AXIS Capital Holdings Limited (AXS) 10-Q 1 May 24 2024 Q1 Quarterly report Financial data

COVER

COVER - shares	3 Months Ended
	Mar. 31, 2024	Apr. 26, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-31721
Entity Registrant Name	AXIS CAPITAL HOLDINGS LIMITED
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-0395986
Entity Address, Address Line One	92 Pitts Bay Road
Entity Address, City or Town	Pembroke
Entity Address, Country	BM
Entity Address, Postal Zip Code	HM 08
City Area Code	441
Local Phone Number	496-2600
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		84,659,970
Amendment flag	false
Document fiscal year focus	2024
Document fiscal period focus	Q1
Entity central index key	0001214816
Current fiscal year-end date	--12-31
Common shares
Document Information [Line Items]
Title of 12(b) Security	Common shares, par value $0.0125 per share
Trading Symbol	AXS
Security Exchange Name	NYSE
Depositary Shares, each representing a 1/100th interest in a 5.50% Series E preferred share
Document Information [Line Items]
Title of 12(b) Security	Depositary shares, each representing a 1/100th interest in a 5.50% Series E preferred share
Trading Symbol	AXS PRE
Security Exchange Name	NYSE

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investments:
Fixed maturities, available for sale, at fair value (Amortized cost 2024: $12,714,210; 2023: $12,634,254 Allowance for expected credit losses 2024: $4,237; 2023: $10,759)	$ 12,269,310	$ 12,234,742
Fixed maturities, held to maturity, at amortized cost (Fair value 2024: $683,726; 2023: $675,851 Allowance for expected credit losses 2024: $nil; 2023: $nil)	693,042	686,296
Equity securities, at fair value (Cost 2024: $545,538; 2023: $543,833)	582,178	588,511
Mortgage loans, held for investment, at fair value (Allowance for expected credit losses 2024: $8,113; 2023: $6,220)	609,704	610,148
Other investments, at fair value	934,724	949,413
Equity method investments	182,594	174,634
Short-term investments, at fair value	75,879	17,216
Total investments	15,347,431	15,260,960
Cash and cash equivalents	1,143,951	953,476
Restricted cash and cash equivalents	697,623	430,509
Accrued interest receivable	107,131	106,055
Insurance and reinsurance premium balances receivable (Allowance for expected credit losses 2024: $13,103; 2023: $11,997)	3,517,242	3,067,554
Reinsurance recoverable on unpaid losses and loss expenses (Allowance for expected credit losses 2024: $37,888; 2023: $36,611)	6,503,188	6,323,083
Reinsurance recoverable on paid losses and loss expenses	472,660	575,847
Deferred acquisition costs	543,343	450,950
Prepaid reinsurance premiums	2,060,717	1,916,087
Receivable for investments sold	5,686	8,767
Goodwill	100,801	100,801
Intangible assets	184,155	186,883
Operating lease right-of-use assets	104,162	108,093
Loan advances made	345,065	305,222
Other assets	625,535	456,385
Total assets	31,758,690	30,250,672
Liabilities
Reserve for losses and loss expenses	16,630,897	16,434,018
Unearned premiums	5,353,827	4,747,602
Insurance and reinsurance balances payable	1,909,309	1,792,719
Debt	1,314,074	1,313,714
Federal Home Loan Bank advances	85,790	85,790
Payable for investments purchased	493,582	26,093
Operating lease liabilities	119,124	123,101
Other liabilities	346,932	464,439
Total liabilities	26,253,535	24,987,476
Shareholders’ equity
Preferred shares	550,000	550,000
Common shares (shares issued 2024: 176,580; 2023: 176,580 shares outstanding 2024: 84,687; 2023: 85,286)	2,206	2,206
Additional paid-in capital	2,368,144	2,383,030
Accumulated other comprehensive income (loss)	(411,849)	(365,836)
Retained earnings	6,790,558	6,440,528
Treasury shares, at cost (2024: 91,893; 2023: 91,294)	(3,793,904)	(3,746,732)
Total shareholders’ equity	5,505,155	5,263,196
Total liabilities and shareholders’ equity	$ 31,758,690	$ 30,250,672

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Amortized cost	$ 12,714,210	$ 12,634,254
Fixed maturities, available for sale, allowance for credit loss	4,237	10,759
Fixed maturities, held to maturity, fair value	683,726	675,851
Fixed maturities, held to maturity, allowance for credit loss	0	0
Equity securities, cost	545,538	543,833
Mortgage loans, held for investment, allowance for credit loss	8,113	6,220
Allowance for expected credit losses on insurance and reinsurance premium balances receivable	13,103	11,997
Allowance for expected credit losses on reinsurance recoverable for unpaid losses and loss expenses	$ 37,888	$ 36,611
Common shares, shares issued (in shares)	176,580	176,580
Common shares, shares outstanding (in shares)	84,687	85,286
Treasury shares, shares (in shares)	91,893	91,294

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues
Net premiums earned	$ 1,258,041	$ 1,230,199
Net investment income	167,383	133,771
Other insurance related income	8,340	577
Net investment gains (losses):
(Increase) decrease in allowance for expected credit losses	4,664	(2,811)
Impairment losses	(8)	0
Other realized and unrealized investment gains (losses)	(13,863)	(17,379)
Total net investment gains (losses)	(9,207)	(20,190)
Total revenues	1,424,557	1,344,357
Expenses
Net losses and loss expenses	728,671	720,642
Acquisition costs	254,254	230,373
General and administrative expenses	163,373	166,811
Foreign exchange losses (gains)	(23,552)	8,710
Interest expense and financing costs	17,147	16,894
Reorganization expenses	12,299	0
Amortization of intangible assets	2,729	2,729
Total expenses	1,154,921	1,146,159
Income before income taxes and interest in income (loss) of equity method investments	269,636	198,198
Income tax (expense) benefit	124,654	(15,896)
Interest in income (loss) of equity method investments	1,169	(2,205)
Net income	395,459	180,097
Preferred share dividends	7,563	7,563
Net income available to common shareholders	$ 387,896	$ 172,534
Earnings per common share:
Earnings per common share (in usd per share)	$ 4.57	$ 2.03
Earnings per diluted common share (in usd per share)	$ 4.53	$ 2.01
Weighted average common shares outstanding (in shares)	84,879	84,864
Weighted average diluted common shares outstanding (in shares)	85,693	85,853

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME(UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 395,459	$ 180,097
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) arising during the period, net of reclassification adjustment	(37,062)	188,939
Foreign currency translation adjustment	(8,951)	(535)
Total other comprehensive income (loss), net of tax	(46,013)	188,404
Comprehensive income	349,446	368,501
Unrealized gains (losses) on available for sale investments
Other comprehensive income (loss), net of tax:
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	23,415	40,750
Unrealized gains (losses) arising during the period, net of reclassification adjustment	(37,062)	188,939
Unrealized gains (losses) on available for sale investments | Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has not been recognized
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) arising during period	(60,059)	134,567
Unrealized gains (losses) on available for sale investments | Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has been recognized
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) arising during period	$ (418)	$ 13,622

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands		Total	Preferred shares	Common shares (par value)	Additional paid-in capital	Accumulated other comprehensive income (loss)	Unrealized gains (losses) on available for sale investments, net of tax:	Cumulative foreign currency translation adjustments, net of tax:	Retained earnings	Treasury shares, at cost
Balance at beginning of period at Dec. 31, 2022			$ 550,000	$ 2,206	$ 2,366,253	$ (760,300)	$ (743,695)	$ (16,605)	$ 6,247,022	$ (3,765,271)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares reissued					(30,593)					32,297
Share-based compensation expense					11,977
Unrealized gains (losses) arising during the period, net of reclassification adjustment		$ 188,939					188,939
Foreign currency translation adjustment		(535)						(535)
Net income		180,097							180,097
Preferred share dividends	[1]								(7,563)
Common share dividends	[1]								(38,355)
Shares repurchased										(15,945)
Balance at end of period at Mar. 31, 2023		4,960,229	550,000	2,206	2,347,637	(571,896)	(554,756)	(17,140)	6,381,201	(3,748,919)
Balance at beginning of period at Dec. 31, 2023		5,263,196	550,000	2,206	2,383,030	(365,836)	(347,659)	(18,177)	6,440,528	(3,746,732)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares reissued					(26,312)					28,556
Share-based compensation expense					11,426
Unrealized gains (losses) arising during the period, net of reclassification adjustment		(37,062)					(37,062)
Foreign currency translation adjustment		(8,951)						(8,951)
Net income		395,459							395,459
Preferred share dividends	[1]								(7,563)
Common share dividends	[1]								(37,866)
Shares repurchased										(75,728)
Balance at end of period at Mar. 31, 2024		$ 5,505,155	$ 550,000	$ 2,206	$ 2,368,144	$ (411,849)	$ (384,721)	$ (27,128)	$ 6,790,558	$ (3,793,904)
[1]Refer to Note 9 'Shareholders' Equity' for details on dividends declared and paid related to the Company's common and preferred shares.

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Cash flows from operating activities:
Net income	$ 395,459	$ 180,097
Adjustments to reconcile net income to net cash provided by operating activities:
Net investment (gains) losses	9,207	20,190
Net realized and unrealized gains on other investments	(4,973)	(486)
Amortization of fixed maturities	(8,630)	(2,425)
Interest in (income) loss of equity method investments	(1,169)	2,205
Other amortization and depreciation	14,257	14,971
Share-based compensation expense, net of cash payments	13,670	8,935
Changes in:
Accrued interest receivable	(1,411)	(3,826)
Reinsurance recoverable on unpaid losses and loss expenses	(186,791)	6,675
Reinsurance recoverable on paid losses and loss expenses	98,362	(58,631)
Deferred acquisition costs	(94,737)	(88,700)
Prepaid reinsurance premiums	(144,311)	(80,592)
Reserve for losses and loss expenses	209,390	150,410
Unearned premiums	611,974	462,751
Insurance and reinsurance balances, net	(267,456)	(314,642)
Other items	(258,702)	(56,368)
Net cash provided by operating activities	384,139	240,564
Purchases of:
Fixed maturities, available for sale	(2,450,714)	(1,614,005)
Fixed maturities, held to maturity	(46,534)	(20,001)
Equity securities	(76,270)	(77,560)
Mortgage loans	(1,552)	(14,030)
Other investments	(18,368)	(26,308)
Equity method investments	(6,791)	0
Short-term investments	(82,199)	(54,895)
Proceeds from the sale of:
Fixed maturities, available for sale	2,367,906	1,330,744
Equity securities	97,434	13,162
Other investments	38,027	14,825
Short-term investments	19,325	44,949
Proceeds from redemption of fixed maturities, available for sale	435,700	221,094
Proceeds from redemption of fixed maturities, held to maturity	39,791	1,596
Proceeds from redemption of short-term investments	4,510	10,520
Proceeds from the repayment of mortgage loans	211	5,206
Proceeds from the (purchase) sale of other assets, net	(8,208)	5,299
Loan advances made	(101,229)	(18,130)
Net cash provided by (used in) investing activities	211,039	(177,534)
Cash flows from financing activities:
Repurchase of common shares - open market	(61,607)	0
Taxes paid on withholding shares	(14,121)	(15,945)
Dividends paid - common shares	(40,208)	(40,323)
Dividends paid - preferred shares	(7,563)	(7,563)
Federal Home Loan Bank advances, net	0	5,250
Net cash used in financing activities	(123,499)	(58,581)
Effect of exchange rate changes on foreign currency cash, cash equivalents and restricted cash	(14,090)	193
Increase in cash, cash equivalents and restricted cash	457,589	4,642
Cash, cash equivalents and restricted cash - beginning of period	1,383,985	1,174,653	$ 1,174,653
Cash, cash equivalents and restricted cash - end of period	1,841,574	1,179,295	$ 1,383,985
Supplemental disclosures of cash flow information:
Income taxes paid (refund)	6,796	(2,403)
Interest paid	$ 17,504	$ 17,110

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (PARENTHETICAL) - Related Party - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Reinsurance premiums		$ 31
Monarch Point Re
Non-cash repayment of advance	$ 48
Monarch Point Re | Retrocession Agreement With Monarch Point Re
Reinsurance premiums	46
Ceded losses and loss expenses	4
Monarch Point Re | Loan With Monarch Point Re
Interest received on advance	6
Third Party Reinsurer
Non-cash repayment of advance		31
Reinsurance premiums	$ 25
Ceded losses and loss expenses		$ 5

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation These unaudited consolidated financial statements (the "financial statements") have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information and with the U.S. Securities and Exchange Commission's ("SEC") instructions to Form 10-Q and Article 10 of Regulation S-X and include AXIS Capital Holdings Limited ("AXIS Capital") and its subsidiaries (the "Company"). Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in AXIS Capital's Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the SEC. In the opinion of management, these financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the Company's financial position and results of operations for the periods presented. The results of operations for any interim period are not necessarily indicative of the results for a full year. All inter-company accounts and transactions have been eliminated. To facilitate comparison of information across periods, certain reclassifications have been made to prior year amounts to conform to the current year's presentation. At March 31, 2024, the Company presented loan advances made in 2023 separately in the consolidated statements of cash flows. These loan advances made were previously included in insurance and reinsurance balances payable in the consolidated statements of cash flows. This presentation was adopted to facilitate comparison to loan advances made in 2024. This reclassification did not impact results of operations, financial condition or liquidity. Tabular dollar and share amounts are in thousands, with the exception of per share amounts. All amounts are reported in U.S. dollars. Significant Accounting Policies There were no notable changes to the Company's significant accounting policies subsequent to its Annual Report on Form 10-K for the year ended December 31, 2023.

