty insurance and reinsurance on a global basis. Hamilton Re US is a tax partnership that was formed pursuant to an arrangement between Hamilton Re and its Bermuda-incorporated affiliate, Hamilton ILS Holdings Limited. The tax partnership is treated as a U.S. corporation for U.S. tax purposes and is registered with the U.S. Internal Revenue Service, such that underwriting and investment income derived from capital allocated to Hamilton Re US are subject to U.S. taxation. Ada Capital Management Limited ("ACML"), a wholly owned insurance agent incorporated and regulated in Bermuda, is authorized to underwrite on behalf of Ada Re, Ltd. ("Ada Re"). Our London operations are comprised of Hamilton Managing Agency Limited ("HMA"), a Lloyd’s managing agency, which manages our wholly aligned Syndicate 4000 and a third-party funded Lloyd’s Syndicate. Syndicate 4000 operates in the Lloyd’s market and underwrites property, casualty, and specialty insurance and reinsurance business on a subscription basis. Our Dublin operations are comprised of Hamilton Insurance Designated Activity Company ("HIDAC"), a Dublin-based insurer with a U.K. branch and extensive licensing in the United States, including excess and surplus lines and reinsurance in all 50 states. Hamilton Managing General Agency Americas LLC ("HMGA Americas") is licensed throughout the United States and underwrites on behalf of the Group's London, Dublin and Bermuda operations solely in respect of Hamilton Re US, providing access from the U.S. to the Lloyd's market, the Group's rated Irish carrier and the Group's Bermuda balance sheet, respectively. Hamilton Select Insurance Inc. ("Hamilton Select") is a U.S. domestic excess and surplus lines carrier incorporated in Delaware and authorized to write excess and surplus business in all 50 states. Two Sigma Hamilton Fund, LLC ("TS Hamilton Fund"), is a Delaware limited liability company. In 2013, Hamilton Re entered into a limited liability company agreement with TS Hamilton Fund and Two Sigma Principals, LLC (the "Managing Member") as the managing member of TS Hamilton Fund. Effective July 1, 2023, Hamilton Re has committed to an investment in TS Hamilton Fund in an amount up to the lesser of (i) $1.8 billion or (ii) 60% of Hamilton Group’s net tangible assets (previously equal to a minimum of 95% of the consolidated net tangible assets of Hamilton Group). TS Hamilton Fund has engaged Two Sigma Investments, LP ("Two Sigma"), a related party Delaware limited partnership, to serve as its investment manager. Two Sigma is a United States Securities and Exchange Commission registered investment adviser specializing in quantitative analysis (see Note 3, Investments for further details). Unconsolidated Related Parties Ada Re is a special purpose insurer funded by third party investors and formed to provide fully collateralized reinsurance and retrocession to both Hamilton Group and third party cedants. Easton Re has issued an industry loss index-triggered catastrophe bond that provides the Company's operating platforms with multi-year risk transfer capacity to protect against named storm risk in the United States and earthquake risk in the United States and Canada. See Note 7, Reinsurance

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies a. Basis of Presentation These audited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP") and include the accounts of Hamilton Group, Hamilton Re, Hamilton U.K. Holdings Limited, Hamilton Select, HMGA Americas, ACML, and TS Hamilton Fund (collectively the "Company"). All significant intercompany transactions and balances have been eliminated on consolidation . Certain comparative information has been reclassified to conform to the current year presentation. b. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The major estimates recorded in the Company’s financial statements include, but are not limited to, premiums written, provisions for estimated future credit losses, the reserve for losses and loss adjustment expenses and the fair value of investments. c. Fair Value Measurements Details on assets and liabilities that have been included under the requirements of authoritative guidance on fair value measurements to illustrate the bases for determining the fair values of these items held by the Company are included in Note 4, Fair Value and each respective section of this significant accounting policies note. Where the Company has elected to account for certain of its assets and liabilities at fair value in accordance with FASB ASC Topic Fair Value Measurements and Disclosures , the Company recognizes the change in unrealized gains and losses arising from changes in fair value in its statements of operations. See Note 2j, Investments for further detail. d. Premiums and Acquisition Costs Premiums written and ceded on a losses occurring basis are earned pro-rata over the terms of the related contracts and policies. For contracts written on a risks-attaching basis, premiums written and ceded are earned over the terms of the underlying contracts and policies. Premiums written and ceded include estimates based on information received from insureds, brokers and ceding companies, and any subsequent differences arising on such estimates are recorded in the periods in which they are determined. The portion of the premiums written and ceded applicable to the unexpired terms of the underlying contracts and policies are recorded as unearned premiums and prepaid reinsurance premiums, respectively. Amounts are computed by pro-rata methods based on statistical data or reports received from insureds, brokers or ceding companies. Reinstatement premiums are estimated after the occurrence of a significant loss and are recorded in accordance with the contract terms based upon paid losses and case reserves. Reinstatement premiums are earned when written. Acquisition expenses are costs that vary with, and are directly related to, the successful acquisition of new or renewal business and consist principally of commissions, brokerage and premium tax expenses. These costs are deferred and amortized over the periods in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated losses and loss adjustment expenses, based on historical and current experience, and anticipated net investment income related to the premiums are considered in determining the recoverability of deferred acquisition costs. e. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of fixed maturity and short-term investments, cash and cash equivalents, premiums receivable and reinsurance balances recoverable. Cash and cash equivalents are held with financial institutions of high credit quality, and fixed maturity and short-term investments primarily consist of U.S. government, U.S. government agencies, and high credit quality issuers of corporate and debt securities. The Company limits the amount of credit exposure with any one financial institution or issuer and believe that no significant concentration of credit risk exists with respect to cash and investments. f. Reinsurance In the normal course of business, the Company seeks to reduce the potential amount of loss arising from claims events by reinsuring certain levels of risk with other reinsurers. Ceded reinsurance contracts do not relieve the Company of its primary obligation to policyholders. Prepaid reinsurance represents the portion of premiums ceded to reinsurers applicable to the unexpired coverage terms of the reinsurance contracts in place. Amounts recoverable from reinsurers are estimated based on the terms and conditions of the reinsurance contracts, in a manner consistent with the underlying liabilities insured or reinsured by the Company. If the Company determines that adjustments to earlier estimates are appropriate, such adjustments are recorded in the periods in which they are determined. Amounts recoverable from reinsurers are recorded net of an allowance for expected credit losses. See Note 7, Reinsurance , for further details. Retroactive reinsurance agreements are reinsurance agreements under which a reinsurer agrees to reimburse the Company as a result of past insurable events. For these agreements, the excess of the amounts ultimately collectible under the agreement over the consideration paid is recognized as a deferred gain liability which is amortized into income as a reduction of losses and loss adjustment expenses over the estimated ceded reserve settlement period. The amount of the deferred gain is recalculated each period based on actual loss payments and updated estimates of ultimate losses. If cumulative adverse development occurs subsequent to signing of a retroactive reinsurance agreement, it may result in significant losses from operations until periods when the recalculated deferred gain is recognized as a benefit to earnings. If the consideration paid for a retroactive reinsurance agreement exceeds the ultimate losses collectible under the agreement, the net loss on the retroactive reinsurance agreement is immediately recognized in income. g. Credit Loss Provisions The Company routinely evaluates its premiums receivable and paid and unpaid losses recoverable for potential specific credit or collection issues that might indicate an impairment. Premiums receivable and paid and unpaid losses recoverable are presented net of the resulting credit provisions, with the corresponding debits offset against gross premiums written or losses and loss adjustment expenses, as applicable, in the consolidated statement of operations and comprehensive income (loss). The method for calculating the best estimate of losses depends on the size, nature, and risk characteristics of the related underwriting receivable. Such an estimate requires consideration of historical loss experience, current economic conditions, and judgments about the probable effects of relevant observable data, including historical information, counterparty financial strength ratings and the extent of collateralization. The underlying assumptions, estimates and assessments are updated periodically to reflect the Company's view of current conditions. Changes in estimates may significantly affect the allowance and provision for losses. It is possible that the Company's actual credit loss experience will differ materially from current estimates. Adjustments, if any, are recorded in earnings in the periods in which they become known. See Note 7, Reinsurance , for further details. h. Reserve for Losses and Loss Adjustment Expenses The reserve for losses and loss adjustment expenses includes reserves for unpaid reported losses and for losses incurred but not reported ("IBNR"). The reserve for unpaid reported losses and loss adjustment expenses is established by management based on reports from insureds, brokers and ceding companies and represents the estimated ultimate cost of events or conditions that have been reported to or specifically identified by the Company. The reserve for IBNR losses and loss adjustment expenses is established by management based on estimates of ultimate losses and loss adjustment expenses. Inherent in the estimates of ultimate losses and loss adjustment expenses are expected trends in claim severity and frequency, the expected duration of the respective claims development period, inadequacies in the data provided by industry participants, the potential for further reporting lags, significant uncertainty as it relates to legal issues under the relevant terms of insurance and reinsurance contracts, and other factors, which may vary significantly as claims are settled. Accordingly, ultimate losses and loss adjustment expenses may differ materially from the amounts recorded in the financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, are recorded in earnings in the periods in which they become known. See Note 8, Reserve for Losses and Loss Adjustment Expenses , for further details. i. Cash and Cash Equivalents and Restricted Cash and Cash Equivalents Cash and cash equivalents include money market funds and highly liquid short-term deposits and securities with maturities of 90 days or less at the time of purchase. Money market funds are classified as Level 1 as these instruments are considered actively traded; however, certificates of deposit are classified as Level 2. Restricted cash and cash equivalents typically relates to funds held in trust supporting a portion of the Lloyd's capital requirements and other underwriting obligations. See Note 3, Investments , for further details. j. Investments Investments - Trading The Company elects the fair value option for its fixed maturity investments, short-term investments and certain other invested assets (excluding those that are accounted for using specialized investment company accounting as noted below). All changes in the fair value of investments are recorded within net realized and unrealized gains (losses) on investments in the consolidated statements of operations. See Note 4, Fair Value , for further details. All investment transactions are recorded on a trade-date basis and are valued using pricing data received from third parties. Realized gains or losses on sales of investments are determined on a weighted average basis. Investment income is recognized when earned and includes interest and dividend income, recorded as of the ex-dividend date, together with the amortization of premium and discount on fixed maturities and short-term investments computed using the effective yield method. Net investment income includes related investment expenses. Short-Term Investments Short-term investments comprise securities with a maturity greater than three months but less than one year from the date of purchase. Investments in Two Sigma Funds TS Hamilton Fund invests in Two Sigma Funds ("Two Sigma Funds"), which are stated at their estimated fair values, which generally represent the Company’s proportionate interest in the members’ equity of the Two Sigma Funds as reported by the respective funds based on the net asset value ("NAV") provided by the fund administrator. The Company accounts for its investment in Two Sigma Funds under the variable interest model at NAV as a practical expedient for fair value in the consolidated balance sheets. Increases or decreases in such fair values are recorded within net realized and unrealized gains (losses) on investments in the consolidated statements of operations. Realized gains or losses upon any withdrawals of investments in the Two Sigma Funds are calculated using the weighted average method. The assets and liabilities of the Two Sigma Funds are recorded at fair value, or at amounts approximating fair value. The Company records contributions and withdrawals related to its investments in the Two Sigma Funds on the transaction date. The specialized investment company accounting, as described above, is retained in the Company’s audited consolidated financial statements upon consolidation of TS Hamilton Fund. k. Foreign Exchange Monetary assets and liabilities denominated in foreign currencies are revalued into the functional currency of each entity using the exchange rates in effect at the balance sheet date, with the resulting foreign exchange gains and losses included in earnings. Revenues and expenses denominated in foreign currencies are revalued at the exchange rates in effect on the transaction date. The Company’s reporting currency as at December 31, 2024 is the U.S. Dollar ("USD"). The functional currency of the Company's U.K. subsidiaries changed from GBP to USD on January 1, 2017. The accumulated other comprehensive loss recorded prior to the change in functional currency will remain on the balance sheet until such time as the U.K. operations are sold, or substantially liquidated. l. Share Based Compensation The Company issues restricted stock units, performance stock units and warrants and may issue other equity-based awards to its employees. Compensation cost is measured at the grant date fair value and expensed over the period for which the employee is required to provide services in exchange for the award. For awards subject to graded vesting, the awards are separated into vesting tranches, which are amortized over their respective vesting periods. Forfeitures are recognized as they occur. See Note 12, Share Incentive Plans , for further details of the accounting treatment for the Value Appreciation Pool ("VAP"). m. Intangible Assets The Company accounts for goodwill and other intangible assets that arise from business combinations in accordance with FASB ASC Topic Intangibles - Goodwill and Other . A purchase price that is in excess of the fair value of the net assets acquired arising from a business combination is recorded as goodwill or other intangible assets, according to their nature. Goodwill and other intangible assets with indefinite useful lives are not amortized. Other intangible assets with a finite life are amortized over the estimated useful lives of the assets. All recorded goodwill was written down in the year ended December 31, 2022, primarily as a result of the annual impairment assessment, and the Company has no recorded goodwill at December 31, 2024 or 2023. The Company's indefinite lived intangible assets are tested for impairment on an annual basis or more frequently if events or changes in circumstances warrant. Finite lived intangible assets are reviewed for indicators of impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable and tested for impairment if appropriate. If indefinite lived intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense recorded in the Company's consolidated statement of operations. As part of the annual impairment test of finite lived intangible assets, the Company has the option to first assess qualitative factors to determine whether it's necessary to perform a quantitative impairment test. Under this option, the Company would not be required to calculate the fair value of a reporting unit unless the Company determines, based on its qualitative assessment, that it is more likely than not that a reporting unit's fair value is less than its carrying amount. If finite lived intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense recorded in the Company's consolidated statement of operations. n. Variable Interest Entities The Company accounts for variable interest entities ("VIE") in accordance with GAAP guidance, which requires the consolidation of all VIEs by the primary beneficiary: the investor that has the power to direct the activities of the VIE and will absorb a majority of the VIE’s expected losses or residual returns. The Company determines whether it is the primary beneficiary of a VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the terms between the VIE and its variable interest holders and other parties involved with the VIE; (iv) which variable interest holders have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance; (v) which variable interest holders have the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE; and (vi) related party relationships. The Company reassesses its initial evaluation of an entity as a VIE upon the occurrence of certain reconsideration events. The Company also reassesses its determination of whether the Company is the primary beneficiary of a VIE upon changes in facts and circumstances that could potentially alter the Company’s assessment. o. Non-Controlling Interest The share classes related to the redeemable non-controlling interest portion of TS Hamilton Fund are not considered liabilities in accordance with GAAP and have redemption features that are not solely within the control of TS Hamilton Fund. Therefore, the redeemable non-controlling interest in TS Hamilton Fund is presented in the mezzanine section on the Company’s consolidated balance sheets. The net income or loss attributable to non-controlling interest is presented separately in the Company’s consolidated statements of operations. See Note 5, Variable Interest Entities , for further details. p. Earnings Per Share The Company calculates earnings per share in accordance with FASB ASC Topic Earnings per Share . Basic earnings per share are based on weighted average common shares outstanding during the period and exclude any dilutive effects of restricted stock units and warrants. Diluted earnings per share includes the estimated impact under the Treasury Stock method where all dilutive restricted stock grants to vest and all dilutive warrants to be exercised during the period. q. Income Taxes The Company records deferred income taxes that reflect the tax effect of the temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and their respective tax bases. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the fiscal period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is not more likely than not that all, or some portion, of the benefits related to deferred tax assets will be realized. The valuation allowance assessment considers tax planning strategies, where applicable. r. Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07 Segment Reporting, which enhances the qualitative and quantitative disclosures related to reportable segments. The Company adopted this guidance for the year ended December 31, 2024 and it did not have a material impact on the Company’s results of operations, financial position, cash flows or disclosures. Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09 Income Taxes , which enhances the quantitative annual disclosures related to tax rate reconciliations and income taxes paid and requires additional qualitative discussion of applicable tax jurisdictions and the nature of certain reconciling items. The guidance is effective for annual periods beginning after December 15, 2024. Early adoption is permitted. This guidance will not have a material impact on the Company's results of operations, financial position, or cash flows. In November 2024, the FASB issued ASU 2024-03 Disaggregation of Income Statement Expenses , which enhances the quantitative and qualitative disclosures related to specified information about certain costs and expenses. The guidance is effective for annual periods beginning after December 15, 2026. Early adoption is permitted. The Company is currently evaluating the impact of this guidance.

Investments

Investments	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Fixed Maturity and Short-Term Investments - Trading The Company’s fixed maturity and short-term investments are as follows: December 31, 2024 ($ in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities: U.S. government treasuries $ 724,785 $ 611 $ (14,293) $ 711,103 U.S. states, territories and municipalities 13,533 25 (327) 13,231 Non-U.S. sovereign governments and supranationals 70,435 454 (3,362) 67,527 Corporate 1,153,612 6,484 (17,036) 1,143,060 Residential mortgage-backed securities - Agency 288,760 160 (16,309) 272,611 Residential mortgage-backed securities - Non-agency 17,432 6 (684) 16,754 Commercial mortgage-backed securities - Non-agency 40,363 72 (749) 39,686 Other asset-backed securities 113,997 249 (356) 113,890 Total fixed maturities 2,422,917 8,061 (53,116) 2,377,862 Short-term investments 495,630 1,484 (4) 497,110 Total $ 2,918,547 $ 9,545 $ (53,120) $ 2,874,972 December 31, 2023 ($ in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities: U.S. government treasuries $ 717,134 $ 5,137 $ (14,021) $ 708,250 U.S. states, territories and municipalities 4,656 — (286) 4,370 Non-U.S. sovereign governments and supranationals 55,662 2,175 (1,591) 56,246 Corporate 877,493 8,443 (22,060) 863,876 Residential mortgage-backed securities - Agency 180,661 435 (12,583) 168,513 Residential mortgage-backed securities - Non-agency 5,639 16 (671) 4,984 Commercial mortgage-backed securities - Non-agency 11,473 — (1,050) 10,423 Other asset-backed securities 14,781 20 (195) 14,606 Total fixed maturities 1,867,499 16,226 (52,457) 1,831,268 Short-term investments 427,437 1,441 — 428,878 Total $ 2,294,936 $ 17,667 $ (52,457) $ 2,260,146 Contractual Maturities Summary The following table presents contractual maturities of fixed maturity securities. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. December 31, 2024 ($ in thousands) Amortized Cost Fair Value Due less than one year $ 191,976 $ 190,229 Due after one through five years 1,438,250 1,419,173 Due after five through ten years 327,869 321,983 Due after ten years 4,270 3,536 Mortgage-backed securities 346,555 329,051 Asset-backed securities 113,997 113,890 Total $ 2,422,917 $ 2,377,862 Investments in Two Sigma Funds The Company’s investments in Two Sigma Funds are as follows: December 31, 2024 December 31, 2023 ($ in thousands) Cost Net Unrealized Gains (Losses) Fair Value Cost Net Unrealized Gains (Losses) Fair Value Two Sigma Futures Portfolio, LLC (FTV) $ 308,061 $ (15,520) $ 292,541 $ 433,911 $ (38,105) $ 395,806 Two Sigma Spectrum Portfolio, LLC (STV) 360,997 102,267 463,264 193,299 88,228 281,527 Two Sigma Equity Spectrum Portfolio, LLC (ESTV) 136,565 47,011 183,576 142,981 31,156 174,137 Total $ 805,623 $ 133,758 $ 939,381 $ 770,191 $ 81,279 $ 851,470 The Company, through its investments in FTV, STV and ESTV, seeks to achieve absolute dollar-denominated returns on a substantial capital base, primarily by combining multiple hedged and leveraged systematic investment strategies with proprietary risk management and execution techniques. These systematic strategies include, but are not limited to, technical and statistically-based, fundamental-based, event-based, market condition-based and spread-based strategies as well as contributor-based and/or sentiment-based strategies and blended strategies. • FTV primarily utilizes systematic strategies to gain broad macro exposure to FX, fixed income, equity and credit indices and commodities, predominantly by trading futures, spots, forwards, options, swaps, cash bonds and exchange traded products. • STV primarily utilizes systematic strategies to trade U.S.-listed equity securities and related instruments and derivatives. • ESTV primarily utilizes systematic strategies to trade non-U.S.-listed equity securities and related instruments and derivatives. At December 31, 2024, the Company owns a 14.3%, 17.8% and 9.8% interest in each of the FTV, STV and ESTV funds, respectively. The following table summarizes certain investments of FTV, STV and ESTV where TS Hamilton Fund’s proportionate share of the fair value of the investment represents more than 5% of TS Hamilton Fund’s members’ equity: December 31, 2024 ($ in thousands) Principal / Shares (1) Fair Value (1) % of Members' Equity Goldman Sachs Financial Square Treasury Obligations Fund 111,926 $ 111,926 5.9 % Morgan Stanley Institutional Liquidity Funds Treasury Portfolio 109,471 $ 109,471 5.8 % JP Morgan U.S. Treasury Plus Money Market Fund - Capital 101,940 $ 101,940 5.4 % U.S. Treasury Securities, 0.0000% - 4.6250%, due 1/9/2025 - 11/15/2054 2,105,796 $ 2,086,814 110.6 % Invesco Treasury Portfolio Money Market Fund 96,844 $ 96,844 5.1 % U.S. Treasury Securities, 4.0000% - 4.6250%, due 12/31/2026 - 11/15/2054 (241,100) $ (236,974) (12.6) % (1) Values represent TS Hamilton Fund’s proportionate share of the aggregate of FTV, STV and ESTV total holdings. Two Sigma and the Managing Member are related parties to the Company as described further in Note 1, Organization . Effective July 1, 2023, a revised investment management agreement with Two Sigma requires TS Hamilton Fund to incur a management fee of 2.5% of the non-managing members' equity in the net asset value of the TS Hamilton Fund per annum (previously 3%). The management fee for the years ended December 31, 2024, 2023 and 2022 was $46.9 million, $45.2 million and $53.1 million, respectively. Under the terms of the revised limited liability company agreement between Hamilton Re and the Managing Member, the Managing Member remains entitled to an incentive allocation equal to 30% of TS Hamilton Fund’s net profits, subject to high watermark provisions, and adjusted for withdrawals and any incentive allocation to the Managing Member. In the event there is a net loss during a quarter and a net profit during any subsequent quarter, the Managing Member is entitled to a modified incentive allocation whereby the regular incentive allocation will be reduced by 50% until subsequent cumulative net profits are credited in an amount equal to 200% of the previously allocated net losses. The Managing Member is also entitled to receive a revised additional incentive allocation as of the end of each fiscal year (or on any date Hamilton Re withdraws all or a portion of its capital), in an amount equal to 25% of the Excess Profits (previously 20%). "Excess Profits" for any given fiscal year (or other such accounting period) means the net profits over 10% for such fiscal year (previously 15%), net of management fees and expenses and gross of incentive allocations, but only after recouping previously unrecouped net losses. To the extent Hamilton Re contributes capital other than at the beginning of a fiscal year or withdraws capital other than at the end of a fiscal year, the additional incentive allocation hurdle with respect to such capital is prorated. The aggregate incentive allocation (inclusive of the additional incentive allocation) for the years ended December 31, 2024, 2023 and 2022 was $212.7 million, $21.5 million and $68.0 million, respectively. Hamilton Re has a commitment with TS Hamilton Fund to maintain an amount up to the lesser of (i) $1.8 billion or (ii) 60% of Hamilton Insurance Group’s net tangible assets in TS Hamilton Fund, such lesser amount, the "Minimum Commitment Amount", for a three-year period (the "Initial Term") and for rolling three-year periods thereafter (each such three-year period the "Commitment Period"), subject to certain circumstances and the liquidity options described below, with the Commitment Period ending on June 30, 2027. The Commitment Period consists of a 3-year rolling term that automatically renews on an annual basis unless Hamilton Re or the Managing Member provide advance notice of non-renewal. The TS Hamilton Fund generally has two liquidity options, subject to Hamilton Re’s minimum investment commitment, which are as follows: • Monthly liquidity - Subject to certain conditions, Hamilton Re may request a whole or partial withdrawal of its capital account, no later than fifteen days prior to the end of a calendar month, effective as of the last day of such calendar month. • Daily liquidity - Subject to certain limited circumstances, including the need to meet obligations pursuant to Hamilton Re’s underwriting operations, Hamilton Re may request a withdrawal of all or a portion of its capital account upon at least one At its discretion, the Managing Member may permit or require Hamilton Re to withdraw all or any portion of its respective capital account at other times, or waive or reduce certain notice periods, or allow a notice to be revoked. The Managing Member may withdraw all or any portion of its capital account at any time. Total Net Realized and Unrealized Gains (Losses) on Investments and Net Investment Income (Loss) The components of total net realized and unrealized gains (losses) on investments and net investment income (loss) are as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Net realized and unrealized gains (losses) on investments: Net realized gains (losses) on investments $ 468,068 $ 84,513 $ 258,653 Change in net unrealized gains (losses) on investments 43,339 125,097 (165,305) Net realized and unrealized gains (losses) on investments 511,407 209,610 93,348 Net investment income (loss): Fixed maturities 81,872 47,970 22,375 Short-term investments 67 295 155 TS Hamilton Fund 12,373 16,084 10,395 Cash and cash equivalents 17,006 12,523 2,634 Other 2,293 1,580 (1,397) Interest and other 113,611 78,452 34,162 Management fees (49,102) (47,049) (54,581) Other expenses (1,242) (947) (1,068) Net investment income (loss) 63,267 30,456 (21,487) Total net realized and unrealized gains (losses) on investments and net investment income (loss) $ 574,674 $ 240,066 $ 71,861 Net Realized Gains (Losses) on Investments The components of net realized gains (losses) on investments are as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Fixed maturities and short-term investments $ (2,307) $ (16,628) $ (14,968) TS Hamilton Fund 470,091 100,930 266,630 Other 284 211 6,991 Net realized gains (losses) on investments $ 468,068 $ 84,513 $ 258,653 Net Unrealized Gains (Losses) on Investments The components of net unrealized gains (losses) on investments are as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Fixed maturities and short-term investments $ (8,908) $ 52,751 $ (87,254) TS Hamilton Fund 52,247 72,346 (78,051) Net unrealized gains (losses) on investments $ 43,339 $ 125,097 $ (165,305) Pledged Assets At December 31, 2024 and 2023, pledged investments at fair value were comprised of $245.3 million and $232.2 million, respectively, securing a portion of the capital requirements for business written at Lloyd's, $89.1 million and $54.1 million, respectively, held in trust accounts for the benefit of U.S. state regulatory authorities and $31.9 million and $37.2 million, respectively, securing other underwriting obligations. In addition, certain investments were pledged as security for letter of credit facilities as described further in Note 10, Debt and Credit Facilities . At December 31, 2024 and 2023, restricted cash and cash equivalents balances were comprised of $101.8 million and $97.4 million, respectively, securing other underwriting obligations, $1.1 million and $7.2 million, respectively, securing a portion of the capital requirements for business written at Lloyd's, $1.5 million and $1.5 million, respectively, in trust accounts for the benefit of regulatory authorities, and $Nil and $0.3 million, respectively, of escrow funds. Total cash and cash equivalents and restricted cash and cash equivalents of $1.1 billion presented in the statement of cash flows was comprised of cash and cash equivalents of $996.5 million and restricted cash and cash equivalents of $104.4 million on the balance sheet at December 31, 2024. Total cash and cash equivalents and restricted cash and cash equivalents of $900.9 million presented in the statement of cash flows was comprised of cash and cash equivalents of $794.5 million and restricted cash and cash equivalents of $106.4 million on the balance sheet at December 31, 2023.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Financial Instruments Subject to Fair Value Measurements Accounting guidance over fair value measurements requires that a fair value measurement reflect the assumptions market participants would use in pricing an asset or liability based on the best information available. Assumptions include the risks inherent in a particular valuation technique (such as a pricing model) and/or the risks inherent in the inputs to the model. The fair value of a financial instrument is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (the "exit price"). Instruments that the Company owns are marked to bid prices. Basis of Fair Value Measurements Fair value measurement accounting guidance also establishes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. 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). An asset or liability’s classification within the fair value hierarchy is based on the lowest level of significant input to its valuation. The three levels of the fair value hierarchy are: • Level 1 - Inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date; • Level 2 - Inputs other than quoted prices included within Level 1 that are observable for the asset or liability either directly or indirectly, including inputs in markets that are not considered to be active; and • Level 3 - Inputs that are both significant to the fair value measurement and unobservable. Assets Recorded at Fair Value - Fixed Maturity and Short-term Investments The following section describes the valuation methodologies used to determine the fair value of the Company’s fixed maturity and short-term investments by asset class: • U.S. government treasuries : fair value based on observable market inputs such as quoted prices, reported trades, quoted prices for similar issuances and benchmark yields; • U.S. states, territories and municipalities : fair value based on observable market inputs such as quoted market prices, quoted prices for similar securities, benchmark yields and credit spreads; • Non-U.S. sovereign governments and supranationals : fair value based on observable market inputs such as quoted market prices, quoted prices for similar securities and models with observable inputs such as benchmark yields and credit spreads, and then, where applicable, converted to U.S. Dollars using an exchange rate from a nationally recognized source; • Corporate : fair value based on observable market inputs such as quoted market prices, quoted prices for similar securities, benchmark yields and credit spreads; • Asset-backed and mortgage-backed securities : fair value based on observable inputs such as quoted prices, reported trades, quoted prices for similar issuances or benchmark yields and cash flow models using observable inputs such as prepayment speeds, collateral performance and default spreads; and • Short-term investments : fair value based on observable market inputs such as quoted prices, reported trades, quoted prices for similar issuances and benchmark yields. The following table presents the financial instruments measured at fair value on a recurring basis: December 31, 2024 ($ in thousands) Level 1 Level 2 Level 3 Total Fixed maturities: U.S. government treasuries $ — $ 711,103 $ — $ 711,103 U.S. states, territories and municipalities — 13,231 — 13,231 Non-U.S. sovereign governments and supranationals — 67,527 — 67,527 Corporate — 1,143,060 — 1,143,060 Residential mortgage-backed securities - Agency — 272,611 — 272,611 Residential mortgage-backed securities - Non-agency — 16,754 — 16,754 Commercial mortgage-backed securities - Non-agency — 39,686 — 39,686 Other asset-backed securities — 113,890 — 113,890 Total fixed maturities — 2,377,862 — 2,377,862 Short-term investments — 497,110 — 497,110 Total $ — $ 2,874,972 $ — $ 2,874,972 December 31, 2023 ($ in thousands) Level 1 Level 2 Level 3 Total Fixed maturities: U.S. government treasuries $ — $ 708,250 $ — $ 708,250 U.S. states, territories and municipalities — 4,370 — 4,370 Non-U.S. sovereign governments and supranationals — 56,246 — 56,246 Corporate — 863,876 — 863,876 Residential mortgage-backed securities - Agency — 168,513 — 168,513 Residential mortgage-backed securities - Non-agency — 4,984 — 4,984 Commercial mortgage-backed securities - Non-agency — 10,423 — 10,423 Other asset-backed securities — 14,606 — 14,606 Total fixed maturities — 1,831,268 — 1,831,268 Short-term investments — 428,878 — 428,878 Total $ — $ 2,260,146 $ — $ 2,260,146

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities TS Hamilton Fund TS Hamilton Fund meets the definition of a variable interest entity ("VIE") principally because the Managing Member does not hold substantive equity at risk in the entity but controls all of the decision making authority over it. Therefore, the Company assessed its ownership in the VIE to determine if it is the primary beneficiary. The Managing Member is a related party to the Company and collectively they hold all of the variable interest. The Company performed an assessment of all relevant facts and circumstances and determined that it is the entity within the related party group for whom substantially all of the activities of the VIE are conducted. As a result, the Company concluded that it is the primary beneficiary of TS Hamilton Fund. Activity in the non-controlling interest of TS Hamilton Fund was as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Balance - beginning of year $ 133 $ 119 $ 124 Withdrawals (212,734) (21,546) (68,069) Equity in earnings 43 14 14 Incentive allocation 212,686 21,546 68,050 Balance - end of year $ 128 $ 133 $ 119 The following table presents the total assets and total liabilities of TS Hamilton Fund. Creditors or beneficial interest holders of TS Hamilton Fund have no recourse to the general credit of the Company as the Company’s obligation is limited to the amount of its committed investment. December 31, ($ in thousands) 2024 2023 Assets Cash and cash equivalents $ 578,230 $ 479,255 Short-term investments 496,008 428,878 Investments in Two Sigma Funds, at fair value 939,381 851,470 Receivables for investments sold 73,322 41,087 Interest and dividends receivable 945 966 Total assets 2,087,886 1,801,656 Liabilities Payable for investments purchased 100,469 62,440 Withdrawal payable 100,420 6,480 Accounts payable and accrued expenses 233 191 Total liabilities 201,122 69,111 Total net assets managed by TS Hamilton Fund $ 1,886,764 $ 1,732,545