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION The Company's underwriting operations are organized around its global underwriting platforms, AXIS Insurance and AXIS Re. The Company has determined that it has two reportable segments, insurance and reinsurance. The Company does not allocate its assets by segment, with the exception of goodwill and intangible assets. Insurance The Company's insurance segment offers specialty insurance products to a variety of niche markets on a worldwide basis. The product lines in this segment are professional lines, property, liability, cyber, marine and aviation, accident and health, and credit and political risk. Reinsurance The Company's reinsurance segment provides treaty reinsurance to insurance companies on a worldwide basis. The product lines in this segment are liability, accident and health, professional lines, credit and surety, motor, agriculture, marine and aviation, and run-off lines which include catastrophe and property lines of business that the Company placed into run-off in 2022 and engineering lines of business that the Company placed into run-off in 2020. The following tables present the underwriting results of the Company's reportable segments, as well as the carrying amounts of allocated goodwill and intangible assets: 2024 2023 Three months ended and at March 31, Insurance Reinsurance Total Insurance Reinsurance Total Gross premiums written $ 1,574,505 $ 1,079,922 $ 2,654,427 $ 1,415,612 $ 966,364 $ 2,381,976 Net premiums written 1,022,354 699,719 1,722,073 882,576 725,780 1,608,356 Net premiums earned 917,946 340,095 1,258,041 816,456 413,743 1,230,199 Other insurance related income 21 8,319 8,340 54 523 577 Net losses and loss expenses (496,864) (231,807) (728,671) (449,467) (271,175) (720,642) Acquisition costs (176,029) (78,225) (254,254) (147,058) (83,315) (230,373) Underwriting-related general and administrative expenses (122,087) (15,706) (137,793) (116,630) (23,765) (140,395) Underwriting income $ 122,987 $ 22,676 145,663 $ 103,355 $ 36,011 139,366 Net investment income 167,383 133,771 Net investment gains (losses) (9,207) (20,190) Corporate expenses (25,580) (26,416) Foreign exchange (losses) gains 23,552 (8,710) Interest expense and financing costs (17,147) (16,894) Reorganization expenses (12,299) — Amortization of intangible assets (2,729) (2,729) Income before income taxes and interest in income (loss) of equity method investments 269,636 198,198 Income tax (expense) benefit 124,654 (15,896) Interest in income (loss) of equity method investments 1,169 (2,205) Net income 395,459 180,097 Preferred share dividends 7,563 7,563 Net income available to common shareholders $ 387,896 $ 172,534 Net losses and loss expenses ratio 54.1 % 68.2 % 57.9 % 55.1 % 65.5 % 58.6 % Acquisition cost ratio 19.2 % 23.0 % 20.2 % 18.0 % 20.1 % 18.7 % General and administrative expense ratio 13.3 % 4.6 % 13.0 % 14.2 % 5.8 % 13.6 % Combined ratio 86.6 % 95.8 % 91.1 % 87.3 % 91.4 % 90.9 % Goodwill and intangible assets $ 284,956 $ — $ 284,956 $ 295,872 $ — $ 295,872