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets The following table provides a summary of the Company's goodwill and intangible assets: ($ in thousands) Goodwill Intangible Assets Intangible Assets not Subject to Amortization Total Net balance, December 31, 2022 $ — $ 49,750 $ 37,208 $ 86,958 Plus: additions — 14,821 — 14,821 Less: amortization — (10,783) — (10,783) Net balance, December 31, 2023 — 53,788 37,208 90,996 Plus: additions — 17,645 — 17,645 Less: amortization — (15,520) — (15,520) Net balance, December 31, 2024 $ — $ 55,913 $ 37,208 $ 93,121 Gross balance, December 31, 2024 $ — $ 106,681 $ 37,208 $ 143,889 Accumulated amortization — (50,768) — (50,768) Net balance, December 31, 2024 $ — $ 55,913 $ 37,208 $ 93,121 As at December 31, 2024, there was no goodwill recorded on the balance sheet. In the year ended December 31, 2022, the Company conducted its annual evaluation of recorded goodwill for impairment using both a market model and an income model and concluded that the associated reporting units’ fair value did not exceed their carrying value, and consequently recorded an impairment to goodwill of $24.1 million in the International segment. Impairment charges are recorded in the consolidated statement of operations for the year ended December 31, 2022 in the line "Impairment of goodwill". The following tables present the components of intangible assets: December 31, 2024 ($ in thousands) Gross Balance Accumulated Amortization and Impairment Net Balance Intangible assets subject to amortization Coverholder and broker relationships $ 44,515 $ (23,707) $ 20,808 Internally developed software 62,166 (27,061) 35,105 Intangible assets not subject to amortization Lloyd's syndicate capacity 35,583 — 35,583 Licenses 1,625 — 1,625 $ 143,889 $ (50,768) $ 93,121 December 31, 2023 ($ in thousands) Gross Balance Accumulated Amortization and Impairment Net Balance Intangible assets subject to amortization Coverholder and broker relationships $ 44,515 $ (19,255) $ 25,260 Internally developed software 44,519 (15,991) 28,528 Intangible assets not subject to amortization Lloyd's syndicate capacity 35,583 — 35,583 Licenses 1,625 — 1,625 $ 126,242 $ (35,246) $ 90,996 The Company's finite-lived intangible assets are amortized on a straight-line basis over their useful lives. As of December 31, 2024, the estimated weighted average amortization period by class consisted of coverholder and broker relationships (10 years) and internally developed software (5 years). Costs incurred to renew or extend the assets' useful lives are expensed straight-line over the remaining life of the related asset or asset class. The weighted-average amortization period is 2.5 years and the estimated amortization expense for each of the five succeeding fiscal years and thereafter related to these assets is as follows: ($ in thousands) Estimated Amortization Expense Year Ending December 31, 2025 $ 15,656 2026 13,551 2027 12,353 2028 9,463 2029 4,890 Total $ 55,913 Intangible assets not subject to amortization consist of Lloyd's syndicate capacity and insurance licenses. The Company did not recognize any impairment losses as a result of the annual impairment review of indefinite-lived assets for the years ended December 31, 2024, 2023 or 2022.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2024
Insurance [Abstract]
Reinsurance	Reinsurance The Company purchases reinsurance and other protection to manage its risk portfolio and to reduce its exposure to large losses. The Company currently has in place contracts that provide for recovery of a portion of certain loss and loss adjustment expenses, generally in excess of various retentions or on a proportional basis. Amounts recoverable under reinsurance contracts are recorded as assets. The Company remains liable to the extent that any reinsurance company fails to meet its obligations. The following tables set forth the effect of reinsurance and retrocessional activity on premiums written and earned and on losses and loss adjustment expenses incurred: Premiums Written Years Ended December 31, ($ in thousands) 2024 2023 2022 Assumed $ 1,144,798 $ 838,547 $ 709,194 Direct 1,277,784 1,112,491 937,479 Ceded (501,413) (470,600) (424,809) Net $ 1,921,169 $ 1,480,438 $ 1,221,864 Premiums Earned Years Ended December 31, ($ in thousands) 2024 2023 2022 Assumed $ 1,030,595 $ 742,378 $ 670,272 Direct 1,180,932 1,016,762 886,488 Ceded (476,798) (440,607) (413,046) Net $ 1,734,729 $ 1,318,533 $ 1,143,714 Losses and Loss Adjustment Expenses Years Ended December 31, ($ in thousands) 2024 2023 2022 Gross losses and loss adjustment expenses $ 1,290,131 $ 972,347 $ 1,133,469 Losses and loss adjustment expenses ceded (279,958) (257,744) (375,136) Net $ 1,010,173 $ 714,603 $ 758,333 Allowance for Expected Credit Losses Premiums receivable, paid losses recoverable, and unpaid losses and loss adjustment expenses recoverable comprise the Company's most significant credit exposures not carried at fair value. The Company has not historically experienced significant credit losses. In determining an allowance for these assets, the Company considers historical information in combination with counterparty financial strength ratings and the extent to which balances are collateralized. The Company assesses the risk of future default by evaluating current market conditions for the likelihood of default and calculates its provision for current expected credit losses under the probability of default and loss given default methodology. Premiums Receivable Premiums receivable are estimated based on policy terms and reports received from the underlying counterparties, supplemented by management's judgment. Due to the nature of the (re)insurance business, the Company routinely receives reports and premiums subsequent to the inception of the coverage period. At December 31, 2024, the Company’s premiums receivable balance, net of credit provisions of $3.0 million, was $771.7 million. At December 31, 2023, the Company’s premiums receivable balance, net of credit provisions of $3.0 million, was $658.4 million. The following table provides a roll forward of the provision for current expected credit losses of the Company's premiums receivable: Years Ended December 31, ($ in thousands) 2024 2023 2022 Beginning balance $ 3,000 $ 2,856 $ 2,165 Increase (decrease) in allowance (7) 144 691 Ending balance $ 2,993 $ 3,000 $ 2,856 Reinsurance Balances Recoverable Reinsurance balances recoverable is comprised of amounts due from reinsurers based on the claim liabilities associated with the reinsured policy. The Company accrues amounts due from reinsurers based on estimated ultimate contract losses. At December 31, 2024, the Company’s paid and unpaid reinsurance recoverable balances net of credit provisions were $134.4 million and $1.2 billion, respectively, with a total corresponding provision for current expected credit losses of $1.5 million. At December 31, 2023, the Company’s paid and unpaid reinsurance recoverable balances net of credit provisions were $145.2 million and $1.2 billion, respectively, with a total corresponding provision for current expected credit losses of $0.7 million. The following table provides a roll forward of the provision for current expected credit losses of the Company's reinsurance recoverable: Years Ended December 31, ($ in thousands) 2024 2023 2022 Beginning balance $ 687 $ 777 $ 616 Increase (decrease) in allowance 782 (90) 161 Ending balance $ 1,469 $ 687 $ 777 The distribution of the Company’s paid losses recoverable and unpaid losses and loss adjustment expenses recoverable as categorized by major rating agencies were as follows: December 31, Classification 2024 2023 Collateralized 23.7 % 28.5 % A- or better 76.2 % 71.0 % Below A- 0.1 % 0.5 % Total 100.0 % 100.0 % At December 31, 2024 and 2023, the three largest balances by reinsurer accounted fo r 22% , 19% and 13% , and 27%, 20% and 12%, respectively, of paid losses recoverable and unpaid losses and loss adjustment expenses recoverable. Loss Portfolio Transfer On February 6, 2020, the Company entered into a loss portfolio transfer agreement (the "LPT"), under which the insurance liabilities arising from certain casualty risks for the Lloyd's Years of Account ("YOA") 2016, 2017 and 2018 were retroceded to a third party in exchange for total premium of $72.1 million. This transaction was accounted for as retroactive reinsurance under which cumulative ceded losses exceeding the LPT premium are recognized as a deferred gain liability and amortized into income over the settlement period of the ceded reserves in proportion to cumulative losses collected over the estimated ultimate reinsurance recoverable. The amount of the deferral is recalculated each reporting period based on updated ultimate loss estimates. Consequently, cumulative adverse development subsequent to the signing of the LPT may result in significant losses from operations until periods when the deferred gain is recognized as a benefit to earnings. At December 31, 2024 and 2023, the balance of reinsurance recoverable on unpaid losses due under this LPT was $23.7 million and $49.8 million, respectively. Amortization of the deferred gain was an expense of $9.4 million for the year ended December 31, 2024 and income of $4.2 million and $1.9 million for the years ended December 31, 2023 and 2022, respectively, which was recorded through losses and loss adjustment expenses in accordance with the actual loss payments and updated estimates of ultimate losses of the subject business. Catastrophe Bond Reinsurance In December 2023, Hamilton Group sponsored an industry loss index-triggered catastrophe bond through the issuance of Series 2024-1 Class A Principal-at-Risk Variable Rate Notes by Bermuda-domiciled Easton Re Ltd. ("Easton Re"), which provide the Company's operating platforms with multi-year risk transfer capacity of $200 million to protect against named storm risk in the United States and earthquake risk in the United States and Canada. The risk period for Easton Re is from January 1, 2024 to December 31, 2026. The Company recorded reinsurance premiums ceded of $14.6 million during the year ended December 31, 2024. In December 2020, Hamilton Group sponsored an industry loss index-triggered catastrophe bond through the issuance of Series 2020-1 Class A Principal-at-Risk Variable Rate Notes by Singapore-domiciled Easton Re Pte, Ltd. (also "Easton Re"). Easton Re provided the Company's operating platforms with multi-year risk transfer capacity of $150 million to protect against named storm and earthquake risk in the United States. The risk period for Easton Re was from January 1, 2021 to December 31, 2023. The Company recorded reinsurance premiums ceded $7.2 million and $6.3 million during the years ended December 31, 2023 and 2022, respectively.

Reserve for Losses and Loss Adj

Reserve for Losses and Loss Adjustment Expenses	12 Months Ended
	Dec. 31, 2024
Insurance [Abstract]
Reserve for Losses and Loss Adjustment Expenses	Reserve for Losses and Loss Adjustment Expenses The following table presents a reconciliation of unpaid losses and loss adjustment expenses ("LAE"): Years Ended December 31, ($ in thousands) 2024 2023 2022 Gross unpaid losses and loss adjustment expenses, beginning of year $ 3,030,037 $ 2,856,275 $ 2,415,491 Reinsurance recoverable on unpaid losses 1,161,077 1,177,863 1,112,543 Net unpaid losses and loss adjustment expenses, beginning of year 1,868,960 1,678,412 1,302,948 Net losses and loss adjustment expenses incurred in respect of losses occurring in: Current year 1,030,612 730,220 778,936 Prior years (20,439) (15,617) (20,603) Total incurred 1,010,173 714,603 758,333 Net losses and loss adjustment expenses paid in respect of losses occurring in: Current year 58,726 62,811 61,649 Prior years 458,040 501,987 315,537 Total paid 516,766 564,798 377,186 Foreign currency revaluation and other (916) 40,743 (5,683) Net unpaid losses and loss adjustment expenses, end of year 2,361,451 1,868,960 1,678,412 Reinsurance recoverable on unpaid losses 1,171,040 1,161,077 1,177,863 Gross unpaid losses and loss adjustment expenses, end of year $ 3,532,491 $ 3,030,037 $ 2,856,275 Net favorable prior year development of $20.4 million for the year ended December 31, 2024, was comprised of $21.2 million of favorable prior year development on catastrophe losses, partially offset by $0.8 million of unfavorable prior year development on attritional losses. See below for further details: • Net favorable development of $37.5 million on property contracts, primarily driven by favorable prior year development on catastrophe losses and overall lower than expected claims development across various classes; partially offset by • Net unfavorable development of $14.2 million on casualty contracts, primarily driven by higher than expected claims development across certain classes and unfavorable development of one specific large loss; • Net unfavorable development of $8.8 million on specialty contracts, primarily driven by two specific large losses; and • In addition, casualty business protected by the LPT discussed in Note 7, Reinsurance , benefited from favorable development in the underlying reserves of $15.3 million, which was partially offset by a change in the deferred gain of $9.4 million, for a total net positive earnings impact of $5.9 million. Net favorable prior year development of $15.6 million for the year ended December 31, 2023 was comprised of $10.4 million and $5.2 million of favorable prior year development on attritional and catastrophe losses, respectively. See below for further details: • Net favorable development of $18.6 million on specialty contracts, driven by lower loss estimates across various classes; partially offset by • Net unfavorable development of $4.6 million on property contracts, primarily driven by higher than expected claims related to Winterstorm Elliott and development on certain attritional claims, including claims arising from exited classes of business; • Net unfavorable development of $3.4 million on casualty contracts, reflecting modest unfavorable development on certain classes of business; and • In addition, casualty business protected by the LPT discussed in Note 7, Reinsurance , benefited from $4.2 million in amortization of the associated deferred gain and favorable development in the underlying reserves of $0.8 million, for a total net positive earnings impact of $5.0 million. Net favorable prior year development of $20.6 million for the year ended December 31, 2022 was comprised of $17.4 million and $3.2 million of favorable prior year development on catastrophe and attritional losses, respectively. See below for further details: • Net favorable development of $36.9 million on specialty contracts, driven by reductions in loss estimates across multiple classes; • Net favorable development of $0.4 million on property contracts, related to $9.5 million of favorable development on Hurricane Ida that was partially offset by $7.0 million of unfavorable attritional loss development and $2.1 million of unfavorable development on various other catastrophes; partially offset by • Net unfavorable development of $23.7 million on casualty contracts, primarily related to discontinued business; and • In addition, casualty business protected by the LPT discussed in Note 7, Reinsurance , recorded favorable gross development which was partially offset by amortization of the associated deferred gain, resulting in a net positive earnings impact of $7.0 million. Reinsurance recoverable on unpaid losses related to the LPT discussed in Note 7, Reinsurance was recognized in the reconciliation of beginning and ending gross and net loss and LAE reserves. Acquisition Costs The Company amortized acquisition costs of $388.9 million, $309.1 million and $271.2 million for the years ended December 31, 2024, 2023 and 2022, respectively. Baltimore Bridge Our net reserves for losses and loss adjustment expenses related to the Francis Scott Key Baltimore Bridge collapse on March 26, 2024 are subject to significant uncertainty. As at December 31, 2024 and 2023, our net recorded reserves totaled $34.8 million and $Nil, respectively. Ukraine Conflict Our net reserves for losses and loss adjustment expenses related to the ongoing Ukraine conflict are also subject to significant uncertainty. As at December 31, 2024 and 2023, our net recorded reserves totaled $63.2 million and $64.9 million, respectively. Covid-19 Our Covid-19 losses are also subject to significant uncertainty. As at December 31, 2024 and 2023, our net recorded reserves relating to Covid-19 totaled $13.3 million and $14.1 million, respectively. While the Company believes, based on current facts and circumstances, that its estimates of net reserves for losses and loss adjustment expenses are adequate for losses and loss adjustment expenses that have been incurred at December 31, 2024, the Company will continue to monitor its assumptions as new information becomes available and will adjust its estimate of net reserves for losses and loss adjustment expenses as appropriate. Actual ultimate losses for these events may differ materially from the Company's current estimates. Reserving The Company's reserve for losses and loss adjustment expenses consists of case reserves and IBNR reserves. Case reserves are reserves for reported losses and loss adjustment expenses that have not yet been settled. IBNR are reserves for incurred but not reported losses and loss adjustment expenses, and include reserves for reported losses in excess of case reserves. Case Reserves For reinsurance business, the Company typically receives loss notifications from its cedants in the form of loss bordereaux or individual loss notifications. These notifications generally include varying amounts of information about the nature and quantum of the loss, including paid amounts and estimates of outstanding loss. The Company records the estimates of outstanding loss from its cedants as case reserves. Typically there is a timing lag between the cedant establishing a reserve and notifying the loss to the Company. In addition, different cedants have different claims handling practices which result in case reserve estimates that vary in the level of embedded prudence. For insurance business, the Company records a case reserve for the estimated amount of settlement. This amount is based on the judgment of the Company’s claims team and takes into account the class of business, nature of the claim and, if appropriate, the advice of specialist legal counsel and external loss adjusters, and includes the estimated expenses of settling the claim, such as legal and other fees. The Company may sometimes use third party claims administrators to handle claims and set case reserves, within defined authority levels and service level agreements. In syndicated markets such as Lloyd’s, the Company’s case reserve will be based in part on information provided by the lead insurer, where the Company is not an agreement party. Any adjustments to case reserves are accounted for as changes in estimates and recorded in the period in which such changes are identified. IBNR Reserves The Company establishes IBNR reserves for large events based on a number of different factors, including discussions with brokers and cedants, proprietary loss modelling and pricing software, estimates of market loss and market share, experience from historical large events and other information that can guide the estimates of loss reserves. The Company's actuaries may use other approaches in addition to those described, and supplement these methods with judgement where they deem appropriate, depending upon the characteristics of the class of business and available data. These estimates are reviewed periodically as new information emerges. IBNR reserves for attritional losses are established using actuarial loss reserving techniques. These techniques include the loss development factor method, Bornheutter Ferguson method, the Initial Expected Loss Ratio method, and other techniques. These techniques rely on estimates of paid and reported loss development patterns and estimates of the loss ratio at the inception of the contract. The Company’s actuaries review the estimates of IBNR reserves on a quarterly basis and adjust the estimates as new information becomes available. Any such adjustments are accounted for as changes in estimates and recorded in the periods in which they become known. To establish IBNR reserves for attritional losses, contracts are grouped into cohorts, or reserving classes, that have similar coverage, inception period and loss reporting characteristics. The paid and reported losses for these reserving classes are tracked over time against expectations and against the actuarial loss reserving indications and IBNR reserve selected for each cohort. Claims Development and Frequency For incurred and paid accident year claims denominated in foreign currency, the Company used the current year-end balance sheet foreign exchange rate for all periods provided, thereby eliminating the effects of changes in foreign currency translation rates from the incurred and paid accident year claims development information included in the following tables. In determining the cumulative number of reported claims, the Company measures claim counts on its insurance business by individual claimant where information is available. The claim counts include all claims reported where the Company has identified a potential liability for the claim even if there is no existing reserve. Reinsurance business is typically written under either proportional (quota share arrangements) or non-proportional arrangements (excess of loss or other facultative covers). The Company typically does not have direct access to claim frequency information underlying its assumed quota share arrangements, given the nature of that business. In addition, multiple claims are often aggregated by the ceding company before being reported to the Company. The Company generally does not use claim frequency information in the determination of loss reserves or for other internal purposes relating to proportional business. In addition, the nature, size, terms and conditions of contracts entered into by the Company may change from one accident year to the next and the quantum of contractual or policy limits, and accordingly, the potential amount of losses and loss adjustment expenses associated with a reported claim, can range from nominal to significant, and therefore the Company does not believe providing claims frequency information is practicable as it relates to its proportional business. The Company has developed claims frequency information associated with its non-proportional reinsurance contracts. In determining claims frequency for its excess-of-loss reinsurance contracts, claims counts include all claims reported by each insured where a reserve for losses and loss adjustment expenses has been recorded. The Company has assumed that claims below the loss layer of a contract are excluded; if an insured's claim impacts multiple layers of a contract, the Company considers each impact to be a separate claim, and for an insured loss impacting more than one operating subsidiary, each impact is considered a separate claim. Claims Development The information provided herein about incurred and paid accident year claims development, net of reinsurance, for the periods ended prior to December 31, 2024 and the annual percentage payouts of incurred claims by age, net of reinsurance, is presented as supplementary information. The following tables show the paid and incurred loss development by broad classification based on groupings of contracts that are similar in coverage and duration: International Property ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $1 $1 $1 $— $— $— $— $— $— $— $— 2 2016 7,527 6,551 6,212 6,351 6,011 7,155 7,261 7,349 7,306 27 903 2017 38,379 42,986 44,911 41,819 41,260 41,224 41,230 40,456 (974) 1,166 2018 24,037 26,191 24,873 24,537 24,542 24,466 23,869 114 1,122 2019 32,695 33,895 36,609 36,672 36,687 34,824 411 1,436 2020 134,743 144,201 143,676 143,418 142,802 5,261 2,236 2021 113,813 124,917 121,907 117,228 3,371 1,566 2022 81,324 74,560 68,686 4,035 1,077 2023 53,085 48,480 10,278 681 2024 73,513 55,074 598 Total $557,164 $77,597 10,787 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $— $— $— $— $— $— $— $— $— 2016 171 3,428 4,567 6,668 7,049 6,891 7,003 7,277 7,277 2017 9,249 29,283 34,363 40,193 39,984 40,832 40,900 41,333 2018 1,322 12,036 17,340 20,053 20,905 21,964 23,603 2019 8,307 21,106 20,940 25,818 32,942 34,066 2020 24,365 90,859 115,587 132,191 136,041 2021 23,564 63,784 101,064 112,184 2022 9,996 46,856 57,551 2023 5,502 29,362 2024 5,071 Total $446,488 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $110,676 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 2 3 4 5 6 7 8 9 16 % 44 % 19 % 12 % 5 % 3 % 3 % 1 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. International Casualty ($ in thousands, except claim count) The following table discloses losses incurred, losses paid and claims data excluding the impact of the loss portfolio transfer discussed in further detail in Note 7, Reinsurance. Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $— $— $— $— $— $— $— $— $— $— — 2016 171 278 243 342 342 342 388 367 166 — 32 2017 648 5,187 7,354 6,332 5,857 5,121 5,079 4,579 328 73 2018 697 5,890 5,686 4,941 4,351 4,453 4,300 110 554 2019 19,882 19,199 18,867 18,112 16,817 15,846 704 2,704 2020 28,692 24,123 17,870 19,426 19,265 2,451 3,641 2021 101,549 109,013 107,024 106,824 69,619 3,602 2022 144,543 145,030 149,180 87,661 3,912 2023 145,783 147,005 108,769 5,639 2024 198,705 182,784 3,909 Total $645,870 $452,426 24,066 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $— $— $— $— $— $— $— $— $— 2016 — — 82 — — — — — — 2017 — 22 629 2,285 2,406 3,964 4,043 4,046 2018 35 439 2,266 3,167 3,800 4,011 4,066 2019 177 2,719 6,813 13,332 14,992 15,131 2020 3,363 8,420 12,480 16,706 16,813 2021 795 11,243 20,079 30,286 2022 3,240 9,452 27,217 2023 5,240 19,429 2024 4,749 Total $121,737 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $524,133 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 2 3 4 5 6 7 8 9 3 % 9 % 12 % 16 % 6 % 8 % 1 % 0 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. International Specialty ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $93 $138 $218 $212 $144 $149 $94 $100 $101 $— 65 2016 2,534 4,771 5,383 5,232 5,370 3,668 3,367 3,325 4,427 504 766 2017 22,378 17,430 16,943 15,256 22,030 25,397 27,714 31,279 2,277 1,300 2018 31,724 30,606 29,176 33,129 37,834 42,995 42,921 (287) 1,617 2019 108,035 109,971 104,017 97,777 95,702 95,306 5,405 2,852 2020 119,790 116,242 106,774 105,314 105,310 4,426 2,943 2021 124,844 136,998 138,471 140,697 10,573 3,073 2022 129,423 119,581 121,981 15,941 2,864 2023 178,429 178,984 68,974 2,529 2024 221,168 201,273 1,580 Total $942,174 $309,086 19,589 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $16 $62 $119 $147 $150 $150 $94 $94 $94 2016 248 2,141 4,000 3,098 3,446 3,600 3,265 3,265 3,874 2017 2,427 8,992 16,986 21,763 21,256 23,043 25,858 28,928 2018 2,054 17,155 30,652 30,839 35,614 40,792 43,177 2019 14,076 59,152 77,532 78,807 86,733 89,858 2020 12,218 53,425 84,864 94,657 100,757 2021 9,743 45,838 67,950 105,231 2022 9,001 41,596 77,303 2023 17,943 72,227 2024 10,319 Total $531,768 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $410,406 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 2 3 4 5 6 7 8 9 8 % 32 % 24 % 12 % 7 % 6 % 6 % 8 % 13 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Bermuda Property ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $29,519 $17,011 $12,643 $12,184 $7,821 $6,492 $6,467 $6,439 $5,667 $6,705 $— 41 2016 56,248 38,658 37,476 35,938 35,120 36,340 35,652 35,132 35,011 — 107 2017 100,603 98,094 93,332 81,032 79,484 83,413 83,603 82,467 898 272 2018 62,057 80,131 77,845 78,132 73,819 70,675 69,594 371 241 2019 14,775 44,540 56,265 57,939 57,631 56,413 2,010 141 2020 112,056 120,840 126,275 126,583 127,579 5,620 295 2021 144,924 161,604 157,881 150,283 8,385 205 2022 181,052 209,797 199,762 37,648 232 2023 102,739 100,047 45,914 79 2024 168,850 118,912 92 Total $996,711 $219,758 1,705 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $1,775 $4,664 $5,163 $5,297 $5,417 $5,608 $5,630 $5,646 $5,647 $6,700 2016 12,840 25,596 29,623 31,685 32,882 33,985 34,609 34,741 34,823 2017 24,533 90,864 71,190 82,940 71,795 75,524 78,356 79,097 2018 12,631 71,557 85,660 67,547 65,583 67,410 67,938 2019 2,401 32,433 38,002 46,504 49,705 51,248 2020 13,253 48,246 75,445 104,870 113,365 2021 16,080 71,293 106,089 130,528 2022 35,261 109,215 137,313 2023 26,199 38,728 2024 24,366 Total $684,106 Outstanding liabilities for accident year 2014 and prior, net of reinsurance $33 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $312,638 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 (unaudited) 2 (unaudited) 3 (unaudited) 4 (unaudited) 5 (unaudited) 6 (unaudited) 7 (unaudited) 8 (unaudited) 9 (unaudited) 17 % 42 % 13 % 11 % 0 % 3 % 2 % 1 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Bermuda Casualty ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $19,729 $18,378 $31,552 $30,313 $38,585 $39,331 $50,570 $49,546 $41,677 $41,378 $7,888 38 2016 44,749 49,876 54,253 54,619 56,863 56,353 60,342 54,997 57,154 4,682 7 2017 84,754 96,345 101,443 105,558 113,594 126,190 137,924 139,565 9,057 39 2018 101,397 115,594 123,114 121,692 131,717 133,476 142,520 14,967 34 2019 85,454 96,207 101,614 100,758 105,390 98,242 22,097 18 2020 81,925 84,493 88,400 88,632 88,992 26,122 21 2021 69,766 79,096 80,015 79,183 40,792 7 2022 110,317 110,095 107,522 75,580 3 2023 169,608 171,462 127,989 30 2024 268,201 247,492 3 Total $1,194,219 $576,666 200 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $708 $2,111 $3,569 $11,246 $16,953 $18,828 $25,671 $34,198 $30,726 $37,260 2016 1,541 5,169 12,678 20,504 27,103 35,482 39,381 41,115 44,726 2017 3,792 10,961 22,829 50,471 70,548 91,855 106,013 117,341 2018 3,782 22,800 50,903 66,889 70,939 87,677 105,495 2019 3,965 11,094 23,445 36,161 53,528 58,930 2020 5,417 14,495 19,713 35,047 49,768 2021 1,934 4,523 11,255 26,962 2022 696 4,744 14,565 2023 2,025 21,821 2024 8,203 Total $485,071 Outstanding liabilities for accident year 2014 and prior, net of reinsurance $524 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $709,672 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 (unaudited) 2 (unaudited) 3 (unaudited) 4 (unaudited) 5 (unaudited) 6 (unaudited) 7 (unaudited) 8 (unaudited) 9 3 % 8 % 11 % 16 % 12 % 11 % 11 % 9 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Bermuda Specialty ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $27,712 $26,686 $19,342 $19,237 $17,466 $16,820 $15,383 $15,672 $15,288 $15,277 $16 39 2016 38,154 34,835 28,913 23,171 19,826 16,850 15,846 15,851 15,684 565 58 2017 57,528 44,156 36,230 29,590 24,470 26,820 27,334 26,216 735 74 2018 58,551 52,420 48,323 45,096 38,658 39,920 40,386 953 89 2019 62,075 56,189 48,874 49,114 48,508 49,857 5,280 109 2020 63,176 56,807 52,195 54,645 54,586 3,468 116 2021 53,732 46,023 35,610 33,499 8,721 33 2022 117,538 114,225 111,565 73,277 76 2023 62,095 70,783 49,590 28 2024 82,306 72,328 4 Total $500,159 $214,933 626 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $3,330 $8,638 $13,136 $13,115 $14,192 $14,397 $14,432 $14,767 $14,832 $14,911 2016 2,938 8,661 5,632 10,814 13,116 13,589 13,810 14,413 14,603 2017 2,217 10,194 14,114 16,417 17,726 22,638 24,384 24,267 2018 7,607 19,326 25,826 28,223 27,789 33,653 36,457 2019 6,373 20,505 29,083 36,472 45,062 42,679 2020 9,160 25,585 32,653 43,226 47,047 2021 3,862 7,248 15,938 19,114 2022 3,465 17,086 29,008 2023 5,028 14,233 2024 4,706 Total $247,025 Outstanding liabilities for accident year 2014 and prior, net of reinsurance $218 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $253,352 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 (unaudited) 2 (unaudited) 3 (unaudited) 4 (unaudited) 5 (unaudited) 6 (unaudited) 7 (unaudited) 8 (unaudited) 9 (unaudited) 10 % 21 % 14 % 13 % 8 % 6 % 5 % 1 % 1 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Reconciliation December 31, ($ in thousands) 2024 Net outstanding liabilities International - Property $ 110,676 International - Casualty 524,133 International - Specialty 410,406 Bermuda - Property 312,638 Bermuda - Casualty 709,672 Bermuda - Specialty 253,352 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance 2,320,877 Reinsurance recoverable on unpaid claims International - Property 63,625 International - Casualty 608,333 International - Specialty 210,968 Bermuda - Property 44,045 Bermuda - Casualty 161,778 Bermuda - Specialty 82,291 Total reinsurance recoverable on unpaid claims 1,171,040 Other insurance lines 3,302 Unallocated loss adjustment expenses 37,272 40,574 Total gross liability for unpaid losses and loss adjustment expenses $ 3,532,491

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company has determined its reportable business segments based on the information used by management in assessing performance and allocating resources to underwriting operations and has identified two reportable business segments - International and Bermuda. Each of the Company's identified reportable segments has a Chief Executive Officer who is responsible for the overall profitability of their segment and who regularly reports and is directly accountable to the chief operating decision maker ("CODM"): the Chief Executive Officer of the consolidated group. The CODM's responsibilities include providing leadership to all levels of employees; developing culture, values, and ethos; setting the Company's strategy, vision and direction; and overall responsibility for the success and profitability of the Company, including evaluating segment performance. The CODM evaluates reportable segment performance based on the segments' respective underwriting income or loss. Underwriting income or loss is calculated as net premiums earned less losses and loss adjustment expenses, acquisition costs, and other underwriting expenses, net of third party fee income. General and administrative expenses not incurred by the reportable segments are included in corporate and other expenses as part of the reconciliation of net underwriting income or loss to net income or loss attributable to common shareholders. As the Company does not manage its assets by reportable segment, investment income and assets are not allocated to reportable segments. The Company's core business is underwriting and its underwriting results are reflected in its reportable segments: (1) International, which is comprised of property, casualty and specialty insurance and reinsurance classes of business originating from the Company’s London, Dublin, and Hamilton Select operations; and (2) Bermuda, which is comprised of property, casualty, and specialty insurance and reinsurance classes of business originating from Hamilton Re, Bermuda and Hamilton Re US and subsidiaries. The Company considers many factors, including the nature of each segment’s products, client types, production sources, distribution methods and the regulatory environment, in determining the aggregated operating segments. Corporate includes net realized and unrealized gains (losses) on investments, net investment income (loss), other income (loss) not incurred by the reportable segments, net foreign exchange gains (losses), general and administrative expenses not incurred by the reportable segments, impairment of goodwill, amortization of intangible assets, interest expense, and income tax expense (benefit). ($ in thousands) For the Year Ended December 31, 2024 International Bermuda Corporate Total Gross premiums written $ 1,308,460 $ 1,114,122 $ — $ 2,422,582 Net premiums written $ 969,605 $ 951,564 $ — $ 1,921,169 Net premiums earned $ 886,934 $ 847,795 $ — $ 1,734,729 Third party fee income 16,317 7,435 — 23,752 Losses and loss adjustment expenses 498,023 512,150 — 1,010,173 Acquisition costs 216,971 171,960 — 388,931 Other underwriting expenses 148,824 61,189 — 210,013 Underwriting income (loss) $ 39,433 $ 109,931 $ — $ 149,364 Net realized and unrealized gains (losses) on investments 511,407 511,407 Net investment income (loss) 63,267 63,267 Net foreign exchange gains (losses) (3,231) (3,231) Corporate expenses (61,111) (61,111) Amortization of intangible assets (15,520) (15,520) Interest expense (22,616) (22,616) Income (loss) before income tax 621,560 Income tax (expense) benefit (8,402) (8,402) Net income (loss) 613,158 Net income (loss) attributable to non-controlling interest 212,729 212,729 Net income (loss) attributable to common shareholders $ 400,429 Key Ratios Attritional loss ratio - current year 53.5 % 52.7 % 53.1 % Attritional loss ratio - prior year development (0.4) % 0.5 % 0.0 % Catastrophe loss ratio - current year 3.9 % 8.9 % 6.3 % Catastrophe loss ratio - prior year development (0.8) % (1.7) % (1.2) % Loss and loss adjustment expense ratio 56.2 % 60.4 % 58.2 % Acquisition cost ratio 24.5 % 20.3 % 22.4 % Other underwriting expense ratio 14.9 % 6.3 % 10.7 % Combined ratio 95.6 % 87.0 % 91.3 % ($ in thousands) For the Year Ended December 31, 2023 International Bermuda Corporate Total Gross premiums written $ 1,105,522 $ 845,516 $ — $ 1,951,038 Net premiums written $ 770,399 $ 710,039 $ — $ 1,480,438 Net premiums earned $ 703,508 $ 615,025 $ — $ 1,318,533 Third party fee income 9,685 8,549 — 18,234 Losses and loss adjustment expenses 362,137 352,466 — 714,603 Acquisition costs 186,698 122,450 — 309,148 Other underwriting expenses 127,402 55,763 — 183,165 Underwriting income (loss) $ 36,956 $ 92,895 $ — $ 129,851 Net realized and unrealized gains (losses) on investments 209,610 209,610 Net investment income (loss) 30,456 30,456 Other income (loss), excluding third party fee income 397 397 Net foreign exchange gains (losses) (6,185) (6,185) Corporate expenses (76,691) (76,691) Amortization of intangible assets (10,783) (10,783) Interest expense (21,434) (21,434) Income (loss) before income tax 255,221 Income tax (expense) benefit 25,066 25,066 Net income (loss) 280,287 Net income (loss) attributable to non-controlling interest 21,560 21,560 Net income (loss) attributable to common shareholders $ 258,727 Key Ratios Attritional loss ratio - current year 53.2 % 51.1 % 52.2 % Attritional loss ratio - prior year development (3.5) % 2.3 % (0.8) % Catastrophe loss ratio - current year 1.5 % 5.1 % 3.2 % Catastrophe loss ratio - prior year development 0.3 % (1.2) % (0.4) % Loss and loss adjustment expense ratio 51.5 % 57.3 % 54.2 % Acquisition cost ratio 26.5 % 19.9 % 23.4 % Other underwriting expense ratio 16.7 % 7.7 % 12.5 % Combined ratio 94.7 % 84.9 % 90.1 % ($ in thousands) For the Year Ended December 31, 2022 International Bermuda Corporate Total Gross premiums written $ 933,241 $ 713,432 $ — $ 1,646,673 Net premiums written $ 635,773 $ 586,091 $ — $ 1,221,864 Net premiums earned $ 623,047 $ 520,667 $ — $ 1,143,714 Third party fee income 11,430 201 — 11,631 Losses and loss adjustment expenses 335,484 422,849 — 758,333 Acquisition costs 170,571 100,618 — 271,189 Other underwriting expenses 108,239 49,301 — 157,540 Underwriting income (loss) $ 20,183 $ (51,900) $ — $ (31,717) Net realized and unrealized gains (losses) on investments 93,348 93,348 Net investment income (loss) (21,487) (21,487) Other income (loss), excluding third party fee income (315) (315) Net foreign exchange gains (losses) 6,137 6,137 Corporate expenses (20,142) (20,142) Impairment of goodwill (24,082) (24,082) Amortization of intangible assets (12,832) (12,832) Interest expense (15,741) (15,741) Income (loss) before income tax (26,831) Income tax (expense) benefit (3,104) (3,104) Net income (loss) (29,935) Net income (loss) attributable to non-controlling interest 68,064 68,064 Net income (loss) attributable to common shareholders $ (97,999) Key Ratios Attritional loss ratio - current year 50.9 % 52.9 % 51.8 % Attritional loss ratio - prior year development (4.8) % 5.1 % (0.3) % Catastrophe loss ratio - current year 7.2 % 27.1 % 16.3 % Catastrophe loss ratio - prior year development 0.5 % (3.9) % (1.5) % Loss and loss adjustment expense ratio 53.8 % 81.2 % 66.3 % Acquisition cost ratio 27.4 % 19.3 % 23.7 % Other underwriting expense ratio 15.5 % 9.4 % 12.8 % Combined ratio 96.7 % 109.9 % 102.8 % The following table presents gross premiums written by the geographical location of the Company's subsidiaries: Years Ended December 31, ($ in thousands) 2024 2023 2022 International Lloyd's of London $ 792,830 $ 677,415 $ 561,432 Ireland 399,061 349,896 345,088 U.S. 116,569 78,211 26,721 Total International 1,308,460 1,105,522 933,241 Bermuda 1,114,122 845,516 713,432 Total $ 2,422,582 $ 1,951,038 $ 1,646,673