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS a) Fixed Maturities, Available for Sale The following table provides the amortized cost and fair values of the Company's fixed maturities classified as available for sale: Amortized cost Allowance for expected credit losses Gross Gross unrealized losses Fair value At March 31, 2024 Available for sale U.S. government and agency $ 2,649,595 $ — $ 1,590 $ (57,468) $ 2,593,717 Non-U.S. government 757,162 (17) 4,851 (23,798) 738,198 Corporate debt 5,095,372 (3,973) 37,431 (212,892) 4,915,938 Agency RMBS (1) 1,684,869 — 4,273 (103,522) 1,585,620 CMBS (2) 870,433 — 545 (50,585) 820,393 Non-agency RMBS 152,322 (198) 518 (12,650) 139,992 ABS (3) 1,336,681 (49) 2,148 (20,875) 1,317,905 Municipals (4) 167,776 — 371 (10,600) 157,547 Total fixed maturities, available for sale $ 12,714,210 $ (4,237) $ 51,727 $ (492,390) $ 12,269,310 At December 31, 2023 Available for sale U.S. government and agency $ 3,049,445 $ — $ 13,211 $ (55,128) $ 3,007,528 Non-U.S. government 729,761 (30) 13,089 (18,861) 723,959 Corporate debt 4,651,654 (10,438) 49,434 (216,478) 4,474,172 Agency RMBS (1) 1,706,204 — 11,495 (83,038) 1,634,661 CMBS (2) 897,553 — 551 (58,408) 839,696 Non-agency RMBS 165,910 (194) 713 (13,033) 153,396 ABS (3) 1,265,187 (50) 2,855 (25,021) 1,242,971 Municipals (4) 168,540 (47) 414 (10,548) 158,359 Total fixed maturities, available for sale $ 12,634,254 $ (10,759) $ 91,762 $ (480,515) $ 12,234,742 (1) Residential mortgage-backed securities ("RMBS") originated by U.S. government-sponsored agencies. (2) Commercial mortgage-backed securities ("CMBS"). (3) Asset-backed securities ("ABS") include debt tranched securities collateralized primarily by auto loans, student loans, credit card receivables and collateralized loan obligations ("CLOs"). (4) Municipals include bonds issued by states, municipalities and political subdivisions. Contractual Maturities Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The table below provides the contractual maturities of fixed maturities classified as available for sale: Amortized cost Fair value % of Total fair value At March 31, 2024 Maturity Due in one year or less $ 435,592 $ 427,428 3.6 % Due after one year through five years 5,891,599 5,759,009 46.9 % Due after five years through ten years 2,164,623 2,046,280 16.7 % Due after ten years 178,091 172,683 1.4 % 8,669,905 8,405,400 68.6 % Agency RMBS 1,684,869 1,585,620 12.9 % CMBS 870,433 820,393 6.7 % Non-agency RMBS 152,322 139,992 1.1 % ABS 1,336,681 1,317,905 10.7 % Total $ 12,714,210 $ 12,269,310 100.0 % At December 31, 2023 Maturity Due in one year or less $ 474,557 $ 463,789 3.6 % Due after one year through five years 5,902,571 5,790,493 47.3 % Due after five years through ten years 2,064,619 1,954,449 16.0 % Due after ten years 157,653 155,287 1.3 % 8,599,400 8,364,018 68.2 % Agency RMBS 1,706,204 1,634,661 13.4 % CMBS 897,553 839,696 6.9 % Non-agency RMBS 165,910 153,396 1.3 % ABS 1,265,187 1,242,971 10.2 % Total $ 12,634,254 $ 12,234,742 100.0 % Gross Unrealized Losses The following table summarizes fixed maturities, available for sale in an unrealized loss position and the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 12 months or greater Less than 12 months Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses At March 31, 2024 Fixed maturities, available for sale U.S. government and agency $ 657,958 $ (40,409) $ 1,669,439 $ (17,059) $ 2,327,397 $ (57,468) Non-U.S. government 224,688 (20,529) 274,043 (3,269) 498,731 (23,798) Corporate debt 2,337,348 (202,913) 862,666 (9,979) 3,200,014 (212,892) Agency RMBS 810,334 (96,973) 414,071 (6,549) 1,224,405 (103,522) CMBS 665,150 (47,233) 86,723 (3,352) 751,873 (50,585) Non-agency RMBS 86,352 (12,562) 15,966 (88) 102,318 (12,650) ABS 447,941 (19,575) 343,163 (1,300) 791,104 (20,875) Municipals 124,038 (10,203) 7,081 (397) 131,119 (10,600) Total fixed maturities, available for sale $ 5,353,809 $ (450,397) $ 3,673,152 $ (41,993) $ 9,026,961 $ (492,390) At December 31, 2023 Fixed maturities, available for sale U.S. government and agency $ 846,503 $ (42,465) $ 867,733 $ (12,663) $ 1,714,236 $ (55,128) Non-U.S. government 233,038 (18,178) 115,112 (683) 348,150 (18,861) Corporate debt 2,623,304 (210,512) 240,813 (5,966) 2,864,117 (216,478) Agency RMBS 778,656 (80,070) 218,606 (2,968) 997,262 (83,038) CMBS 703,411 (54,856) 75,242 (3,552) 778,653 (58,408) Non-agency RMBS 98,483 (13,013) 10,017 (20) 108,500 (13,033) ABS 879,743 (24,747) 83,582 (274) 963,325 (25,021) Municipals 129,969 (10,156) 6,238 (392) 136,207 (10,548) Total fixed maturities, available for sale $ 6,293,107 $ (453,997) $ 1,617,343 $ (26,518) $ 7,910,450 $ (480,515) At March 31, 2024, 4,138 fixed maturities (2023: 3,535) were in an unrealized loss position of $492 million (2023: $481 million), of which $11 million (2023: $13 million) was related to securities below investment grade or not rated. At March 31, 2024 , 3,004 fixed maturities (2023: 3,212) had been in a continuous unrealized loss position for twelve months or greater and had a fair value of $5,354 million (2023 : $6,293 million ). The unrealized loss es of $492 million (2023: $481 million) were due to non-credit factors and were expected to be recovered as the related securities approach maturity. At March 31, 2024, the Company did not intend to sell the securities in an unrealized loss position and it is more likely than not that the Company will not be required to sell these securities before the anticipated recovery of their amortized costs. b) Fixed Maturities, Held to Maturity The following table provides the amortized cost and fair values of the Company's fixed maturities classified as held to maturity: Amortized cost Allowance for expected credit losses Net carrying value Gross Gross unrealized losses Fair value At March 31, 2024 Held to maturity Corporate debt $ 100,217 $ — $ 100,217 $ 177 $ (9,360) $ 91,034 ABS (1) 592,825 — 592,825 270 (403) 592,692 Total fixed maturities, held to maturity $ 693,042 $ — $ 693,042 $ 447 $ (9,763) $ 683,726 At December 31, 2023 Held to maturity Corporate debt $ 95,200 $ — $ 95,200 $ 298 $ (8,827) $ 86,671 ABS (1) 591,096 — 591,096 5 (1,921) 589,180 Total fixed maturities, held to maturity $ 686,296 $ — $ 686,296 $ 303 $ (10,748) $ 675,851 (1) Asset-backed securities ("ABS") include debt tranched securities collateralized primarily by collateralized loan obligations ("CLOs"). At March 31, 2024, fixed maturities, held to maturity of $693 million (2023: $686 million ) were presented net of an allowance for expected credit losse s of $nil (2023: $nil). The Company's ABS, held to maturity consist of CLO debt tranched securities. The Company uses a scenario-based approach to review its CLO debt portfolio and reviews subordination levels of these securities to determine their ability to absorb credit losses of the underlying collateral. If losses are forecast to be below the subordination level for a tranche held by the Company, the security is determined not to have a credit loss. At March 31, 2024, the allowance for credit losses expected to be recognized over the life of the Company's ABS, held to maturity w as $nil. To estimate expected credit losses for corporate debt securities, held to maturity, the Company's projected cash flows are primarily driven by assumptions regarding the severity of loss, which is a function of the probability of default and projected recovery rates. The Company's default and recovery rates are based on credit ratings, credit analysis and macroeconomic forecasts. At March 31, 2024, the allowance for credit losses expected to be recognized over the life of the Company's corporate debt, held to m aturity was $nil. Contractual Maturities Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. ABS classified as held to maturity had a carrying value of $593 million (2023: $591 million). Corpo rate debt classified as held to maturity with a net carrying value of $17 million (2023: $nil) is due between 1 year and 3 years and corporate debt classified as held to maturity with a net carrying value of $83 million (2023: $95 million) is due between 3 years and 10 years. c) Equity Securities The following table provides the cost and fair values of the Company's equity securities: Cost Gross unrealized gains Gross unrealized losses Fair value At March 31, 2024 Equity securities Common stocks $ 2,843 $ 25 $ (416) $ 2,452 Preferred stocks 5,654 161 (113) 5,702 Exchange-traded funds 188,548 99,734 (1,116) 287,166 Bond mutual funds 348,493 2,327 (63,962) 286,858 Total equity securities $ 545,538 $ 102,247 $ (65,607) $ 582,178 At December 31, 2023 Equity securities Common stocks $ 2,843 $ 101 $ (398) $ 2,546 Preferred stocks 5,496 218 (113) 5,601 Exchange-traded funds 182,989 105,858 (1,572) 287,275 Bond mutual funds 352,505 4,119 (63,535) 293,089 Total equity securities $ 543,833 $ 110,296 $ (65,618) $ 588,511 d) Mortgage Loans The following table provides details of the Company's mortgage loans, held for investment: March 31, 2024 December 31, 2023 Carrying value % of Total Carrying value % of Total Mortgage loans, held for investment: Commercial $ 617,817 101 % $ 616,368 101 % Allowance for expected credit losses (8,113) (1 %) (6,220) (1) % Total mortgage loans, held for investment $ 609,704 100 % $ 610,148 100 % The primary credit quality indicators for commercial mortgage loans are the debt service coverage ratio which compares a property’s net operating income to amounts needed to service the principal and interest due under the loan, (generally, the lower the debt service coverage ratio, the higher the risk of experiencing a credit loss) and the loan-to-value ratio which compares the unpaid principal balance of the loan to the estimated fair value of the underlying collateral (generally, the higher the loan-to-value ratio, the higher the risk of experiencing a credit loss). The debt service coverage ratio and loan-to-value ratio, as well as the values utilized in calculating these ratios, are updated quarterly. The Company has a high quality mortgage loan portfolio with a weighted average debt service coverage ratio of 1.9x (2023: 1.9x) and a weighted average loan-to-value ratio of 71% (2023: 71%). At March 31, 2024, and 2023 there were no past due amounts associated with the commercial mortgage loans held by the Company. On a quarterly basis, collateral dependent mortgage loans (e.g., when the borrower is experiencing financial difficulty, including when foreclosure is reasonably possible or probable) are evaluated individually for credit losses. The allowance for expected credit losses for a collateral dependent loan is established as the excess of amortized cost over the estimated fair value of the loan's underlying collateral, less selling cost when foreclosure is probable. Accordingly, the change in the estimated fair value of collateral dependent loans, which are evaluated individually for credit losses, is recognized as a change in the allowance for expected credit losses which is recorded in net investment gains (losses). At March 31, 2024, there are three collateral dependent loans with estimated loan-to-value ratios in excess of 100%, resulting in an allowance for expected credit loss of $8 million (2023: $6 million). e) Other Investments The following table provides a summary of the Company's other investments, together with additional information relating to the liquidity of each category: Fair value Redemption frequency (if currently eligible) Redemption notice period At March 31, 2024 Multi-strategy funds $ 24,950 3 % Quarterly 60-90 days Direct lending funds 168,987 18 % Quarterly (1) 90 days Private equity funds 309,399 33 % n/a n/a Real estate funds 309,545 33 % Quarterly (2) , Annually (3) 45-90 days CLO-Equities 4,986 — % n/a n/a Other privately held investments 116,857 13 % n/a n/a Total other investments $ 934,724 100 % At December 31, 2023 Multi-strategy funds $ 24,619 3 % Quarterly 60-90 days Direct lending funds 192,270 20 % Quarterly (1) 90 days Private equity funds 301,712 32 % n/a n/a Real estate funds 317,325 33 % Quarterly (2) , Annually (3) 45-90 days CLO-Equities 5,300 1 % n/a n/a Other privately held investments 108,187 11 % n/a n/a Total other investments $ 949,413 100 % n/a - not applicable (1) Applies to one fund with a fair va lue of $13 million (2023: $17 million). (2) Applies to one fund with a fair value of $64 million (2023: $66 million ). (3) Applies to one fund with a fair value of $24 million (2023: $25 million ). Two common redemption restrictions which may impact the Company's ability to redeem multi-strategy funds are gates and lockups. A gate is a suspension of redemptions which may be implemented by the general partner or investment manager of the fund in order to defer, in whole or in part, the redemption request in the event the aggregate amount of redemption requests exceeds a predetermined percentage of the fund's net assets which may otherwise hinder the general partner or investment manager's ability to liquidate holdings in an orderly fashion in order to generate the cash necessary to fund extraordinarily large redemption payouts. A lockup period is the initial amount of time an investor is contractually required to hold the security before having the ability to redeem. During the three months ended March 31, 2024 and 2023, neither of these restrictions impacted the Company's redemption requests. At March 31, 2024, there w ere no multi-strategy fund holdings (2023: $nil) where the Company is still within the lockup period. At March 31, 2024, the Company h ad $28 million (2023: $28 million) of unfunded commitments as a limited partner in multi-strategy hedge funds. Once the full amount of committed capital has been called by the General Partner of each of these funds, the assets will not be fully returned until after the completion of the funds' investment term. These funds have investment terms ranging from two years to the dissolution of the underlying fund. At March 31, 2024, the Company had $190 million (2023: $192 million) of unfunded commitments as a limited partner in direct lending funds. Once the full amount of committed capital has been called by the General Partner of each of these funds, the assets will not be fully returned until the completion of the fund's investment term. These funds have investment terms ranging from four At March 31, 2024, the Company had $134 million (2023: $145 million) of unfunded commitments as a limited partner in private equity funds. The life of the funds is subject to the dissolution of the underlying funds. The Company expects the overall holding period to be over six years. At March 31, 2024, the Company had $105 million (2023: $107 million) of unfunded commitments as a limited partner in real estate funds. These funds include an open-ended fund and funds with investment terms ranging from two years to the dissolution of the underlying fund. At March 31, 2024, the Company had $23 million (2023: $30 million) of unfunded commitments as a limited partner in three private company investment funds focusing on financial services technology companies with an emphasis on insurance technology companies ("private company investment funds ") . Two of these funds have investment terms of 5 years and one fund has an investment term of 10 years. f) Equity Method Investments During 2023, the Company paid $22 million to acquire 18% of the common equity of Monarch Point Re (ISAC) Ltd. and Monarch Point Re (ISA 2023) Ltd., a collateralized reinsurance company formed under the laws of Bermuda as an incorporated segregated accounts company under the Incorporated Segregated Accounts Companies Act 2019, as amended (the "ISAC Act"). During 2024, the Company paid $7 million to acquire 18% of the common equity of Monarch Point Re (ISA 2024) Ltd., (Monarch Point Re (ISAC) Ltd., Monarch Point Re (ISA 2023) Ltd. and Monarch Point Re (ISA 2024) Ltd., individually or collectively "Monarch Point Re"). Monarch Point Re is an independent reinsurer jointly sponsored by the Company and Stone Point Credit, LLC ("Stone Point"). The Company retrocedes a diversified portfolio of casualty reinsurance business to Monarch Point Re and Stone Point serves as its investment manager. As an investor, the Company expects to benefit from underwriting fees generated by Monarch Point Re and the income and capital appreciation Stone Point seeks to deliver through its investment management services. Monarch Point Re is not a Variable Interest Entity ("VIE") that is required to be included in the Company's consolidated financial statements. The Company accounts for its ownership interest in Monarch Point Re under the equity method of accounting. During 2016, the Company paid $108 million including direct transaction costs to acquire 19% of the common equity of Harrington Reinsurance Holdings Limited ("Harrington"), the parent company of Harrington Re Ltd. ("Harrington Re"), an independent reinsurance company jointly sponsored by the Company and The Blackstone Group L.P. ("Blackstone"). Through long-term service agreements, the Company serves as Harrington Re's reinsurance underwriting manager and Blackstone serves as exclusive investment management service provider. As an investor, the Company expects to benefit from underwriting profit generated by Harrington Re and the income and capital appreciation Blackstone seeks to deliver through its investment management services. In addition, the Company has entered into an arrangement with Blackstone under which underwriting and investment related fees will be shared equally. Harrington is not a VIE that is required to be included in the Company's consolidated financial statements. The Company accounts for its ownership interest in Harrington under the equity method of accounting. The Company's proportionate share of the underlying equity in net assets resulted in a basis difference of $5 million which represents initial transactions costs. g) Variable Interest Entities In the normal course of investing activities, the Company actively manages allocations to non-controlling tranches of structured securities which are variable interests issued by VIEs . These structured securities include RMBS, CMBS and ABS. The Company also invests in limited partnerships which represent 74% of the Company's other investments. The investments in limited partnerships include multi-strategy funds , direct lending funds, private equity funds, real estate funds and CLO equity tranched securities, which are variable interests issued by VIEs (refer to Note 3(e) ' Other Investments '). The Company does not have the power to direct the activities that are most significant to the economic performance of these VIEs. Therefore, the Company is not the primary beneficiary of these VIEs. The maximum exposure to loss on these interests is limited to the amount of commitment made by the Company. The Company has not provided financial or other support to these structured securities other than the original investment. h) Net Investment Income Net investment income was derived from the following sources: Three months ended March 31, 2024 2023 Fixed maturities $ 139,396 $ 118,262 Other investments 5,673 486 Equity securities 2,762 2,455 Mortgage loans 9,130 8,386 Cash and cash equivalents 13,661 10,012 Short-term investments 3,463 1,660 Gross investment income 174,085 141,261 Investment expenses (6,702) (7,490) Net investment income $ 167,383 $ 133,771 i) Net Investment Gains (Losses) The following table provides an analysis of net investment gains (losses): Three months ended March 31, 2024 2023 Gross realized investment gains Fixed maturities and short-term investments $ 14,399 $ 12,370 Equity securities 30,626 1,517 Gross realized investment gains 45,025 13,887 Gross realized investment losses Fixed maturities and short-term investments (43,932) (53,649) Equity securities (7,712) (396) Gross realized investment losses (51,644) (54,045) (Increase) decrease in allowance for expected credit losses, fixed maturities, available for sale 6,522 (911) (Increase) decrease in allowance for expected credit losses, mortgage loans (1,858) (1,900) Impairment losses (1) (8) — Change in fair value of investment derivatives (2) 795 (947) Net unrealized gains (losses) on equity securities (8,039) 23,726 Net investment losses $ (9,207) $ (20,190) (1) Related to instances where the Company intends to sell securities or it is more likely than not that the Company will be required to sell securities before their anticipated recovery. (2) Refer to Note 5 ' Derivative Instruments'. The following table provides a reconciliation of the beginning and ending balances of the allowance for expected credit losses on fixed maturities classified as available for sale: Three months ended March 31, 2024 2023 Balance at beginning of period $ 10,759 $ 11,733 Expected credit losses on securities where credit losses were not previously recognized 31 613 Additions (reductions) for expected credit losses on securities where credit losses were previously recognized (1,553) 919 Impairments of securities which the Company intends to sell or more likely than not will be required to sell — — Securities sold/redeemed/matured (5,000) (620) Balance at end of period $ 4,237 $ 12,645 j ) Reverse Repurchase Agreements At March 31, 2024, the Company held $53 million (2023: $12 million) of reverse repurchase agreements. These loans are fully collateralized, are generally outstanding for a short period of time and are presented on a gross basis as part of cash and cash equivalents in the Company's consolidated balance sheets. The required collateral for these loans is either cash or U.S. Treasuries at a minimum rate of 102% of the loan principal. Upon maturity, the Company receives principal and interest income. The Company monitors the estimated fair value of the securities loaned and borrowed on a daily basis with additional collateral obtained as necessary throughout the duration of the transaction.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair Value Hierarchy Fair value is defined as the price to sell an asset or transfer a liability (i.e., the "exit price") in an orderly transaction between market participants. U.S. GAAP prescribes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. The level in the hierarchy within which a given fair value measurement falls is determined based on the lowest level input that is significant to the measurement. The hierarchy is broken down into three levels as follows: • Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. • Level 2 - Valuations based on quoted prices in active markets for similar assets or liabilities, quoted prices for identical assets or liabilities in inactive markets, or for which significant inputs are observable (e.g., interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data. • Level 3 - Valuations based on inputs that are unobservable and significant to the overall fair value measurement. The unobservable inputs reflect the Company's judgments about assumptions that market participants might use. The availability of observable inputs can vary from financial instrument to financial instrument and is affected by a wide variety of factors including, for example, the type of financial instrument, whether the financial instrument is new and not yet established in the marketplace, and other characteristics particular to the transaction. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires significantly more judgment. Accordingly, the degree of judgment exercised by management in determining fair value is greatest for financial instruments categorized as Level 3. In periods of market dislocation, the observability of prices and inputs may be reduced for many financial instruments. This may lead the Company to change the selection of valuation technique (from market to cash flow approach) or may cause the Company to use multiple valuation techniques to estimate the fair value of a financial instrument. This circumstance could cause an instrument to be reclassified between levels within the fair value hierarchy. Valuation Techniques The valuation techniques, including significant inputs and assumptions generally used to determine the fair values of the Company's financial instruments as well as the classification of the fair values of its financial instruments in the fair value hierarchy are described in detail below. Fixed Maturities At each valuation date, the Company uses the market approach valuation technique to estimate the fair value of its fixed maturities portfolio, where possible. The market approach includes, but is not limited to, prices obtained from third-party pricing services for identical or comparable securities and the use of "pricing matrix models" using observable market inputs such as yield curves, credit risks and spreads, measures of volatility, and prepayment speeds. Pricing from third-party pricing services is sourced from multiple vendors, where available, and the Company maintains a vendor hierarchy by asset type based on historical pricing experience and vendor expertise. Where prices are unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers who are active in the corresponding markets. The valuation techniques including significant inputs and assumptions generally used to determine the fair values of the Company's fixed maturities by asset class as well as the classifications of the fair values of these securities in the fair value hierarchy are described in detail below. U.S. Government and Agency U.S. government and agency securities consist primarily of bonds issued by the U.S. Treasury and mortgage pass-through agencies such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Government National Mortgage Association. As the fair values of U.S. Treasury securities are based on unadjusted quoted market prices in active markets, the fair values of these securities are classified as Level 1. The fair values of U.S. government agency securities are determined using the spread above the risk-free yield curve. As the yields for the risk-free yield curve and the spreads are observable market inputs, the fair values of U.S. government agency securities are classified as Level 2. Non-U.S. Government Non-U.S. government securities include bonds issued by non-U.S. governments and their agencies along with supranational organizations (collectively also known as sovereign debt securities). The fair values of these securities are based on prices obtained from international indices or valuation models that include inputs such as interest rate yield curves, cross-currency basis index spreads and country credit spreads for structures similar to the sovereign bond in terms of issuer, maturity and seniority. As the significant inputs used to price these securities are observable market inputs, the fair values of non-U.S. government securities are classified as Level 2. Corporate Debt Corporate debt securities consist primarily of investment grade debt of a wide variety of corporate issuers and industries. The fair values of these securities are generally determined using the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As the yields for the risk-free yield curve and the spreads are observable market inputs, the fair values of corporate debt securities are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. In this event, the fair values of these securities are classified as Level 3. Agency RMBS Agency RMBS consist of bonds issued by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Government National Mortgage Association. The fair values of these securities are priced using a mortgage pool specific model which uses daily inputs from the active to be announced market and the spread associated with each mortgage pool based on vintage. As the significant inputs used to price these securities are observable market inputs, the fair values of Agency RMBS are classified as Level 2. CMBS CMBS mainly include investment grade bonds originated by non-agencies. The fair values of these securities are determined using a pricing model which uses dealer quotes and other available trade information along with security level characteristics to determine deal specific spreads. As the significant inputs used to price these securities are observable market inputs, the fair values of CMBS are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. I n this event, the fair values of these securities are classified as Level 3. Non-agency RMBS Non-agency RMBS mainly include investment grade bonds originated by non-agencies. The fair values of these securities are determined using an option adjusted spread model or other relevant models, which use inputs including available trade information or broker quotes, prepayment and default projections based on historical statistics of the underlying collateral and current market data. As the significant inputs used to price these securities are observable market inputs, the fair values of non-agency RMBS are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. I n this event, the fair values of these securities are classified as Level 3. ABS ABS mainly include investment grade bonds backed by pools of loans with a variety of underlying collateral, including auto loans, student loans, credit card receivables and collateralized loan obligations ("CLOs"), originated by a variety of financial institutions. The fair values of these securities are determined using a model which uses prepayment speeds and spreads sourced primarily from the new issue market. As the significant inputs used to price these securities are observable market inputs, the fair values of ABS are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers t o estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. I n this event, the fair values of these securities are classified as Level 3. Municipals Municipals comprise revenue bonds and general obligation bonds issued by U.S. domiciled state and municipal entities. The fair values of these securities are determined using spreads obtained from the new issue market, trade prices and broker-dealers quotes. As the significant inputs used to price these securities are observable market inputs, the fair values of municipals are classified as Level 2. Equity Securities Equity securities include common stocks, preferred stocks, exchange-traded funds and bond mutual funds. As the fair values of common stocks and exchange-traded funds are based on unadjusted quoted market prices in active markets, the fair values of these securities are classified as Level 1. As the significant inputs used to price preferred stocks are observable market inputs, the fair value of these securities are classified as Level 2. As bond mutual funds have daily liquidity, the fair values of these securities are classified as Level 2. Other Investments The fair value of an indirect investment in CLO-Equities is estimated using an income approach valuation technique, specifically an externally developed discounted cash flow model due to the lack of observable and relevant trades in secondary markets. As the significant inputs used to price this security are unobservable, the fair value of the indirect investment in CLO-Equities is classified as Level 3. Other privately held investments include common shares, preferred shares, private company investment funds, investments in limited partnerships, convertible notes, convertible preferred shares, and a variable yield security. These investments are initially valued at cost, which approximates fair value. In subsequent measurement periods, the fair values of these investments are generally derived from one or a combination of valuation methodologies which consider factors including recent capital raises by the investee companies, comparable precedent transaction multiples, comparable publicly traded multiples, third-party valuations, discounted cash-flow models, and other techniques that consider the industry and develo pment stage of each investee company. The fair value of the variable yield security is determined using an externally developed discounted cash flow model. In order to assess the reasonableness of the information received from investee companies, the Company maintains an understanding of current market conditions, historical results, and emerging trends that may impact the results of operations, financial condition or liquidity of these companies. In addition, the Company engages in regular communication with management at investee companies. As the significant inputs used to price these investments are unobservable, the fair values of other privately held investments are classified as Level 3. The fair values of private company investment funds are estimated using NAVs as advised by external fund managers or third-party administrators. Short-term Investments Short-term investments primarily comprise highly liquid securities with maturities greater than three months but less than one year from the date of purchase. These securities are typically not actively traded due to their approaching maturity, therefore their amortized cost approximates fair value. The fair values of short-term investments are classified as Level 2. Derivative Instruments Derivative instruments include foreign exchange forward contracts that are customized to the Company's economic hedging strategies and trade in the over-the-counter derivative market. The fair values of these derivatives are determined using a market approach valuation technique based on significant observable market inputs from third-party pricing vendors, non-binding broker-dealer quotes and/or recent trading activity. As the significant inputs used to price these derivatives are observable market inputs, the fair values of these derivatives are classified as Level 2. The tables below present the financial instruments measured at fair value on a recurring basis for the periods indicated: Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At March 31, 2024 Assets Fixed maturities, available for sale U.S. government and agency $ 2,576,715 $ 17,002 $ — $ — $ 2,593,717 Non-U.S. government — 738,198 — — 738,198 Corporate debt — 4,789,463 126,475 — 4,915,938 Agency RMBS — 1,585,620 — — 1,585,620 CMBS — 820,393 — — 820,393 Non-agency RMBS — 139,992 — — 139,992 ABS — 1,317,905 — — 1,317,905 Municipals — 157,547 — — 157,547 2,576,715 9,566,120 126,475 — 12,269,310 Equity securities Common stocks 2,452 — — — 2,452 Preferred stocks 2 5,700 — — 5,702 Exchange-traded funds 287,166 — — — 287,166 Bond mutual funds — 286,858 — — 286,858 289,620 292,558 — — 582,178 Other investments Multi-strategy funds — — — 24,950 24,950 Direct lending funds — — — 168,987 168,987 Private equity funds — — — 309,399 309,399 Real estate funds — — — 309,545 309,545 CLO-Equities — — 4,986 — 4,986 Other privately held investments — — 96,255 20,602 116,857 — — 101,241 833,483 934,724 Short-term investments — 75,879 — — 75,879 Other assets Derivative instruments (refer to Note 5) — 1,232 — — 1,232 Total Assets $ 2,866,335 $ 9,935,789 $ 227,716 $ 833,483 $ 13,863,323 Liabilities Derivative instruments (refer to Note 5) $ — $ 2,282 $ — $ — $ 2,282 Total Liabilities $ — $ 2,282 $ — $ — $ 2,282 Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At December 31, 2023 Assets Fixed maturities, available for sale U.S. government and agency $ 2,989,612 $ 17,916 $ — $ — $ 3,007,528 Non-U.S. government — 723,959 — — 723,959 Corporate debt — 4,338,419 135,753 — 4,474,172 Agency RMBS — 1,634,661 — — 1,634,661 CMBS — 839,696 — — 839,696 Non-agency RMBS — 153,396 — — 153,396 ABS — 1,242,971 — — 1,242,971 Municipals — 158,359 — — 158,359 2,989,612 9,109,377 135,753 — 12,234,742 Equity securities Common stocks 2,546 — — — 2,546 Preferred stocks 1 5,600 — — 5,601 Exchange-traded funds 287,275 — — — 287,275 Bond mutual funds — 293,089 — — 293,089 289,822 298,689 — — 588,511 Other investments Multi-strategy funds — — — 24,619 24,619 Direct lending funds — — — 192,270 192,270 Private equity funds — — — 301,712 301,712 Real estate funds — — — 317,325 317,325 CLO-Equities — — 5,300 — 5,300 Other privately held investments — — 87,289 20,898 108,187 — — 92,589 856,824 949,413 Short-term investments — 17,216 — — 17,216 Other assets Derivative instruments (refer to Note 5) — 4,424 — — 4,424 Total Assets $ 3,279,434 $ 9,429,706 $ 228,342 $ 856,824 $ 13,794,306 Liabilities Derivative instruments (refer to Note 5) $ — $ 10,165 $ — $ — $ 10,165 Total Liabilities $ — $ 10,165 $ — $ — $ 10,165 The following table quantifies the significant unobservable inputs used in estimating fair values at March 31, 2024 of investments classified as Level 3 in the fair value hierarchy: Asset fair value Valuation technique Unobservable input Amount / Range Weighted average Other investments - CLO-Equities $ 4,986 Discounted cash flow Default rate 4.5% 4.5% Loss severity rate 50.0% 50.0% Collateral spread 3.0% 3.0% Estimated maturity date 4 years 4 years Other investments - Other privately held investments $ 18,728 Discounted cash flow Discount rate 6.0% 6.0% Default rate 0.5% 0.5% Loss absorption yield 1.0% 1.0% Estimated maturity date 0-2 years 1 year Note: Fixed maturities of $126 million that are classified as Level 3 are excluded from the above table as these securities are priced using broker-dealer quotes. In addition, other privately held investments of $78 million that are classified as Level 3 are excluded from the above table as these investments are priced using capital statements received from investee companies. Other Investments - CLO-Equities The CLO-Equities market continues to be relatively inactive with only a small number of transactions being observed, particularly related to transactions involving CLO-Equities held by the Company. Accordingly, the fair value of the Company's indirect investment in CLO-Equities is determined using a discounted cash flow model prepared by an external investment manager. The default and loss severity rates are the most judgmental unobservable market inputs to the discounted cash flow model to which the valuation of the Company's indirect investment in CLO-Equities is most sensitive. A significant increase (decrease) in either of these significant inputs in isolation would result in a lower (higher) fair value estimate for the investment in CLO-Equities and, in general, a change in default rate assumptions would be accompanied by a directionally similar change in loss severity rate assumptions. Collateral spreads and estimated maturity dates are less judgmental inputs as they are based on the historical average of actual spreads and the weighted average life of the current underlying portfolios, respectively. A significant increase (decrease) in either of these significant inputs in isolation would result in a higher (lower) fair value estimate for the investment in CLO-Equities. In general, these inputs have no significant interrelationship with each other or with default and loss severity rates. On a quarterly basis, the Company's valuation process for its indirect investment in CLO-Equities includes a review of the underlying cash flows and key assumptions used in the discounted cash flow model. The above significant unobservable inputs are reviewed and updated based on information obtained from secondary markets, including information received from the managers of the Company's CLO-Equities investment. In order to assess the reasonableness of the inputs the Company uses in the discounted cash flow model, the Company maintains an understanding of current market conditions, historical results, and emerging trends that may impact future cash flows. In addition, the assumptions the Company uses in its models are updated through regular communication with industry participants and o ngoing monitoring of the deals in which the Company participates. Other Investments - Other Privately Held Securities Other privately held securities are initially valued at cost which approximates fair value. In subsequent measurement periods, the fair value of the variable yield security was determined using an externally developed discounted cash flow model. This model includes inputs that are specific to that investment. The inputs used in the fair value measurement include an appropriate discount rate, default rate, loss absorption rate and estimated maturity date. The selection of an appropriate discount rate is judgmental and is the most significant unobservable input used in the valuation of this investment. A significant increase (decrease) in this input in isolation could result in significantly lower (higher) fair value measurement for this investment. In order to assess the reasonableness of the inputs the Company uses in the discounted cash flow model, the Company maintains an understanding of current market conditions, historical results, as well as investee specific information that may impact future cash flows. The following table presents changes in Level 3 for financial instruments measured at fair value on a recurring basis: Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized gains/(losses) (3) Three months ended March 31, 2024 Fixed maturities, available for sale Corporate debt $ 135,753 $ — $ — $ (834) $ (495) $ 4,231 $ — $ (12,180) $ 126,475 $ — 135,753 — — (834) (495) 4,231 — (12,180) 126,475 — Other investments CLO-Equities 5,300 — — — — — — (314) 4,986 — Other privately held investments 87,289 — — 1,728 — 7,238 — — 96,255 1,728 92,589 — — 1,728 — 7,238 — (314) 101,241 1,728 Total assets $ 228,342 $ — $ — $ 894 $ (495) $ 11,469 $ — $ (12,494) $ 227,716 $ 1,728 Three months ended March 31, 2023 Fixed maturities, available for sale Corporate debt $ 119,104 $ — $ — $ (7) $ 1,183 $ 18,910 $ — $ (8,763) $ 130,427 $ — 119,104 — — (7) 1,183 18,910 — (8,763) 130,427 — Other investments CLO-Equities 5,016 — — 411 — — — (408) 5,019 411 Other privately held investments 136,158 — — 336 — 4,459 — — 140,953 336 141,174 — — 747 — 4,459 — (408) 145,972 747 Total assets $ 260,278 $ — $ — $ 740 $ 1,183 $ 23,369 $ — $ (9,171) $ 276,399 $ 747 (1) Realized gains (losses) on fixed maturities and realized and unrealized gains (losses) on other assets and other liabilities included in net income are included in net investment gains (losses). Realized and unrealized gains (losses) on other investments included in net income are included in net investment income. (2) Unrealized gains (losses) on fixed maturities are included in other comprehensive income ("OCI"). (3) Change in unrealized gains (losses) relating to assets and liabilities held at the reporting date. Transfers into Level 3 from Level 2 There were no transfers into Level 3 from Level 2 during the three months ended March 31, 2024 and 2023. Transfers out of Level 3 into Level 2 There were no transfers out of Level 3 into Level 2 during the three months ended March 31, 2024 and 2023. Measuring the Fair Value of Other Investments Using Net Asset Valuations The fair values of multi-strategy funds, direct lending funds, private equity funds, real estate funds and private company investment funds are estimated using net asset valuations ("NAVs") as advised by external fund managers or third-party administrators. For these funds, NAVs are based on the manager's or administrator's valuation of the underlying holdings in accordance with the fund's governing documents and in accordance with U.S. GAAP. For multi-strategy funds, direct lending funds, private equity funds, real estate funds and private company investment funds, valuation statements are typically released on a reporting lag. Therefore, the Company estimates the fair value of these funds by starting with the most recent fund valuations and adjusting for capital calls, redemptions, drawdowns and distributions. Return estimates are not available from the relevant fund managers for these funds, therefore the Company typically has a reporting lag in its fair value measurements of these funds. At March 31, 2024 and December 31, 2023 all funds measured at fair value using NAVs are reported generally on a one quarter lag. The Company often does not have access to financial information relating to the underlying securities held within the funds, therefore, management is unable to corroborate the fair values placed on the securities underlying the asset valuations provided by fund managers or fund administrators. In order to assess the reasonableness of the NAVs, the Company performs a number of monitoring procedures on a quarterly basis, to assess the quality of the information provided by fund managers and fund administrators. These procedures include, but are not limited to, regular review and discussion of each fund's performance with its manager, regular evaluation of fund performance against applicable benchmarks and the backtesting of the Company's fair value estimates against subsequently received NAVs. Backtesting involves comparing the Company's previously reported fair values for each fund against NAVs per audited financial statements (for year-end values) and final NAVs from fund managers and fund administrators (for interim values). The fair values of multi-strategy funds, direct lending funds, private equity funds, real estate funds and private company investment funds, are measured using the NAV practical expedient, therefore the fair values of these funds have not been categorized within the fair value hierarchy. Financial Instruments Disclosed, But Not Carried, at Fair Value The fair value of financial instruments accounting guidance also applies to financial instruments disclosed, but not carried, at fair value, except for certain financial instruments, including insurance contracts. At March 31, 2024, the carrying values of cash and cash equivalents including restricted amounts, accrued investment income, receivable for investments sold, certain other assets, payable for investments purchased and certain other liabilities approximated fair values due to their short maturities. As these financial instruments are not actively traded, their fair values are classified as Level 2. At March 31, 2024, the Company's fixed maturities, held to maturity, were recorded at amortized cost with a carrying value of $693 million (2023: $686 million) and a fair value of $684 million (2023: $676 million). The fair values of these securities are determined using a model which uses prepayment speeds and spreads sourced primarily from the new issue market. As the significant inputs used to price these securities are observable market inputs, their fair values are classified as Level 2. At March 31, 2024, the carrying value of mortgage loans, held for investment, approximated fair value. The fair values of mortgage loans are primarily determined by estimating expected future cash flows and discounting them using current interest rates for similar mortgage loans with similar credit risk or are determined from pricing for similar loans. As mortgage loans are not actively traded, their fair values are classified as Level 3. At March 31, 2024, the Company's debt was recorded at amortized cost with a carrying value of $1,314 million (2023: $1,314 million) and a fair value of $1,204 million (2023: $1,198 million). The fair value of the Company's debt is based on prices obtained from a third-party pricing service and is determined using the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As the yields for the risk-free yield curve and the spreads are observable market inputs, the fair value of this debt is classified as Level 2. At March 31, 2024, Federal Home Loan Bank advances were recorded at amortized cost with a carrying value of $86 million (2023: $86 million) and a fair value of $86 million (2023: $86 million). As these advances are not actively traded, their fair values are classified as Level 2.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS The following table provides the balance sheet classifications of derivatives recorded at fair value: March 31, 2024 December 31, 2023 Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Relating to investment portfolio: Foreign exchange forward contracts $ 110,733 $ 204 $ 2 $ 49,307 $ 66 $ 274 Relating to underwriting portfolio: Foreign exchange forward contracts 1,547,244 1,028 2,280 1,347,559 4,358 9,891 Total derivatives $ 1,232 $ 2,282 $ 4,424 $ 10,165 (1) Derivative assets and derivative liabilities are classified within other assets and other liabilities in the consolidated balance sheets. The notional amounts of derivative contracts represent the basis on which amounts paid or received are calculated and are presented in the above table to quantify the volume of the Company's derivative activities. Notional amounts are not reflective of credit risk. None of the Company's derivative instruments are designated as hedges. Offsetting Assets and Liabilities The Company's derivative instruments are generally traded under International Swaps and Derivatives Association master netting agreements which establish terms that apply to all transactions. In the event of a bankruptcy or other stipulated event, master netting agreements provide that individual positions be replaced with a new amount, usually referred to as the termination amount, determined by taking into account market prices and converting into a single currency. Effectively, this contractual close-out netting reduces credit exposure from gross to net exposure. The following table provides a reconciliation of gross derivative assets and liabilities to the net amounts presented in the consolidated balance sheets, with the difference being attributable to the impact of master netting agreements: March 31, 2024 December 31, 2023 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 4,516 $ (3,284) $ 1,232 $ 8,708 $ (4,284) $ 4,424 Derivative liabilities $ 5,566 $ (3,284) $ 2,282 $ 14,449 $ (4,284) $ 10,165 (1) Net asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets. Refer to Note 3 'Investments' for information on reverse repurchase agreements. a) Relating to Investment Portfolio Foreign Currency Risk The Company's investment portfolio is exposed to foreign currency risk. Therefore, the fair values of its investments are partially influenced by changes in foreign exchange rates. The Company may enter into foreign exchange forward contracts to manage the effect of this foreign currency risk. These foreign currency hedging activities are not designated as specific hedges for financial reporting purposes. b) Relating to Underwriting Portfolio Foreign Currency Risk The Company's insurance and reinsurance subsidiaries and branches operate in various countries. Some of its business is written in currencies other than the U.S. dollar, therefore the underwriting portfolio is exposed to significant foreign currency risk. The Company manages foreign currency risk by seeking to match its foreign-denominated net liabilities under insurance and reinsurance contracts with cash and investments that are denominated in the same currencies. The Company uses derivative instruments, specifically, forward contracts to economically hedge foreign currency exposures. The following table provides the total unrealized and realized gains (losses) recognized in net income (loss) for derivatives not designated as hedges: Consolidated statement of operations line item that includes gain (loss) recognized in net income (loss) Three months ended March 31, 2024 2023 Relating to investment portfolio: Foreign exchange forward contracts Net investment gains (losses) $ 795 $ (947) Relating to underwriting portfolio: Foreign exchange forward contracts Foreign exchange (losses) gains (2,015) 11,250 Total $ (1,220) $ 10,303