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt and Credit Facilities	Debt and Credit Facilities Debt On June 23, 2022, Hamilton Group renewed its unsecured $150 million term loan credit arrangement, as amended from time to time (the "Facility"), with various lenders as arranged by Wells Fargo Securities, LLC. All or a portion of the loan issued under the Facility bears interest at either (a) the Base Rate plus the Applicable Margin or (b) the Adjusted Term Secured Overnight Financing Rate ("SOFR") plus the Applicable Margin, at Hamilton Group's discretion. In the event of default, an additional 2% interest in excess of (a) or (b) will be levied, not to exceed the highest rate permissible under applicable law, and certain types of loans may not be available for borrowing by Hamilton Group under the Facility. The Facility matures on June 23, 2025, unless accelerated pursuant to the terms of the Facility, and it contains usual and customary representations, warranties, conditions and covenants for bank loan facilities of this type. The Facility also contains certain financial covenants which cap the ratio of consolidated debt to capital and require that Hamilton Group maintain a certain minimum consolidated net worth. The net worth requirement is recalculated effective as of the end of each fiscal quarter. As of December 31, 2024, the Company was in compliance with all covenants . The following table presents the gross outstanding loan balance, loan fair value and unamortized loan issuance costs: December 31, ($ in thousands) 2024 2023 Outstanding loan balance $ 150,000 $ 150,000 Loan fair value 150,463 150,981 Unamortized loan issuance costs $ 55 $ 170 Debt issuance costs are amortized over the period during which the Facility is outstanding, as an offset to net investment income (loss). The Company amortized debt issuance costs of $0.1 million or less in each of the years ended December 31, 2024, 2023 and 2022. The Company’s debt is classified as Level 3 within the fair value hierarchy because it is valued using an income approach, which utilizes a discounted cash flow technique that considers the credit profile of the Company. Credit Facilities The Company has several available letter of credit facilities and a revolving loan facility provided by commercial banks. The letter of credit facilities are utilized to provide collateral to reinsureds of Hamilton Re and its affiliates to the extent required under insurance and reinsurance agreements and to support capital requirements at Lloyd’s. On December 5, 2018 and December 27, 2018, Hamilton Re entered into a Master Agreement for Issuance of Payment Instruments and a Facility Letter for Issuance of Payment Instruments respectively, with CitiBank Europe Plc ("CitiBank Europe"), under which CitiBank Europe agreed to provide an uncommitted secured letter of credit facility for the issuance of standby letters of credit or similar instruments in multiple currencies. On November 15, 2024, letter of credit capacity under this facility was increased to $250 million. At all times during which it is a party to the facility, Hamilton Re is obligated to pledge to CitiBank Europe cash and/or securities with a value that equals or exceeds the aggregate face amount of its then-outstanding letters of credit. The Master Agreement contains events of default customary for facilities of this type. In the facility letter, Hamilton Re makes representations and warranties that are customary for facilities of this type and agrees that it will comply with certain informational and other undertakings. On June 23, 2022, Hamilton Group and Hamilton Re amended and restated their unsecured credit agreement with a syndication of lenders (the "Unsecured Facility"). Under the Unsecured Facility, the lenders have agreed to provide up to an aggregate of $415 million of letter of credit capacity for Hamilton Re, up to $150 million of which may be utilized for revolving loans to be issued to Hamilton Group. At December 31, 2024, there were no loan amounts outstanding under this facility. Margin rates reflect contractually agreed rates, which are based on Hamilton Re’s current Financial Strength Rating as assigned by A.M. Best. As of April 30, 2024, letters of credit issued under the facility bear interest at a rate of 137.5 basis points (previously 150 basis points), while revolving loans if issued are subject to a fee of SOFR plus a margin of 162.5 basis points (previously 185 basis points). To the extent such loans are issued, the available letter of credit capacity shall decrease proportionally, such that the aggregate credit exposure for the lenders under the credit agreement is $415 million. Amounts unutilized under the facility are subject to a fee of 17.5 basis points (previously 22.5 basis points). Capacity is provided by Wells Fargo, National Association, Truist Bank, BMO Harris Bank N.A., Commerzbank AG, New York Branch, HSBC Bank USA, N. A., and Barclays Bank PLC. Unless renewed or otherwise terminated in accordance with its terms, the Unsecured Facility is scheduled to terminate on June 23, 2025. On August 12, 2024, Hamilton Re and HIDAC amended their committed letter of credit facility agreement with Bank of Montreal ("BMO"), with Hamilton Group as guarantor, under which BMO agreed to make available a secured letter of credit facility of $50 million for a term that will expire on August 13, 2025. The facility bears a fee of 40 basis points for letters of credit issued and 15 basis points on any unutilized portion of the facility. Effective October 25, 2024, Hamilton Re amended its letter of credit facility agreement with UBS AG ("UBS") under which UBS and certain of its affiliates agreed to make available to Hamilton Re a secured letter of credit facility of $100 million for a term that will expire on October 25, 2025. The facility bears a fee of 140 basis points on the total available capacity. In addition, on October 28, 2024, Hamilton Re amended the unsecured letter of credit facility agreement that it utilizes to provide Funds at Lloyd's ("FAL") ("FAL LOC Facility") to support the FAL requirements of Syndicate 4000. Capacity is provided by Barclays Bank PLC, ING Bank N.V., London Branch, and Bank of Montreal, London Branch. The FAL LOC Facility of $230 million was renewed for an additional one year term that expires on October 28, 2025. The facility bears a fee of 162.5 basis points on the borrowed amount. The Company’s obligations under its credit facilities require Hamilton Group, Hamilton Re and the other parties thereto to comply with various financial and reporting covenants. All applicable entities were in compliance with all such covenants at December 31, 2024. Certain of the Company's credit facilities are secured by pledged interests in the TS Hamilton Fund, the Company's fixed income security portfolio, or cash. The Company’s credit facilities and associated securities pledged, were as follows: ($ in thousands) December 31, Available letter of credit and revolving loan facilities - commitments $ 1,045,000 Available letter of credit and revolving loan facilities - in use 789,993 Security pledged under letter of credit and revolving loan facilities: Pledged interests in TS Hamilton Fund $ 230,833 Pledged interests in fixed income portfolio 296,464 Cash 4,713

Share Capital

Share Capital	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Share Capital	Share Capital Authorized and Issued Hamilton Group’s share capital is comprised as follows: ($ in thousands, except share information) Authorized: Common shares of $0.01 par value each (2024 and 2023: 150,000,000) December 31, Issued, outstanding and fully paid: 2024 2023 Class A common shares (2024: 17,820,078 and 2023: 28,644,807) $ 178 $ 286 Class B common shares (2024: 64,271,249 and 2023: 56,036,067) 643 560 Class C common shares (2024: 19,375,670 and 2023: 25,544,229) 194 255 Total $ 1,015 $ 1,101 The following is a summary of the activity related to common shares authorized: Class A Class B Class C Unclassified Total Balance - December 31, 2021 53,793,690 46,898,612 34,307,698 — 135,000,000 Share class conversions 200,000 3,582,072 (3,782,072) — — Balance - December 31, 2022 53,993,690 50,480,684 30,525,626 — 135,000,000 Increase in authorized share capital — 15,000,000 — — 15,000,000 Share class conversions (25,348,883) 6,856,668 (4,981,397) 23,473,612 — Balance - December 31, 2023 28,644,807 72,337,352 25,544,229 23,473,612 150,000,000 Share class conversions (1,700,000) 7,868,559 (6,168,559) — — Balance - December 31, 2024 26,944,807 80,205,911 19,375,670 23,473,612 150,000,000 The following is a summary of the activity related to common shares issued and outstanding: Class A Class B Class C Total Balance - December 31, 2021 30,320,078 37,935,266 34,307,698 102,563,042 Share class conversions 200,000 3,582,072 (3,782,072) — Vesting of awards — 580,935 — 580,935 Employee and director share purchases — 22,750 — 22,750 Director share awards granted — 25,805 — 25,805 Share repurchases — (104,673) — (104,673) Balance - December 31, 2022 30,520,078 42,042,155 30,525,626 103,087,859 Share class conversions (1,875,271) 6,856,668 (4,981,397) — IPO shares issued — 6,250,000 — 6,250,000 Vesting of awards — 735,013 — 735,013 Exercise of warrants — 271,097 — 271,097 Director share awards granted — 44,892 — 44,892 Share repurchases — (163,758) — (163,758) Balance - December 31, 2023 28,644,807 56,036,067 25,544,229 110,225,103 Share class conversions (1,700,000) 7,868,559 (6,168,559) — Vesting of awards — 2,291,495 — 2,291,495 Exercise of warrants — 245,779 — 245,779 Director share awards granted — 20,383 — 20,383 Share repurchases (9,124,729) (2,191,034) — (11,315,763) Balance - December 31, 2024 17,820,078 64,271,249 19,375,670 101,466,997 On May 8, 2024, the Company entered into an agreement to repurchase 9.1 million Class A common shares at $12.00 per share. The total purchase price was $109.5 million. The common shares purchased by the Company were cancelled following the repurchase transaction. On August 7, 2024, the Board of Directors authorized a repurchase of the Company's common shares in the aggregate amount of $150.0 million (the "Authorization"), under which the Company may repurchase shares through open market repurchases and/or privately negotiated transactions. The Authorization will expire when the Company has repurchased the full value of shares authorized, unless terminated earlier by the Board of Directors. For the year ended December 31, 2024, 1.5 million Class B common shares at an aggregate cost of $28.1 million and an average price of $18.89 per common share were repurchased and cancelled and $121.9 million remained available for purchase under the Authorization. In general, holders of Class A common shares and Class B common shares have one vote for each common share held while the Class C common shares have no voting rights, except as required by law. However, each holder of Class A common shares and Class B common shares is limited to voting (directly, indirectly or constructively, as determined for U.S. federal income tax purposes) that number of common shares equal to 9.5% of the total combined voting power of all classes of shares of the Company (or, in the case of a class vote by the holders of our Class B common shares, such as in respect of the election or removal of directors other than for directors who are appointed by certain shareholders pursuant to the Shareholders Agreement and our Bye-laws, a maximum of 14.92% of the total combined voting power, calculated by multiplying (a) 9.5% and (b) the quotient of dividing (x) the total number of directors by (y) the number of directors elected by holders of Class B common shares). In addition, the Board of Directors may, in its absolute discretion, limit a shareholder’s voting rights when it deems it appropriate to do so to avoid certain material adverse tax, legal or regulatory consequences to the Company, any subsidiary of the Company, or any direct or indirect shareholder or its affiliates. The Company Bye-laws provide for the automatic redesignation of shares upon any transfer, whether or not for value, from (i) Class A common shares to Class B common shares and from (ii) Class C common shares to Class B common shares. Upon notice from a Class A Member to the Company that certain Class B common shares are held by a Class A Member or a Permitted Transferee thereof, if so requested by the Class A Member and upon approval by a Simple Majority of the Board, such Class B common shares shall convert automatically into the same number of Class A common shares. The number of authorized and issued Class B common shares shall be reduced by the aggregate number of such issued Class B common shares so converted and the number of authorized and issued Class A common shares shall be correspondingly increased by the same amount. Upon notice from a Class A Member and/or Class B Member to the Company and upon approval by a Simple Majority of the Board, such consent not to be unreasonably withheld or unduly delayed, such Class A common shares and/or Class B common shares shall be redesignated as Class C common shares. In such instance, the authorized and issued number of Class A common shares and/or Class B common shares shall be reduced by the aggregate number of such shares so converted and the number of Class C common shares shall be correspondingly increased by the same amount. Upon notice from a Class C Member to the Company and upon approval of a Simple Majority of the Board, such consent not to be unreasonably withheld or unduly delayed, such Class C common shares shall be redesignated Class B common shares. In such instance, the authorized and issued number of Class C common shares shall be reduced by the aggregate number of such Class C common shares so converted and the number of authorized and issued Class B common shares shall be correspondingly increased by the same amount. On September 13, 2024, 1.7 million Class A common shares were converted into Class C common shares at the request of the Class A Members and as approved by the Board. During the year ended December 31, 2024, 7.9 million Class C common shares were converted into Class B common shares at the request of the respective Class C Members and as approved by the Board.

Share Incentive Plans

Share Incentive Plans	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Share Incentive Plans	Share Incentive Plans The Company is authorized to issue restricted stock units ("RSUs"), performance stock units ("PSUs"), restricted stock awards ("RSAs"), options (including incentive stock options and non-qualified stock options), stock appreciation rights, stock bonus awards, other stock based awards, or any combination thereof to its employees and directors under the 2023 Equity Incentive Plan, which was adopted by the Board of Directors and approved by the shareholders in connection with the Company's IPO. The 2023 Equity Incentive Plan became effective upon the completion of the IPO and replaced the 2013 Equity Incentive Plan. No new awards will be granted under the 2013 Equity Incentive Plan. The total number of Class B common shares available for issuance under the 2023 Equity Incentive Plan may be increased on the first day of each fiscal year for a period of not more than nine years, commencing on the first day of the second fiscal year following the date on which the 2023 Equity Incentive Plan is adopted in an amount equal to the lesser of (i) two percent (2%) of the outstanding Class B common shares on the last day of the immediately preceding fiscal year, and (ii) such number of Class B common shares as determined by the Company's Board of Directors (or a committee thereof) in its discretion. As of December 31, 2024, 6,690,374 Class B common shares are available for issuance of awards of all types. Separately, the Value Appreciation Pool ("VAP") is a long-term incentive compensation plan that rewarded employees with 10% of the increase in the multiple of the Company's estimated fair market value to GAAP shareholders' equity between the December 1, 2020 VAP inception date and the Company's Initial Public Offering on November 10, 2023. The following table presents the compensation expense recognized relating to each award type: Years Ended December 31, ($ in thousands) 2024 2023 2022 Share based compensation expense: RSUs $ 12,933 $ 11,358 $ 10,884 VAP RSUs 9,210 30,352 — PSUs 8,241 2,668 (100) Total share based compensation expense: 30,384 44,378 10,784 Tax benefit (1,750) (1,251) (1,074) Share based compensation expense, net of taxes: $ 28,634 $ 43,127 $ 9,710 The following table presents the unrecognized compensation expense relating to each award type and the weighted-average period in years over which it is expected to be recognized. December 31, 2024 ($ in thousands, except for weighted-average recognition period) Unrecognized Share Based Compensation Expense Weighted-Average Recognition Period Unrecognized share based compensation expense: RSUs $ 9,998 1.2 VAP RSUs 3,134 0.9 PSUs 9,666 1.7 Total unrecognized share based compensation expense: $ 22,798 The aggregate fair value of vested awards for the years ended December 31, 2024, 2023 and 2022 was $38.6 million, $10.1 million, and $8.6 million, respectively. Restricted Stock Units The grant date fair value of restricted stock awards is established at the fair market value of the Company’s Class B common shares on the date of grant. During the years ended December 31, 2024, 2023 and 2022 , the Company granted employees RSUs with a total estimated fair valu e of $14.5 million, $14.2 million, and $11.8 million, respectively, which generally vest over a three-year period. During the year ended December 31, 2024, the Company granted non-employee directors RSUs with a total fair value of $1.4 million , which vest over a one -year period. The following table presents a roll forward of the Company’s RSUs based on expected vesting: Year Ended December 31, 2024 Number of RSUs Weighted-Average Grant Date Fair Value Balance, beginning of year 1,660,978 $14.06 Granted 1,078,711 $14.67 Vested (719,836) $13.94 Forfeited (65,457) $14.20 Balance, end of year 1,954,396 $14.43 Value Appreciation Pool Restricted Stock Units The VAP, which was granted by a then nonpublic company, was initially measured as a liability award at intrinsic value and no compensation cost was recorded over the period December 1, 2020 to March 31, 2023. On May 15, 2023, the Company became a public business entity and the VAP was remeasured at fair value. The fair value of the compensation cost was estimated at each reporting date and expensed over the period for which the employee is required to provide services in exchange for the award, with any changes recorded in compensation expense by a cumulative catch-up adjustment. The Company consummated an IPO of its Class B common shares and, on November 10, 2023, closed its first day of trading. In accordance with the Compensation Committee's decision that the VAP award would be settled in shares if triggered by an IPO, the VAP became subject to equity award accounting. The VAP RSUs vest in two tranches, subject to continued service: 50% on each of the first and second anniversaries of the November 10, 2023 trigger event. Participants who leave prior to vesting forfeit any previously unsettled portion of their awards. The Company recorded a compensation expense of $9.2 million and $34.5 million, for the years ended December 31, 2024 and 2023, respectively. Of the total expense recognized for the year ended December 31, 2023, $4.2 million was recorded as an adjustment to retained earnings in "Share compensation expense" in the second quarter of 2023. The following table presents a roll forward of the Company’s VAP RSUs based upon expected vesting: Year Ended December 31, 2024 Number of Weighted-Average Grant Date Fair Value Balance, beginning of year 3,147,507 $15.32 Vested (1,530,234) $15.32 Forfeited (88,464) $15.32 Balance, end of year 1,528,809 $15.32 Performance Stock Units During the year ended December 31, 2024, the Company granted PSUs that vest over three years and entitle participants to between 0-200% of the target award. Settlement of the PSUs is subject to achievement of defined performance metrics and to each participant's continued employment through each vesting date. During the years ended December 31, 2023 and 2022, the Company granted PSUs that vest on the third January 1st following their grant dates and entitle participants to between 0-200% of the target award. All other significant terms and conditions are consistent with the PSUs described above. Prior to August 7, 2024, the PSU performance payout calculation was subject to specified adjustments and was ultimately adjustable at the discretion of the Compensation Committee. The fair value of awards with performance conditions was remeasured at each reporting period with any changes in the expected outcome of the performance conditions recorded in compensation expense by a cumulative adjustment to apply the revised estimate. On August 7, 2024, the Compensation Committee formally ceded their discretion over the ultimate settlement of the PSUs and a grant date fair value of $15.47 was established for all PSU awards outstanding at that date. The following table presents a roll forward of the Company's PSUs based upon expected vesting: Year Ended December 31, 2024 Number of PSUs Balance, beginning of year 444,339 Granted 289,804 Vested (41,418) Change in performance factor 610,723 Balance, end of year 1,303,448 Warrants The Company's remaining outstanding and exercisable warrants were issued in 2014, had a 10-year term and were fully exercised during the year ended December 31, 2024. Each warrant entitled the holder to purchase one common share of Hamilton Group at an exercise price of $10.00. The following table presents a summary of the Company's outstanding and exercisable warrants: (Intrinsic value in $ in thousands) Year Ended December 31, 2024 Warrants Outstanding and Exercisable Number of Warrants Weighted-Average Exercise Price Weighted-Average Grant Date Fair Value Total Intrinsic Value Weighted-Average Remaining Contractual Term At December 31, 2022 1,152,500 $ 10.00 $ 4.44 $ 4,287 1.3 Exercised (342,500) $ 10.00 $ 4.27 $ 2,398 At December 31, 2023 810,000 $ 10.00 $ 4.52 $ 4,010 0.3 Exercised (810,000) $ 10.00 $ 4.52 $ 4,140 At December 31, 2024 — $ — $ — $ — 0.0 Board of Directors' Fees The Company settled a portion of its board of directors fees in shares at each director's option. Expense relating to stock-settled directors' fees for the years ended December 31, 2024, 2023 and 2022 was $0.6 million, $0.6 million, and $0.7 million, respectively.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of basic and diluted income (loss) per common share: Years Ended December 31, ($ in thousands, except share and per share information) 2024 2023 2022 Numerator: Net income (loss) attributable to common shareholders $ 400,429 $ 258,727 $ (97,999) Denominator: Weighted average common shares outstanding - basic 105,133 104,563 103,062 Effect of dilutive securities 3,968 1,640 — Weighted average common shares outstanding - diluted 109,101 106,203 103,062 Basic income (loss) per share attributable to common shareholders $ 3.81 $ 2.47 $ (0.95) Diluted income (loss) per share attributable to common shareholders $ 3.67 $ 2.44 $ (0.95)

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Hamilton Group and its Bermuda domiciled subsidiaries were not subject to income tax in Bermuda in 2023 and prior. On December 27, 2023, Bermuda enacted a 15% corporate income tax that generally became effective on January 1, 2025. The legislation defers the effective date until 2030 for Bermuda companies that meet certain requirements. Hamilton Group expects to meet the requirements to remain exempt until 2030. The legislation includes a provision referred to as the economic transition adjustment, which is intended to provide a fair and equitable transition into the tax regime. As of December 31, 2024, the Company holds a deferred tax asset of $35.4 million relating to economic transition adjustment on its balance sheet, which it expects to utilize to reduce future taxes paid. The Company expects to incur increased taxes beginning in 2030. Hamilton Group has global subsidiaries and branches that are subject to tax in the jurisdictions in which they operate. The jurisdictions in which Hamilton Group’s subsidiaries and branches are currently subject to tax are the United Kingdom, Ireland and the United States. The Company and some of its subsidiaries file income tax returns in the U.S. federal jurisdiction, various U.S. states, and certain foreign jurisdictions. Income (loss) before taxes by tax jurisdiction is as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Jurisdiction Domestic: Bermuda $ 581,915 $ 247,113 $ 66,823 Foreign: United States 9,122 (2,263) (23,540) United Kingdom 32,249 12,362 (67,213) Ireland (1,726) (1,991) (2,901) Income (loss) before income tax $ 621,560 $ 255,221 $ (26,831) Income tax expense (benefit) consists of the following components: Years Ended December 31, ($ in thousands) 2024 2023 2022 Current income tax expense (benefit) Bermuda $ 9,276 $ 10,376 $ 2,625 United States 652 537 1,818 United Kingdom 91 61 48 Ireland (111) 92 (122) Total current tax expense (benefit) 9,908 11,066 4,369 Deferred income tax expense (benefit) Bermuda (375) (35,063) — United States — — 705 United Kingdom (1,027) (1,087) (1,927) Ireland (104) 18 (43) Total deferred tax expense (benefit) (1,506) (36,132) (1,265) Total income tax expense (benefit) $ 8,402 $ (25,066) $ 3,104 The following table presents a reconciliation of taxes calculated using the 0% Bermudian statutory rate (the tax rate at which the majority of Hamilton Group's worldwide operations are taxed) to the income tax expense (benefit) on pre-tax income (loss): Years Ended December 31, ($ in thousands) 2024 2023 2022 Expected tax provision at Bermuda statutory tax rate of 0% $ — $ — $ — Permanent differences: Taxes on earnings subject to rate other than Bermuda statutory rate 9,762 2,182 (18,077) Change in valuation allowance (12,496) (3,567) 17,060 Impairment of goodwill — — 4,161 Other permanent adjustments (318) (42) (112) Other prior year adjustments 2,234 376 28 Tax rate changes — 273 (2,655) Withholding tax 9,381 10,377 2,625 Bermuda economic transition adjustment — (35,063) — State income tax (161) 398 74 Total income tax expense (benefit): $ 8,402 $ (25,066) $ 3,104 Net income tax (refunds) payments, primarily comprised of withholding taxes on investment income from TS Hamilton Fund, totaled $10.7 million, $4.2 million and $10.0 million for the years ended December 31, 2024, 2023 and 2022, respectively. Deferred tax assets and liabilities are valued at the tax rate at which they are expected to be realized. In June 2021, the U.K. enacted a tax rate of 25% with an effective date of April 1, 2023, an increase from the previous corporation tax rate of 19%. Accordingly, for the year ended November 30, 2021, the Company revalued all of its U.K. deferred tax assets and liabilities that were expected to reverse after December 31, 2023. Revaluations of U.K. deferred tax assets and liabilities were recognized until January 1, 2024, when both the current and deferred tax rates were 25%. The revaluation of the deferred tax assets resulted in a tax expense (benefit) of $0.0 million, $0.3 million and $(2.7) million for the years ended December 31, 2024, 2023 and 2022, respectively. The financial statement impact of the rate changes were offset in each period by a valuation allowance, resulting in a related net tax expense (benefit) after valuation allowance of $Nil, $0.1 million, and $(0.2) million for the years ended December 31, 2024, 2023 and 2022, respectively. Deferred taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts for tax purposes. The following table presents Hamilton Group’s significant deferred tax assets and liabilities: December 31, ($ in thousands) 2024 2023 Deferred tax assets: U.K. net operating loss carryforwards $ 45,590 $ 50,845 U.S. net operating loss carryforwards 3,255 7,121 Ireland net operating loss carryforwards 218 275 Bermuda intangible assets 28,875 28,500 Reserve for losses and loss adjustment expenses 9,198 7,935 Unearned premium reserve 5,486 4,384 Share based compensation 5,213 7,524 Foreign tax credit 1,949 925 Capital loss carryforward 1,733 419 U.K. deferred interest 685 5,278 Deferred acquisition costs 547 (1,540) Loss portfolio transfer 263 2,356 Other 2,763 1,609 Total deferred tax assets 105,775 115,631 Deferred tax liabilities: U.K. intangible assets (14,233) (15,364) Fixed assets (3,520) (2,573) Lloyd's deferred taxable income (3,340) — Other (446) (2,468) Total deferred tax liabilities (21,539) (20,405) Net deferred tax asset (liability) before valuation allowance 84,236 95,226 Valuation allowance (63,032) (75,528) Net deferred tax asset (liability) $ 21,204 $ 19,698 Hamilton Group records a valuation allowance against deferred tax assets if it becomes more likely than not that all or a portion of a deferred tax asset will not be realized. Changes in valuation allowances from period to period are included in income tax expense (benefit) in the period of change. When evaluating the Company’s ability to realize the benefit of its deferred tax assets and liabilities, the Company considers the relevant impact of all available positive and negative evidence, including historical operating results and forecasts of future taxable income. A significant piece of objectively verifiable negative evidence considered in the Company’s evaluation is a three-year cumulative pre-tax loss. Based on all available evidence, management has concluded that a valuation allowance of $63.0 million should be recorded against all deferred tax assets in the U.K., the U.S. and Ireland, net of any reversing tax liabilities, as of December 31, 2024. Future realization of the Company’s deferred tax asset will ultimately depend on the existence of objectively verifiable positive evidence including sufficient taxable income of the appropriate character (ordinary income versus capital gains) within the applicable carry-forward periods provided under the tax law. The Company had the following net operating loss carry-forwards, inclusive of cumulative currency translation adjustments: ($ in thousands) December 31, 2024 Tax jurisdiction Losses Carried Forward Tax Expiration Bermuda $ — $ — n/a Ireland 1,742 218 No expiry United States 15,501 3,255 2042-2044 United Kingdom $ 182,360 $ 45,590 No expiry Recognition of the benefit of a given tax position is based upon whether a company determines that it is more likely than not that a tax position will be sustained upon examination based upon the technical merits of the position. At December 31, 2024, the Company believes that it has no uncertain tax positions that, if challenged on technical merits, would cause a material effect on the Company's audited consolidated financial statements. Hamilton Group classifies all interest and penalties on income taxes as part of income tax expense (benefit). During the years ended December 31, 2024, 2023 and 2022, the Company did not recognize any interest income or expense. There was no accrued interest as of December 31, 2024. With few exceptions, Hamilton Group is no longer subject to tax examinations by U.S. federal or state examinations before 2021 or non-U.S. tax examinations before 2020.

Commitment and Contingencies

Commitment and Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Concentrations of Credit Risks Credit risk arises out of the failure of a counterparty to perform according to the terms of the contract. Instruments which potentially subject the Company to concentration of credit risk consist primarily of fixed maturity and short-term investments, cash and cash equivalents, premiums receivable and reinsurance balances recoverable. The Company limits the amount of credit exposure to any one financial institution and, except for the securities of the U.S. Government and U.S. Government related entities, none of the Company’s fixed maturity and short-term investments exceeded 10% of shareholders’ equity at December 31, 2024. The Company evaluates the financial condition of its reinsurers, whom primarily consist of highly rated reinsurers and may require collateralization of those recoverable balances. See Note 2g, Credit Loss Provisions and Note 7, Reinsurance , for further details. Operating Leases The Company leases office space under operating leases in Bermuda, the United States, the United Kingdom, and Ireland. These leases expire at various dates through 2030, with a weighted average lease term of 2.5 years. As a result of the Company's adoption of ASU 2016-02 Leases , the balance sheet reflects a $9.1 million and $6.9 million right of use asset in " Other assets Accounts payable and accrued expenses Future minimum lease payments under the leases are expected to be as follows: ($ in thousands) Minimum Lease Payments Year ended December 31, 2025 $ 2,431 2026 2,977 2027 2,703 2028 1,262 2029 647 Thereafter 118 Total undiscounted lease liabilities 10,138 Less: present value discount (966) Total recorded lease liability at present value $ 9,172 Lloyd's Capital Requirements Lloyd’s bases the capital funding requirements of the Company's corporate member, Hamilton Corporate Member Limited ("HCML"), on their latest approved Economic Capital Assessments which are determined by reference to their business plans, internal capital models, and actual performance, among other factors, as well as any other relevant corporate member obligations or receivables. Capital is in the form of Funds at Lloyd's ("FAL") which is generally available to settle the obligations of the corporate members. Syndicate 4000 is solely supported by HCML. The Company's operations consist of a managing agent, Hamilton Managing Agency Limited, which manages the affairs of Syndicate 4000 on behalf of HCML. The total available capital in support of the capital requirements for Syndicate 4000 is comprised of the following FAL: ($ in thousands) December 31, Unsecured LOC capacity $ 230,000 Fixed income securities 245,254 Cash 1,082 Total $ 476,336 Indemnifications In the ordinary course of its business, the Company may enter into contracts or agreements that contain indemnifications. Future events could occur that lead to the execution of these provisions against the Company. Management currently believes that the likelihood of such an event is remote. Litigation and Regulatory Matters The Company is subject to legal and regulatory investigations in the ordinary course of business. As at December 31, 2024, the Company was not a party to any material legal proceeding or investigation which is expected to have a material adverse effect on our results of operations, financial condition or liquidity.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Ada Capital Management Limited In 2020, the Company established ACML, an insurance agent authorized to underwrite on behalf of Ada Re, as more fully described in Note 1, Organization . The following tables summarize the impact of transactions with Ada Re: Years Ended December 31, ($ in thousands) 2024 2023 2022 Reinsurance premiums ceded $ (21,584) $ (19,524) $ (11,999) Net premiums earned (21,585) (21,744) (9,780) Other income (loss) 7,434 8,549 201 Losses and loss adjustment expenses 7,676 8,702 5,719 Acquisition costs 5,126 5,125 1,769 Net gain (loss) on related party reinsurance $ (1,349) $ 632 $ (2,091) December 31, ($ in thousands) 2024 2023 Paid losses recoverable $ 2,278 $ 4,319 Unpaid losses and loss adjustment expenses recoverable 13,262 11,149 Other assets 970 8,765 Reinsurance balances payable $ 1,670 $ 3,759