RESERVE FOR LOSSES AND LOSS EXP

RESERVE FOR LOSSES AND LOSS EXPENSES	3 Months Ended
	Mar. 31, 2024
Insurance [Abstract]
RESERVE FOR LOSSES AND LOSS EXPENSES	RESERVE FOR LOSSES AND LOSS EXPENSES Reserve Roll-Forward The following table presents a reconciliation of the Company's beginning and ending gross reserve for losses and loss expenses and net reserve for unpaid losses and loss expenses: Three months ended March 31, 2024 2023 Gross reserve for losses and loss expenses, beginning of period $ 16,434,018 $ 15,168,863 Less reinsurance recoverable on unpaid losses and loss expenses, beginning of period (6,323,083) (5,831,172) Net reserve for unpaid losses and loss expenses, beginning of period 10,110,935 9,337,691 Net incurred losses and loss expenses related to: Current year 728,671 724,680 Prior years — (4,038) 728,671 720,642 Net paid losses and loss expenses related to: Current year (50,724) (38,662) Prior years (612,571) (574,538) (663,295) (613,200) Foreign exchange and other (48,602) 46,094 Net reserve for unpaid losses and loss expenses, end of period 10,127,709 9,491,227 Reinsurance recoverable on unpaid losses and loss expenses, end of period 6,503,188 5,823,417 Gross reserve for losses and loss expenses, end of period $ 16,630,897 $ 15,314,644 Estimates for Significant Catastrophe Events At March 31, 2024, net reserves for losses and loss expenses included estimated amounts for numerous catastrophe events. The magnitude and complexity of losses arising from certain of these events inherently increase the level of uncertainty and, therefore, the level of management judgment involved in arriving at estimated net reserves for losses and loss expenses. These events include Hurricane Ian, Winter Storm Elliot, June European Convective Storms, the Russia-Ukraine war and COVID-19 which occurred in 2022. As a result, actual losses for these events may ultimately differ materially from current estimates. During the three months ended March 31, 2024, the Company recognized catastrophe and weather-related losses, net of reinsurance, of $20 million (2023: $38 million). Prior Year Reserve Development The Company's net prior year reserve development arises from changes to estimates of losses and loss expenses related to loss events that occurred in previous calendar years. The following table presents net prior year reserve development by segment: Three months ended March 31, 2024 2023 Favorable (Adverse) Favorable (Adverse) Insurance $ — $ 1,041 Reinsurance — 2,997 Total $ — $ 4,038 The following sections provide further details on net prior year reserve development by segment, line of business and accident year: Insurance Segment: Prior year reserve development by line of business was as follows: Three months ended March 31, 2024 2023 Favorable (Adverse) Favorable (Adverse) Property $ 8,011 $ 5,900 Accident and health — (304) Marine and aviation (8,011) 13,221 Cyber — 8,452 Professional lines — (12,594) Credit and political risk — 4,519 Liability — (18,153) Total $ — $ 1,041 2024 For the three months ended March 31, 2024, net prior year reserve development of $nil was recognized, the principal components of which were: • $8 million of net favorable prior year reserve development on property business primarily due to better than expected loss emergence mainly related to the 2021 and 2022 accident years. • $8 million of net adverse prior year reserve development on marine and aviation business primarily due to an increase in the loss estimate attributable to a specific large claim related to the 2019 accident year. 2023 For the three months ended March 31, 2023, the Company recognized $1 million of net favorable prior year reserve development, the principal components of which were: • $13 million of net favorable prior year reserve development on marine and aviation business primarily due to better than expected loss emergence mainly related to the 2021 and 2022 accident years. • $8 million of net favorable prior year reserve development on cyber business primarily due to better than expected loss emergence mainly related to 2019 and older accident years. • $6 million of net favorable prior year reserve development on property business primarily due to better than expected loss emergence attributable to 2018 and older accident years, partially offset by reserve strengthening related to the 2021 accident year. • $5 million of net favorable prior year reserve development on credit and political risk business primarily due to a decrease in the loss estimate attributable to a specific large claim related to the 2020 accident year and better than expected loss emergence attributable to the Lloyds book of business related to several accident years. • $18 million of net adverse prior year reserve development on liability business primarily due to reserve strengthening within the U.S. primary casualty book of business mainly related to the 2015, 2018 and 2021 accident years. • $13 million of net adverse prior year reserve development on professional lines business primarily due to reserve strengthening within the U.S. commercial management solutions book of business related to several accident years and U.S. financial institutions book of business mainly related to the 2018 accident year. Reinsurance Segment: Prior year reserve development by line of business was as follows: Three months ended March 31, 2024 2023 Favorable Favorable Accident and health $ — $ 6,988 Agriculture — 11,891 Marine and aviation — (250) Professional lines — (3,225) Credit and surety — (546) Motor — (17,122) Liability — (32,853) Run-off lines Catastrophe — 31,058 Property — 6,883 Engineering — 173 Total run-off lines — 38,114 Total $ — $ 2,997 2024 For the three months ended March 31, 2024, net prior year reserve development of $nil was recogni zed. 2023 For the three months ended March 31, 2023, the Company recognized $3 million of net favorable prior year reserve development, the principal components of which were: • $12 million of net favorable development on agriculture business primarily due to better than expected loss emergence mainly related to the 2022 accident year. • $7 million of net favorable development on accident and health business primarily due to better than expected loss emergence mainly related to the 2022 accident year. • $33 million of net adverse development on liability business primarily due to reserve strengthening to reflect increased estimates of future loss trend due to inflation, increases in loss estimates attributable to one large claim within the European book of business related to the 2021 accident year and reserve strengthening within the U.S. proportional book of business related to 2019 and older accident years. • $17 million of net adverse development on motor business primarily due to reserve strengthening to reflect increased estimates of future loss trend due to inflation. Run-off lines • $31 million of net favorable development on catastrophe business primarily due to better than expected loss emergence mainly related to the 2022 accident year. • $7 million of net favorable development on property business primarily due to better than expected loss emergence attributable to 2022 catastrophe events.