Statutory Requirements

Statutory Requirements	12 Months Ended
	Dec. 31, 2024
Insurance [Abstract]
Statutory Requirements	Statutory Requirements The Company is subject to the laws and statutory requirements of each jurisdiction in which the Company and its subsidiaries operate. These laws establish the Company's applicable minimum required statutory capital and surplus requirements and govern its ability to pay dividends. The minimum required statutory capital and surplus is the amount of statutory capital and surplus necessary to satisfy regulatory requirements based on the Company’s current operations. The difference between statutory financial statements and statements prepared in accordance with GAAP varies by jurisdiction; however, the primary difference is that statutory financial statements generally do not reflect goodwill or intangible assets. Group The Bermuda Monetary Authority ("BMA") is the Company's group supervisor and its group capital and solvency requirements determine the minimum capital thresholds that Hamilton Group must meet. Hamilton Group is dependent on dividends from its subsidiaries to pay its operating and financing expenses. The actual and minimum required statutory capital and surplus for the Company’s principal operating subsidiaries by regulatory jurisdiction were as follows: Bermuda (1) United Kingdom (2) Ireland (3) United States (4) As at December 31, ($ in thousands) 2024 2023 2024 2023 2024 2023 2024 2023 Required statutory capital and surplus $ 739,605 $ 579,916 $ 125,232 $ 129,995 $ 77,269 $ 68,643 $ 33,780 $ 23,410 Actual statutory capital and surplus $ 2,168,031 $ 1,882,833 $ 624,596 $ 539,016 $ 139,446 $ 127,082 $ 58,017 $ 53,988 ____________ (1) Minimum statutory capital and surplus at December 31, 2024 for the Bermuda operating subsidiary is required to be maintained at the greater of a minimum solvency margin ("MSM"), as disclosed in the table above, and the Enhanced Capital Requirement ("ECR"), where applicable. (2) Minimum statutory capital and surplus at December 31, 2024 for the U.K. operating entities is determined by reference to the entities' Solvency Capital Requirement and the Solvency II capital regime. U.K. operations are subject to Lloyd’s requirements where underwriting members hold acceptable FAL and/or Syndicates hold acceptable Funds In Syndicate ("FIS") for their own account, in support of the total actual statutory capital and surplus amount. Actual statutory capital and surplus is comprised of an Economic Capital Assessment ("ECA"), derived from an approved Solvency II basis Internal model, less any accumulated trading surpluses or plus any accumulated trading deficits, as calculated on a Solvency II basis. (3) The Company's Irish operations are subject to the Solvency II regime, which requires insurance companies to hold assets that cover at least the best estimate of insurance liabilities, a risk margin, plus a risk-based Solvency Capital Requirement designed to protect against extreme stress events. (4) Minimum statutory capital and surplus at December 31, 2024 for U.S. operating subsidiaries is determined with reference to the Company Action Level Risk-Based Capital requirements. The statutory net income (loss) for the Company’s principal operating subsidiaries by regulatory jurisdiction was as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Bermuda $ 432,769 $ 270,309 $ 1,993 United Kingdom 61,879 59,778 25,470 Ireland 8,069 (1,911) (32,331) United States $ (12,512) $ (13,250) $ (9,962) Bermuda Operations Hamilton Re is subject to the requirements of the Insurance Act 1978, amendments thereto and Related Regulations of Bermuda (the "Insurance Act"). As a Class 4 (re)insurer, Hamilton Re must maintain capital at the greater of their MSM and their ECR, which are established by reference to the Bermuda Solvency Capital Requirement ("BSCR") model. The Insurance Act also requires Hamilton Re to maintain certain measures of solvency and liquidity. Independent of the Insurance Act, the BMA has also established a target capital level ("TCL") for Class 4 (re)insurers, equal to 120% of their ECR. The TCL serves as an early warning tool for the BMA and failure to maintain statutory capital at least equal to the TCL will likely result in increased regulatory oversight. Hamilton Re's actual capital and surplus levels exceed the TCL at December 31, 2024. Hamilton Re's BSCR for the year ended December 31, 2024 must be filed with the BMA by April 30, 2025. As a result, the required statutory capital and surplus disclosed as of December 31, 2024 is based on the MSM. At December 31, 2024, the actual statutory capital and surplus of Hamilton Re was $2.2 billion and the MSM was $739.6 million. Hamilton Re received approval from the BMA to treat its investment in TS Hamilton Fund as a "Relevant Asset" for the purpose of computing its "Liquidity Ratio" (under which relevant assets must be maintained at not less than 75% of relevant liabilities) in respect of 2024. Hamilton Re is in compliance with the Liquidity Ratio at December 31, 2024. Under the Insurance Act, Hamilton Re is restricted as to the payment of dividends and/or distributions for amounts greater than 25% of the prior year’s statutory capital and surplus. In addition, before reducing its total statutory capital by 15% or more (as set out in its previous year's statutory financial statements), as a Class 4 Bermuda insurance subsidiary, Hamilton Re must apply to the BMA for permission to do so. For the year ended December 31, 2024, Hamilton Re had capacity to pay dividends of $470.7 million without prior approval under Bermuda law, of which $184.5 million of dividends were paid during the year. It is estimated that Hamilton Re will have capacity to pay dividends of $542.0 million in 2025. United Kingdom Operations A U.K. company’s ability to propose and pay dividends is dependent upon U.K. law and may require the approval of a local regulatory body where a minimum capital requirement applies. As discussed in Note 15, Commitments and Contingencies , Lloyd’s bases the capital funding requirements of the Company's corporate members on their latest approved Economic Capital Assessments. As of December 31, 2024, actual levels of solvency, liquidity, and capital were in compliance with the Lloyd's requirements. Following distributions received from Hamilton Syndicate 4000, profits arising in HCML are available for distribution subject to U.K. law. Profits arising in HMA, which is subject to Lloyds' oversight and regulation by both the Prudential Regulation Authority ("PRA") and the Financial Conduct Authority ("FCA"), are available for distribution subject to U.K. law and the preservation of a minimum capital requirement calculated with reference to Lloyd's capital tests. The PRA regulatory requirements impose no explicit restrictions on the U.K. subsidiaries' ability to pay a dividend, but the Company must notify the PRA 28 days prior to any proposed dividend payment. Dividends may only be distributed from profits available for distribution. It is estimated that Hamilton's U.K. subsidiaries will have capacity to pay dividends of $5.0 million in 2025. Ireland Operations HIDAC is regulated by the Central Bank of Ireland ("CBI") pursuant to the Insurance Acts 1909 to 2018 (as amended), the Central Bank Acts 1942 to 2018 and all statutory instruments relating to insurance made or adopted under the European Communities Acts 1972 to 2012, including the European Union (Insurance and Reinsurance) Regulations, 2015 (as amended) and the Solvency II regime. HIDAC is required to maintain the Minimum Capital Requirement ("MCR") and the Solvency Capital Requirement ("SCR") at all times. Capital requirements are calculated by reference to Solvency II definitions. If an entity falls below the MCR or SCR, the CBI is authorized to take action to restore the financial position of the subsidiary. HIDAC was at all times in compliance with these requirements for the year ended December 31, 2024. The amount of dividends that HIDAC is permitted to distribute is restricted to accumulated realized profits that have not been capitalized or distributed, less accumulated realized losses that have not been written off. The solvency and capital requirements must still be met subsequent to any distribution. As at December 31, 2024, HIDAC did not have retained profits available for distribution. United States Operations The Company’s U.S. insurance subsidiary is registered in Delaware and subject to restrictions on statutory net income and statutory surplus as determined in accordance with the relevant statutory accounting requirements established by the National Association of Insurance Commissioners, subject to state modifications thereof. They are also required to file annual statements with insurance regulatory authorities prepared in accordance with statutory accounting principles prescribed or permitted by such authorities. The U.S. insurance subsidiary is also generally required to maintain minimum levels of solvency and liquidity as determined by law and regulation, comply with regulatory capital requirements and licensing rules.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events California Wildfires The Company estimates that losses from the California wildfires, net of reinsurance and reinstatement premiums, will be in the range of $120 million to $150 million, based on an insured industry loss range of $35 billion to $45 billion. The level of uncertainty within the Company’s loss estimates is increased by the recent occurrence of the event and the preliminary nature of the information available, among other factors. The estimated losses for this event will be reported in the Company’s first quarter 2025 financial results.

Schedule I - Summary of Investm

Schedule I - Summary of Investments	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I - Summary of Investments	($ in thousands) December 31, 2024 Type of investment Cost or Fair Amount at which shown in the balance sheet Fixed maturities: Bonds: U.S. government treasuries $ 724,785 $ 711,103 $ 711,103 U.S. states, territories and municipalities 13,533 13,231 13,231 Non-U.S. sovereign governments and supranationals 70,435 67,527 67,527 Corporate 1,153,612 1,143,060 1,143,060 Residential mortgage-backed securities - Agency 288,760 272,611 272,611 Residential mortgage-backed securities - Non-agency 17,432 16,754 16,754 Commercial mortgage-backed securities - Non-agency 40,363 39,686 39,686 Other asset-backed securities 113,997 113,890 113,890 Total fixed maturities $ 2,422,917 2,377,862 2,377,862 Investments in Two Sigma Funds 939,381 939,381 Short-term investments 497,110 497,110 Total investments $ 3,814,353 $ 3,814,353

Schedule II - Parent Company

Schedule II - Parent Company	12 Months Ended
	Dec. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Schedule II - Parent Company	($ in thousands) December 31, 2024 December 31, 2023 Assets Cash and cash equivalents $ 13,624 $ 24,898 Investment in subsidiaries 2,358,386 2,077,926 Intercompany loan receivable 113,423 113,423 Interest receivable on intercompany loan 5,555 5,555 Other assets 5,036 4,821 Total assets $ 2,496,024 $ 2,226,623 Liabilities and Shareholders' Equity Liabilities Due to subsidiaries $ 11,785 $ 25,201 Term loan payable 149,945 149,830 Accounts payable and accrued liabilities 5,585 3,742 Total liabilities 167,315 178,773 Shareholders' Equity Common shares Class A 178 286 Class B 643 560 Class C 194 255 Additional paid-in capital 1,163,609 1,249,817 Accumulated other comprehensive loss (4,441) (4,441) Retained earnings 1,168,526 801,373 Total shareholders' equity 2,328,709 2,047,850 Total liabilities and shareholders' equity $ 2,496,024 $ 2,226,623 (1) The condensed financial information should be read in conjunction with the consolidated U.S. GAAP financial statements and notes thereto. Years Ended December 31, ($ in thousands) 2024 2023 2022 Revenues Intercompany loan interest $ 7,393 $ 7,296 $ 6,784 Net foreign exchange gains (losses) 8 24 (131) Other income (loss) 633 626 65 Total revenues 8,034 7,946 6,718 Expenses General and administrative expenses 55,011 52,280 20,524 Interest expense 16,352 15,500 9,858 Total expenses 71,363 67,780 30,382 Net income (loss) before equity in earnings of subsidiaries (63,329) (59,834) (23,664) Equity in earnings of subsidiaries 266,261 274,538 (211,335) Dividend income 197,497 44,023 137,000 Net income (loss) attributable to common shareholders $ 400,429 $ 258,727 $ (97,999) (1) The condensed financial information should be read in conjunction with the consolidated U.S. GAAP financial statements and notes thereto. Years Ended December 31, ($ in thousands) 2024 2023 2022 Cash flows provided by (used in) operating activities Net income (loss) attributable to common shareholders $ 400,429 $ 258,727 $ (97,999) Less: dividend income and equity in earnings of subsidiaries (463,758) (318,561) 74,335 Net income (loss) before equity in earnings of subsidiaries (63,329) (59,834) (23,664) Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities Other operating inflows (outflows) 18,927 63,035 7,033 Net cash provided by (used) in operating activities (44,402) 3,201 (16,631) Cash flows provided by (used in) investing activities Other investing inflows (outflows) (216) (146) (706) Dividends from subsidiaries 197,497 44,023 137,000 Capital contributions to subsidiaries (14,199) (113,350) (118,839) Net cash provided by (used in) investing activities 183,082 (69,473) 17,455 Cash flows provided by (used in) financing activities Other financing inflows (outflows) — — (345) Repurchase of common shares (150,350) (2,435) (1,518) Issuance of common shares 396 82,997 315 Net cash provided by (used in) financing activities (149,954) 80,562 (1,548) Net increase (decrease) in cash and cash equivalents (11,274) 14,290 (724) Cash and cash equivalents, beginning of period 24,898 10,608 11,332 Cash and cash equivalents, end of period $ 13,624 $ 24,898 $ 10,608 (1) The condensed financial information should be read in conjunction with the consolidated U.S. GAAP financial statements and notes thereto.

Schedule IV - Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Schedule IV - Reinsurance	December 31, 2024 Year Ended December 31, 2024 ($ in thousands) Deferred policy acquisition costs Future policy benefits, losses, claims and Unearned premiums Net premiums earned Total net realized and unrealized gains (losses) on investments and net investment income (loss) 1 Benefits, claims, losses, and settlement expenses Amortization of deferred policy acquisition costs Other operating expenses Net premiums written International $ 110,032 $ 1,957,679 $ 650,287 $ 886,934 $ 498,023 $ 216,971 $ 148,824 $ 969,605 Bermuda 98,953 1,574,812 471,990 847,795 512,150 171,960 61,189 951,564 Total $ 208,985 $ 3,532,491 $ 1,122,277 $ 1,734,729 $ 574,674 $ 1,010,173 $ 388,931 $ 210,013 $ 1,921,169 December 31, 2023 Year Ended December 31, 2023 ($ in thousands) Deferred policy acquisition costs Future policy benefits, losses, claims and Unearned premiums Net premiums earned Total net realized and unrealized gains (losses) on investments and net investment income (loss) 1 Benefits, claims, losses, and settlement expenses Amortization of deferred policy acquisition costs Other operating expenses Net premiums written International $ 84,983 $ 1,717,422 $ 547,629 $ 703,508 $ 362,137 $ 186,698 $ 127,402 $ 770,399 Bermuda 71,912 1,312,615 363,593 615,025 352,466 122,450 55,763 710,039 Total $ 156,895 $ 3,030,037 $ 911,222 $ 1,318,533 $ 239,855 $ 714,603 $ 309,148 $ 183,165 $ 1,480,438 December 31, 2022 Year Ended December 31, 2022 ($ in thousands) Deferred policy acquisition costs Future policy benefits, losses, claims and Unearned premiums Net premiums earned Total net realized and unrealized gains (losses) on investments and net investment income (loss) 1 Benefits, claims, losses, and settlement expenses Amortization of deferred policy acquisition costs Other operating expenses Net premiums written International $ 68,257 $ 1,582,410 $ 453,254 $ 623,047 $ 335,484 $ 170,571 $ 108,239 $ 635,773 Bermuda 46,890 1,273,865 264,934 520,667 422,849 100,618 49,301 586,091 Total $ 115,147 $ 2,856,275 $ 718,188 $ 1,143,714 $ 64,870 $ 758,333 $ 271,189 $ 157,540 $ 1,221,864 (1) The Company does not manage its investments by reportable segment and therefore total net realized and unrealized gains (losses) on investments and net investment income (loss) is not allocated to each reportable segment. ($ in thousands) Gross premiums earned Ceded to other companies Assumed from other companies Net Percentage of amount assumed to net Year ended December 31, 2024 Premiums earned $ 1,180,932 $ 476,798 $ 1,030,595 $ 1,734,729 59 % Year ended December 31, 2023 Premiums earned 1,016,762 440,607 742,378 1,318,533 56 % Year ended December 31, 2022 Premiums earned 886,488 413,046 670,272 1,143,714 59 %

Schedule V - Valuation and Qual

Schedule V - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule V - Valuation and Qualifying Accounts	($ in thousands) Opening Balance Additions Deductions Closing Balance December 31, 2024 Allowance for expected credit losses (1) $ 3,687 $ 782 $ (7) $ 4,462 December 31, 2023 Allowance for expected credit losses (1) 3,633 54 — 3,687 December 31, 2022 Allowance for expected credit losses (1) — 3,633 — 3,633 (1) Deducted from Premiums Receivable and Paid and Unpaid losses and loss adjustment expenses recoverable.

Schedule VI - Supplemental Insu

Schedule VI - Supplemental Insurance Information Concerning Property - Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Schedule VI - Supplemental Insurance Information Concerning Property - Casualty Insurance Operations	($ in thousands) Affiliation with Registrant Deferred policy Reserves for unpaid claims and claim adjustments expenses Discount, if any, deducted Unearned premiums Net premiums earned Total net realized and unrealized gains (losses) on investments and net investment income (loss) Consolidated subsidiaries Year ended December 31, 2024 $ 208,985 $ 3,532,491 $ — $ 1,122,277 $ 1,734,729 $ 574,674 Year ended December 31, 2023 156,895 3,030,037 — 911,222 1,318,533 240,066 Year ended December 31, 2022 115,147 2,856,275 — 718,188 1,143,714 71,861 Claims and claims adjustment expenses incurred related to ($ in thousands) Affiliation with Registrant Current Year Prior Year Amortization of deferred policy acquisition costs Paid claims and claim adjusted expenses Net premiums written Consolidated subsidiaries Year ended December 31, 2024 $ 1,030,612 $ (20,439) $ 388,931 $ 516,766 $ 1,921,169 Year ended December 31, 2023 730,220 (15,617) 309,148 564,798 1,480,438 Year ended December 31, 2022 778,936 (20,603) 271,189 377,186 1,221,864

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2024 shares	Dec. 31, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Adrian Daws [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On November 12, 2024, Mr. Adrian Daws, Chief Executive Officer Hamilton Global Specialty and an officer of the Company as defined in Rule 16a-1(f) of the Securities Exchange Act of 1934, adopted a Rule 10b5-1 trading arrangement for the sale of securities of the Company’s common shares. Mr. Daws’ Rule 10b5-1 trading arrangement, which has a plan end date of September 2, 2025, provides for the sale of up to 24,000 Class B common shares pursuant to the terms of the plan and is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act.
Name	Adrian Daws
Title	Chief Executive Officer Hamilton Global Specialty
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	November 12, 2024
Expiration Date	September 2, 2025
Arrangement Duration	294 days
Aggregate Available	24,000	24,000
Megan Graves [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On December 31, 2024, Ms. Megan Graves, Chief Executive Officer Hamilton Re, Ltd. and an officer of the Company as defined in Rule 16a-1(f) of the Securities Exchange Act of 1934, adopted a Rule 10b5-1 trading arrangement for the sale of securities of the Company’s common shares. Ms. Graves’ Rule trading arrangement, which has a plan end date of September 15, 2025, provides for the sale of up to 153,449 Class B common shares pursuant to the terms of the plan and is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act.
Name	Megan Graves
Title	Chief Executive Officer Hamilton Re, Ltd
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 31, 2024,
Expiration Date	September 15, 2025
Arrangement Duration	258 days
Aggregate Available	153,449	153,449

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Managing risk related to cybersecurity is a top priority for Hamilton, and we concentrate on assessing, identifying, and managing material risks associated with “cybersecurity threats,” as such term is defined in Item 106(a) of Regulation S-K. Both our management and Board of Directors recognize the importance of developing, implementing and maintaining appropriate cybersecurity measures and, as described below, are actively involved in cybersecurity and overall enterprise risk management. Cybersecurity Risk Management and Strategy We maintain a cybersecurity risk management program that is an important part of, and integrated into, our enterprise risk management function. The program is designed to assess, identify, manage and protect our information systems and data from unauthorized access, use, disclosure, disruption, modification or destruction. Identifying, assessing, and managing cybersecurity risk shares common methodologies, reporting channels and governance processes that apply across our risk management process, including other legal, compliance, strategic, operational and financial risk areas. We have implemented and maintain several safeguards and processes designed to identify cybersecurity risks and protect our information systems from cybersecurity threats. For example, we have implemented internal IT general controls such as data encryption, monitoring, data storage, identity / authentication controls and anti-malware and anti-virus solutions. We also routinely conduct internal IT audits around our cybersecurity posture as well as scenario-based cybersecurity risk assessments to ensure the right controls are in place to address identified risks. To protect against, detect, and respond to cybersecurity incidents, we, among other things, require our employees to undergo annual cybersecurity awareness training, monitor emerging laws and regulations related to data protection and information security and utilize a variety of multilayered technical tools to conduct proactive privacy and cybersecurity vulnerability assessments of our systems and applications, including scanning for and resolving open tickets. Additionally, to stay current on cybersecurity matters affecting the insurance industry and the marketplace in general, our Chief Information Security Officer & Global Head of IT Operations ("CISO") is an active member of the ISC2 organization and regularly participates in cybersecurity-focused conferences and forums, including serving on the Chief Information Security Officers Committee of Lloyd’s Market Association. Senior management, including our Chief Technology Officer & Chief Data Officer ("CTO") and our CISO, in coordination with our legal and compliance teams, are responsible for implementing our cybersecurity risk management program, as well as being involved in all aspects of incident response and breach management processes. These processes involve six stages: 1) detection, 2) analysis, 3) containment, 4) eradication, 5) recovery, and 6) notification. Security events and data incidents are evaluated for severity and impact on our operations, business, and data, and our response is prioritized accordingly. Our security team collaborates with stakeholders across the Company and forms strategies for addressing identified issues. This involves regularly testing, as part of our business continuity and disaster recovery strategies, our ability to restore our systems if they are impacted by a cybersecurity event or incident. In addition, as part of the foregoing processes, we annually engage third-party advisors to perform penetration tests against our infrastructure. As part of our risk management program, we also assess third-party risks, including risks posed by vendors, suppliers, and other business partners. Cybersecurity practices and risks are evaluated when selecting third-party service providers and when negotiating contractual provisions related to security and privacy, including information security audit rights. Specifically, before engaging new critical IT vendors, we require them to complete questionnaires concerning their IT and security processes, controls, and certifications. The responses in these questionnaires are then reviewed by our CISO and assessed against a checklist of minimum requirements that must be met for Hamilton to consider the service provider to be a vendor of trust whose services may be used by our organization. Thereafter, we annually follow up with approved vendors for updated certifications. As discussed above, we maintain an incident response plan to address cybersecurity incidents, which identifies key stakeholders, defines escalation processes and sets the thresholds above which our cybersecurity, legal and crisis management teams will inform senior management as well as our Board of Directors of a cybersecurity incident. For cybersecurity incidents below these crisis thresholds, we maintain subordinate incident response plans and standard operating procedures used by our security incident response team. Although we identify and respond to small security events and risks as a normal part of our cybersecurity risk management processes, to date, we are not aware of any direct or third-party cybersecurity incidents or otherwise identified any ongoing or previous risks from cybersecurity threats that have materially affected or are reasonably likely to materially affect Hamilton, including its business strategy, results of operations, or financial condition. While there have been no material cybersecurity incidents that have affected Hamilton for the period covered by this annual report, there can be no guarantee that (i) our policies and procedures will be properly followed in every instance or that those policies and procedures will be effective or (ii) that there will not be incidents in the future or that they will not materially affect us, including our strategy, results of operations, or financial condition. For a further discussion of the risks associated with cybersecurity threats see "Risk Factors — Risks Related to Our Business and Industry—We are subject to cybersecurity risks, including cyber-attacks, security breaches and other similar incidents with respect to our and our service providers’ information technology systems, which could result in regulatory scrutiny, legal liability or reputational harm, and we may incur increasing costs to minimize those risks” and "Risk Factors—Risks Related to Regulation — Our business is subject to cybersecurity, privacy and data protection laws, rules and regulations in the jurisdictions in which we operate, which can increase the cost of doing business, compliance risks and potential liability."
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	Managing risk related to cybersecurity is a top priority for Hamilton, and we concentrate on assessing, identifying, and managing material risks associated with “cybersecurity threats,” as such term is defined in Item 106(a) of Regulation S-K. Both our management and Board of Directors recognize the importance of developing, implementing and maintaining appropriate cybersecurity measures and, as described below, are actively involved in cybersecurity and overall enterprise risk management.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Cybersecurity Board Oversight and Governance Cybersecurity is important to our Board of Directors and management. On a quarterly basis, our CISO reports on cybersecurity matters to a risk committee comprised of a cross-functional management team (“Risk Committee”). He has reported on, among other things, cybersecurity risks and incidents, a business continuity and disaster recovery exercise, completed and ongoing cyber audits, security metrics and key performance indicators, penetration testing results and remediation progress, the status of Hamilton’s data governance program, and cyber insurance coverage. The Risk Committee escalates important issues identified in these reports to our Audit Committee, to which our full Board of Directors, while having ultimate responsibility for risk management oversight generally, has delegated primary oversight of cybersecurity risks. In addition to quarterly reports to the Risk Committee, senior management, including our CTO and CISO, are responsible for directly reporting to the Audit Committee on cybersecurity matters. This includes reporting, on a quarterly basis and as significant matters arise, about existing and new cybersecurity risks, how management is addressing and/or mitigating those risks, cybersecurity and data privacy incidents (if any), and status on key information security initiatives. The Audit Committee convenes prior to each quarterly Board meeting to discuss cybersecurity risks and other information security matters. The Audit Committee also periodically reviews our processes and policies for managing material risks from cybersecurity threats. Any material risks, cybersecurity incidents or other matters are subsequently discussed with the full Board at the Board meeting. The members of senior management involved in managing our material risks from cybersecurity threats have extensive cybersecurity and IT experience. For example, prior to joining Hamilton, over the past two and a half decades, our CTO has held leadership roles in the areas of software development, IT governance, IT operations, and security operations, ranging from executive director to chief technology officer. This experience spanned various companies, including an expert network/knowledge broker, an educational publishing company, a financial data vendor, a media conglomerate, and an investment bank. Among other things, he has provided leadership in building out global technology platforms, which have operated with multi-jurisdictional cybersecurity policies. He holds a Bachelor of Science degree in electronics and communications engineering, holds a Master’s degree in computer science, is a Certified Information Systems Security Professional and serves as a director on the board of ACORD, which is an organization responsible for setting digital standards for insurance and reinsurance companies globally.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Cybersecurity is important to our Board of Directors and management. On a quarterly basis, our CISO reports on cybersecurity matters to a risk committee comprised of a cross-functional management team (“Risk Committee”).
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Risk Committee escalates important issues identified in these reports to our Audit Committee, to which our full Board of Directors, while having ultimate responsibility for risk management oversight generally, has delegated primary oversight of cybersecurity risks.
Cybersecurity Risk Role of Management [Text Block]	Cybersecurity Board Oversight and Governance Cybersecurity is important to our Board of Directors and management. On a quarterly basis, our CISO reports on cybersecurity matters to a risk committee comprised of a cross-functional management team (“Risk Committee”). He has reported on, among other things, cybersecurity risks and incidents, a business continuity and disaster recovery exercise, completed and ongoing cyber audits, security metrics and key performance indicators, penetration testing results and remediation progress, the status of Hamilton’s data governance program, and cyber insurance coverage. The Risk Committee escalates important issues identified in these reports to our Audit Committee, to which our full Board of Directors, while having ultimate responsibility for risk management oversight generally, has delegated primary oversight of cybersecurity risks. In addition to quarterly reports to the Risk Committee, senior management, including our CTO and CISO, are responsible for directly reporting to the Audit Committee on cybersecurity matters. This includes reporting, on a quarterly basis and as significant matters arise, about existing and new cybersecurity risks, how management is addressing and/or mitigating those risks, cybersecurity and data privacy incidents (if any), and status on key information security initiatives. The Audit Committee convenes prior to each quarterly Board meeting to discuss cybersecurity risks and other information security matters. The Audit Committee also periodically reviews our processes and policies for managing material risks from cybersecurity threats. Any material risks, cybersecurity incidents or other matters are subsequently discussed with the full Board at the Board meeting. The members of senior management involved in managing our material risks from cybersecurity threats have extensive cybersecurity and IT experience. For example, prior to joining Hamilton, over the past two and a half decades, our CTO has held leadership roles in the areas of software development, IT governance, IT operations, and security operations, ranging from executive director to chief technology officer. This experience spanned various companies, including an expert network/knowledge broker, an educational publishing company, a financial data vendor, a media conglomerate, and an investment bank. Among other things, he has provided leadership in building out global technology platforms, which have operated with multi-jurisdictional cybersecurity policies. He holds a Bachelor of Science degree in electronics and communications engineering, holds a Master’s degree in computer science, is a Certified Information Systems Security Professional and serves as a director on the board of ACORD, which is an organization responsible for setting digital standards for insurance and reinsurance companies globally.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	CTO and CISO
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	The members of senior management involved in managing our material risks from cybersecurity threats have extensive cybersecurity and IT experience.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	This includes reporting, on a quarterly basis and as significant matters arise, about existing and new cybersecurity risks, how management is addressing and/or mitigating those risks, cybersecurity and data privacy incidents (if any), and status on key information security initiatives.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These audited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP") and include the accounts of Hamilton Group, Hamilton Re, Hamilton U.K. Holdings Limited, Hamilton Select, HMGA Americas, ACML, and TS Hamilton Fund (collectively the "Company"). All significant intercompany transactions and balances have been eliminated on consolidation
Basis of Presentation and Non-Controlling Interest	Basis of Presentation These audited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP") and include the accounts of Hamilton Group, Hamilton Re, Hamilton U.K. Holdings Limited, Hamilton Select, HMGA Americas, ACML, and TS Hamilton Fund (collectively the "Company"). All significant intercompany transactions and balances have been eliminated on consolidation . Certain comparative information has been reclassified to conform to the current year presentation. Non-Controlling Interest
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The major estimates recorded in the Company’s financial statements include, but are not limited to, premiums written, provisions for estimated future credit losses, the reserve for losses and loss adjustment expenses and the fair value of investments.
Fair Value Measurements	Fair Value Measurements Details on assets and liabilities that have been included under the requirements of authoritative guidance on fair value measurements to illustrate the bases for determining the fair values of these items held by the Company are included in Note 4, Fair Value and each respective section of this significant accounting policies note. Where the Company has elected to account for certain of its assets and liabilities at fair value in accordance with FASB ASC Topic Fair Value Measurements and Disclosures
Premiums and Acquisition Costs	Premiums and Acquisition Costs Premiums written and ceded on a losses occurring basis are earned pro-rata over the terms of the related contracts and policies. For contracts written on a risks-attaching basis, premiums written and ceded are earned over the terms of the underlying contracts and policies. Premiums written and ceded include estimates based on information received from insureds, brokers and ceding companies, and any subsequent differences arising on such estimates are recorded in the periods in which they are determined. The portion of the premiums written and ceded applicable to the unexpired terms of the underlying contracts and policies are recorded as unearned premiums and prepaid reinsurance premiums, respectively. Amounts are computed by pro-rata methods based on statistical data or reports received from insureds, brokers or ceding companies. Reinstatement premiums are estimated after the occurrence of a significant loss and are recorded in accordance with the contract terms based upon paid losses and case reserves. Reinstatement premiums are earned when written. Acquisition expenses are costs that vary with, and are directly related to, the successful acquisition of new or renewal business and consist principally of commissions, brokerage and premium tax expenses. These costs are deferred and amortized over the periods in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated losses and loss adjustment expenses, based on historical and current experience, and anticipated net investment income related to the premiums are considered in determining the recoverability of deferred acquisition costs.
Concentration of Credit Risk	Concentrations of Credit Risk
Reinsurance	Reinsurance In the normal course of business, the Company seeks to reduce the potential amount of loss arising from claims events by reinsuring certain levels of risk with other reinsurers. Ceded reinsurance contracts do not relieve the Company of its primary obligation to policyholders. Prepaid reinsurance represents the portion of premiums ceded to reinsurers applicable to the unexpired coverage terms of the reinsurance contracts in place. Amounts recoverable from reinsurers are estimated based on the terms and conditions of the reinsurance contracts, in a manner consistent with the underlying liabilities insured or reinsured by the Company. If the Company determines that adjustments to earlier estimates are appropriate, such adjustments are recorded in the periods in which they are determined. Amounts recoverable from reinsurers are recorded net of an allowance for expected credit losses. See Note 7, Reinsurance , for further details.
Credit Loss Provisions	Credit Loss Provisions The Company routinely evaluates its premiums receivable and paid and unpaid losses recoverable for potential specific credit or collection issues that might indicate an impairment. Premiums receivable and paid and unpaid losses recoverable are presented net of the resulting credit provisions, with the corresponding debits offset against gross premiums written or losses and loss adjustment expenses, as applicable, in the consolidated statement of operations and comprehensive income (loss).
Reserve for Losses and Loss Adjustment Expenses	Reserve for Losses and Loss Adjustment Expenses The reserve for losses and loss adjustment expenses includes reserves for unpaid reported losses and for losses incurred but not reported ("IBNR"). The reserve for unpaid reported losses and loss adjustment expenses is established by management based on reports from insureds, brokers and ceding companies and represents the estimated ultimate cost of events or conditions that have been reported to or specifically identified by the Company. The reserve for IBNR losses and loss adjustment expenses is established by management based on estimates of ultimate losses and loss adjustment expenses.
Cash and Cash Equivalents and Restricted Cash and Cash Equivalents	Cash and Cash Equivalents and Restricted Cash and Cash Equivalents Cash and cash equivalents include money market funds and highly liquid short-term deposits and securities with maturities of 90 days or less at the time of purchase. Money market funds are classified as Level 1 as these instruments are considered actively traded; however, certificates of deposit are classified as Level 2.
Cash and Cash Equivalents and Restricted Cash and Cash Equivalents	Cash and Cash Equivalents and Restricted Cash and Cash Equivalents Cash and cash equivalents include money market funds and highly liquid short-term deposits and securities with maturities of 90 days or less at the time of purchase. Money market funds are classified as Level 1 as these instruments are considered actively traded; however, certificates of deposit are classified as Level 2.
Investments	Investments Investments - Trading The Company elects the fair value option for its fixed maturity investments, short-term investments and certain other invested assets (excluding those that are accounted for using specialized investment company accounting as noted below). All changes in the fair value of investments are recorded within net realized and unrealized gains (losses) on investments in the consolidated statements of operations. See Note 4, Fair Value , for further details. All investment transactions are recorded on a trade-date basis and are valued using pricing data received from third parties. Realized gains or losses on sales of investments are determined on a weighted average basis. Investment income is recognized when earned and includes interest and dividend income, recorded as of the ex-dividend date, together with the amortization of premium and discount on fixed maturities and short-term investments computed using the effective yield method. Net investment income includes related investment expenses. Short-Term Investments Short-term investments comprise securities with a maturity greater than three months but less than one year from the date of purchase. Investments in Two Sigma Funds TS Hamilton Fund invests in Two Sigma Funds ("Two Sigma Funds"), which are stated at their estimated fair values, which generally represent the Company’s proportionate interest in the members’ equity of the Two Sigma Funds as reported by the respective funds based on the net asset value ("NAV") provided by the fund administrator. The Company accounts for its investment in Two Sigma Funds under the variable interest model at NAV as a practical expedient for fair value in the consolidated balance sheets. Increases or decreases in such fair values are recorded within net realized and unrealized gains (losses) on investments in the consolidated statements of operations. Realized gains or losses upon any withdrawals of investments in the Two Sigma Funds are calculated using the weighted average method. The assets and liabilities of the Two Sigma Funds are recorded at fair value, or at amounts approximating fair value. The Company records contributions and withdrawals related to its investments in the Two Sigma Funds on the transaction date. The specialized investment company accounting, as described above, is retained in the Company’s audited consolidated financial statements upon consolidation of TS Hamilton Fund.
Foreign Exchange	Foreign Exchange Monetary assets and liabilities denominated in foreign currencies are revalued into the functional currency of each entity using the exchange rates in effect at the balance sheet date, with the resulting foreign exchange gains and losses included in earnings. Revenues and expenses denominated in foreign currencies are revalued at the exchange rates in effect on the transaction date. The Company’s reporting currency as at December 31, 2024 is the U.S. Dollar ("USD"). The functional currency of the Company's U.K. subsidiaries changed from GBP to USD on January 1, 2017. The accumulated other comprehensive loss recorded prior to the change in functional currency will remain on the balance sheet until such time as the U.K. operations are sold, or substantially liquidated.
Share Based Compensation	Share Based Compensation The Company issues restricted stock units, performance stock units and warrants and may issue other equity-based awards to its employees. Compensation cost is measured at the grant date fair value and expensed over the period for which the employee is required to provide services in exchange for the award. For awards subject to graded vesting, the awards are separated into vesting tranches, which are amortized over their respective vesting periods. Forfeitures are recognized as they occur.
Intangible Assets	Intangible Assets The Company accounts for goodwill and other intangible assets that arise from business combinations in accordance with FASB ASC Topic Intangibles - Goodwill and Other . A purchase price that is in excess of the fair value of the net assets acquired arising from a business combination is recorded as goodwill or other intangible assets, according to their nature. Goodwill and other intangible assets with indefinite useful lives are not amortized. Other intangible assets with a finite life are amortized over the estimated useful lives of the assets. All recorded goodwill was written down in the year ended December 31, 2022, primarily as a result of the annual impairment assessment, and the Company has no recorded goodwill at December 31, 2024 or 2023. The Company's indefinite lived intangible assets are tested for impairment on an annual basis or more frequently if events or changes in circumstances warrant. Finite lived intangible assets are reviewed for indicators of impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable and tested for impairment if appropriate. If indefinite lived intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense recorded in the Company's consolidated statement of operations.
Variable Interest Entities	Variable Interest Entities The Company accounts for variable interest entities ("VIE") in accordance with GAAP guidance, which requires the consolidation of all VIEs by the primary beneficiary: the investor that has the power to direct the activities of the VIE and will absorb a majority of the VIE’s expected losses or residual returns. The Company determines whether it is the primary beneficiary of a VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the terms between the VIE and its variable interest holders and other parties involved with the VIE; (iv) which variable interest holders have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance; (v) which variable interest holders have the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE; and (vi) related party relationships. The Company reassesses its initial evaluation of an entity as a VIE upon the occurrence of certain reconsideration events. The Company also reassesses its determination of whether the Company is the primary beneficiary of a VIE upon changes in facts and circumstances that could potentially alter the Company’s assessment.
Earnings Per Share	Earnings Per Share The Company calculates earnings per share in accordance with FASB ASC Topic Earnings per Share . Basic earnings per share are based on weighted average common shares outstanding during the period and exclude any dilutive effects of restricted stock units and warrants. Diluted earnings per share includes the estimated impact under the Treasury Stock method where all dilutive restricted stock grants to vest and all dilutive warrants to be exercised during the period.
Income Taxes	Income Taxes The Company records deferred income taxes that reflect the tax effect of the temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and their respective tax bases. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the fiscal period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is not more likely than not that all, or some portion, of the benefits related to deferred tax assets will be realized. The valuation allowance assessment considers tax planning strategies, where applicable.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07 Segment Reporting, which enhances the qualitative and quantitative disclosures related to reportable segments. The Company adopted this guidance for the year ended December 31, 2024 and it did not have a material impact on the Company’s results of operations, financial position, cash flows or disclosures. Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09 Income Taxes , which enhances the quantitative annual disclosures related to tax rate reconciliations and income taxes paid and requires additional qualitative discussion of applicable tax jurisdictions and the nature of certain reconciling items. The guidance is effective for annual periods beginning after December 15, 2024. Early adoption is permitted. This guidance will not have a material impact on the Company's results of operations, financial position, or cash flows. In November 2024, the FASB issued ASU 2024-03 Disaggregation of Income Statement Expenses , which enhances the quantitative and qualitative disclosures related to specified information about certain costs and expenses. The guidance is effective for annual periods beginning after December 15, 2026. Early adoption is permitted. The Company is currently evaluating the impact of this guidance.

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Schedule of Fixed Maturity and Short-Term Investments	The Company’s fixed maturity and short-term investments are as follows: December 31, 2024 ($ in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities: U.S. government treasuries $ 724,785 $ 611 $ (14,293) $ 711,103 U.S. states, territories and municipalities 13,533 25 (327) 13,231 Non-U.S. sovereign governments and supranationals 70,435 454 (3,362) 67,527 Corporate 1,153,612 6,484 (17,036) 1,143,060 Residential mortgage-backed securities - Agency 288,760 160 (16,309) 272,611 Residential mortgage-backed securities - Non-agency 17,432 6 (684) 16,754 Commercial mortgage-backed securities - Non-agency 40,363 72 (749) 39,686 Other asset-backed securities 113,997 249 (356) 113,890 Total fixed maturities 2,422,917 8,061 (53,116) 2,377,862 Short-term investments 495,630 1,484 (4) 497,110 Total $ 2,918,547 $ 9,545 $ (53,120) $ 2,874,972 December 31, 2023 ($ in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities: U.S. government treasuries $ 717,134 $ 5,137 $ (14,021) $ 708,250 U.S. states, territories and municipalities 4,656 — (286) 4,370 Non-U.S. sovereign governments and supranationals 55,662 2,175 (1,591) 56,246 Corporate 877,493 8,443 (22,060) 863,876 Residential mortgage-backed securities - Agency 180,661 435 (12,583) 168,513 Residential mortgage-backed securities - Non-agency 5,639 16 (671) 4,984 Commercial mortgage-backed securities - Non-agency 11,473 — (1,050) 10,423 Other asset-backed securities 14,781 20 (195) 14,606 Total fixed maturities 1,867,499 16,226 (52,457) 1,831,268 Short-term investments 427,437 1,441 — 428,878 Total $ 2,294,936 $ 17,667 $ (52,457) $ 2,260,146
Schedule of Contractual Maturities of Fixed Maturity Securities	The following table presents contractual maturities of fixed maturity securities. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. December 31, 2024 ($ in thousands) Amortized Cost Fair Value Due less than one year $ 191,976 $ 190,229 Due after one through five years 1,438,250 1,419,173 Due after five through ten years 327,869 321,983 Due after ten years 4,270 3,536 Mortgage-backed securities 346,555 329,051 Asset-backed securities 113,997 113,890 Total $ 2,422,917 $ 2,377,862
Schedule of Investments in Two Sigma Funds	The Company’s investments in Two Sigma Funds are as follows: December 31, 2024 December 31, 2023 ($ in thousands) Cost Net Unrealized Gains (Losses) Fair Value Cost Net Unrealized Gains (Losses) Fair Value Two Sigma Futures Portfolio, LLC (FTV) $ 308,061 $ (15,520) $ 292,541 $ 433,911 $ (38,105) $ 395,806 Two Sigma Spectrum Portfolio, LLC (STV) 360,997 102,267 463,264 193,299 88,228 281,527 Two Sigma Equity Spectrum Portfolio, LLC (ESTV) 136,565 47,011 183,576 142,981 31,156 174,137 Total $ 805,623 $ 133,758 $ 939,381 $ 770,191 $ 81,279 $ 851,470
Schedule of Certain Investments of FTV, STV and ESTV	The following table summarizes certain investments of FTV, STV and ESTV where TS Hamilton Fund’s proportionate share of the fair value of the investment represents more than 5% of TS Hamilton Fund’s members’ equity: December 31, 2024 ($ in thousands) Principal / Shares (1) Fair Value (1) % of Members' Equity Goldman Sachs Financial Square Treasury Obligations Fund 111,926 $ 111,926 5.9 % Morgan Stanley Institutional Liquidity Funds Treasury Portfolio 109,471 $ 109,471 5.8 % JP Morgan U.S. Treasury Plus Money Market Fund - Capital 101,940 $ 101,940 5.4 % U.S. Treasury Securities, 0.0000% - 4.6250%, due 1/9/2025 - 11/15/2054 2,105,796 $ 2,086,814 110.6 % Invesco Treasury Portfolio Money Market Fund 96,844 $ 96,844 5.1 % U.S. Treasury Securities, 4.0000% - 4.6250%, due 12/31/2026 - 11/15/2054 (241,100) $ (236,974) (12.6) % (1)
Schedule of Realized and Unrealized Gains (Losses) on Investments and Net Investment Income (Loss)	The components of total net realized and unrealized gains (losses) on investments and net investment income (loss) are as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Net realized and unrealized gains (losses) on investments: Net realized gains (losses) on investments $ 468,068 $ 84,513 $ 258,653 Change in net unrealized gains (losses) on investments 43,339 125,097 (165,305) Net realized and unrealized gains (losses) on investments 511,407 209,610 93,348 Net investment income (loss): Fixed maturities 81,872 47,970 22,375 Short-term investments 67 295 155 TS Hamilton Fund 12,373 16,084 10,395 Cash and cash equivalents 17,006 12,523 2,634 Other 2,293 1,580 (1,397) Interest and other 113,611 78,452 34,162 Management fees (49,102) (47,049) (54,581) Other expenses (1,242) (947) (1,068) Net investment income (loss) 63,267 30,456 (21,487) Total net realized and unrealized gains (losses) on investments and net investment income (loss) $ 574,674 $ 240,066 $ 71,861
Schedule of Realized Gain (Loss) on Investments	The components of net realized gains (losses) on investments are as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Fixed maturities and short-term investments $ (2,307) $ (16,628) $ (14,968) TS Hamilton Fund 470,091 100,930 266,630 Other 284 211 6,991 Net realized gains (losses) on investments $ 468,068 $ 84,513 $ 258,653
Schedule of Unrealized Gain (Loss) on Investments	The components of net unrealized gains (losses) on investments are as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Fixed maturities and short-term investments $ (8,908) $ 52,751 $ (87,254) TS Hamilton Fund 52,247 72,346 (78,051) Net unrealized gains (losses) on investments $ 43,339 $ 125,097 $ (165,305)

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial Instruments Measured at Fair Value on a Recurring Basis	The following table presents the financial instruments measured at fair value on a recurring basis: December 31, 2024 ($ in thousands) Level 1 Level 2 Level 3 Total Fixed maturities: U.S. government treasuries $ — $ 711,103 $ — $ 711,103 U.S. states, territories and municipalities — 13,231 — 13,231 Non-U.S. sovereign governments and supranationals — 67,527 — 67,527 Corporate — 1,143,060 — 1,143,060 Residential mortgage-backed securities - Agency — 272,611 — 272,611 Residential mortgage-backed securities - Non-agency — 16,754 — 16,754 Commercial mortgage-backed securities - Non-agency — 39,686 — 39,686 Other asset-backed securities — 113,890 — 113,890 Total fixed maturities — 2,377,862 — 2,377,862 Short-term investments — 497,110 — 497,110 Total $ — $ 2,874,972 $ — $ 2,874,972 December 31, 2023 ($ in thousands) Level 1 Level 2 Level 3 Total Fixed maturities: U.S. government treasuries $ — $ 708,250 $ — $ 708,250 U.S. states, territories and municipalities — 4,370 — 4,370 Non-U.S. sovereign governments and supranationals — 56,246 — 56,246 Corporate — 863,876 — 863,876 Residential mortgage-backed securities - Agency — 168,513 — 168,513 Residential mortgage-backed securities - Non-agency — 4,984 — 4,984 Commercial mortgage-backed securities - Non-agency — 10,423 — 10,423 Other asset-backed securities — 14,606 — 14,606 Total fixed maturities — 1,831,268 — 1,831,268 Short-term investments — 428,878 — 428,878 Total $ — $ 2,260,146 $ — $ 2,260,146

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Activity In and Total Assets and Total Liabilities of TS Hamilton Fund	Activity in the non-controlling interest of TS Hamilton Fund was as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Balance - beginning of year $ 133 $ 119 $ 124 Withdrawals (212,734) (21,546) (68,069) Equity in earnings 43 14 14 Incentive allocation 212,686 21,546 68,050 Balance - end of year $ 128 $ 133 $ 119 The following table presents the total assets and total liabilities of TS Hamilton Fund. Creditors or beneficial interest holders of TS Hamilton Fund have no recourse to the general credit of the Company as the Company’s obligation is limited to the amount of its committed investment. December 31, ($ in thousands) 2024 2023 Assets Cash and cash equivalents $ 578,230 $ 479,255 Short-term investments 496,008 428,878 Investments in Two Sigma Funds, at fair value 939,381 851,470 Receivables for investments sold 73,322 41,087 Interest and dividends receivable 945 966 Total assets 2,087,886 1,801,656 Liabilities Payable for investments purchased 100,469 62,440 Withdrawal payable 100,420 6,480 Accounts payable and accrued expenses 233 191 Total liabilities 201,122 69,111 Total net assets managed by TS Hamilton Fund $ 1,886,764 $ 1,732,545

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Goodwill and Intangible Assets	The following table provides a summary of the Company's goodwill and intangible assets: ($ in thousands) Goodwill Intangible Assets Intangible Assets not Subject to Amortization Total Net balance, December 31, 2022 $ — $ 49,750 $ 37,208 $ 86,958 Plus: additions — 14,821 — 14,821 Less: amortization — (10,783) — (10,783) Net balance, December 31, 2023 — 53,788 37,208 90,996 Plus: additions — 17,645 — 17,645 Less: amortization — (15,520) — (15,520) Net balance, December 31, 2024 $ — $ 55,913 $ 37,208 $ 93,121 Gross balance, December 31, 2024 $ — $ 106,681 $ 37,208 $ 143,889 Accumulated amortization — (50,768) — (50,768) Net balance, December 31, 2024 $ — $ 55,913 $ 37,208 $ 93,121 The following tables present the components of intangible assets: December 31, 2024 ($ in thousands) Gross Balance Accumulated Amortization and Impairment Net Balance Intangible assets subject to amortization Coverholder and broker relationships $ 44,515 $ (23,707) $ 20,808 Internally developed software 62,166 (27,061) 35,105 Intangible assets not subject to amortization Lloyd's syndicate capacity 35,583 — 35,583 Licenses 1,625 — 1,625 $ 143,889 $ (50,768) $ 93,121 December 31, 2023 ($ in thousands) Gross Balance Accumulated Amortization and Impairment Net Balance Intangible assets subject to amortization Coverholder and broker relationships $ 44,515 $ (19,255) $ 25,260 Internally developed software 44,519 (15,991) 28,528 Intangible assets not subject to amortization Lloyd's syndicate capacity 35,583 — 35,583 Licenses 1,625 — 1,625 $ 126,242 $ (35,246) $ 90,996
Schedule of Estimated Amortization Expense	The weighted-average amortization period is 2.5 years and the estimated amortization expense for each of the five succeeding fiscal years and thereafter related to these assets is as follows: ($ in thousands) Estimated Amortization Expense Year Ending December 31, 2025 $ 15,656 2026 13,551 2027 12,353 2028 9,463 2029 4,890 Total $ 55,913

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2024
Insurance [Abstract]
Schedule of Effects of Reinsurance	The following tables set forth the effect of reinsurance and retrocessional activity on premiums written and earned and on losses and loss adjustment expenses incurred: Premiums Written Years Ended December 31, ($ in thousands) 2024 2023 2022 Assumed $ 1,144,798 $ 838,547 $ 709,194 Direct 1,277,784 1,112,491 937,479 Ceded (501,413) (470,600) (424,809) Net $ 1,921,169 $ 1,480,438 $ 1,221,864 Premiums Earned Years Ended December 31, ($ in thousands) 2024 2023 2022 Assumed $ 1,030,595 $ 742,378 $ 670,272 Direct 1,180,932 1,016,762 886,488 Ceded (476,798) (440,607) (413,046) Net $ 1,734,729 $ 1,318,533 $ 1,143,714 Losses and Loss Adjustment Expenses Years Ended December 31, ($ in thousands) 2024 2023 2022 Gross losses and loss adjustment expenses $ 1,290,131 $ 972,347 $ 1,133,469 Losses and loss adjustment expenses ceded (279,958) (257,744) (375,136) Net $ 1,010,173 $ 714,603 $ 758,333
Premium Receivable, Allowance for Credit Loss	The following table provides a roll forward of the provision for current expected credit losses of the Company's premiums receivable: Years Ended December 31, ($ in thousands) 2024 2023 2022 Beginning balance $ 3,000 $ 2,856 $ 2,165 Increase (decrease) in allowance (7) 144 691 Ending balance $ 2,993 $ 3,000 $ 2,856
Reinsurance Recoverable, Allowance for Credit Loss	The following table provides a roll forward of the provision for current expected credit losses of the Company's reinsurance recoverable: Years Ended December 31, ($ in thousands) 2024 2023 2022 Beginning balance $ 687 $ 777 $ 616 Increase (decrease) in allowance 782 (90) 161 Ending balance $ 1,469 $ 687 $ 777
Schedule of Paid and Unpaid Losses and Loss Adjustment Expenses Recoverable	The distribution of the Company’s paid losses recoverable and unpaid losses and loss adjustment expenses recoverable as categorized by major rating agencies were as follows: December 31, Classification 2024 2023 Collateralized 23.7 % 28.5 % A- or better 76.2 % 71.0 % Below A- 0.1 % 0.5 % Total 100.0 % 100.0 %

Reserve for Losses and Loss A_2

Reserve for Losses and Loss Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2024
Insurance [Abstract]
Schedule of Reconciliation of Unpaid Losses and Loss Adjustment Expenses	The following table presents a reconciliation of unpaid losses and loss adjustment expenses ("LAE"): Years Ended December 31, ($ in thousands) 2024 2023 2022 Gross unpaid losses and loss adjustment expenses, beginning of year $ 3,030,037 $ 2,856,275 $ 2,415,491 Reinsurance recoverable on unpaid losses 1,161,077 1,177,863 1,112,543 Net unpaid losses and loss adjustment expenses, beginning of year 1,868,960 1,678,412 1,302,948 Net losses and loss adjustment expenses incurred in respect of losses occurring in: Current year 1,030,612 730,220 778,936 Prior years (20,439) (15,617) (20,603) Total incurred 1,010,173 714,603 758,333 Net losses and loss adjustment expenses paid in respect of losses occurring in: Current year 58,726 62,811 61,649 Prior years 458,040 501,987 315,537 Total paid 516,766 564,798 377,186 Foreign currency revaluation and other (916) 40,743 (5,683) Net unpaid losses and loss adjustment expenses, end of year 2,361,451 1,868,960 1,678,412 Reinsurance recoverable on unpaid losses 1,171,040 1,161,077 1,177,863 Gross unpaid losses and loss adjustment expenses, end of year $ 3,532,491 $ 3,030,037 $ 2,856,275
Schedule of Short-Duration Insurance Contracts, Claims Development	The following tables show the paid and incurred loss development by broad classification based on groupings of contracts that are similar in coverage and duration: International Property ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $1 $1 $1 $— $— $— $— $— $— $— $— 2 2016 7,527 6,551 6,212 6,351 6,011 7,155 7,261 7,349 7,306 27 903 2017 38,379 42,986 44,911 41,819 41,260 41,224 41,230 40,456 (974) 1,166 2018 24,037 26,191 24,873 24,537 24,542 24,466 23,869 114 1,122 2019 32,695 33,895 36,609 36,672 36,687 34,824 411 1,436 2020 134,743 144,201 143,676 143,418 142,802 5,261 2,236 2021 113,813 124,917 121,907 117,228 3,371 1,566 2022 81,324 74,560 68,686 4,035 1,077 2023 53,085 48,480 10,278 681 2024 73,513 55,074 598 Total $557,164 $77,597 10,787 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $— $— $— $— $— $— $— $— $— 2016 171 3,428 4,567 6,668 7,049 6,891 7,003 7,277 7,277 2017 9,249 29,283 34,363 40,193 39,984 40,832 40,900 41,333 2018 1,322 12,036 17,340 20,053 20,905 21,964 23,603 2019 8,307 21,106 20,940 25,818 32,942 34,066 2020 24,365 90,859 115,587 132,191 136,041 2021 23,564 63,784 101,064 112,184 2022 9,996 46,856 57,551 2023 5,502 29,362 2024 5,071 Total $446,488 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $110,676 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 2 3 4 5 6 7 8 9 16 % 44 % 19 % 12 % 5 % 3 % 3 % 1 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. International Casualty ($ in thousands, except claim count) The following table discloses losses incurred, losses paid and claims data excluding the impact of the loss portfolio transfer discussed in further detail in Note 7, Reinsurance. Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $— $— $— $— $— $— $— $— $— $— — 2016 171 278 243 342 342 342 388 367 166 — 32 2017 648 5,187 7,354 6,332 5,857 5,121 5,079 4,579 328 73 2018 697 5,890 5,686 4,941 4,351 4,453 4,300 110 554 2019 19,882 19,199 18,867 18,112 16,817 15,846 704 2,704 2020 28,692 24,123 17,870 19,426 19,265 2,451 3,641 2021 101,549 109,013 107,024 106,824 69,619 3,602 2022 144,543 145,030 149,180 87,661 3,912 2023 145,783 147,005 108,769 5,639 2024 198,705 182,784 3,909 Total $645,870 $452,426 24,066 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $— $— $— $— $— $— $— $— $— 2016 — — 82 — — — — — — 2017 — 22 629 2,285 2,406 3,964 4,043 4,046 2018 35 439 2,266 3,167 3,800 4,011 4,066 2019 177 2,719 6,813 13,332 14,992 15,131 2020 3,363 8,420 12,480 16,706 16,813 2021 795 11,243 20,079 30,286 2022 3,240 9,452 27,217 2023 5,240 19,429 2024 4,749 Total $121,737 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $524,133 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 2 3 4 5 6 7 8 9 3 % 9 % 12 % 16 % 6 % 8 % 1 % 0 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. International Specialty ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $93 $138 $218 $212 $144 $149 $94 $100 $101 $— 65 2016 2,534 4,771 5,383 5,232 5,370 3,668 3,367 3,325 4,427 504 766 2017 22,378 17,430 16,943 15,256 22,030 25,397 27,714 31,279 2,277 1,300 2018 31,724 30,606 29,176 33,129 37,834 42,995 42,921 (287) 1,617 2019 108,035 109,971 104,017 97,777 95,702 95,306 5,405 2,852 2020 119,790 116,242 106,774 105,314 105,310 4,426 2,943 2021 124,844 136,998 138,471 140,697 10,573 3,073 2022 129,423 119,581 121,981 15,941 2,864 2023 178,429 178,984 68,974 2,529 2024 221,168 201,273 1,580 Total $942,174 $309,086 19,589 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $— $16 $62 $119 $147 $150 $150 $94 $94 $94 2016 248 2,141 4,000 3,098 3,446 3,600 3,265 3,265 3,874 2017 2,427 8,992 16,986 21,763 21,256 23,043 25,858 28,928 2018 2,054 17,155 30,652 30,839 35,614 40,792 43,177 2019 14,076 59,152 77,532 78,807 86,733 89,858 2020 12,218 53,425 84,864 94,657 100,757 2021 9,743 45,838 67,950 105,231 2022 9,001 41,596 77,303 2023 17,943 72,227 2024 10,319 Total $531,768 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $410,406 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 2 3 4 5 6 7 8 9 8 % 32 % 24 % 12 % 7 % 6 % 6 % 8 % 13 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Bermuda Property ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $29,519 $17,011 $12,643 $12,184 $7,821 $6,492 $6,467 $6,439 $5,667 $6,705 $— 41 2016 56,248 38,658 37,476 35,938 35,120 36,340 35,652 35,132 35,011 — 107 2017 100,603 98,094 93,332 81,032 79,484 83,413 83,603 82,467 898 272 2018 62,057 80,131 77,845 78,132 73,819 70,675 69,594 371 241 2019 14,775 44,540 56,265 57,939 57,631 56,413 2,010 141 2020 112,056 120,840 126,275 126,583 127,579 5,620 295 2021 144,924 161,604 157,881 150,283 8,385 205 2022 181,052 209,797 199,762 37,648 232 2023 102,739 100,047 45,914 79 2024 168,850 118,912 92 Total $996,711 $219,758 1,705 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $1,775 $4,664 $5,163 $5,297 $5,417 $5,608 $5,630 $5,646 $5,647 $6,700 2016 12,840 25,596 29,623 31,685 32,882 33,985 34,609 34,741 34,823 2017 24,533 90,864 71,190 82,940 71,795 75,524 78,356 79,097 2018 12,631 71,557 85,660 67,547 65,583 67,410 67,938 2019 2,401 32,433 38,002 46,504 49,705 51,248 2020 13,253 48,246 75,445 104,870 113,365 2021 16,080 71,293 106,089 130,528 2022 35,261 109,215 137,313 2023 26,199 38,728 2024 24,366 Total $684,106 Outstanding liabilities for accident year 2014 and prior, net of reinsurance $33 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $312,638 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 (unaudited) 2 (unaudited) 3 (unaudited) 4 (unaudited) 5 (unaudited) 6 (unaudited) 7 (unaudited) 8 (unaudited) 9 (unaudited) 17 % 42 % 13 % 11 % 0 % 3 % 2 % 1 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Bermuda Casualty ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $19,729 $18,378 $31,552 $30,313 $38,585 $39,331 $50,570 $49,546 $41,677 $41,378 $7,888 38 2016 44,749 49,876 54,253 54,619 56,863 56,353 60,342 54,997 57,154 4,682 7 2017 84,754 96,345 101,443 105,558 113,594 126,190 137,924 139,565 9,057 39 2018 101,397 115,594 123,114 121,692 131,717 133,476 142,520 14,967 34 2019 85,454 96,207 101,614 100,758 105,390 98,242 22,097 18 2020 81,925 84,493 88,400 88,632 88,992 26,122 21 2021 69,766 79,096 80,015 79,183 40,792 7 2022 110,317 110,095 107,522 75,580 3 2023 169,608 171,462 127,989 30 2024 268,201 247,492 3 Total $1,194,219 $576,666 200 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $708 $2,111 $3,569 $11,246 $16,953 $18,828 $25,671 $34,198 $30,726 $37,260 2016 1,541 5,169 12,678 20,504 27,103 35,482 39,381 41,115 44,726 2017 3,792 10,961 22,829 50,471 70,548 91,855 106,013 117,341 2018 3,782 22,800 50,903 66,889 70,939 87,677 105,495 2019 3,965 11,094 23,445 36,161 53,528 58,930 2020 5,417 14,495 19,713 35,047 49,768 2021 1,934 4,523 11,255 26,962 2022 696 4,744 14,565 2023 2,025 21,821 2024 8,203 Total $485,071 Outstanding liabilities for accident year 2014 and prior, net of reinsurance $524 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $709,672 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 (unaudited) 2 (unaudited) 3 (unaudited) 4 (unaudited) 5 (unaudited) 6 (unaudited) 7 (unaudited) 8 (unaudited) 9 3 % 8 % 11 % 16 % 12 % 11 % 11 % 9 % 0 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle. Bermuda Specialty ($ in thousands, except claim count) Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended As of December 31, 2024 November 30, December 31, IBNR (1) Cumulative Number of Reported Claims Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $27,712 $26,686 $19,342 $19,237 $17,466 $16,820 $15,383 $15,672 $15,288 $15,277 $16 39 2016 38,154 34,835 28,913 23,171 19,826 16,850 15,846 15,851 15,684 565 58 2017 57,528 44,156 36,230 29,590 24,470 26,820 27,334 26,216 735 74 2018 58,551 52,420 48,323 45,096 38,658 39,920 40,386 953 89 2019 62,075 56,189 48,874 49,114 48,508 49,857 5,280 109 2020 63,176 56,807 52,195 54,645 54,586 3,468 116 2021 53,732 46,023 35,610 33,499 8,721 33 2022 117,538 114,225 111,565 73,277 76 2023 62,095 70,783 49,590 28 2024 82,306 72,328 4 Total $500,159 $214,933 626 (1) Total of incurred but not reported liabilities plus expected development on reported claims Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the years ended November 30, December 31, Accident 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 (unaudited) 2020 (unaudited) 2021 (unaudited) 2022 (unaudited) 2023 (unaudited) 2024 2015 $3,330 $8,638 $13,136 $13,115 $14,192 $14,397 $14,432 $14,767 $14,832 $14,911 2016 2,938 8,661 5,632 10,814 13,116 13,589 13,810 14,413 14,603 2017 2,217 10,194 14,114 16,417 17,726 22,638 24,384 24,267 2018 7,607 19,326 25,826 28,223 27,789 33,653 36,457 2019 6,373 20,505 29,083 36,472 45,062 42,679 2020 9,160 25,585 32,653 43,226 47,047 2021 3,862 7,248 15,938 19,114 2022 3,465 17,086 29,008 2023 5,028 14,233 2024 4,706 Total $247,025 Outstanding liabilities for accident year 2014 and prior, net of reinsurance $218 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance $253,352 Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (1) Years 1 (unaudited) 2 (unaudited) 3 (unaudited) 4 (unaudited) 5 (unaudited) 6 (unaudited) 7 (unaudited) 8 (unaudited) 9 (unaudited) 10 % 21 % 14 % 13 % 8 % 6 % 5 % 1 % 1 % (1) Unaudited supplementary information is a weighted average derived from the incurred losses and allocated loss adjustment expenses, net of reinsurance triangle and cumulative paid losses and allocated loss adjustment expenses, net of reinsurance triangle.
Schedule of Short-Duration Insurance Contracts, Reconciliation of Claims Development to Liability	Reconciliation December 31, ($ in thousands) 2024 Net outstanding liabilities International - Property $ 110,676 International - Casualty 524,133 International - Specialty 410,406 Bermuda - Property 312,638 Bermuda - Casualty 709,672 Bermuda - Specialty 253,352 Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance 2,320,877 Reinsurance recoverable on unpaid claims International - Property 63,625 International - Casualty 608,333 International - Specialty 210,968 Bermuda - Property 44,045 Bermuda - Casualty 161,778 Bermuda - Specialty 82,291 Total reinsurance recoverable on unpaid claims 1,171,040 Other insurance lines 3,302 Unallocated loss adjustment expenses 37,272 40,574 Total gross liability for unpaid losses and loss adjustment expenses $ 3,532,491

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	($ in thousands) For the Year Ended December 31, 2024 International Bermuda Corporate Total Gross premiums written $ 1,308,460 $ 1,114,122 $ — $ 2,422,582 Net premiums written $ 969,605 $ 951,564 $ — $ 1,921,169 Net premiums earned $ 886,934 $ 847,795 $ — $ 1,734,729 Third party fee income 16,317 7,435 — 23,752 Losses and loss adjustment expenses 498,023 512,150 — 1,010,173 Acquisition costs 216,971 171,960 — 388,931 Other underwriting expenses 148,824 61,189 — 210,013 Underwriting income (loss) $ 39,433 $ 109,931 $ — $ 149,364 Net realized and unrealized gains (losses) on investments 511,407 511,407 Net investment income (loss) 63,267 63,267 Net foreign exchange gains (losses) (3,231) (3,231) Corporate expenses (61,111) (61,111) Amortization of intangible assets (15,520) (15,520) Interest expense (22,616) (22,616) Income (loss) before income tax 621,560 Income tax (expense) benefit (8,402) (8,402) Net income (loss) 613,158 Net income (loss) attributable to non-controlling interest 212,729 212,729 Net income (loss) attributable to common shareholders $ 400,429 Key Ratios Attritional loss ratio - current year 53.5 % 52.7 % 53.1 % Attritional loss ratio - prior year development (0.4) % 0.5 % 0.0 % Catastrophe loss ratio - current year 3.9 % 8.9 % 6.3 % Catastrophe loss ratio - prior year development (0.8) % (1.7) % (1.2) % Loss and loss adjustment expense ratio 56.2 % 60.4 % 58.2 % Acquisition cost ratio 24.5 % 20.3 % 22.4 % Other underwriting expense ratio 14.9 % 6.3 % 10.7 % Combined ratio 95.6 % 87.0 % 91.3 % ($ in thousands) For the Year Ended December 31, 2023 International Bermuda Corporate Total Gross premiums written $ 1,105,522 $ 845,516 $ — $ 1,951,038 Net premiums written $ 770,399 $ 710,039 $ — $ 1,480,438 Net premiums earned $ 703,508 $ 615,025 $ — $ 1,318,533 Third party fee income 9,685 8,549 — 18,234 Losses and loss adjustment expenses 362,137 352,466 — 714,603 Acquisition costs 186,698 122,450 — 309,148 Other underwriting expenses 127,402 55,763 — 183,165 Underwriting income (loss) $ 36,956 $ 92,895 $ — $ 129,851 Net realized and unrealized gains (losses) on investments 209,610 209,610 Net investment income (loss) 30,456 30,456 Other income (loss), excluding third party fee income 397 397 Net foreign exchange gains (losses) (6,185) (6,185) Corporate expenses (76,691) (76,691) Amortization of intangible assets (10,783) (10,783) Interest expense (21,434) (21,434) Income (loss) before income tax 255,221 Income tax (expense) benefit 25,066 25,066 Net income (loss) 280,287 Net income (loss) attributable to non-controlling interest 21,560 21,560 Net income (loss) attributable to common shareholders $ 258,727 Key Ratios Attritional loss ratio - current year 53.2 % 51.1 % 52.2 % Attritional loss ratio - prior year development (3.5) % 2.3 % (0.8) % Catastrophe loss ratio - current year 1.5 % 5.1 % 3.2 % Catastrophe loss ratio - prior year development 0.3 % (1.2) % (0.4) % Loss and loss adjustment expense ratio 51.5 % 57.3 % 54.2 % Acquisition cost ratio 26.5 % 19.9 % 23.4 % Other underwriting expense ratio 16.7 % 7.7 % 12.5 % Combined ratio 94.7 % 84.9 % 90.1 % ($ in thousands) For the Year Ended December 31, 2022 International Bermuda Corporate Total Gross premiums written $ 933,241 $ 713,432 $ — $ 1,646,673 Net premiums written $ 635,773 $ 586,091 $ — $ 1,221,864 Net premiums earned $ 623,047 $ 520,667 $ — $ 1,143,714 Third party fee income 11,430 201 — 11,631 Losses and loss adjustment expenses 335,484 422,849 — 758,333 Acquisition costs 170,571 100,618 — 271,189 Other underwriting expenses 108,239 49,301 — 157,540 Underwriting income (loss) $ 20,183 $ (51,900) $ — $ (31,717) Net realized and unrealized gains (losses) on investments 93,348 93,348 Net investment income (loss) (21,487) (21,487) Other income (loss), excluding third party fee income (315) (315) Net foreign exchange gains (losses) 6,137 6,137 Corporate expenses (20,142) (20,142) Impairment of goodwill (24,082) (24,082) Amortization of intangible assets (12,832) (12,832) Interest expense (15,741) (15,741) Income (loss) before income tax (26,831) Income tax (expense) benefit (3,104) (3,104) Net income (loss) (29,935) Net income (loss) attributable to non-controlling interest 68,064 68,064 Net income (loss) attributable to common shareholders $ (97,999) Key Ratios Attritional loss ratio - current year 50.9 % 52.9 % 51.8 % Attritional loss ratio - prior year development (4.8) % 5.1 % (0.3) % Catastrophe loss ratio - current year 7.2 % 27.1 % 16.3 % Catastrophe loss ratio - prior year development 0.5 % (3.9) % (1.5) % Loss and loss adjustment expense ratio 53.8 % 81.2 % 66.3 % Acquisition cost ratio 27.4 % 19.3 % 23.7 % Other underwriting expense ratio 15.5 % 9.4 % 12.8 % Combined ratio 96.7 % 109.9 % 102.8 %
Schedule of Revenue from External Customers by Geographic Areas	The following table presents gross premiums written by the geographical location of the Company's subsidiaries: Years Ended December 31, ($ in thousands) 2024 2023 2022 International Lloyd's of London $ 792,830 $ 677,415 $ 561,432 Ireland 399,061 349,896 345,088 U.S. 116,569 78,211 26,721 Total International 1,308,460 1,105,522 933,241 Bermuda 1,114,122 845,516 713,432 Total $ 2,422,582 $ 1,951,038 $ 1,646,673

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments	The following table presents the gross outstanding loan balance, loan fair value and unamortized loan issuance costs: December 31, ($ in thousands) 2024 2023 Outstanding loan balance $ 150,000 $ 150,000 Loan fair value 150,463 150,981 Unamortized loan issuance costs $ 55 $ 170
Schedule of Credit Facilities	The Company’s credit facilities and associated securities pledged, were as follows: ($ in thousands) December 31, Available letter of credit and revolving loan facilities - commitments $ 1,045,000 Available letter of credit and revolving loan facilities - in use 789,993 Security pledged under letter of credit and revolving loan facilities: Pledged interests in TS Hamilton Fund $ 230,833 Pledged interests in fixed income portfolio 296,464 Cash 4,713