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE The following table presents a comparison of earnings per common share and earnings per diluted common share: Three months ended March 31, 2024 2023 Earnings per common share Net income $ 395,459 $ 180,097 Less: Preferred share dividends 7,563 7,563 Net income available to common shareholders $ 387,896 $ 172,534 Weighted average common shares outstanding 84,879 84,864 Earnings per common share $ 4.57 $ 2.03 Earnings per diluted common share Net income available to common shareholders $ 387,896 $ 172,534 Weighted average common shares outstanding 84,879 84,864 Share-based compensation plans 814 989 Weighted average diluted common shares outstanding 85,693 85,853 Earnings per diluted common share $ 4.53 $ 2.01 Weighted average anti-dilutive shares excluded from the dilutive computation 748 805

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION Performance Restricted Stock Units Performance Restricted Stock Units granted in 2024 with a market condition Certain share-settled performance restricted stock units granted in 2024 include a market condition which is the Company’s total shareholder return relative to its peer group ("Relative TSR") over the performance period. Relative TSR is calculated in accordance with the terms of the applicable award agreement. If performance goals are achieved, these awards will cliff vest at the end of a three-year performance period within a range of 0% to 200% of target. Performance Restricted Stock Units granted in 2024 with a performance condition Certain share-settled performance restricted stock units granted in 2024 include a performance condition which is the Company’s average annual growth in book value per diluted common share, plus accumulated dividends over the performance period, adjusted to exclude unrealized investment gains (losses) recognized in accumulated other comprehensive income, and share repurchases during the performance period ("Adjusted DBVPS"). Adjusted DBVPS is calculated in accordance with the terms of the applicable award agreement. If performance goals are achieved, these awards will cliff vest at the end of a three-year performance period within a range of 0% to 200% of target. Valuation assumptions Performance Restricted Stock Units granted in 2024 and 2023 with a market condition The fair value of these performance restricted stock units was measured on the grant date using a Monte Carlo simulation model. The following table provides details of the significant inputs used in the Monte Carlo simulation model: Three months ended March 31, 2024 2023 (1) 2023 (2) Expected volatility 26.00% 36.24% 29.30% Expected term (in years) 3.0 3.0 1.0 Expected dividend yield n/a n/a n/a Risk-free interest rate 4.06% 3.79% 4.61% n/a - not applicable (1) Performance restricted stock units granted in the ordinary course of business (2) Performance restricted stock units granted in the three months ended March 31, 2023 in relation to senior leadership transition Beginning share price, Ending share price and Expected term Performance restricted stock units granted in 2024 The beginning share price for awards was based on the average closing share price over the 30 trading days preceding and including the start of the performance period. The ending share price was based on the average projected closing share price over the 30 trading days preceding and including the end of the performance period. Performance for these awards is measured from January 1, 2024 to December 31, 2026. Performance restricted stock units granted in 2023 and performance restricted stock units granted in the three months ended March 31, 2023 in relation to senior leadership transition The beginning share price for awards was based on the average closing share price over the 10 trading days preceding and including the start of the performance period. The ending share price was based on the projected average closing share price over the 10 trading days preceding and including the end of the performance period. Performance for awards granted in 2023 is generally measured from January 1, 2023 to December 31, 2025, with performance for awards granted to one senior leader being measured from January 1, 2023 to December 31, 2023. Expected volatility The expected volatility is estimated based on the Company's historical share price volatility. Expected dividend yield The expected dividend yield is not applicable to the performance restricted stock units as dividends are paid at the end of the vesting period and do not affect the value of the performance restricted stock units. Risk-free interest rate The risk-free rate is estimated based on the yield on a U.S. treasury zero-coupon bond issued with a remaining term equal to the vesting period of the performance restricted stock units. Compensation expense associated with performance restricted stock units granted in 2024 and 2023 is determined on the grant date based on the fair value calculated by the Monte Carlo simulation model, and is recognized on a straight-line basis over the requisite service period. During the three months ended March 31, 2023, the transition in our senior leadership resulted in a modification of the previously existing vesting terms of the outstanding restricted stock units and performance restricted stock units granted in 2022 and earlier of one senior leader, and a modification of the performance period of that leader's performance restricted stock units granted in 2022. The modifications did not result in incremental compensation expense. Performance Restricted Stock Units granted in 2024 with a performance condition The fair value of these performance restricted stock units was determined based on the closing price of the Company's common shares on the grant date, and compensation expense is recognized on a straight-line basis over the requisite service period, and is subject to periodic adjustment based on the achievement of established performance criteria during the performance period. The following table provides an activity summary of the Company's share-settled restricted stock units for the three months ended March 31, 2024: Share-Settled Performance Share-Settled Service Number of restricted stock units Weighted Number of restricted stock units Weighted average Non-vested restricted stock units - beginning of period 144 $ 65.69 1,855 $ 55.21 Granted 104 65.77 696 59.34 Vested — — (682) 54.67 Forfeited — — (78) 55.29 Non-vested restricted stock units - end of period 248 $ 65.73 1,791 $ 57.02 The following table provides additional information related to share-based compensation: Three months ended March 31, 2024 2023 Share-based compensation expense $ 13,671 $ 12,526 Tax benefits associated with share-based compensation expense $ 2,763 $ 2,647 Fair value of restricted stock units vested (1) $ 41,156 $ 50,714 Unrecognized share-based compensation expense $ 92,556 $ 108,882 Expected weighted average period associated with the recognition of unrecognized share-based compensation expense 2.9 years 2.8 years (1) Fair value is based on the closing price of the Company's common shares on the vest date.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
SHAREHOLDERS' EQUITY	SHAREHOLDERS' EQUITY The following table presents changes in common shares issued and outstanding: Three months ended March 31, 2024 2023 Shares issued, balance at beginning of period 176,580 176,580 Shares issued — — Total shares issued at end of period 176,580 176,580 Treasury shares, balance at beginning of period (91,294) (91,912) Shares repurchased (1,281) (262) Shares reissued 682 777 Total treasury shares at end of period (91,893) (91,397) Total shares outstanding 84,687 85,183 Treasury Shares The following table presents common shares repurchased from shares held in Treasury: Three months ended March 31, 2024 2023 In the open market: (1) Total shares 1,048 — Total cost $ 61,607 $ — Average price per share (2) $ 58.79 $ — From employees: (3) Total shares 233 262 Total cost $ 14,121 $ 15,945 Average price per share (2) $ 60.70 $ 60.82 Total shares repurchased: Total shares 1,281 262 Total cost $ 75,728 $ 15,945 Average price per share (2) $ 59.13 $ 60.82 (1) Shares are repurchased pursuant to the Company's Board-authorized share repurchase program announced in December 2023, effective January 1, 2024 through to December 31, 2024. (2) Calculated using whole numbers. (3) Shares are repurchased from employees to satisfy personal withholding tax liabilities that arise on the vesting of share-settled restricted stock units. Dividends The following table presents dividends declared and paid related to the Company's common and preferred shares: Per share data Dividends declared Dividends paid in period of declaration Dividends paid in period following declaration Three months ended March 31, 2024 Common shares $ 0.44 $ — $ 0.44 Series E preferred shares $ 34.38 $ — $ 34.38 Three months ended March 31, 2023 Common shares $ 0.44 $ — $ 0.44 Series E preferred shares $ 34.38 $ — $ 34.38

DEBT AND FINANCING ARRANGEMENTS

DEBT AND FINANCING ARRANGEMENTS	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
DEBT AND FINANCING ARRANGEMENTS	DEBT AND FINANCING ARRANGEMENTS Loan Advances made to a Third Party Reinsurer At March 31, 2024, loan advances of $25 million (2023: $82 million) were repaid and were treated as a non-cash activity in the consolidated statement of cash flows. The loan balance receivable at March 31, 2024, of $55 million (2023: $80 million) is included in loan advances made in the consolidated balance sheets. At December 31, 2023, the Company had committed to advance a further $26 million to the third party reinsurer. During 2024, the third party reinsurer advised the Company that this advance was no longer required. Letter of Credit Facility

FEDERAL HOME LOAN BANK ADVANCES

FEDERAL HOME LOAN BANK ADVANCES	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
FEDERAL HOME LOAN BANK ADVANCES	FEDERAL HOME LOAN BANK ADVANCES The Company's subsidiaries, AXIS Insurance Company and AXIS Surplus Insurance Company, are members of the Federal Home Loan Bank of Chicago ("FHLB"). At March 31, 2024, the companies had admitted assets of approximately $3 billion (2023: $3 billion) which provides borrowing capacity of up to approximately $759 million (2023: $759 million). At March 31, 2024, the Company had $86 million (2023: $86 million) of borrowings under the FHLB program, with maturities in 2024 and 2025 and interest payable at interest rates between 5.6% and 5.7% (2023: 5.6% and 5.9%) . The Company incurred interest expense of $1 million for the three months ended March 31, 2024 and 2023. The borrowings under the FHLB program are secured by investments with a fair value of $90 million (2023: $95 million)

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENT AND CONTINGENCIES Legal Proceedings From time to time, the Company is subject to routine legal proceedings, including arbitrations, arising in the ordinary course of business. These legal proceedings generally relate to claims asserted by or against the Company in the ordinary course of its insurance or reinsurance operations. Estimated amounts payable related to these proceedings are included in the reserve for losses and loss expenses in the Company's consolidated balance sheets. The Company is not party to any material legal proceedings arising outside the ordinary course of business. Investments Refer to Note 3 - 'Investments' for information on the Company's unfunded investment commitments related to the Company's other investment portfolio.

OTHER COMPREHENSIVE INCOME (LOS

OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
OTHER COMPREHENSIVE INCOME (LOSS)	OTHER COMPREHENSIVE INCOME (LOSS) The following table presents the tax effects allocated to each component of other comprehensive income (loss): 2024 2023 Before tax amount Income tax (expense) benefit Net of tax amount Before tax amount Income tax (expense) benefit Net of tax amount Three months ended March 31, Available for sale investments: Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has not been recognized $ (76,408) $ 16,349 $ (60,059) $ 153,851 $ (19,284) $ 134,567 Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has been recognized (434) 16 (418) 14,950 (1,328) 13,622 Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss) 24,879 (1,464) 23,415 44,121 (3,371) 40,750 Unrealized gains (losses) arising during the period, net of reclassification adjustment (51,963) 14,901 (37,062) 212,922 (23,983) 188,939 Foreign currency translation adjustment (8,951) — (8,951) (535) — (535) Total other comprehensive income (loss), net of tax $ (60,914) $ 14,901 $ (46,013) $ 212,387 $ (23,983) $ 188,404 The following table presents details of amounts reclassified from accumulated other comprehensive income (loss) ("AOCI") to net income (loss): Amount reclassified from AOCI (1) AOCI Components Consolidated statement of operations line item that includes reclassification adjustment Three months ended March 31, 2024 2023 Unrealized gains (losses) on available for sale investments Other realized gains (losses) $ (24,871) $ (44,121) Impairment losses (8) — Total before tax (24,879) (44,121) Income tax (expense) benefit 1,464 3,371 Net of tax $ (23,415) $ (40,750) (1) Amounts in parentheses are charges to net income (loss).