Share Capital (Tables)

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Schedule of Share Capital	Hamilton Group’s share capital is comprised as follows: ($ in thousands, except share information) Authorized: Common shares of $0.01 par value each (2024 and 2023: 150,000,000) December 31, Issued, outstanding and fully paid: 2024 2023 Class A common shares (2024: 17,820,078 and 2023: 28,644,807) $ 178 $ 286 Class B common shares (2024: 64,271,249 and 2023: 56,036,067) 643 560 Class C common shares (2024: 19,375,670 and 2023: 25,544,229) 194 255 Total $ 1,015 $ 1,101
Schedule of Activity Related to Common Shares	The following is a summary of the activity related to common shares authorized: Class A Class B Class C Unclassified Total Balance - December 31, 2021 53,793,690 46,898,612 34,307,698 — 135,000,000 Share class conversions 200,000 3,582,072 (3,782,072) — — Balance - December 31, 2022 53,993,690 50,480,684 30,525,626 — 135,000,000 Increase in authorized share capital — 15,000,000 — — 15,000,000 Share class conversions (25,348,883) 6,856,668 (4,981,397) 23,473,612 — Balance - December 31, 2023 28,644,807 72,337,352 25,544,229 23,473,612 150,000,000 Share class conversions (1,700,000) 7,868,559 (6,168,559) — — Balance - December 31, 2024 26,944,807 80,205,911 19,375,670 23,473,612 150,000,000 The following is a summary of the activity related to common shares issued and outstanding: Class A Class B Class C Total Balance - December 31, 2021 30,320,078 37,935,266 34,307,698 102,563,042 Share class conversions 200,000 3,582,072 (3,782,072) — Vesting of awards — 580,935 — 580,935 Employee and director share purchases — 22,750 — 22,750 Director share awards granted — 25,805 — 25,805 Share repurchases — (104,673) — (104,673) Balance - December 31, 2022 30,520,078 42,042,155 30,525,626 103,087,859 Share class conversions (1,875,271) 6,856,668 (4,981,397) — IPO shares issued — 6,250,000 — 6,250,000 Vesting of awards — 735,013 — 735,013 Exercise of warrants — 271,097 — 271,097 Director share awards granted — 44,892 — 44,892 Share repurchases — (163,758) — (163,758) Balance - December 31, 2023 28,644,807 56,036,067 25,544,229 110,225,103 Share class conversions (1,700,000) 7,868,559 (6,168,559) — Vesting of awards — 2,291,495 — 2,291,495 Exercise of warrants — 245,779 — 245,779 Director share awards granted — 20,383 — 20,383 Share repurchases (9,124,729) (2,191,034) — (11,315,763) Balance - December 31, 2024 17,820,078 64,271,249 19,375,670 101,466,997

Share Incentive Plans (Tables)

Share Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Compensation Expense Recognized	The following table presents the compensation expense recognized relating to each award type: Years Ended December 31, ($ in thousands) 2024 2023 2022 Share based compensation expense: RSUs $ 12,933 $ 11,358 $ 10,884 VAP RSUs 9,210 30,352 — PSUs 8,241 2,668 (100) Total share based compensation expense: 30,384 44,378 10,784 Tax benefit (1,750) (1,251) (1,074) Share based compensation expense, net of taxes: $ 28,634 $ 43,127 $ 9,710
Schedule of Compensation Expense Unrecognized	The following table presents the unrecognized compensation expense relating to each award type and the weighted-average period in years over which it is expected to be recognized. December 31, 2024 ($ in thousands, except for weighted-average recognition period) Unrecognized Share Based Compensation Expense Weighted-Average Recognition Period Unrecognized share based compensation expense: RSUs $ 9,998 1.2 VAP RSUs 3,134 0.9 PSUs 9,666 1.7 Total unrecognized share based compensation expense: $ 22,798
Schedule of Restricted Stock Unit Activity	The following table presents a roll forward of the Company’s RSUs based on expected vesting: Year Ended December 31, 2024 Number of RSUs Weighted-Average Grant Date Fair Value Balance, beginning of year 1,660,978 $14.06 Granted 1,078,711 $14.67 Vested (719,836) $13.94 Forfeited (65,457) $14.20 Balance, end of year 1,954,396 $14.43 The following table presents a roll forward of the Company’s VAP RSUs based upon expected vesting: Year Ended December 31, 2024 Number of Weighted-Average Grant Date Fair Value Balance, beginning of year 3,147,507 $15.32 Vested (1,530,234) $15.32 Forfeited (88,464) $15.32 Balance, end of year 1,528,809 $15.32
Schedule of PSU Activity	The following table presents a roll forward of the Company's PSUs based upon expected vesting: Year Ended December 31, 2024 Number of PSUs Balance, beginning of year 444,339 Granted 289,804 Vested (41,418) Change in performance factor 610,723 Balance, end of year 1,303,448
Schedule of Outstanding and Exercisable Warrants	The following table presents a summary of the Company's outstanding and exercisable warrants: (Intrinsic value in $ in thousands) Year Ended December 31, 2024 Warrants Outstanding and Exercisable Number of Warrants Weighted-Average Exercise Price Weighted-Average Grant Date Fair Value Total Intrinsic Value Weighted-Average Remaining Contractual Term At December 31, 2022 1,152,500 $ 10.00 $ 4.44 $ 4,287 1.3 Exercised (342,500) $ 10.00 $ 4.27 $ 2,398 At December 31, 2023 810,000 $ 10.00 $ 4.52 $ 4,010 0.3 Exercised (810,000) $ 10.00 $ 4.52 $ 4,140 At December 31, 2024 — $ — $ — $ — 0.0

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Income (Loss) per Common Share	The following table sets forth the computation of basic and diluted income (loss) per common share: Years Ended December 31, ($ in thousands, except share and per share information) 2024 2023 2022 Numerator: Net income (loss) attributable to common shareholders $ 400,429 $ 258,727 $ (97,999) Denominator: Weighted average common shares outstanding - basic 105,133 104,563 103,062 Effect of dilutive securities 3,968 1,640 — Weighted average common shares outstanding - diluted 109,101 106,203 103,062 Basic income (loss) per share attributable to common shareholders $ 3.81 $ 2.47 $ (0.95) Diluted income (loss) per share attributable to common shareholders $ 3.67 $ 2.44 $ (0.95)

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Income (Loss) Before Taxes by Tax Jurisdiction	Income (loss) before taxes by tax jurisdiction is as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Jurisdiction Domestic: Bermuda $ 581,915 $ 247,113 $ 66,823 Foreign: United States 9,122 (2,263) (23,540) United Kingdom 32,249 12,362 (67,213) Ireland (1,726) (1,991) (2,901) Income (loss) before income tax $ 621,560 $ 255,221 $ (26,831)
Schedule of Components of Income Tax Expense (Benefit)	Income tax expense (benefit) consists of the following components: Years Ended December 31, ($ in thousands) 2024 2023 2022 Current income tax expense (benefit) Bermuda $ 9,276 $ 10,376 $ 2,625 United States 652 537 1,818 United Kingdom 91 61 48 Ireland (111) 92 (122) Total current tax expense (benefit) 9,908 11,066 4,369 Deferred income tax expense (benefit) Bermuda (375) (35,063) — United States — — 705 United Kingdom (1,027) (1,087) (1,927) Ireland (104) 18 (43) Total deferred tax expense (benefit) (1,506) (36,132) (1,265) Total income tax expense (benefit) $ 8,402 $ (25,066) $ 3,104
Reconciliation of Taxes	The following table presents a reconciliation of taxes calculated using the 0% Bermudian statutory rate (the tax rate at which the majority of Hamilton Group's worldwide operations are taxed) to the income tax expense (benefit) on pre-tax income (loss): Years Ended December 31, ($ in thousands) 2024 2023 2022 Expected tax provision at Bermuda statutory tax rate of 0% $ — $ — $ — Permanent differences: Taxes on earnings subject to rate other than Bermuda statutory rate 9,762 2,182 (18,077) Change in valuation allowance (12,496) (3,567) 17,060 Impairment of goodwill — — 4,161 Other permanent adjustments (318) (42) (112) Other prior year adjustments 2,234 376 28 Tax rate changes — 273 (2,655) Withholding tax 9,381 10,377 2,625 Bermuda economic transition adjustment — (35,063) — State income tax (161) 398 74 Total income tax expense (benefit): $ 8,402 $ (25,066) $ 3,104
Schedule of Deferred Tax Assets and Liabilities	The following table presents Hamilton Group’s significant deferred tax assets and liabilities: December 31, ($ in thousands) 2024 2023 Deferred tax assets: U.K. net operating loss carryforwards $ 45,590 $ 50,845 U.S. net operating loss carryforwards 3,255 7,121 Ireland net operating loss carryforwards 218 275 Bermuda intangible assets 28,875 28,500 Reserve for losses and loss adjustment expenses 9,198 7,935 Unearned premium reserve 5,486 4,384 Share based compensation 5,213 7,524 Foreign tax credit 1,949 925 Capital loss carryforward 1,733 419 U.K. deferred interest 685 5,278 Deferred acquisition costs 547 (1,540) Loss portfolio transfer 263 2,356 Other 2,763 1,609 Total deferred tax assets 105,775 115,631 Deferred tax liabilities: U.K. intangible assets (14,233) (15,364) Fixed assets (3,520) (2,573) Lloyd's deferred taxable income (3,340) — Other (446) (2,468) Total deferred tax liabilities (21,539) (20,405) Net deferred tax asset (liability) before valuation allowance 84,236 95,226 Valuation allowance (63,032) (75,528) Net deferred tax asset (liability) $ 21,204 $ 19,698
Summary of Operating Loss Carryforwards	The Company had the following net operating loss carry-forwards, inclusive of cumulative currency translation adjustments: ($ in thousands) December 31, 2024 Tax jurisdiction Losses Carried Forward Tax Expiration Bermuda $ — $ — n/a Ireland 1,742 218 No expiry United States 15,501 3,255 2042-2044 United Kingdom $ 182,360 $ 45,590 No expiry

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	Future minimum lease payments under the leases are expected to be as follows: ($ in thousands) Minimum Lease Payments Year ended December 31, 2025 $ 2,431 2026 2,977 2027 2,703 2028 1,262 2029 647 Thereafter 118 Total undiscounted lease liabilities 10,138 Less: present value discount (966) Total recorded lease liability at present value $ 9,172
Schedule of Capital Requirements	The total available capital in support of the capital requirements for Syndicate 4000 is comprised of the following FAL: ($ in thousands) December 31, Unsecured LOC capacity $ 230,000 Fixed income securities 245,254 Cash 1,082 Total $ 476,336

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following tables summarize the impact of transactions with Ada Re: Years Ended December 31, ($ in thousands) 2024 2023 2022 Reinsurance premiums ceded $ (21,584) $ (19,524) $ (11,999) Net premiums earned (21,585) (21,744) (9,780) Other income (loss) 7,434 8,549 201 Losses and loss adjustment expenses 7,676 8,702 5,719 Acquisition costs 5,126 5,125 1,769 Net gain (loss) on related party reinsurance $ (1,349) $ 632 $ (2,091) December 31, ($ in thousands) 2024 2023 Paid losses recoverable $ 2,278 $ 4,319 Unpaid losses and loss adjustment expenses recoverable 13,262 11,149 Other assets 970 8,765 Reinsurance balances payable $ 1,670 $ 3,759

Statutory Requirements (Tables)

Statutory Requirements (Tables)	12 Months Ended
	Dec. 31, 2024
Insurance [Abstract]
Schedule of Statutory Accounting Practices	The actual and minimum required statutory capital and surplus for the Company’s principal operating subsidiaries by regulatory jurisdiction were as follows: Bermuda (1) United Kingdom (2) Ireland (3) United States (4) As at December 31, ($ in thousands) 2024 2023 2024 2023 2024 2023 2024 2023 Required statutory capital and surplus $ 739,605 $ 579,916 $ 125,232 $ 129,995 $ 77,269 $ 68,643 $ 33,780 $ 23,410 Actual statutory capital and surplus $ 2,168,031 $ 1,882,833 $ 624,596 $ 539,016 $ 139,446 $ 127,082 $ 58,017 $ 53,988 ____________ (1) Minimum statutory capital and surplus at December 31, 2024 for the Bermuda operating subsidiary is required to be maintained at the greater of a minimum solvency margin ("MSM"), as disclosed in the table above, and the Enhanced Capital Requirement ("ECR"), where applicable. (2) Minimum statutory capital and surplus at December 31, 2024 for the U.K. operating entities is determined by reference to the entities' Solvency Capital Requirement and the Solvency II capital regime. U.K. operations are subject to Lloyd’s requirements where underwriting members hold acceptable FAL and/or Syndicates hold acceptable Funds In Syndicate ("FIS") for their own account, in support of the total actual statutory capital and surplus amount. Actual statutory capital and surplus is comprised of an Economic Capital Assessment ("ECA"), derived from an approved Solvency II basis Internal model, less any accumulated trading surpluses or plus any accumulated trading deficits, as calculated on a Solvency II basis. (3) The Company's Irish operations are subject to the Solvency II regime, which requires insurance companies to hold assets that cover at least the best estimate of insurance liabilities, a risk margin, plus a risk-based Solvency Capital Requirement designed to protect against extreme stress events. (4) Minimum statutory capital and surplus at December 31, 2024 for U.S. operating subsidiaries is determined with reference to the Company Action Level Risk-Based Capital requirements. The statutory net income (loss) for the Company’s principal operating subsidiaries by regulatory jurisdiction was as follows: Years Ended December 31, ($ in thousands) 2024 2023 2022 Bermuda $ 432,769 $ 270,309 $ 1,993 United Kingdom 61,879 59,778 25,470 Ireland 8,069 (1,911) (32,331) United States $ (12,512) $ (13,250) $ (9,962)

Organization (Details)

Organization (Details) - Two Sigma Hamilton Fund, LLC - Hamilton Re - USD ($) $ in Billions	Jul. 01, 2023	Jun. 30, 2023
Schedule of Equity Method Investments [Line Items]
Commitment for investment in Two Sigma Funds	$ 1.8
Investment in Two Sigma Funds, as a percentage of net tangible assets	60%	95%

Investments - Schedule of Fixed

Investments - Schedule of Fixed Maturity and Short-Term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 2,918,547	$ 2,294,936
Gross Unrealized Gains	9,545	17,667
Gross Unrealized Losses	(53,120)	(52,457)
Investments, at fair value	2,874,972	2,260,146
U.S. government treasuries
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	724,785	717,134
Gross Unrealized Gains	611	5,137
Gross Unrealized Losses	(14,293)	(14,021)
Investments, at fair value	711,103	708,250
U.S. states, territories and municipalities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	13,533	4,656
Gross Unrealized Gains	25	0
Gross Unrealized Losses	(327)	(286)
Investments, at fair value	13,231	4,370
Non-U.S. sovereign governments and supranationals
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	70,435	55,662
Gross Unrealized Gains	454	2,175
Gross Unrealized Losses	(3,362)	(1,591)
Investments, at fair value	67,527	56,246
Corporate
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	1,153,612	877,493
Gross Unrealized Gains	6,484	8,443
Gross Unrealized Losses	(17,036)	(22,060)
Investments, at fair value	1,143,060	863,876
Residential mortgage-backed securities - Agency
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	288,760	180,661
Gross Unrealized Gains	160	435
Gross Unrealized Losses	(16,309)	(12,583)
Investments, at fair value	272,611	168,513
Residential mortgage-backed securities - Non-agency
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	17,432	5,639
Gross Unrealized Gains	6	16
Gross Unrealized Losses	(684)	(671)
Investments, at fair value	16,754	4,984
Commercial mortgage-backed securities - Non-agency
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	40,363	11,473
Gross Unrealized Gains	72	0
Gross Unrealized Losses	(749)	(1,050)
Investments, at fair value	39,686	10,423
Other asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	113,997	14,781
Gross Unrealized Gains	249	20
Gross Unrealized Losses	(356)	(195)
Investments, at fair value	113,890	14,606
Total fixed maturities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	2,422,917	1,867,499
Gross Unrealized Gains	8,061	16,226
Gross Unrealized Losses	(53,116)	(52,457)
Investments, at fair value	2,377,862	1,831,268
Total short-term investments
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	495,630	427,437
Gross Unrealized Gains	1,484	1,441
Gross Unrealized Losses	(4)	0
Investments, at fair value	$ 497,110	$ 428,878

Investments - Schedule of Contr

Investments - Schedule of Contractual Maturities of Fixed Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Amortized Cost
Amortized Cost	$ 2,918,547	$ 2,294,936
Fair Value
Fair Value	2,874,972	2,260,146
Total fixed maturities
Amortized Cost
Amortized Cost	2,422,917	1,867,499
Fair Value
Fair Value	2,377,862	$ 1,831,268
Fixed Maturities, Excluding Mortgage-backed and Asset-backed Securities
Amortized Cost
Due less than one year	191,976
Due after one through five years	1,438,250
Due after five through ten years	327,869
Due after ten years	4,270
Fair Value
Due less than one year	190,229
Due after one through five years	1,419,173
Due after five through ten years	321,983
Due after ten years	3,536
Mortgage-backed securities
Amortized Cost
Mortgage/Asset-backed	346,555
Fair Value
Mortgage/Asset-backed	329,051
Asset-backed securities
Amortized Cost
Mortgage/Asset-backed	113,997
Fair Value
Mortgage/Asset-backed	$ 113,890

Investments - Schedule of Inves

Investments - Schedule of Investments in Two Sigma Funds (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Cost	$ 805,623	$ 770,191
Investments in Two Sigma Funds, at fair value	939,381	851,470
Two Sigma Funds
Marketable Securities [Line Items]
Net Unrealized Gains (Losses)	133,758	81,279
Investments in Two Sigma Funds, at fair value	939,381	851,470
Two Sigma Futures Portfolio, LLC (FTV)
Marketable Securities [Line Items]
Cost	308,061	433,911
Net Unrealized Gains (Losses)	(15,520)	(38,105)
Investments in Two Sigma Funds, at fair value	292,541	395,806
Two Sigma Spectrum Portfolio, LLC (STV)
Marketable Securities [Line Items]
Cost	360,997	193,299
Net Unrealized Gains (Losses)	102,267	88,228
Investments in Two Sigma Funds, at fair value	463,264	281,527
Two Sigma Equity Spectrum Portfolio, LLC (ESTV)
Marketable Securities [Line Items]
Cost	136,565	142,981
Net Unrealized Gains (Losses)	47,011	31,156
Investments in Two Sigma Funds, at fair value	$ 183,576	$ 174,137

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
	Jul. 01, 2023	Jun. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Investment Income [Line Items]
Management fees			$ 49,102	$ 47,049	$ 54,581
Restricted cash and cash equivalents			104,359	106,351
Cash, cash equivalents and restricted cash			1,100,852	900,860	1,207,203	$ 964,126
Cash and cash equivalents			996,493	794,509
Capital Requirements | Asset Pledged as Collateral
Net Investment Income [Line Items]
Investments, fair value			245,300	232,200
Restricted cash and cash equivalents			1,100	7,200
Trust Accounts | Asset Pledged as Collateral
Net Investment Income [Line Items]
Investments, fair value			89,100	54,100
Restricted cash and cash equivalents			1,500	1,500
Underwriting Obligations | Asset Pledged as Collateral
Net Investment Income [Line Items]
Investments, fair value			31,900	37,200
Restricted cash and cash equivalents			101,800	97,400
Escrow Funds | Asset Pledged as Collateral
Net Investment Income [Line Items]
Restricted cash and cash equivalents			0	300
TS Hamilton Fund
Net Investment Income [Line Items]
Management fee percentage	2.50%	3%
Management fees			46,900	45,200	53,100
Incentive allocation	30%
Incentive allocation, reduction (as a percent)	50%
Incentive allocation, cumulative net profits (as a percent)	200%
Incentive allocation, excess profits (as a percent)	25%	20%
Incentive allocation, net profits (as a percent)	10%	15%
Incentive allocation			212,700	21,500	$ 68,000
Cash and cash equivalents			$ 578,230	$ 479,255
TS Hamilton Fund | Hamilton Re
Net Investment Income [Line Items]
Initial term			3 years
Capital account withdrawal, monthly liquidity, number of calendar days prior to month end			15 days
Capital account withdrawal, daily liquidity, number of business day's written notice			1 day
Two Sigma Futures Portfolio, LLC (FTV)
Net Investment Income [Line Items]
Percentage of ownership in funds			14.30%
Two Sigma Spectrum Portfolio, LLC (STV)
Net Investment Income [Line Items]
Percentage of ownership in funds			17.80%
Two Sigma Equity Spectrum Portfolio, LLC (ESTV)
Net Investment Income [Line Items]
Percentage of ownership in funds			9.80%
Two Sigma Hamilton Fund, LLC | Hamilton Re
Net Investment Income [Line Items]
Commitment for investment in Two Sigma Funds	$ 1,800,000
Investment in Two Sigma Funds, as a percentage of net tangible assets	60%	95%

Investments - Schedule of Certa

Investments - Schedule of Certain Investments (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Net Investment Income [Line Items]
Investments in Two Sigma Funds, at fair value	$ 939,381	$ 851,470
TS Hamilton Fund
Net Investment Income [Line Items]
Investments in Two Sigma Funds, at fair value	$ 939,381	$ 851,470
Goldman Sachs Financial Square Treasury Obligations Fund | TS Hamilton Fund | Long
Net Investment Income [Line Items]
Principal / Shares	111,926
Investments in Two Sigma Funds, at fair value	$ 111,926
Goldman Sachs Financial Square Treasury Obligations Fund | Members' Equity | Investment Concentration Risk | TS Hamilton Fund | Long
Net Investment Income [Line Items]
% of Members' Equity	5.90%
Morgan Stanley Institutional Liquidity Funds Treasury Portfolio | TS Hamilton Fund | Long
Net Investment Income [Line Items]
Principal / Shares	109,471
Investments in Two Sigma Funds, at fair value	$ 109,471
Morgan Stanley Institutional Liquidity Funds Treasury Portfolio | Members' Equity | Investment Concentration Risk | TS Hamilton Fund | Long
Net Investment Income [Line Items]
% of Members' Equity	5.80%
JP Morgan U.S. Treasury Plus Money Market Fund - Capital | TS Hamilton Fund | Long
Net Investment Income [Line Items]
Principal / Shares	101,940
Investments in Two Sigma Funds, at fair value	$ 101,940
JP Morgan U.S. Treasury Plus Money Market Fund - Capital | Members' Equity | Investment Concentration Risk | TS Hamilton Fund | Long
Net Investment Income [Line Items]
% of Members' Equity	5.40%
U.S. Treasury Securities, 0.0000% - 4.6250%, due 1/9/2025 - 11/15/2054 | TS Hamilton Fund | Long
Net Investment Income [Line Items]
Principal / Shares	2,105,796
Investments in Two Sigma Funds, at fair value	$ 2,086,814
U.S. Treasury Securities, 0.0000% - 4.6250%, due 1/9/2025 - 11/15/2054 | Members' Equity | Investment Concentration Risk | TS Hamilton Fund | Long
Net Investment Income [Line Items]
% of Members' Equity	110.60%
Invesco Treasury Portfolio Money Market Fund | TS Hamilton Fund | Long
Net Investment Income [Line Items]
Principal / Shares	96,844
Investments in Two Sigma Funds, at fair value	$ 96,844
Invesco Treasury Portfolio Money Market Fund | Members' Equity | Investment Concentration Risk | TS Hamilton Fund | Long
Net Investment Income [Line Items]
% of Members' Equity	5.10%
U.S. Treasury Securities, 4.0000% - 4.6250%, due 12/31/2026 - 11/15/2054 | TS Hamilton Fund | Short
Net Investment Income [Line Items]
Principal / Shares	241,100
Investments in Two Sigma Funds, at fair value	$ 236,974
U.S. Treasury Securities, 4.0000% - 4.6250%, due 12/31/2026 - 11/15/2054 | Members' Equity | Investment Concentration Risk | TS Hamilton Fund | Short
Net Investment Income [Line Items]
% of Members' Equity	12.60%

Investments - Schedule of Reali

Investments - Schedule of Realized and Unrealized Gains (Losses) on Investments and Net Investment Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net realized and unrealized gains (losses) on investments:
Net realized gains (losses) on investments	$ 468,068	$ 84,513	$ 258,653
Change in net unrealized gains (losses) on investments	43,339	125,097	(165,305)
Net realized and unrealized gains (losses) on investments	511,407	209,610	93,348
Net investment income (loss):
Interest and other	113,611	78,452	34,162
Management fees	(49,102)	(47,049)	(54,581)
Other expenses	(1,242)	(947)	(1,068)
Net investment income (loss)	63,267	30,456	(21,487)
Total net realized and unrealized gains (losses) on investments and net investment income (loss)	574,674	240,066	71,861
Total fixed maturities
Net investment income (loss):
Interest and other	81,872	47,970	22,375
Total short-term investments
Net investment income (loss):
Interest and other	67	295	155
TS Hamilton Fund
Net realized and unrealized gains (losses) on investments:
Change in net unrealized gains (losses) on investments	52,247	72,346	(78,051)
Net investment income (loss):
Interest and other	12,373	16,084	10,395
Cash and cash equivalents
Net investment income (loss):
Interest and other	17,006	12,523	2,634
Other
Net investment income (loss):
Interest and other	$ 2,293	$ 1,580	$ (1,397)

Investments - Net Realized Gain

Investments - Net Realized Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Marketable Securities [Line Items]
Net realized gains (losses) on investments	$ 468,068	$ 84,513	$ 258,653
Fixed maturities and short-term investments
Marketable Securities [Line Items]
Net realized gains (losses) on investments	(2,307)	(16,628)	(14,968)
TS Hamilton Fund
Marketable Securities [Line Items]
Net realized gains (losses) on investments	470,091	100,930	266,630
Other
Marketable Securities [Line Items]
Net realized gains (losses) on investments	$ 284	$ 211	$ 6,991

Investments - Net Unrealized Ga

Investments - Net Unrealized Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Marketable Securities [Line Items]
Unrealized gain (loss) on investments	$ 43,339	$ 125,097	$ (165,305)
Fixed maturities and short-term investments
Marketable Securities [Line Items]
Unrealized gain (loss) on investments	(8,908)	52,751	(87,254)
TS Hamilton Fund
Marketable Securities [Line Items]
Unrealized gain (loss) on investments	$ 52,247	$ 72,346	$ (78,051)

Fair Value (Details)

Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	$ 2,874,972	$ 2,260,146
Total	2,874,972	2,260,146
U.S. government treasuries
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	711,103	708,250
U.S. states, territories and municipalities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	13,231	4,370
Non-U.S. sovereign governments and supranationals
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	67,527	56,246
Corporate
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	1,143,060	863,876
Residential mortgage-backed securities - Agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	272,611	168,513
Residential mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	16,754	4,984
Commercial mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	39,686	10,423
Other asset-backed securities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	113,890	14,606
Total fixed maturities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	2,377,862	1,831,268
Total short-term investments
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	497,110	428,878
Level 1
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total	0	0
Level 1 | U.S. government treasuries
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | U.S. states, territories and municipalities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Non-U.S. sovereign governments and supranationals
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Corporate
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Residential mortgage-backed securities - Agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Residential mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Commercial mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Other asset-backed securities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Total fixed maturities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 1 | Total short-term investments
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 2
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total	2,874,972	2,260,146
Level 2 | U.S. government treasuries
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	711,103	708,250
Level 2 | U.S. states, territories and municipalities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	13,231	4,370
Level 2 | Non-U.S. sovereign governments and supranationals
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	67,527	56,246
Level 2 | Corporate
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	1,143,060	863,876
Level 2 | Residential mortgage-backed securities - Agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	272,611	168,513
Level 2 | Residential mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	16,754	4,984
Level 2 | Commercial mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	39,686	10,423
Level 2 | Other asset-backed securities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	113,890	14,606
Level 2 | Total fixed maturities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	2,377,862	1,831,268
Level 2 | Total short-term investments
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	497,110	428,878
Level 3
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total	0	0
Level 3 | U.S. government treasuries
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | U.S. states, territories and municipalities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Non-U.S. sovereign governments and supranationals
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Corporate
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Residential mortgage-backed securities - Agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Residential mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Commercial mortgage-backed securities - Non-agency
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Other asset-backed securities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Total fixed maturities
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	0	0
Level 3 | Total short-term investments
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Investments, at fair value	$ 0	$ 0

Variable Interest Entities - Sc

Variable Interest Entities - Schedule of Activity in the Non-Controlling Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity, Attributable to Noncontrolling Interest [Roll Forward]
Balance - beginning of year	$ 133
Balance - end of year	128	$ 133
TS Hamilton Fund
Equity, Attributable to Noncontrolling Interest [Roll Forward]
Balance - beginning of year	133	119	$ 124
Withdrawals	(212,734)	(21,546)	(68,069)
Equity in earnings	43	14	14
Incentive allocation	212,686	21,546	68,050
Balance - end of year	$ 128	$ 133	$ 119

Variable Interest Entities - _2

Variable Interest Entities - Schedule of Total Assets and Total Liabilities of TS Hamilton Fund (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Assets
Cash and cash equivalents	$ 996,493	$ 794,509
Short-term investments	2,874,972	2,260,146
Investments in Two Sigma Funds, at fair value	939,381	851,470
Receivables for investments sold	74,006	42,419
Total assets	7,796,033	6,671,355
Liabilities
Payable for investments purchased	115,427	66,606
Accounts payable and accrued expenses	185,361	186,887
Total liabilities	5,467,196	4,623,372
Total short-term investments
Assets
Short-term investments	497,110	428,878
TS Hamilton Fund
Assets
Cash and cash equivalents	578,230	479,255
Investments in Two Sigma Funds, at fair value	939,381	851,470
Receivables for investments sold	73,322	41,087
Interest and dividends receivable	945	966
Total assets	2,087,886	1,801,656
Liabilities
Payable for investments purchased	100,469	62,440
Withdrawal payable	100,420	6,480
Accounts payable and accrued expenses	233	191
Total liabilities	201,122	69,111
Total net assets managed by TS Hamilton Fund	1,886,764	1,732,545
TS Hamilton Fund | Total short-term investments
Assets
Short-term investments	$ 496,008	$ 428,878

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Summary of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill
Beginning Balance	$ 0	$ 0
Ending Balance	0	0	$ 0
Gross Balance	0
Intangible Assets Subject to Amortization
Beginning balance	53,788	49,750
Plus: additions	17,645	14,821
Less: amortization	(15,520)	(10,783)	(12,832)
Accumulated amortization	(50,768)	(35,246)
Ending balance	55,913	53,788	49,750
Gross Balance	106,681
Intangible Assets not Subject to Amortization
Beginning balance	37,208	37,208
Ending balance	37,208	37,208	37,208
Plus: additions	17,645	14,821
Gross balance	143,889
Intangible assets	$ 93,121	$ 90,996	$ 86,958

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Impairment of goodwill	$ 0	$ 0	$ 24,082
Weighted-average amortization period	2 years 6 months
Coverholder and broker relationships
Goodwill [Line Items]
Useful life	10 years
Internally developed software
Goodwill [Line Items]
Useful life	5 years

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Components of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Gross Balance	$ 106,681
Gross Balance	37,208	$ 37,208	$ 37,208
Gross Balance	143,889	126,242
Accumulated amortization	(50,768)	(35,246)
Total	55,913	53,788	$ 49,750
Net Balance	93,121	90,996
Lloyd's syndicate capacity
Goodwill [Line Items]
Gross Balance	35,583	35,583
Licenses
Goodwill [Line Items]
Gross Balance	1,625	1,625
Coverholder and broker relationships
Goodwill [Line Items]
Gross Balance	44,515	44,515
Accumulated amortization	(23,707)	(19,255)
Total	20,808	25,260
Internally developed software
Goodwill [Line Items]
Gross Balance	62,166	44,519
Accumulated amortization	(27,061)	(15,991)
Total	$ 35,105	$ 28,528

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2025	$ 15,656
2026	13,551
2027	12,353
2028	9,463
2029	4,890
Total	$ 55,913	$ 53,788	$ 49,750

Reinsurance - Schedule of Effec

Reinsurance - Schedule of Effect of Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Premiums Written
Assumed	$ 1,144,798	$ 838,547	$ 709,194
Direct	1,277,784	1,112,491	937,479
Reinsurance premiums ceded	(501,413)	(470,600)	(424,809)
Net premiums written	1,921,169	1,480,438	1,221,864
Premiums Earned
Assumed	1,030,595	742,378	670,272
Direct	1,180,932	1,016,762	886,488
Ceded	(476,798)	(440,607)	(413,046)
Net premiums earned	1,734,729	1,318,533	1,143,714
Losses and Loss Adjustment Expenses
Gross losses and loss adjustment expenses	1,290,131	972,347	1,133,469
Losses and loss adjustment expenses ceded	(279,958)	(257,744)	(375,136)
Total incurred	$ 1,010,173	$ 714,603	$ 758,333

Reinsurance - Narrative (Detail

Reinsurance - Narrative (Details) - USD ($) $ in Thousands		1 Months Ended		12 Months Ended
	Feb. 06, 2020	Dec. 31, 2023	Dec. 31, 2020	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Ceded Credit Risk [Line Items]
Premiums receivable balance, credit provisions		$ 3,000		$ 2,993	$ 3,000	$ 2,856	$ 2,165
Premiums receivable		658,363		771,707	658,363
Paid losses recoverable		145,202		134,406	145,202
Unpaid losses and loss adjustment expenses recoverable		1,161,077		1,171,040	1,161,077	1,177,863	1,112,543
Reinsurance recoverable, provisions		687		1,469	687	777	$ 616
Ceded to other companies				501,413	470,600	424,809
Related Party
Ceded Credit Risk [Line Items]
Ceded to other companies				14,600	7,200	6,300
Risk transfer capacity		200,000	$ 150,000
Reinsurance Contract [Axis]: Loss Portfolio Transfer Agreement
Ceded Credit Risk [Line Items]
Unpaid losses and loss adjustment expenses recoverable		$ 49,800		23,700	49,800
Ceded to other companies	$ 72,100
Amortization of the deferred gain				$ (9,400)	$ 4,200	$ 1,900
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Reinsurer Concentration Risk
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable				100%	100%
Reinsurer One | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Reinsurer Concentration Risk
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable				22%	27%
Reinsurer Two | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Reinsurer Concentration Risk
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable				19%	20%
Reinsurer Three | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Reinsurer Concentration Risk
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable				13%	12%

Reinsurance - Schedule of Rollf

Reinsurance - Schedule of Rollforward of Provision of Company's Premiums Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Accounts, Notes, Loans and Financing Receivable [Rollforward]
Beginning balance	$ 3,000	$ 2,856	$ 2,165
Increase (decrease) in allowance	(7)	144	691
Ending balance	$ 2,993	$ 3,000	$ 2,856

Reinsurance - Schedule of Rol_2

Reinsurance - Schedule of Rollforward of Provision of Company's Reinsurance Recoverable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Accounts, Notes, Loans and Financing Receivable [Rollforward]
Beginning balance	$ 687	$ 777	$ 616
Increase (decrease) in allowance	782	(90)	161
Ending balance	$ 1,469	$ 687	$ 777

Reinsurance - Schedule of Paid

Reinsurance - Schedule of Paid and Unpaid Losses and Loss Adjustment Expenses Recoverable (Details) - Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments - Reinsurer Concentration Risk	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable	100%	100%
A- or better
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable	76.20%	71%
Below A-
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable	0.10%	0.50%
Collateralized
Ceded Credit Risk [Line Items]
% of total paid and unpaid losses and loss adjustment expenses recoverable	23.70%	28.50%

Reserve for Losses and Loss A_3

Reserve for Losses and Loss Adjustment Expenses - Schedule of Reconciliation of Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross unpaid losses and loss adjustment expenses, beginning of year	$ 3,030,037	$ 2,856,275	$ 2,415,491
Reinsurance recoverable on unpaid losses	1,161,077	1,177,863	1,112,543
Net unpaid losses and loss adjustment expenses, beginning of year	1,868,960	1,678,412	1,302,948
Net losses and loss adjustment expenses incurred in respect of losses occurring in:
Current year	1,030,612	730,220	778,936
Prior years	(20,439)	(15,617)	(20,603)
Total incurred	1,010,173	714,603	758,333
Net losses and loss adjustment expenses paid in respect of losses occurring in:
Current year	58,726	62,811	61,649
Prior years	458,040	501,987	315,537
Total paid	516,766	564,798	377,186
Foreign currency revaluation and other	(916)	40,743	(5,683)
Net unpaid losses and loss adjustment expenses, end of year	2,361,451	1,868,960	1,678,412
Reinsurance recoverable on unpaid losses	1,171,040	1,161,077	1,177,863
Gross unpaid losses and loss adjustment expenses, end of year	$ 3,532,491	$ 3,030,037	$ 2,856,275

Reserve for Losses and Loss A_4

Reserve for Losses and Loss Adjustment Expenses - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	$ (20,439)	$ (15,617)	$ (20,603)
Acquisition costs	388,931	309,148	271,189
Reserve for losses and loss adjustment expenses	3,532,491	3,030,037	2,856,275	$ 2,415,491
Ukrainian Conflict
Liability for Claims and Claims Adjustment Expense [Line Items]
Reserve for losses and loss adjustment expenses	63,200	64,900
Covid-19
Liability for Claims and Claims Adjustment Expense [Line Items]
Reserve for losses and loss adjustment expenses	13,300	14,100
Baltimore Bridge
Liability for Claims and Claims Adjustment Expense [Line Items]
Reserve for losses and loss adjustment expenses	34,800	0
Property Contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	(37,500)	4,600	(400)
Casualty Lines
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	14,200	3,400	23,700
Casualty Lines | Reinsurance Contract [Axis]: Loss Portfolio Transfer Agreement
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	(5,900)	(5,000)	(7,000)
Net unfavorable (favorable) development in the underlying reserves	15,300	800
Amortization of deferred gain	(9,400)	(4,200)
Specialty Contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	8,800	(18,600)	(36,900)
Hurricane Ida
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)			(9,500)
Attritional Losses
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)			7,000
Other Catastrophes
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)			2,100
Attritional Losses
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	800	(5,200)	(3,200)
Catastrophe Losses
Liability for Claims and Claims Adjustment Expense [Line Items]
Net prior year development, unfavorable (favorable)	$ (21,200)	$ (10,400)	$ (17,400)

Reserve for Losses and Loss A_5

Reserve for Losses and Loss Adjustment Expenses - Incurred and Paid Accident Year Claims Development, Net of Reinsurance (Details) $ in Thousands	Dec. 31, 2024 USD ($) claim	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Nov. 30, 2021 USD ($)	Nov. 30, 2020 USD ($)	Nov. 30, 2019 USD ($)	Nov. 30, 2018 USD ($)	Nov. 30, 2017 USD ($)	Nov. 30, 2016 USD ($)	Nov. 30, 2015 USD ($)
International - Property
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 557,164
IBNR	$ 77,597
Cumulative Number of Reported Claims | claim	10,787
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 446,488
International - Property | 2015
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 1	$ 1	$ 1
IBNR	$ 0
Cumulative Number of Reported Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0	0	0	0	0
International - Property | 2016
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	7,306	7,349	7,261	7,155	6,011	6,351	6,212	6,551	7,527
IBNR	$ 27
Cumulative Number of Reported Claims | claim	903
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,277	7,277	7,003	6,891	7,049	6,668	4,567	3,428	171
International - Property | 2017
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	40,456	41,230	41,224	41,260	41,819	44,911	42,986	38,379
IBNR	$ (974)
Cumulative Number of Reported Claims | claim	1,166
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 41,333	40,900	40,832	39,984	40,193	34,363	29,283	9,249
International - Property | 2018
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	23,869	24,466	24,542	24,537	24,873	26,191	24,037
IBNR	$ 114
Cumulative Number of Reported Claims | claim	1,122
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 23,603	21,964	20,905	20,053	17,340	12,036	1,322
International - Property | 2019
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	34,824	36,687	36,672	36,609	33,895	32,695
IBNR	$ 411
Cumulative Number of Reported Claims | claim	1,436
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 34,066	32,942	25,818	20,940	21,106	8,307
International - Property | 2020
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	142,802	143,418	143,676	144,201	134,743
IBNR	$ 5,261
Cumulative Number of Reported Claims | claim	2,236
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 136,041	132,191	115,587	90,859	24,365
International - Property | 2021
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	117,228	121,907	124,917	113,813
IBNR	$ 3,371
Cumulative Number of Reported Claims | claim	1,566
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 112,184	101,064	63,784	23,564
International - Property | 2022
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	68,686	74,560	81,324
IBNR	$ 4,035
Cumulative Number of Reported Claims | claim	1,077
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 57,551	46,856	9,996
International - Property | 2023
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	48,480	53,085
IBNR	$ 10,278
Cumulative Number of Reported Claims | claim	681
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 29,362	5,502
International - Property | 2024
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	73,513
IBNR	$ 55,074
Cumulative Number of Reported Claims | claim	598
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 5,071
International - Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	645,870
IBNR	$ 452,426
Cumulative Number of Reported Claims | claim	24,066
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 121,737
International - Casualty | 2015
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	0	0	0	0	0	0	0	0	0
IBNR	$ 0
Cumulative Number of Reported Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0	0	0	0	0
International - Casualty | 2016
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	166	367	388	342	342	342	243	278	171
IBNR	$ 0
Cumulative Number of Reported Claims | claim	32
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0	82	0	0
International - Casualty | 2017
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	4,579	5,079	5,121	5,857	6,332	7,354	5,187	648
IBNR	$ 328
Cumulative Number of Reported Claims | claim	73
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,046	4,043	3,964	2,406	2,285	629	22	0
International - Casualty | 2018
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	4,300	4,453	4,351	4,941	5,686	5,890	697
IBNR	$ 110
Cumulative Number of Reported Claims | claim	554
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,066	4,011	3,800	3,167	2,266	439	35
International - Casualty | 2019
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	15,846	16,817	18,112	18,867	19,199	19,882
IBNR	$ 704
Cumulative Number of Reported Claims | claim	2,704
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 15,131	14,992	13,332	6,813	2,719	177
International - Casualty | 2020
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	19,265	19,426	17,870	24,123	28,692
IBNR	$ 2,451
Cumulative Number of Reported Claims | claim	3,641
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 16,813	16,706	12,480	8,420	3,363
International - Casualty | 2021
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	106,824	107,024	109,013	101,549
IBNR	$ 69,619
Cumulative Number of Reported Claims | claim	3,602
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 30,286	20,079	11,243	795
International - Casualty | 2022
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	149,180	145,030	144,543
IBNR	$ 87,661
Cumulative Number of Reported Claims | claim	3,912
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 27,217	9,452	3,240
International - Casualty | 2023
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	147,005	145,783
IBNR	$ 108,769
Cumulative Number of Reported Claims | claim	5,639
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 19,429	5,240
International - Casualty | 2024
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	198,705
IBNR	$ 182,784
Cumulative Number of Reported Claims | claim	3,909
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,749
International - Specialty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	942,174
IBNR	$ 309,086
Cumulative Number of Reported Claims | claim	19,589
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 531,768
International - Specialty | 2015
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	101	100	94	149	144	212	218	138	93	0
IBNR	$ 0
Cumulative Number of Reported Claims | claim	65
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 94	94	94	150	150	147	119	62	16	0
International - Specialty | 2016
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	4,427	3,325	3,367	3,668	5,370	5,232	5,383	4,771	2,534
IBNR	$ 504
Cumulative Number of Reported Claims | claim	766
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,874	3,265	3,265	3,600	3,446	3,098	4,000	2,141	248
International - Specialty | 2017
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	31,279	27,714	25,397	22,030	15,256	16,943	17,430	22,378
IBNR	$ 2,277
Cumulative Number of Reported Claims | claim	1,300
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 28,928	25,858	23,043	21,256	21,763	16,986	8,992	2,427
International - Specialty | 2018
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	42,921	42,995	37,834	33,129	29,176	30,606	31,724
IBNR	$ (287)
Cumulative Number of Reported Claims | claim	1,617
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 43,177	40,792	35,614	30,839	30,652	17,155	2,054
International - Specialty | 2019
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	95,306	95,702	97,777	104,017	109,971	108,035
IBNR	$ 5,405
Cumulative Number of Reported Claims | claim	2,852
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 89,858	86,733	78,807	77,532	59,152	14,076
International - Specialty | 2020
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	105,310	105,314	106,774	116,242	119,790
IBNR	$ 4,426
Cumulative Number of Reported Claims | claim	2,943
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 100,757	94,657	84,864	53,425	12,218
International - Specialty | 2021
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	140,697	138,471	136,998	124,844
IBNR	$ 10,573
Cumulative Number of Reported Claims | claim	3,073
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 105,231	67,950	45,838	9,743
International - Specialty | 2022
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	121,981	119,581	129,423
IBNR	$ 15,941
Cumulative Number of Reported Claims | claim	2,864
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 77,303	41,596	9,001
International - Specialty | 2023
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	178,984	178,429
IBNR	$ 68,974
Cumulative Number of Reported Claims | claim	2,529
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 72,227	17,943
International - Specialty | 2024
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	221,168
IBNR	$ 201,273
Cumulative Number of Reported Claims | claim	1,580
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 10,319
Bermuda - Property
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	996,711
IBNR	$ 219,758
Cumulative Number of Reported Claims | claim	1,705
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 684,106
Bermuda - Property | 2015
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	6,705	5,667	6,439	6,467	6,492	7,821	12,184	12,643	17,011	29,519
IBNR	$ 0
Cumulative Number of Reported Claims | claim	41
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,700	5,647	5,646	5,630	5,608	5,417	5,297	5,163	4,664	1,775
Bermuda - Property | 2016
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	35,011	35,132	35,652	36,340	35,120	35,938	37,476	38,658	56,248
IBNR	$ 0
Cumulative Number of Reported Claims | claim	107
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 34,823	34,741	34,609	33,985	32,882	31,685	29,623	25,596	12,840
Bermuda - Property | 2017
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	82,467	83,603	83,413	79,484	81,032	93,332	98,094	100,603
IBNR	$ 898
Cumulative Number of Reported Claims | claim	272
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 79,097	78,356	75,524	71,795	82,940	71,190	90,864	24,533
Bermuda - Property | 2018
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	69,594	70,675	73,819	78,132	77,845	80,131	62,057
IBNR	$ 371
Cumulative Number of Reported Claims | claim	241
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 67,938	67,410	65,583	67,547	85,660	71,557	12,631
Bermuda - Property | 2019
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	56,413	57,631	57,939	56,265	44,540	14,775
IBNR	$ 2,010
Cumulative Number of Reported Claims | claim	141
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 51,248	49,705	46,504	38,002	32,433	2,401
Bermuda - Property | 2020
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	127,579	126,583	126,275	120,840	112,056
IBNR	$ 5,620
Cumulative Number of Reported Claims | claim	295
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 113,365	104,870	75,445	48,246	13,253
Bermuda - Property | 2021
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	150,283	157,881	161,604	144,924
IBNR	$ 8,385
Cumulative Number of Reported Claims | claim	205
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 130,528	106,089	71,293	16,080
Bermuda - Property | 2022
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	199,762	209,797	181,052
IBNR	$ 37,648
Cumulative Number of Reported Claims | claim	232
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 137,313	109,215	35,261
Bermuda - Property | 2023
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	100,047	102,739
IBNR	$ 45,914
Cumulative Number of Reported Claims | claim	79
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 38,728	26,199
Bermuda - Property | 2024
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	168,850
IBNR	$ 118,912
Cumulative Number of Reported Claims | claim	92
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 24,366
Bermuda - Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,194,219
IBNR	$ 576,666
Cumulative Number of Reported Claims | claim	200
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 485,071
Bermuda - Casualty | 2015
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	41,378	41,677	49,546	50,570	39,331	38,585	30,313	31,552	18,378	19,729
IBNR	$ 7,888
Cumulative Number of Reported Claims | claim	38
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 37,260	30,726	34,198	25,671	18,828	16,953	11,246	3,569	2,111	708
Bermuda - Casualty | 2016
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	57,154	54,997	60,342	56,353	56,863	54,619	54,253	49,876	44,749
IBNR	$ 4,682
Cumulative Number of Reported Claims | claim	7
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 44,726	41,115	39,381	35,482	27,103	20,504	12,678	5,169	1,541
Bermuda - Casualty | 2017
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	139,565	137,924	126,190	113,594	105,558	101,443	96,345	84,754
IBNR	$ 9,057
Cumulative Number of Reported Claims | claim	39
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 117,341	106,013	91,855	70,548	50,471	22,829	10,961	3,792
Bermuda - Casualty | 2018
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	142,520	133,476	131,717	121,692	123,114	115,594	101,397
IBNR	$ 14,967
Cumulative Number of Reported Claims | claim	34
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 105,495	87,677	70,939	66,889	50,903	22,800	3,782
Bermuda - Casualty | 2019
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	98,242	105,390	100,758	101,614	96,207	85,454
IBNR	$ 22,097
Cumulative Number of Reported Claims | claim	18
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 58,930	53,528	36,161	23,445	11,094	3,965
Bermuda - Casualty | 2020
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	88,992	88,632	88,400	84,493	81,925
IBNR	$ 26,122
Cumulative Number of Reported Claims | claim	21
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 49,768	35,047	19,713	14,495	5,417
Bermuda - Casualty | 2021
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	79,183	80,015	79,096	69,766
IBNR	$ 40,792
Cumulative Number of Reported Claims | claim	7
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 26,962	11,255	4,523	1,934
Bermuda - Casualty | 2022
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	107,522	110,095	110,317
IBNR	$ 75,580
Cumulative Number of Reported Claims | claim	3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,565	4,744	696
Bermuda - Casualty | 2023
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	171,462	169,608
IBNR	$ 127,989
Cumulative Number of Reported Claims | claim	30
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 21,821	2,025
Bermuda - Casualty | 2024
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	268,201
IBNR	$ 247,492
Cumulative Number of Reported Claims | claim	3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 8,203
Bermuda - Specialty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	500,159
IBNR	$ 214,933
Cumulative Number of Reported Claims | claim	626
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 247,025
Bermuda - Specialty | 2015
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	15,277	15,288	15,672	15,383	16,820	17,466	19,237	19,342	26,686	27,712
IBNR	$ 16
Cumulative Number of Reported Claims | claim	39
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,911	14,832	14,767	14,432	14,397	14,192	13,115	13,136	8,638	$ 3,330
Bermuda - Specialty | 2016
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	15,684	15,851	15,846	16,850	19,826	23,171	28,913	34,835	38,154
IBNR	$ 565
Cumulative Number of Reported Claims | claim	58
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,603	14,413	13,810	13,589	13,116	10,814	5,632	8,661	$ 2,938
Bermuda - Specialty | 2017
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	26,216	27,334	26,820	24,470	29,590	36,230	44,156	57,528
IBNR	$ 735
Cumulative Number of Reported Claims | claim	74
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 24,267	24,384	22,638	17,726	16,417	14,114	10,194	$ 2,217
Bermuda - Specialty | 2018
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	40,386	39,920	38,658	45,096	48,323	52,420	58,551
IBNR	$ 953
Cumulative Number of Reported Claims | claim	89
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 36,457	33,653	27,789	28,223	25,826	19,326	$ 7,607
Bermuda - Specialty | 2019
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	49,857	48,508	49,114	48,874	56,189	62,075
IBNR	$ 5,280
Cumulative Number of Reported Claims | claim	109
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 42,679	45,062	36,472	29,083	20,505	$ 6,373
Bermuda - Specialty | 2020
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	54,586	54,645	52,195	56,807	63,176
IBNR	$ 3,468
Cumulative Number of Reported Claims | claim	116
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 47,047	43,226	32,653	25,585	$ 9,160
Bermuda - Specialty | 2021
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	33,499	35,610	46,023	53,732
IBNR	$ 8,721
Cumulative Number of Reported Claims | claim	33
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 19,114	15,938	7,248	$ 3,862
Bermuda - Specialty | 2022
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	111,565	114,225	117,538
IBNR	$ 73,277
Cumulative Number of Reported Claims | claim	76
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 29,008	17,086	$ 3,465
Bermuda - Specialty | 2023
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	70,783	62,095
IBNR	$ 49,590
Cumulative Number of Reported Claims | claim	28
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,233	$ 5,028
Bermuda - Specialty | 2024
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	82,306
IBNR	$ 72,328
Cumulative Number of Reported Claims | claim	4
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,706

Reserve for Losses and Loss A_6

Reserve for Losses and Loss Adjustment Expenses - Cumulative Paid Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2015
Claims Development [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	$ 2,320,877
International - Property
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	446,488
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	110,676
International - Property | 2015
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
International - Property | 2016
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	7,277	7,277	7,003	6,891	7,049	6,668	4,567	3,428	171
International - Property | 2017
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	41,333	40,900	40,832	39,984	40,193	34,363	29,283	9,249
International - Property | 2018
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	23,603	21,964	20,905	20,053	17,340	12,036	1,322
International - Property | 2019
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	34,066	32,942	25,818	20,940	21,106	8,307
International - Property | 2020
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	136,041	132,191	115,587	90,859	24,365
International - Property | 2021
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	112,184	101,064	63,784	23,564
International - Property | 2022
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	57,551	46,856	9,996
International - Property | 2023
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	29,362	5,502
International - Casualty
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	121,737
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	524,133
International - Casualty | 2015
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	0	0	0	0	0	0	0	0	0
International - Casualty | 2016
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	0	0	0	0	0	82	0	0
International - Casualty | 2017
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	4,046	4,043	3,964	2,406	2,285	629	22	0
International - Casualty | 2018
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	4,066	4,011	3,800	3,167	2,266	439	35
International - Casualty | 2019
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	15,131	14,992	13,332	6,813	2,719	177
International - Casualty | 2020
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	16,813	16,706	12,480	8,420	3,363
International - Casualty | 2021
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	30,286	20,079	11,243	795
International - Casualty | 2022
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	27,217	9,452	3,240
International - Casualty | 2023
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	19,429	5,240
International - Specialty
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	531,768
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	410,406
International - Specialty | 2015
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	94	94	94	150	150	147	119	62	16	0
International - Specialty | 2016
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	3,874	3,265	3,265	3,600	3,446	3,098	4,000	2,141	248
International - Specialty | 2017
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	28,928	25,858	23,043	21,256	21,763	16,986	8,992	2,427
International - Specialty | 2018
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	43,177	40,792	35,614	30,839	30,652	17,155	2,054
International - Specialty | 2019
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	89,858	86,733	78,807	77,532	59,152	14,076
International - Specialty | 2020
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	100,757	94,657	84,864	53,425	12,218
International - Specialty | 2021
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	105,231	67,950	45,838	9,743
International - Specialty | 2022
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	77,303	41,596	9,001
International - Specialty | 2023
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	72,227	17,943
Bermuda - Property
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	684,106
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	312,638
Bermuda - Property | 2014
Claims Development [Line Items]
Outstanding liabilities for accident year 2014 and prior, net of reinsurance	33
Bermuda - Property | 2015
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	6,700	5,647	5,646	5,630	5,608	5,417	5,297	5,163	4,664	1,775
Bermuda - Property | 2016
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	34,823	34,741	34,609	33,985	32,882	31,685	29,623	25,596	12,840
Bermuda - Property | 2017
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	79,097	78,356	75,524	71,795	82,940	71,190	90,864	24,533
Bermuda - Property | 2018
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	67,938	67,410	65,583	67,547	85,660	71,557	12,631
Bermuda - Property | 2019
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	51,248	49,705	46,504	38,002	32,433	2,401
Bermuda - Property | 2020
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	113,365	104,870	75,445	48,246	13,253
Bermuda - Property | 2021
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	130,528	106,089	71,293	16,080
Bermuda - Property | 2022
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	137,313	109,215	35,261
Bermuda - Property | 2023
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	38,728	26,199
Bermuda - Casualty
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	485,071
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	709,672
Bermuda - Casualty | 2014
Claims Development [Line Items]
Outstanding liabilities for accident year 2014 and prior, net of reinsurance	524
Bermuda - Casualty | 2015
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	37,260	30,726	34,198	25,671	18,828	16,953	11,246	3,569	2,111	708
Bermuda - Casualty | 2016
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	44,726	41,115	39,381	35,482	27,103	20,504	12,678	5,169	1,541
Bermuda - Casualty | 2017
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	117,341	106,013	91,855	70,548	50,471	22,829	10,961	3,792
Bermuda - Casualty | 2018
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	105,495	87,677	70,939	66,889	50,903	22,800	3,782
Bermuda - Casualty | 2019
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	58,930	53,528	36,161	23,445	11,094	3,965
Bermuda - Casualty | 2020
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	49,768	35,047	19,713	14,495	5,417
Bermuda - Casualty | 2021
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	26,962	11,255	4,523	1,934
Bermuda - Casualty | 2022
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	14,565	4,744	696
Bermuda - Casualty | 2023
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	21,821	2,025
Bermuda - Specialty
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	247,025
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	253,352
Bermuda - Specialty | 2014
Claims Development [Line Items]
Outstanding liabilities for accident year 2014 and prior, net of reinsurance	218
Bermuda - Specialty | 2015
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	14,911	14,832	14,767	14,432	14,397	14,192	13,115	13,136	8,638	$ 3,330
Bermuda - Specialty | 2016
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	14,603	14,413	13,810	13,589	13,116	10,814	5,632	8,661	$ 2,938
Bermuda - Specialty | 2017
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	24,267	24,384	22,638	17,726	16,417	14,114	10,194	$ 2,217
Bermuda - Specialty | 2018
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	36,457	33,653	27,789	28,223	25,826	19,326	$ 7,607
Bermuda - Specialty | 2019
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	42,679	45,062	36,472	29,083	20,505	$ 6,373
Bermuda - Specialty | 2020
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	47,047	43,226	32,653	25,585	$ 9,160
Bermuda - Specialty | 2021
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	19,114	15,938	7,248	$ 3,862
Bermuda - Specialty | 2022
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	29,008	17,086	$ 3,465
Bermuda - Specialty | 2023
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,233	$ 5,028

Reserve for Losses and Loss A_7

Reserve for Losses and Loss Adjustment Expenses - Average Annual Percentage Payout (Details) $ in Thousands	Dec. 31, 2024 USD ($) claim	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Nov. 30, 2021 USD ($)	Nov. 30, 2020 USD ($)	Nov. 30, 2019 USD ($)	Nov. 30, 2018 USD ($)	Nov. 30, 2017 USD ($)	Nov. 30, 2016 USD ($)	Nov. 30, 2015 USD ($)
International - Property
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
1	16%
2	44%
3	19%
4	12%
5	5%
6	3%
7	3%
8	1%
9	0%
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 557,164
IBNR	$ 77,597
Cumulative Number of Reported Claims | claim	10,787
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 446,488
International - Property | 2015
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 1	$ 1	$ 1
IBNR	$ 0
Cumulative Number of Reported Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0	0	0	0	0
International - Casualty
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
1	3%
2	9%
3	12%
4	16%
5	6%
6	8%
7	1%
8	0%
9	0%
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 645,870
IBNR	$ 452,426
Cumulative Number of Reported Claims | claim	24,066
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 121,737
International - Casualty | 2015
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0	0	0	0	0	0	0	0	0	0
IBNR	$ 0
Cumulative Number of Reported Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0	0	0	0	0
International - Specialty
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
1	8%
2	32%
3	24%
4	12%
5	7%
6	6%
7	6%
8	8%
9	13%
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 942,174
IBNR	$ 309,086
Cumulative Number of Reported Claims | claim	19,589
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 531,768
International - Specialty | 2015
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	101	100	94	149	144	212	218	138	93	0
IBNR	$ 0
Cumulative Number of Reported Claims | claim	65
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 94	94	94	150	150	147	119	62	16	0
Bermuda - Property
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
1	17%
2	42%
3	13%
4	11%
5	0%
6	3%
7	2%
8	1%
9	0%
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 996,711
IBNR	$ 219,758
Cumulative Number of Reported Claims | claim	1,705
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 684,106
Bermuda - Property | 2015
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	6,705	5,667	6,439	6,467	6,492	7,821	12,184	12,643	17,011	29,519
IBNR	$ 0
Cumulative Number of Reported Claims | claim	41
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,700	5,647	5,646	5,630	5,608	5,417	5,297	5,163	4,664	1,775
Bermuda - Casualty
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
1	3%
2	8%
3	11%
4	16%
5	12%
6	11%
7	11%
8	9%
9	0%
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,194,219
IBNR	$ 576,666
Cumulative Number of Reported Claims | claim	200
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 485,071
Bermuda - Casualty | 2015
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	41,378	41,677	49,546	50,570	39,331	38,585	30,313	31,552	18,378	19,729
IBNR	$ 7,888
Cumulative Number of Reported Claims | claim	38
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 37,260	30,726	34,198	25,671	18,828	16,953	11,246	3,569	2,111	708
Bermuda - Specialty
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
1	10%
2	21%
3	14%
4	13%
5	8%
6	6%
7	5%
8	1%
9	1%
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 500,159
IBNR	$ 214,933
Cumulative Number of Reported Claims | claim	626
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 247,025
Bermuda - Specialty | 2015
Short-Duration Insurance Contracts, Historical Claims Duration [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	15,277	15,288	15,672	15,383	16,820	17,466	19,237	19,342	26,686	27,712
IBNR	$ 16
Cumulative Number of Reported Claims | claim	39
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,911	$ 14,832	$ 14,767	$ 14,432	$ 14,397	$ 14,192	$ 13,115	$ 13,136	$ 8,638	$ 3,330

Reserve for Losses and Loss A_8

Reserve for Losses and Loss Adjustment Expenses - Amounts of Reconciliation (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	$ 2,320,877
Unpaid losses and loss adjustment expenses recoverable	1,171,040	$ 1,161,077	$ 1,177,863	$ 1,112,543
Other insurance lines	3,302
Unallocated loss adjustment expenses	37,272
Unpaid losses and loss adjustment expenses recoverable	40,574
Reserve for losses and loss adjustment expenses	3,532,491	$ 3,030,037	$ 2,856,275	$ 2,415,491
International - Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	110,676
Unpaid losses and loss adjustment expenses recoverable	63,625
International - Casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	524,133
Unpaid losses and loss adjustment expenses recoverable	608,333
International - Specialty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	410,406
Unpaid losses and loss adjustment expenses recoverable	210,968
Bermuda - Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	312,638
Unpaid losses and loss adjustment expenses recoverable	44,045
Bermuda - Casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	709,672
Unpaid losses and loss adjustment expenses recoverable	161,778
Bermuda - Specialty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and loss adjustment expenses, net of reinsurance	253,352
Unpaid losses and loss adjustment expenses recoverable	$ 82,291

Segment Reporting - Segment Rep

Segment Reporting - Segment Reporting Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Gross premiums written	$ 2,422,582	$ 1,951,038	$ 1,646,673
Net premiums written	1,921,169	1,480,438	1,221,864
Net premiums earned	1,734,729	1,318,533	1,143,714
Third party fee income	23,752	18,234	11,631
Losses and loss adjustment expenses	1,010,173	714,603	758,333
Acquisition costs	388,931	309,148	271,189
Other underwriting expenses	210,013	183,165	157,540
Underwriting income (loss)	149,364	129,851	(31,717)
Net realized and unrealized gains (losses) on investments	511,407	209,610	93,348
Net investment income (loss)	63,267	30,456	(21,487)
Other income (loss), excluding third party fee income		397	(315)
Net foreign exchange gains (losses)	(3,231)	(6,185)	6,137
Corporate expenses	(61,111)	(76,691)	(20,142)
Less: impairment	0	0	(24,082)
Amortization of intangible assets	(15,520)	(10,783)	(12,832)
Interest expense	(22,616)	(21,434)	(15,741)
Income (loss) before income tax	621,560	255,221	(26,831)
Income tax expense (benefit)	(8,402)	25,066	(3,104)
Net income (loss)	613,158	280,287	(29,935)
Net income (loss) attributable to non-controlling interest	212,729	21,560	68,064
Net income (loss) and other comprehensive income (loss) attributable to common shareholders	$ 400,429	$ 258,727	$ (97,999)
Attritional loss ratio - current year	53.10%	52.20%	51.80%
Attritional loss ratio - prior year development	0%	(0.80%)	(0.30%)
Catastrophe loss ratio - current year	6.30%	3.20%	16.30%
Catastrophe loss ratio - prior year development	(1.20%)	(0.40%)	(1.50%)
Loss and loss adjustment expense ratio	58.20%	54.20%	66.30%
Acquisition cost ratio	22.40%	23.40%	23.70%
Other underwriting expense ratio	10.70%	12.50%	12.80%
Combined ratio	91.30%	90.10%	102.80%
Operating Segments | International
Segment Reporting Information [Line Items]
Gross premiums written	$ 1,308,460	$ 1,105,522	$ 933,241
Net premiums written	969,605	770,399	635,773
Net premiums earned	886,934	703,508	623,047
Third party fee income	16,317	9,685	11,430
Losses and loss adjustment expenses	498,023	362,137	335,484
Acquisition costs	216,971	186,698	170,571
Other underwriting expenses	148,824	127,402	108,239
Underwriting income (loss)	$ 39,433	$ 36,956	$ 20,183
Attritional loss ratio - current year	53.50%	53.20%	50.90%
Attritional loss ratio - prior year development	(0.40%)	(3.50%)	(4.80%)
Catastrophe loss ratio - current year	3.90%	1.50%	7.20%
Catastrophe loss ratio - prior year development	(0.80%)	0.30%	0.50%
Loss and loss adjustment expense ratio	56.20%	51.50%	53.80%
Acquisition cost ratio	24.50%	26.50%	27.40%
Other underwriting expense ratio	14.90%	16.70%	15.50%
Combined ratio	95.60%	94.70%	96.70%
Operating Segments | Bermuda
Segment Reporting Information [Line Items]
Gross premiums written	$ 1,114,122	$ 845,516	$ 713,432
Net premiums written	951,564	710,039	586,091
Net premiums earned	847,795	615,025	520,667
Third party fee income	7,435	8,549	201
Losses and loss adjustment expenses	512,150	352,466	422,849
Acquisition costs	171,960	122,450	100,618
Other underwriting expenses	61,189	55,763	49,301
Underwriting income (loss)	$ 109,931	$ 92,895	$ (51,900)
Attritional loss ratio - current year	52.70%	51.10%	52.90%
Attritional loss ratio - prior year development	0.50%	2.30%	5.10%
Catastrophe loss ratio - current year	8.90%	5.10%	27.10%
Catastrophe loss ratio - prior year development	(1.70%)	(1.20%)	(3.90%)
Loss and loss adjustment expense ratio	60.40%	57.30%	81.20%
Acquisition cost ratio	20.30%	19.90%	19.30%
Other underwriting expense ratio	6.30%	7.70%	9.40%
Combined ratio	87%	84.90%	109.90%
Corporate
Segment Reporting Information [Line Items]
Gross premiums written	$ 0	$ 0	$ 0
Net premiums written	0	0	0
Net premiums earned	0	0	0
Third party fee income	0	0	0
Losses and loss adjustment expenses	0	0	0
Acquisition costs	0	0	0
Other underwriting expenses	0	0	0
Underwriting income (loss)	0	0	0
Net realized and unrealized gains (losses) on investments	511,407	209,610	93,348
Net investment income (loss)	63,267	30,456	(21,487)
Other income (loss), excluding third party fee income		397	(315)
Net foreign exchange gains (losses)	(3,231)	(6,185)	6,137
Corporate expenses	(61,111)	(76,691)	(20,142)
Less: impairment			(24,082)
Amortization of intangible assets	(15,520)	(10,783)	(12,832)
Interest expense	(22,616)	(21,434)	(15,741)
Income tax expense (benefit)	(8,402)	25,066	(3,104)
Net income (loss) attributable to non-controlling interest	$ 212,729	$ 21,560	$ 68,064

Segment Reporting - Summary of

Segment Reporting - Summary of Gross Premiums Written by Geographical Location of Subsidiaries (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	$ 2,422,582	$ 1,951,038	$ 1,646,673
Total International
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	1,308,460	1,105,522	933,241
Lloyd's of London
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	792,830	677,415	561,432
Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	399,061	349,896	345,088
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	116,569	78,211	26,721
Bermuda
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	$ 1,114,122	$ 845,516	$ 713,432

Debt and Credit Facilities - Sc

Debt and Credit Facilities - Schedule of Company Compliance (Details) - Facility - Unsecured Debt - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Line of Credit Facility [Line Items]
Outstanding loan balance	$ 150,000	$ 150,000
Loan fair value	150,463	150,981
Unamortized loan issuance costs	$ 55	$ 170