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS During 2018, the Company entered into a quota share retrocessional agreement with Harrington Re which was deemed to have met the established criteria for retroactive reinsurance accounting. During 2024, the Company entered into a reinsurer novation and replacement agreement with Harrington Re and a third party reinsurer with respect to this quota share retrocession contract.

REORGANIZATION EXPENSES

REORGANIZATION EXPENSES	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
REORGANIZATION EXPENSES	REORGANIZATION EXPENSES For the three months ended March 31, 2024, reorganization expenses were $12 million (2023: $nil) primarily related to severance costs mainly attributable to the Company's "How We Work" program which is focused on simplifying the Company’s operating structure.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES On December 27, 2023, the Government of Bermuda enacted the Corporate Income Tax Act 2023 (the "Act") which will apply a corporate income tax of 15% for fiscal years beginning on or after January 1, 2025. The Act includes a provision referred to as the economic transition adjustment, which is intended to provide a fair and equitable transition into the tax regime. Pursuant to the Act and subsequently issued guidance, the Company recorded a net deferred tax asset of $163 million in the three months ended March 31, 2024 which it expects to utilize mainly over a 10-year period. The Company expects to incur increased taxes in Bermuda beginning in 2025. The following table provides an analysis of income tax expense (benefit): Three months ended March 31, 2024 2023 Current income tax expense (benefit) U.S. $ 21,498 $ 10,905 Europe 5,528 3,174 Bermuda — 199 Deferred income tax expense (benefit) U.S. 2,745 70 Europe 8,280 1,548 Bermuda (162,705) — Total income tax expense (benefit) $ (124,654) $ 15,896 The following table presents the distribution of income before income taxes between domestic and foreign jurisdictions and a reconciliation of the actual income tax rate to the amount computed by applying the effective tax rate of 0% under Bermuda law to income before income taxes: Three months ended March 31, 2024 2023 Income before income taxes Bermuda (domestic) $ 83,231 $ 106,604 Foreign 187,574 89,388 Total income before income taxes $ 270,805 $ 195,992 Reconciliation of effective tax rate (% of income before income taxes) Expected tax rate — % — % Foreign taxes at local expected rates: U.S. 9.2 % 5.4 % Europe 5.0 % 3.2 % Valuation allowance (0.7 %) (1.8 %) Bermuda Economic Transition Adjustment (60.1 %) — % Other 0.6 % 1.3 % Actual tax rate (46.0 %) 8.1 %

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net income	$ 395,459	$ 180,097

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

BASIS OF PRESENTATION AND SIG_2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	These unaudited consolidated financial statements (the "financial statements") have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information and with the U.S. Securities and Exchange Commission's ("SEC") instructions to Form 10-Q and Article 10 of Regulation S-X and include AXIS Capital Holdings Limited ("AXIS Capital") and its subsidiaries (the "Company"). Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in AXIS Capital's Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the SEC. In the opinion of management, these financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the Company's financial position and results of operations for the periods presented. The results of operations for any interim period are not necessarily indicative of the results for a full year. All inter-company accounts and transactions have been eliminated. To facilitate comparison of information across periods, certain reclassifications have been made to prior year amounts to conform to the current year's presentation. At March 31, 2024, the Company presented loan advances made in 2023 separately in the consolidated statements of cash flows. These loan advances made were previously included in insurance and reinsurance balances payable in the consolidated statements of cash flows. This presentation was adopted to facilitate comparison to loan advances made in 2024. This reclassification did not impact results of operations, financial condition or liquidity.

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Underwriting Results Of Reportable Segments	The following tables present the underwriting results of the Company's reportable segments, as well as the carrying amounts of allocated goodwill and intangible assets: 2024 2023 Three months ended and at March 31, Insurance Reinsurance Total Insurance Reinsurance Total Gross premiums written $ 1,574,505 $ 1,079,922 $ 2,654,427 $ 1,415,612 $ 966,364 $ 2,381,976 Net premiums written 1,022,354 699,719 1,722,073 882,576 725,780 1,608,356 Net premiums earned 917,946 340,095 1,258,041 816,456 413,743 1,230,199 Other insurance related income 21 8,319 8,340 54 523 577 Net losses and loss expenses (496,864) (231,807) (728,671) (449,467) (271,175) (720,642) Acquisition costs (176,029) (78,225) (254,254) (147,058) (83,315) (230,373) Underwriting-related general and administrative expenses (122,087) (15,706) (137,793) (116,630) (23,765) (140,395) Underwriting income $ 122,987 $ 22,676 145,663 $ 103,355 $ 36,011 139,366 Net investment income 167,383 133,771 Net investment gains (losses) (9,207) (20,190) Corporate expenses (25,580) (26,416) Foreign exchange (losses) gains 23,552 (8,710) Interest expense and financing costs (17,147) (16,894) Reorganization expenses (12,299) — Amortization of intangible assets (2,729) (2,729) Income before income taxes and interest in income (loss) of equity method investments 269,636 198,198 Income tax (expense) benefit 124,654 (15,896) Interest in income (loss) of equity method investments 1,169 (2,205) Net income 395,459 180,097 Preferred share dividends 7,563 7,563 Net income available to common shareholders $ 387,896 $ 172,534 Net losses and loss expenses ratio 54.1 % 68.2 % 57.9 % 55.1 % 65.5 % 58.6 % Acquisition cost ratio 19.2 % 23.0 % 20.2 % 18.0 % 20.1 % 18.7 % General and administrative expense ratio 13.3 % 4.6 % 13.0 % 14.2 % 5.8 % 13.6 % Combined ratio 86.6 % 95.8 % 91.1 % 87.3 % 91.4 % 90.9 % Goodwill and intangible assets $ 284,956 $ — $ 284,956 $ 295,872 $ — $ 295,872

INVESTMENTS (Tables)

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Fair Values of Fixed Maturities	The following table provides the amortized cost and fair values of the Company's fixed maturities classified as available for sale: Amortized cost Allowance for expected credit losses Gross Gross unrealized losses Fair value At March 31, 2024 Available for sale U.S. government and agency $ 2,649,595 $ — $ 1,590 $ (57,468) $ 2,593,717 Non-U.S. government 757,162 (17) 4,851 (23,798) 738,198 Corporate debt 5,095,372 (3,973) 37,431 (212,892) 4,915,938 Agency RMBS (1) 1,684,869 — 4,273 (103,522) 1,585,620 CMBS (2) 870,433 — 545 (50,585) 820,393 Non-agency RMBS 152,322 (198) 518 (12,650) 139,992 ABS (3) 1,336,681 (49) 2,148 (20,875) 1,317,905 Municipals (4) 167,776 — 371 (10,600) 157,547 Total fixed maturities, available for sale $ 12,714,210 $ (4,237) $ 51,727 $ (492,390) $ 12,269,310 At December 31, 2023 Available for sale U.S. government and agency $ 3,049,445 $ — $ 13,211 $ (55,128) $ 3,007,528 Non-U.S. government 729,761 (30) 13,089 (18,861) 723,959 Corporate debt 4,651,654 (10,438) 49,434 (216,478) 4,474,172 Agency RMBS (1) 1,706,204 — 11,495 (83,038) 1,634,661 CMBS (2) 897,553 — 551 (58,408) 839,696 Non-agency RMBS 165,910 (194) 713 (13,033) 153,396 ABS (3) 1,265,187 (50) 2,855 (25,021) 1,242,971 Municipals (4) 168,540 (47) 414 (10,548) 158,359 Total fixed maturities, available for sale $ 12,634,254 $ (10,759) $ 91,762 $ (480,515) $ 12,234,742 (1) Residential mortgage-backed securities ("RMBS") originated by U.S. government-sponsored agencies. (2) Commercial mortgage-backed securities ("CMBS"). (3) Asset-backed securities ("ABS") include debt tranched securities collateralized primarily by auto loans, student loans, credit card receivables and collateralized loan obligations ("CLOs"). (4) Municipals include bonds issued by states, municipalities and political subdivisions.
Summary of Contractual Maturities of Fixed Maturities	The table below provides the contractual maturities of fixed maturities classified as available for sale: Amortized cost Fair value % of Total fair value At March 31, 2024 Maturity Due in one year or less $ 435,592 $ 427,428 3.6 % Due after one year through five years 5,891,599 5,759,009 46.9 % Due after five years through ten years 2,164,623 2,046,280 16.7 % Due after ten years 178,091 172,683 1.4 % 8,669,905 8,405,400 68.6 % Agency RMBS 1,684,869 1,585,620 12.9 % CMBS 870,433 820,393 6.7 % Non-agency RMBS 152,322 139,992 1.1 % ABS 1,336,681 1,317,905 10.7 % Total $ 12,714,210 $ 12,269,310 100.0 % At December 31, 2023 Maturity Due in one year or less $ 474,557 $ 463,789 3.6 % Due after one year through five years 5,902,571 5,790,493 47.3 % Due after five years through ten years 2,064,619 1,954,449 16.0 % Due after ten years 157,653 155,287 1.3 % 8,599,400 8,364,018 68.2 % Agency RMBS 1,706,204 1,634,661 13.4 % CMBS 897,553 839,696 6.9 % Non-agency RMBS 165,910 153,396 1.3 % ABS 1,265,187 1,242,971 10.2 % Total $ 12,634,254 $ 12,234,742 100.0 %
Summary of Fixed Maturities and Equities in an Unrealized Loss Position	The following table summarizes fixed maturities, available for sale in an unrealized loss position and the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 12 months or greater Less than 12 months Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses At March 31, 2024 Fixed maturities, available for sale U.S. government and agency $ 657,958 $ (40,409) $ 1,669,439 $ (17,059) $ 2,327,397 $ (57,468) Non-U.S. government 224,688 (20,529) 274,043 (3,269) 498,731 (23,798) Corporate debt 2,337,348 (202,913) 862,666 (9,979) 3,200,014 (212,892) Agency RMBS 810,334 (96,973) 414,071 (6,549) 1,224,405 (103,522) CMBS 665,150 (47,233) 86,723 (3,352) 751,873 (50,585) Non-agency RMBS 86,352 (12,562) 15,966 (88) 102,318 (12,650) ABS 447,941 (19,575) 343,163 (1,300) 791,104 (20,875) Municipals 124,038 (10,203) 7,081 (397) 131,119 (10,600) Total fixed maturities, available for sale $ 5,353,809 $ (450,397) $ 3,673,152 $ (41,993) $ 9,026,961 $ (492,390) At December 31, 2023 Fixed maturities, available for sale U.S. government and agency $ 846,503 $ (42,465) $ 867,733 $ (12,663) $ 1,714,236 $ (55,128) Non-U.S. government 233,038 (18,178) 115,112 (683) 348,150 (18,861) Corporate debt 2,623,304 (210,512) 240,813 (5,966) 2,864,117 (216,478) Agency RMBS 778,656 (80,070) 218,606 (2,968) 997,262 (83,038) CMBS 703,411 (54,856) 75,242 (3,552) 778,653 (58,408) Non-agency RMBS 98,483 (13,013) 10,017 (20) 108,500 (13,033) ABS 879,743 (24,747) 83,582 (274) 963,325 (25,021) Municipals 129,969 (10,156) 6,238 (392) 136,207 (10,548) Total fixed maturities, available for sale $ 6,293,107 $ (453,997) $ 1,617,343 $ (26,518) $ 7,910,450 $ (480,515)
Summary of Fixed Maturities, Held-to-Maturity	The following table provides the amortized cost and fair values of the Company's fixed maturities classified as held to maturity: Amortized cost Allowance for expected credit losses Net carrying value Gross Gross unrealized losses Fair value At March 31, 2024 Held to maturity Corporate debt $ 100,217 $ — $ 100,217 $ 177 $ (9,360) $ 91,034 ABS (1) 592,825 — 592,825 270 (403) 592,692 Total fixed maturities, held to maturity $ 693,042 $ — $ 693,042 $ 447 $ (9,763) $ 683,726 At December 31, 2023 Held to maturity Corporate debt $ 95,200 $ — $ 95,200 $ 298 $ (8,827) $ 86,671 ABS (1) 591,096 — 591,096 5 (1,921) 589,180 Total fixed maturities, held to maturity $ 686,296 $ — $ 686,296 $ 303 $ (10,748) $ 675,851 (1) Asset-backed securities ("ABS") include debt tranched securities collateralized primarily by collateralized loan obligations ("CLOs").
Summary of Cost and Fair Value of Equity Securities	The following table provides the cost and fair values of the Company's equity securities: Cost Gross unrealized gains Gross unrealized losses Fair value At March 31, 2024 Equity securities Common stocks $ 2,843 $ 25 $ (416) $ 2,452 Preferred stocks 5,654 161 (113) 5,702 Exchange-traded funds 188,548 99,734 (1,116) 287,166 Bond mutual funds 348,493 2,327 (63,962) 286,858 Total equity securities $ 545,538 $ 102,247 $ (65,607) $ 582,178 At December 31, 2023 Equity securities Common stocks $ 2,843 $ 101 $ (398) $ 2,546 Preferred stocks 5,496 218 (113) 5,601 Exchange-traded funds 182,989 105,858 (1,572) 287,275 Bond mutual funds 352,505 4,119 (63,535) 293,089 Total equity securities $ 543,833 $ 110,296 $ (65,618) $ 588,511
Summary of Mortgage Loans Net of Valuation Allowance	The following table provides details of the Company's mortgage loans, held for investment: March 31, 2024 December 31, 2023 Carrying value % of Total Carrying value % of Total Mortgage loans, held for investment: Commercial $ 617,817 101 % $ 616,368 101 % Allowance for expected credit losses (8,113) (1 %) (6,220) (1) % Total mortgage loans, held for investment $ 609,704 100 % $ 610,148 100 %
Summary of Portfolio of Other Investments	The following table provides a summary of the Company's other investments, together with additional information relating to the liquidity of each category: Fair value Redemption frequency (if currently eligible) Redemption notice period At March 31, 2024 Multi-strategy funds $ 24,950 3 % Quarterly 60-90 days Direct lending funds 168,987 18 % Quarterly (1) 90 days Private equity funds 309,399 33 % n/a n/a Real estate funds 309,545 33 % Quarterly (2) , Annually (3) 45-90 days CLO-Equities 4,986 — % n/a n/a Other privately held investments 116,857 13 % n/a n/a Total other investments $ 934,724 100 % At December 31, 2023 Multi-strategy funds $ 24,619 3 % Quarterly 60-90 days Direct lending funds 192,270 20 % Quarterly (1) 90 days Private equity funds 301,712 32 % n/a n/a Real estate funds 317,325 33 % Quarterly (2) , Annually (3) 45-90 days CLO-Equities 5,300 1 % n/a n/a Other privately held investments 108,187 11 % n/a n/a Total other investments $ 949,413 100 % n/a - not applicable (1) Applies to one fund with a fair va lue of $13 million (2023: $17 million). (2) Applies to one fund with a fair value of $64 million (2023: $66 million ). (3) Applies to one fund with a fair value of $24 million (2023: $25 million ).
Summary of Net Investment Income	Net investment income was derived from the following sources: Three months ended March 31, 2024 2023 Fixed maturities $ 139,396 $ 118,262 Other investments 5,673 486 Equity securities 2,762 2,455 Mortgage loans 9,130 8,386 Cash and cash equivalents 13,661 10,012 Short-term investments 3,463 1,660 Gross investment income 174,085 141,261 Investment expenses (6,702) (7,490) Net investment income $ 167,383 $ 133,771
Summary of Net Investment Gains (Losses)	The following table provides an analysis of net investment gains (losses): Three months ended March 31, 2024 2023 Gross realized investment gains Fixed maturities and short-term investments $ 14,399 $ 12,370 Equity securities 30,626 1,517 Gross realized investment gains 45,025 13,887 Gross realized investment losses Fixed maturities and short-term investments (43,932) (53,649) Equity securities (7,712) (396) Gross realized investment losses (51,644) (54,045) (Increase) decrease in allowance for expected credit losses, fixed maturities, available for sale 6,522 (911) (Increase) decrease in allowance for expected credit losses, mortgage loans (1,858) (1,900) Impairment losses (1) (8) — Change in fair value of investment derivatives (2) 795 (947) Net unrealized gains (losses) on equity securities (8,039) 23,726 Net investment losses $ (9,207) $ (20,190) (1) Related to instances where the Company intends to sell securities or it is more likely than not that the Company will be required to sell securities before their anticipated recovery. (2) Refer to Note 5 ' Derivative Instruments'.
Summary of Allowance for Credit Loss	The following table provides a reconciliation of the beginning and ending balances of the allowance for expected credit losses on fixed maturities classified as available for sale: Three months ended March 31, 2024 2023 Balance at beginning of period $ 10,759 $ 11,733 Expected credit losses on securities where credit losses were not previously recognized 31 613 Additions (reductions) for expected credit losses on securities where credit losses were previously recognized (1,553) 919 Impairments of securities which the Company intends to sell or more likely than not will be required to sell — — Securities sold/redeemed/matured (5,000) (620) Balance at end of period $ 4,237 $ 12,645