Debt and Credit Facilities - Na

Debt and Credit Facilities - Narrative (Details) - USD ($)						12 Months Ended
	Oct. 28, 2024	Oct. 25, 2024	Aug. 12, 2024	Apr. 30, 2024	Jun. 23, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Nov. 15, 2024
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity						$ 1,045,000,000
Line of credit facility, outstanding						789,993,000
Interest expense						22,616,000	$ 21,434,000	$ 15,741,000
Unsecured Debt | Facility
Line of Credit Facility [Line Items]
Face amount					$ 150,000,000
Increase in interest rate in event of default					2%
Outstanding loan balance						150,000,000	150,000,000
Loan fair value						150,463,000	150,981,000
Unamortized loan issuance costs						55,000	170,000
Amortization of debt issuance costs						100,000	$ 100,000	$ 100,000
Line of Credit | Uncommitted Secured Letter Of Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity									$ 250,000,000
Line of Credit | Unsecured Facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity					$ 415,000,000
Line of credit facility, outstanding						$ 0
Unused commitment fee percentage				0.175%	0.225%
Line of Credit | Unsecured Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity					$ 150,000,000
Basis spread on variable rate				1.625%	1.85%
Line of Credit | Unsecured Facility | Letter of Credit
Line of Credit Facility [Line Items]
Stated interest rate				1.375%	1.50%
Line of Credit | Bank of Montreal, Letter of Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity			$ 50,000,000
Unused commitment fee percentage			0.15%
Commitment fee percentage			0.40%
Line of Credit | UBS Letter of Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 100,000,000
Commitment fee percentage		1.40%
Line of Credit | Unsecured Facility, Lloyd's | Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 230,000,000
Commitment fee percentage	1.625%
Term of debt agreement	1 year

Debt and Credit Facilities - _2

Debt and Credit Facilities - Schedule of Credit Facilities (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,045,000
Available letter of credit and revolving loan facilities - in use	789,993
TS Hamilton Fund
Line of Credit Facility [Line Items]
Security pledged under letter of credit and revolving loan facilities:	230,833
Fixed Income Portfolio
Line of Credit Facility [Line Items]
Security pledged under letter of credit and revolving loan facilities:	296,464
Cash
Line of Credit Facility [Line Items]
Security pledged under letter of credit and revolving loan facilities:	$ 4,713

Share Capital - Schedule of Sha

Share Capital - Schedule of Share Capital (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	150,000,000	150,000,000	135,000,000	135,000,000
Common stock issued (in shares)	101,466,997	110,225,103	103,087,859	102,563,042
Common stock outstanding (in shares)	101,466,997	110,225,103	103,087,859	102,563,042
Common stock	$ 1,015	$ 1,101
Class A
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	26,944,807	28,644,807	53,993,690	53,793,690
Common stock issued (in shares)	17,820,078	28,644,807	30,520,078	30,320,078
Common stock outstanding (in shares)	17,820,078	28,644,807	30,520,078	30,320,078
Common stock	$ 178	$ 286
Class B
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	80,205,911	72,337,352	50,480,684	46,898,612
Common stock issued (in shares)	64,271,249	56,036,067	42,042,155	37,935,266
Common stock outstanding (in shares)	64,271,249	56,036,067	42,042,155	37,935,266
Common stock	$ 643	$ 560
Class C
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	19,375,670	25,544,229	30,525,626	34,307,698
Common stock issued (in shares)	19,375,670	25,544,229	30,525,626	34,307,698
Common stock outstanding (in shares)	19,375,670	25,544,229	30,525,626	34,307,698
Common stock	$ 194	$ 255

Share Capital - Schedule of Com

Share Capital - Schedule of Common Stock Authorized (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares - beginning of period (in shares)	150,000,000	135,000,000	135,000,000
Share class conversions (in shares)	0	0	0
Increase in authorized share capital (in shares)		15,000,000
Common shares - end of period (in shares)	150,000,000	150,000,000	135,000,000
Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares - beginning of period (in shares)	28,644,807	53,993,690	53,793,690
Share class conversions (in shares)	(1,700,000)	(25,348,883)	200,000
Increase in authorized share capital (in shares)		0
Common shares - end of period (in shares)	26,944,807	28,644,807	53,993,690
Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares - beginning of period (in shares)	72,337,352	50,480,684	46,898,612
Share class conversions (in shares)	7,868,559	6,856,668	3,582,072
Increase in authorized share capital (in shares)		15,000,000
Common shares - end of period (in shares)	80,205,911	72,337,352	50,480,684
Class C
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares - beginning of period (in shares)	25,544,229	30,525,626	34,307,698
Share class conversions (in shares)	(6,168,559)	(4,981,397)	(3,782,072)
Increase in authorized share capital (in shares)		0
Common shares - end of period (in shares)	19,375,670	25,544,229	30,525,626
Unclassified
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares - beginning of period (in shares)	23,473,612	0	0
Share class conversions (in shares)	0	23,473,612	0
Increase in authorized share capital (in shares)		0
Common shares - end of period (in shares)	23,473,612	23,473,612	0

Share Capital - Schedule of C_2

Share Capital - Schedule of Common Stock Issued and Outstanding (Details) - shares			12 Months Ended
	Sep. 13, 2024	May 08, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares issued - beginning of period (in shares)			110,225,103	103,087,859	102,563,042
Common shares outstanding - beginning of period (in shares)			110,225,103	103,087,859	102,563,042
Share class conversions (in shares)			0	0	0
IPO share issued (in shares)				6,250,000
Vesting of awards (in shares)			2,291,495	735,013	580,935
Exercise of warrants (in shares)			245,779	271,097
Employee and director share purchases (in shares)					22,750
Director share awards granted (in shares)			20,383	44,892	25,805
Share repurchases (in shares)			(11,315,763)	(163,758)	(104,673)
Common shares issued - end of period (in shares)			101,466,997	110,225,103	103,087,859
Common shares outstanding - end of period (in shares)			101,466,997	110,225,103	103,087,859
Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares issued - beginning of period (in shares)			28,644,807	30,520,078	30,320,078
Common shares outstanding - beginning of period (in shares)			28,644,807	30,520,078	30,320,078
Share class conversions (in shares)			(1,700,000)	(1,875,271)	200,000
IPO share issued (in shares)				0
Vesting of awards (in shares)			0	0	0
Exercise of warrants (in shares)			0	0
Employee and director share purchases (in shares)					0
Director share awards granted (in shares)			0	0	0
Share repurchases (in shares)		(9,100,000)	(9,124,729)	0	0
Common shares issued - end of period (in shares)			17,820,078	28,644,807	30,520,078
Common shares outstanding - end of period (in shares)			17,820,078	28,644,807	30,520,078
Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares issued - beginning of period (in shares)			56,036,067	42,042,155	37,935,266
Common shares outstanding - beginning of period (in shares)			56,036,067	42,042,155	37,935,266
Share class conversions (in shares)			7,868,559	6,856,668	3,582,072
IPO share issued (in shares)				6,250,000
Vesting of awards (in shares)			2,291,495	735,013	580,935
Exercise of warrants (in shares)			245,779	271,097
Employee and director share purchases (in shares)					22,750
Director share awards granted (in shares)			20,383	44,892	25,805
Share repurchases (in shares)			(2,191,034)	(163,758)	(104,673)
Common shares issued - end of period (in shares)			64,271,249	56,036,067	42,042,155
Common shares outstanding - end of period (in shares)			64,271,249	56,036,067	42,042,155
Class C
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares issued - beginning of period (in shares)			25,544,229	30,525,626	34,307,698
Common shares outstanding - beginning of period (in shares)			25,544,229	30,525,626	34,307,698
Share class conversions (in shares)	1,700,000		(6,168,559)	(4,981,397)	(3,782,072)
IPO share issued (in shares)				0
Vesting of awards (in shares)			0	0	0
Exercise of warrants (in shares)			0	0
Employee and director share purchases (in shares)					0
Director share awards granted (in shares)			0	0	0
Share repurchases (in shares)			0	0	0
Common shares issued - end of period (in shares)			19,375,670	25,544,229	30,525,626
Common shares outstanding - end of period (in shares)			19,375,670	25,544,229	30,525,626

Share Capital - Narrative (Deta

Share Capital - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
	Sep. 13, 2024	May 08, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Aug. 07, 2024
Class of Stock [Line Items]
Share repurchases (in shares)			11,315,763	163,758	104,673
Share repurchase authorization						$ 150
Percent of combined voting power, Class A and Class B			9.50%
Share class conversions (in shares)			0	0	0
Open Market Repurchases
Class of Stock [Line Items]
Remaining share repurchase authorization			$ 121.9
Class A
Class of Stock [Line Items]
Share repurchases (in shares)		9,100,000	9,124,729	0	0
Shares acquired (in dollars per share)		$ 12
Share repurchases		$ 109.5
Share class conversions (in shares)			(1,700,000)	(1,875,271)	200,000
Class B
Class of Stock [Line Items]
Share repurchases (in shares)			2,191,034	163,758	104,673
Percent of combined voting power, Class A and Class B			14.92%
Share class conversions (in shares)			7,868,559	6,856,668	3,582,072
Class B | Open Market Repurchases
Class of Stock [Line Items]
Share repurchases (in shares)			1,500,000
Shares acquired (in dollars per share)			$ 18.89
Share repurchases			$ 28.1
Class C
Class of Stock [Line Items]
Share repurchases (in shares)			0	0	0
Share class conversions (in shares)	1,700,000		(6,168,559)	(4,981,397)	(3,782,072)

Share Incentive Plans - Narrati

Share Incentive Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Aug. 07, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Aggregate fair value of vested awards		$ 38,600	$ 10,100	$ 8,600
Director share awards granted (in shares)		20,383	44,892	25,805
Warrants outstanding, term		10 years
Exercise price (in dollars per share)		$ 10	$ 10	$ 10
Compensation expense		$ 30,384	$ 44,378	$ 10,784
Share-Based Payment Arrangement, Nonemployee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total estimated fair value		$ 1,400
Vesting period		1 year
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total estimated fair value		$ 14,500	$ 14,200	11,800
Vesting period		3 years
Director share awards granted (in shares)		1,078,711
Grant date fair value (in dollars per share)		$ 14.43	$ 14.06
Compensation expense		$ 12,933	$ 11,358	10,884
VAP RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percent of increase in Company fair market value awarded to employees		10%
Compensation expense, including adjustment to retained earnings		$ 9,200	$ 34,500
Compensation expense, adjustment to retained earnings	$ 4,200
Grant date fair value (in dollars per share)		$ 15.32	$ 15.32
Compensation expense		$ 9,210	$ 30,352	0
VAP RSUs | Share-Based Payment Arrangement, Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		50%
VAP RSUs | Share-Based Payment Arrangement, Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		50%
PSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		3 years
Director share awards granted (in shares)		289,804
Grant date fair value (in dollars per share)					$ 15.47
Compensation expense		$ 8,241	$ 2,668	$ (100)
PSUs | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		0%	0%	0%
PSUs | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		200%	200%	200%
Stock-Settled Directors' Fees
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expense		$ 600	$ 600	$ 700
Class B
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Director share awards granted (in shares)		20,383	44,892	25,805
2023 Equity Incentive Plan | Class B
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Increase in shares available for issuance, term		9 years
Percentage of outstanding shares		2%
Shares available for issuance (in shares)		6,690,374

Share Incentive Plans - Schedul

Share Incentive Plans - Schedule of Compensation Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense:	$ 30,384	$ 44,378	$ 10,784
Tax benefit	(1,750)	(1,251)	(1,074)
Share based compensation expense, net of taxes:	28,634	43,127	9,710
RSUs
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense:	12,933	11,358	10,884
VAP RSUs
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense:	9,210	30,352	0
PSUs
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense:	$ 8,241	$ 2,668	$ (100)

Share Incentive Plans - Sched_2

Share Incentive Plans - Schedule of Unrecognized Compensation Expense (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Share Based Compensation Expense	$ 22,798
RSUs
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Share Based Compensation Expense	$ 9,998
Weighted-Average Recognition Period (in years)	1 year 2 months 12 days
VAP RSUs
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Share Based Compensation Expense	$ 3,134
Weighted-Average Recognition Period (in years)	10 months 24 days
PSUs
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Share Based Compensation Expense	$ 9,666
Weighted-Average Recognition Period (in years)	1 year 8 months 12 days

Share Incentive Plans - Sched_3

Share Incentive Plans - Schedule of Share-Based Payment Arrangement, Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Number of RSUs and VAP RSUs
Granted (in shares)	20,383	44,892	25,805
Vested (in shares)	(2,291,495)	(735,013)	(580,935)
RSUs
Number of RSUs and VAP RSUs
Balance, beginning of year (in shares)	1,660,978
Granted (in shares)	1,078,711
Vested (in shares)	(719,836)
Forfeited (in shares)	(65,457)
Balance, end of year (in shares)	1,954,396	1,660,978
Weighted-Average Grant Date Fair Value
Balance, beginning of year (in USD per share)	$ 14.06
Granted (in USD per share)	14.67
Vested (in USD per share)	13.94
Forfeited (in USD per share)	14.20
Balance, end of year (in USD per share)	$ 14.43	$ 14.06
VAP RSUs
Number of RSUs and VAP RSUs
Balance, beginning of year (in shares)	3,147,507
Vested (in shares)	(1,530,234)
Forfeited (in shares)	(88,464)
Balance, end of year (in shares)	1,528,809	3,147,507
Weighted-Average Grant Date Fair Value
Balance, beginning of year (in USD per share)	$ 15.32
Vested (in USD per share)	15.32
Forfeited (in USD per share)	15.32
Balance, end of year (in USD per share)	$ 15.32	$ 15.32

Share Incentive Plans - Sched_4

Share Incentive Plans - Schedule of PSU Activity (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
PSU Activity
Granted (in shares)	20,383	44,892	25,805
Vested (in shares)	(2,291,495)	(735,013)	(580,935)
PSUs
PSU Activity
Balance, beginning of year (in shares)	444,339
Granted (in shares)	289,804
Vested (in shares)	(41,418)
Change in expected performance factor (in shares)	610,723
Balance, end of year (in shares)	1,303,448	444,339

Share Incentive Plans - Sched_5

Share Incentive Plans - Schedule of Outstanding and Exercisable Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Warrants, Outstanding [Roll Forward]
Warrants outstanding and exercisable, beginning of year, Number of Warrants (in shares)	810,000	1,152,500
Warrants outstanding and exercisable, beginning of year, Weighted-Average Exercise Price (in USD per share)	$ 10	$ 10
Warrants outstanding and exercisable, beginning of year, Weighted Average Grant Date Fair Value (in USD per share)	$ 4.52	$ 4.44
Warrants outstanding and exercisable, beginning of year, Total Intrinsic Value	$ 4,010	$ 4,287
Exercised, Number of Warrants (in shares)	(810,000)	(342,500)
Exercised, Weighted-Average Exercise Price (in USD per share)	$ 10	$ 10
Exercised, Weighted-Average Grant Date Fair Value (in USD per share)	$ 4.52	$ 4.27
Exercised, Total Intrinsic Value	$ 4,140	$ 2,398
Warrants outstanding and exercisable, end of year, Number of Warrants (in shares)	0	810,000
Warrants outstanding and exercisable, end of year, Weighted-Average Exercise Price (in USD per share)	$ 10	$ 10
Warrants outstanding and exercisable, end of year, Weighted Average Grant Date Fair Value (in USD per share)		$ 4.52
Warrants outstanding and exercisable, end of year, Total Intrinsic Value		$ 4,010
Warrants outstanding, term		3 months 18 days	1 year 3 months 18 days

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net income (loss) attributable to common shareholders	$ 400,429	$ 258,727	$ (97,999)
Denominator:
Weighted average common shares outstanding - basic (in shares)	105,133,000	104,563,000	103,062,000
Effect of dilutive securities (in shares)	3,968,000	1,640,000	0
Weighted average common shares outstanding - diluted (in shares)	109,101,000	106,203,000	103,062,000
Income (loss) per common share - basic (in dollars per share)	$ 3.81	$ 2.47	$ (0.95)
Income (loss) per common share - diluted (in dollars per share)	$ 3.67	$ 2.44	$ (0.95)
Anti-dilutive shares excluded from the calculation of diluted income (loss) per share (in shares)	0	400,000	3,000,000

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2024
Operating Loss Carryforwards [Line Items]
Deferred tax benefit	$ 1,506	$ 36,132	$ 1,265
Net income taxes paid	10,662	4,211	9,971
Tax rate changes	0	273	(2,655)
Net tax expense (benefit) of tax rate changes, after valuation allowance	0	100	(200)
Valuation allowance	63,032	75,528		$ 63,032
Bermuda
Operating Loss Carryforwards [Line Items]
Deferred tax benefit	$ 375	$ 35,063	$ 0	$ 35,400

Income Taxes - Income (Loss) be

Income Taxes - Income (Loss) before Taxes by Tax Jurisdiction (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Income (loss) before income tax	$ 621,560	$ 255,221	$ (26,831)
Bermuda
Operating Loss Carryforwards [Line Items]
Income (loss) before income tax, domestic	581,915	247,113	66,823
United States
Operating Loss Carryforwards [Line Items]
Income (loss) before income tax, foreign	9,122	(2,263)	(23,540)
United Kingdom
Operating Loss Carryforwards [Line Items]
Income (loss) before income tax, foreign	32,249	12,362	(67,213)
Ireland
Operating Loss Carryforwards [Line Items]
Income (loss) before income tax, foreign	$ (1,726)	$ (1,991)	$ (2,901)

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2024
Operating Loss Carryforwards [Line Items]
Total current tax expense (benefit)	$ 9,908	$ 11,066	$ 4,369
Total deferred tax expense (benefit)	(1,506)	(36,132)	(1,265)
Total income tax expense (benefit)	8,402	(25,066)	3,104
Bermuda
Operating Loss Carryforwards [Line Items]
Total current tax expense (benefit)	9,276	10,376	2,625
Total deferred tax expense (benefit)	(375)	(35,063)	0	$ (35,400)
United States
Operating Loss Carryforwards [Line Items]
Total current tax expense (benefit)	652	537	1,818
Total deferred tax expense (benefit)	0	0	705
United Kingdom
Operating Loss Carryforwards [Line Items]
Total current tax expense (benefit)	91	61	48
Total deferred tax expense (benefit)	(1,027)	(1,087)	(1,927)
Ireland
Operating Loss Carryforwards [Line Items]
Total current tax expense (benefit)	(111)	92	(122)
Total deferred tax expense (benefit)	$ (104)	$ 18	$ (43)

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Expected tax provision at Bermuda statutory tax rate of 0%	$ 0	$ 0	$ 0
Permanent differences:
Taxes on earnings subject to rate other than Bermuda statutory rate	9,762	2,182	(18,077)
Change in valuation allowance	(12,496)	(3,567)	17,060
Impairment of goodwill	0	0	4,161
Other permanent adjustments	(318)	(42)	(112)
Other prior year adjustments	2,234	376	28
Tax rate changes	0	273	(2,655)
Withholding tax	9,381	10,377	2,625
Bermuda economic transition adjustment	0	(35,063)	0
State income tax	(161)	398	74
Total income tax expense (benefit)	$ 8,402	$ (25,066)	$ 3,104

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Bermuda intangible assets	$ 28,875	$ 28,500
Reserve for losses and loss adjustment expenses	9,198	7,935
Unearned premium reserve	5,486	4,384
Share based compensation	5,213	7,524
Foreign tax credit	1,949	925
Capital loss carryforward	1,733	419
U.K. deferred interest	685	5,278
Deferred acquisition costs	547	(1,540)
Loss portfolio transfer	263	2,356
Other	2,763	1,609
Total deferred tax assets	105,775	115,631
Deferred tax liabilities:
U.K. intangible assets	(14,233)	(15,364)
Fixed assets	(3,520)	(2,573)
Lloyd's deferred taxable income	(3,340)	0
Other	(446)	(2,468)
Total deferred tax liabilities	(21,539)	(20,405)
Net deferred tax asset (liability) before valuation allowance	84,236	95,226
Valuation allowance	(63,032)	(75,528)
Net deferred tax asset (liability)	21,204	19,698
United Kingdom
Deferred tax assets:
Operating loss carryforwards	45,590	50,845
United States
Deferred tax assets:
Operating loss carryforwards	3,255	7,121
Ireland
Deferred tax assets:
Operating loss carryforwards	$ 218	$ 275

Income Taxes - Operating Loss C

Income Taxes - Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Bermuda
Operating Loss Carryforwards [Line Items]
Losses Carried Forward	$ 0
Operating loss carryforwards	0
Ireland
Operating Loss Carryforwards [Line Items]
Losses Carried Forward	1,742
Operating loss carryforwards	218	$ 275
United States
Operating Loss Carryforwards [Line Items]
Losses Carried Forward	15,501
Operating loss carryforwards	3,255	7,121
United Kingdom
Operating Loss Carryforwards [Line Items]
Losses Carried Forward	182,360
Operating loss carryforwards	$ 45,590	$ 50,845

Commitment and Contingencies -

Commitment and Contingencies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Weighted average lease term	2 years 6 months
Right of use asset	$ 9,100	$ 6,900
Lease liability	$ 9,172	$ 6,700
Weighted average discount rate	5.30%	3.75%
Operating lease, expense	$ 3,400	$ 3,800	$ 3,800
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Accounts payable and accrued expenses	Accounts payable and accrued expenses

Commitment and Contingencies _2

Commitment and Contingencies - Schedule of Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
2025	$ 2,431
2026	2,977
2027	2,703
2028	1,262
2029	647
Thereafter	118
Total undiscounted lease liabilities	10,138
Less: present value discount	(966)
Total recorded lease liability at present value	$ 9,172	$ 6,700

Commitment and Contingencies _3

Commitment and Contingencies - Schedule of Capital Requirements (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Other Commitments [Line Items]
Total	$ 476,336
Capital Requirements Supported By Line Of Credit
Other Commitments [Line Items]
Total	230,000
Capital Requirements Supported By Fixed Income Securities
Other Commitments [Line Items]
Total	245,254
Capital Requirements Supported By Cash
Other Commitments [Line Items]
Total	$ 1,082

Related Party Transactions - Sc

Related Party Transactions - Schedule of Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Reinsurance premiums ceded	$ (501,413)	$ (470,600)	$ (424,809)
Net premiums earned	(1,734,729)	(1,318,533)	(1,143,714)
Other income (loss)	23,752	18,631	11,316
Losses and loss adjustment expenses	1,010,173	714,603	758,333
Acquisition costs	388,931	309,148	271,189
Net income (loss) and other comprehensive income (loss) attributable to common shareholders	400,429	258,727	(97,999)
Paid losses recoverable	134,406	145,202
Unpaid losses and loss adjustment expenses recoverable	1,171,040	1,161,077	1,177,863	$ 1,112,543
Other assets	208,642	209,621
Reinsurance balances payable	261,275	272,310
Related Party
Related Party Transaction [Line Items]
Reinsurance premiums ceded	(14,600)	(7,200)	(6,300)
Ada Capital Management Limited | Related Party
Related Party Transaction [Line Items]
Reinsurance premiums ceded	(21,584)	(19,524)	(11,999)
Net premiums earned	(21,585)	(21,744)	(9,780)
Other income (loss)	7,434	8,549	201
Losses and loss adjustment expenses	7,676	8,702	5,719
Acquisition costs	5,126	5,125	1,769
Net income (loss) and other comprehensive income (loss) attributable to common shareholders	(1,349)	632	$ (2,091)
Paid losses recoverable	2,278	4,319
Unpaid losses and loss adjustment expenses recoverable	13,262	11,149
Other assets	970	8,765
Reinsurance balances payable	$ 1,670	$ 3,759

Statutory Requirements - Statut

Statutory Requirements - Statutory Accounting Practices (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Bermuda
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	$ 739,605	$ 579,916
Actual statutory capital and surplus	2,168,031	1,882,833
Statutory net income (loss)	432,769	270,309	$ 1,993
United Kingdom
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	125,232	129,995
Actual statutory capital and surplus	624,596	539,016
Statutory net income (loss)	61,879	59,778	25,470
Ireland
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	77,269	68,643
Actual statutory capital and surplus	139,446	127,082
Statutory net income (loss)	8,069	(1,911)	(32,331)
United States
Statutory Accounting Practices [Line Items]
Required statutory capital and surplus	33,780	23,410
Actual statutory capital and surplus	58,017	53,988
Statutory net income (loss)	$ (12,512)	$ (13,250)	$ (9,962)

Statutory Requirements - Narrat

Statutory Requirements - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2023
Hamilton Re
Statutory Accounting Practices [Line Items]
Dividend payments without regulatory approval	$ 470,700
Dividends paid	184,500
Forecast | Hamilton Re
Statutory Accounting Practices [Line Items]
Dividend payments without regulatory approval		$ 542,000
Forecast | U.K. Subsidiaries
Statutory Accounting Practices [Line Items]
Dividend payments without regulatory approval		$ 5,000
Bermuda
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	2,168,031		$ 1,882,833
Required statutory capital and surplus	739,605		$ 579,916
Bermuda | Hamilton Re
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	2,200,000
Required statutory capital and surplus	$ 739,600

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - California Wildfires $ in Millions	Feb. 27, 2025 USD ($)
Minimum
Subsequent Event [Line Items]
Estimated losses due to wildfires	$ 120
Insured industry loss range	35,000
Maximum
Subsequent Event [Line Items]
Estimated losses due to wildfires	150
Insured industry loss range	$ 45,000

Schedule I - Summary of Inves_2

Schedule I - Summary of Investments (Details) $ in Thousands	Dec. 31, 2024 USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	$ 3,814,353
Amount at which shown in the balance sheet	3,814,353
Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	2,422,917
Fair Value	2,377,862
Amount at which shown in the balance sheet	2,377,862
Investments in Two Sigma Funds
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	939,381
Amount at which shown in the balance sheet	939,381
Total short-term investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair Value	497,110
Amount at which shown in the balance sheet	497,110
U.S. government treasuries | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	724,785
Fair Value	711,103
Amount at which shown in the balance sheet	711,103
U.S. states, territories and municipalities | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	13,533
Fair Value	13,231
Amount at which shown in the balance sheet	13,231
Non-U.S. sovereign governments and supranationals | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	70,435
Fair Value	67,527
Amount at which shown in the balance sheet	67,527
Corporate | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	1,153,612
Fair Value	1,143,060
Amount at which shown in the balance sheet	1,143,060
Residential mortgage-backed securities - Agency | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	288,760
Fair Value	272,611
Amount at which shown in the balance sheet	272,611
Residential mortgage-backed securities - Non-agency | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	17,432
Fair Value	16,754
Amount at which shown in the balance sheet	16,754
Commercial mortgage-backed securities - Non-agency | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	40,363
Fair Value	39,686
Amount at which shown in the balance sheet	39,686
Other asset-backed securities | Total fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	113,997
Fair Value	113,890
Amount at which shown in the balance sheet	$ 113,890

Schedule II - Condensed Balance

Schedule II - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Assets
Cash and cash equivalents	$ 996,493	$ 794,509
Other assets	208,642	209,621
Total assets	7,796,033	6,671,355
Liabilities
Payables to related parties	100,420	6,480
Term loan, net of issuance costs	149,945	149,830
Accounts payable and accrued expenses	185,361	186,887
Total liabilities	5,467,196	4,623,372
Shareholders' Equity
Common shares:	1,015	1,101
Additional paid-in capital	1,163,609	1,249,817
Accumulated other comprehensive loss	(4,441)	(4,441)
Retained earnings	1,168,526	801,373
Total shareholders' equity	2,328,709	2,047,850	$ 1,664,183
Total liabilities, non-controlling interest, and shareholders’ equity	7,796,033	6,671,355
Class A
Shareholders' Equity
Common shares:	178	286
Class B
Shareholders' Equity
Common shares:	643	560
Class C
Shareholders' Equity
Common shares:	194	255
Parent Company
Assets
Cash and cash equivalents	13,624	24,898
Investment in subsidiaries	2,358,386	2,077,926
Intercompany loan receivable	113,423	113,423
Interest receivable on intercompany loan	5,555	5,555
Other assets	5,036	4,821
Total assets	2,496,024	2,226,623
Liabilities
Payables to related parties	11,785	25,201
Term loan, net of issuance costs	149,945	149,830
Accounts payable and accrued expenses	5,585	3,742
Total liabilities	167,315	178,773
Shareholders' Equity
Additional paid-in capital	1,163,609	1,249,817
Accumulated other comprehensive loss	(4,441)	(4,441)
Retained earnings	1,168,526	801,373
Total shareholders' equity	2,328,709	2,047,850
Total liabilities, non-controlling interest, and shareholders’ equity	2,496,024	2,226,623
Parent Company | Class A
Shareholders' Equity
Common shares:	178	286
Parent Company | Class B
Shareholders' Equity
Common shares:	643	560
Parent Company | Class C
Shareholders' Equity
Common shares:	$ 194	$ 255

Schedule II - Condensed Stateme

Schedule II - Condensed Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Statement of Income Captions [Line Items]
Net foreign exchange gains (losses)	$ (3,231)	$ (6,185)	$ 6,137
Other income (loss)	23,752	18,631	11,316
Total revenues	2,329,924	1,571,045	1,233,028
Expenses
General and administrative expenses	271,124	259,856	177,682
Interest expense	22,616	21,434	15,741
Total expenses	1,708,364	1,315,824	1,259,859
Parent Company
Condensed Statement of Income Captions [Line Items]
Intercompany loan interest	7,393	7,296	6,784
Net foreign exchange gains (losses)	8	24	(131)
Other income (loss)	633	626	65
Total revenues	8,034	7,946	6,718
Expenses
General and administrative expenses	55,011	52,280	20,524
Interest expense	16,352	15,500	9,858
Total expenses	71,363	67,780	30,382
Net income (loss) before equity in earnings of subsidiaries	(63,329)	(59,834)	(23,664)
Equity in earnings of subsidiaries	266,261	274,538	(211,335)
Dividend income	197,497	44,023	137,000
Net income (loss) attributable to common shareholders	$ 400,429	$ 258,727	$ (97,999)

Schedule II - Consolidated Stat

Schedule II - Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Net cash provided by (used in) operating activities	$ 759,303	$ 283,155	$ 190,927
Cash flows provided by (used in) investing activities
Other investing inflows (outflows)	(18,811)	(15,938)	(13,591)
Net cash provided by (used in) investing activities	(184,160)	(652,088)	133,102
Cash flows provided by (used in) financing activities
Repurchases of common shares	(150,350)	(2,435)	(1,518)
Issuance of common shares	26	73	7
Net cash provided by (used in) financing activities	(362,688)	59,016	(69,617)
Net increase (decrease) in cash and cash equivalents and restricted cash and cash equivalents	199,992	(306,343)	243,077
Cash and cash equivalents and restricted cash and cash equivalents, beginning of period	900,860	1,207,203	964,126
Cash and cash equivalents and restricted cash and cash equivalents, end of period	1,100,852	900,860	1,207,203
Parent Company
Operating activities
Net income (loss) attributable to common shareholders	400,429	258,727	(97,999)
Less: dividend income and equity in earnings of subsidiaries	(463,758)	(318,561)	74,335
Net income (loss) before equity in earnings of subsidiaries	(63,329)	(59,834)	(23,664)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Other operating inflows (outflows)	18,927	63,035	7,033
Net cash provided by (used in) operating activities	(44,402)	3,201	(16,631)
Cash flows provided by (used in) investing activities
Other investing inflows (outflows)	(216)	(146)	(706)
Dividends from subsidiaries	197,497	44,023	137,000
Capital contributions to subsidiaries	(14,199)	(113,350)	(118,839)
Net cash provided by (used in) investing activities	183,082	(69,473)	17,455
Cash flows provided by (used in) financing activities
Other financing inflows (outflows)	0	0	(345)
Repurchases of common shares	(150,350)	(2,435)	(1,518)
Issuance of common shares	396	82,997	315
Net cash provided by (used in) financing activities	(149,954)	80,562	(1,548)
Net increase (decrease) in cash and cash equivalents and restricted cash and cash equivalents	(11,274)	14,290	(724)
Cash and cash equivalents and restricted cash and cash equivalents, beginning of period	24,898	10,608	11,332
Cash and cash equivalents and restricted cash and cash equivalents, end of period	$ 13,624	$ 24,898	$ 10,608

Schedule IV - Reinsurance (Deta

Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	$ 208,985	$ 156,895	$ 115,147
Future policy benefits, losses, claims and loss adjustment expenses	3,532,491	3,030,037	2,856,275
Unearned premiums	1,122,277	911,222	718,188
Net premiums earned	1,734,729	1,318,533	1,143,714
Total realized and unrealized gains (losses) on investments and net investment income (loss)	574,674	239,855	64,870
Benefits, claims, losses, and settlement expenses	1,010,173	714,603	758,333
Amortization of deferred policy acquisition costs	388,931	309,148	271,189
Other operating expenses	210,013	183,165	157,540
Net premiums written	1,921,169	1,480,438	1,221,864
International
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	110,032	84,983	68,257
Future policy benefits, losses, claims and loss adjustment expenses	1,957,679	1,717,422	1,582,410
Unearned premiums	650,287	547,629	453,254
Net premiums earned	886,934	703,508	623,047
Benefits, claims, losses, and settlement expenses	498,023	362,137	335,484
Amortization of deferred policy acquisition costs	216,971	186,698	170,571
Other operating expenses	148,824	127,402	108,239
Net premiums written	969,605	770,399	635,773
Bermuda
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	98,953	71,912	46,890
Future policy benefits, losses, claims and loss adjustment expenses	1,574,812	1,312,615	1,273,865
Unearned premiums	471,990	363,593	264,934
Net premiums earned	847,795	615,025	520,667
Benefits, claims, losses, and settlement expenses	512,150	352,466	422,849
Amortization of deferred policy acquisition costs	171,960	122,450	100,618
Other operating expenses	61,189	55,763	49,301
Net premiums written	$ 951,564	$ 710,039	$ 586,091

Schedule IV - Reinsurance Premi

Schedule IV - Reinsurance Premium (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Direct	$ 1,180,932	$ 1,016,762	$ 886,488
Ceded	476,798	440,607	413,046
Assumed	1,030,595	742,378	670,272
Premiums earned	$ 1,734,729	$ 1,318,533	$ 1,143,714
Percentage of amount assumed to net	59%	56%	59%

Schedule V - Valuation and Qu_2

Schedule V - Valuation and Qualifying Accounts (Details) - SEC Schedule, 12-09, Allowance, Credit Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Opening Balance	$ 3,687	$ 3,633	$ 0
Additions	782	54	3,633
Deductions	(7)	0	0
Closing Balance	$ 4,462	$ 3,687	$ 3,633

Schedule VI - Supplemental In_2

Schedule VI - Supplemental Insurance Information Concerning Property - Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Deferred policy acquisition costs	$ 208,985	$ 156,895	$ 115,147
Reserves for unpaid claims and claim adjustments expenses	3,532,491	3,030,037	2,856,275
Discount, if any, deducted	0	0	0
Unearned premiums	1,122,277	911,222	718,188
Net premiums earned	1,734,729	1,318,533	1,143,714
Total net realized and unrealized gains (losses) on investments and net investment income (loss)	574,674	240,066	71,861
Claims and claims adjustment expenses incurred related to, Current Year	1,030,612	730,220	778,936
Claims and claims adjustment expenses incurred related to, Prior Year	(20,439)	(15,617)	(20,603)
Amortization of deferred policy acquisition costs	388,931	309,148	271,189
Paid claims and claim adjusted expenses	516,766	564,798	377,186
Net premiums written	$ 1,921,169	$ 1,480,438	$ 1,221,864