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Measured at Fair Value on a Recurring Basis	The tables below present the financial instruments measured at fair value on a recurring basis for the periods indicated: Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At March 31, 2024 Assets Fixed maturities, available for sale U.S. government and agency $ 2,576,715 $ 17,002 $ — $ — $ 2,593,717 Non-U.S. government — 738,198 — — 738,198 Corporate debt — 4,789,463 126,475 — 4,915,938 Agency RMBS — 1,585,620 — — 1,585,620 CMBS — 820,393 — — 820,393 Non-agency RMBS — 139,992 — — 139,992 ABS — 1,317,905 — — 1,317,905 Municipals — 157,547 — — 157,547 2,576,715 9,566,120 126,475 — 12,269,310 Equity securities Common stocks 2,452 — — — 2,452 Preferred stocks 2 5,700 — — 5,702 Exchange-traded funds 287,166 — — — 287,166 Bond mutual funds — 286,858 — — 286,858 289,620 292,558 — — 582,178 Other investments Multi-strategy funds — — — 24,950 24,950 Direct lending funds — — — 168,987 168,987 Private equity funds — — — 309,399 309,399 Real estate funds — — — 309,545 309,545 CLO-Equities — — 4,986 — 4,986 Other privately held investments — — 96,255 20,602 116,857 — — 101,241 833,483 934,724 Short-term investments — 75,879 — — 75,879 Other assets Derivative instruments (refer to Note 5) — 1,232 — — 1,232 Total Assets $ 2,866,335 $ 9,935,789 $ 227,716 $ 833,483 $ 13,863,323 Liabilities Derivative instruments (refer to Note 5) $ — $ 2,282 $ — $ — $ 2,282 Total Liabilities $ — $ 2,282 $ — $ — $ 2,282 Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At December 31, 2023 Assets Fixed maturities, available for sale U.S. government and agency $ 2,989,612 $ 17,916 $ — $ — $ 3,007,528 Non-U.S. government — 723,959 — — 723,959 Corporate debt — 4,338,419 135,753 — 4,474,172 Agency RMBS — 1,634,661 — — 1,634,661 CMBS — 839,696 — — 839,696 Non-agency RMBS — 153,396 — — 153,396 ABS — 1,242,971 — — 1,242,971 Municipals — 158,359 — — 158,359 2,989,612 9,109,377 135,753 — 12,234,742 Equity securities Common stocks 2,546 — — — 2,546 Preferred stocks 1 5,600 — — 5,601 Exchange-traded funds 287,275 — — — 287,275 Bond mutual funds — 293,089 — — 293,089 289,822 298,689 — — 588,511 Other investments Multi-strategy funds — — — 24,619 24,619 Direct lending funds — — — 192,270 192,270 Private equity funds — — — 301,712 301,712 Real estate funds — — — 317,325 317,325 CLO-Equities — — 5,300 — 5,300 Other privately held investments — — 87,289 20,898 108,187 — — 92,589 856,824 949,413 Short-term investments — 17,216 — — 17,216 Other assets Derivative instruments (refer to Note 5) — 4,424 — — 4,424 Total Assets $ 3,279,434 $ 9,429,706 $ 228,342 $ 856,824 $ 13,794,306 Liabilities Derivative instruments (refer to Note 5) $ — $ 10,165 $ — $ — $ 10,165 Total Liabilities $ — $ 10,165 $ — $ — $ 10,165
Summary of Level 3 Fair Value Measurement Inputs	The following table quantifies the significant unobservable inputs used in estimating fair values at March 31, 2024 of investments classified as Level 3 in the fair value hierarchy: Asset fair value Valuation technique Unobservable input Amount / Range Weighted average Other investments - CLO-Equities $ 4,986 Discounted cash flow Default rate 4.5% 4.5% Loss severity rate 50.0% 50.0% Collateral spread 3.0% 3.0% Estimated maturity date 4 years 4 years Other investments - Other privately held investments $ 18,728 Discounted cash flow Discount rate 6.0% 6.0% Default rate 0.5% 0.5% Loss absorption yield 1.0% 1.0% Estimated maturity date 0-2 years 1 year Note: Fixed maturities of $126 million that are classified as Level 3 are excluded from the above table as these securities are priced using broker-dealer quotes. In addition, other privately held investments of $78 million that are classified as Level 3 are excluded from the above table as these investments are priced using capital statements received from investee companies.
Summary of Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis, Assets	The following table presents changes in Level 3 for financial instruments measured at fair value on a recurring basis: Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized gains/(losses) (3) Three months ended March 31, 2024 Fixed maturities, available for sale Corporate debt $ 135,753 $ — $ — $ (834) $ (495) $ 4,231 $ — $ (12,180) $ 126,475 $ — 135,753 — — (834) (495) 4,231 — (12,180) 126,475 — Other investments CLO-Equities 5,300 — — — — — — (314) 4,986 — Other privately held investments 87,289 — — 1,728 — 7,238 — — 96,255 1,728 92,589 — — 1,728 — 7,238 — (314) 101,241 1,728 Total assets $ 228,342 $ — $ — $ 894 $ (495) $ 11,469 $ — $ (12,494) $ 227,716 $ 1,728 Three months ended March 31, 2023 Fixed maturities, available for sale Corporate debt $ 119,104 $ — $ — $ (7) $ 1,183 $ 18,910 $ — $ (8,763) $ 130,427 $ — 119,104 — — (7) 1,183 18,910 — (8,763) 130,427 — Other investments CLO-Equities 5,016 — — 411 — — — (408) 5,019 411 Other privately held investments 136,158 — — 336 — 4,459 — — 140,953 336 141,174 — — 747 — 4,459 — (408) 145,972 747 Total assets $ 260,278 $ — $ — $ 740 $ 1,183 $ 23,369 $ — $ (9,171) $ 276,399 $ 747 (1) Realized gains (losses) on fixed maturities and realized and unrealized gains (losses) on other assets and other liabilities included in net income are included in net investment gains (losses). Realized and unrealized gains (losses) on other investments included in net income are included in net investment income. (2) Unrealized gains (losses) on fixed maturities are included in other comprehensive income ("OCI"). (3) Change in unrealized gains (losses) relating to assets and liabilities held at the reporting date.

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Location and Amounts of Derivative Fair Values on the Consolidated Balance Sheet	The following table provides the balance sheet classifications of derivatives recorded at fair value: March 31, 2024 December 31, 2023 Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Relating to investment portfolio: Foreign exchange forward contracts $ 110,733 $ 204 $ 2 $ 49,307 $ 66 $ 274 Relating to underwriting portfolio: Foreign exchange forward contracts 1,547,244 1,028 2,280 1,347,559 4,358 9,891 Total derivatives $ 1,232 $ 2,282 $ 4,424 $ 10,165 (1) Derivative assets and derivative liabilities are classified within other assets and other liabilities in the consolidated balance sheets.
Summary of Reconciliation of Gross Derivative Assets to Net Amounts Presented in Balance Sheets	The following table provides a reconciliation of gross derivative assets and liabilities to the net amounts presented in the consolidated balance sheets, with the difference being attributable to the impact of master netting agreements: March 31, 2024 December 31, 2023 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 4,516 $ (3,284) $ 1,232 $ 8,708 $ (4,284) $ 4,424 Derivative liabilities $ 5,566 $ (3,284) $ 2,282 $ 14,449 $ (4,284) $ 10,165 (1) Net asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets.
Summary of Reconciliation of Gross Derivative Liabilities to Net Amounts Presented in Balance Sheets	The following table provides a reconciliation of gross derivative assets and liabilities to the net amounts presented in the consolidated balance sheets, with the difference being attributable to the impact of master netting agreements: March 31, 2024 December 31, 2023 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 4,516 $ (3,284) $ 1,232 $ 8,708 $ (4,284) $ 4,424 Derivative liabilities $ 5,566 $ (3,284) $ 2,282 $ 14,449 $ (4,284) $ 10,165 (1) Net asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets.
Summary of Total Unrealized and Realized Gains (Loss) on Derivatives Not Designated as Hedges Recorded in Earnings	The following table provides the total unrealized and realized gains (losses) recognized in net income (loss) for derivatives not designated as hedges: Consolidated statement of operations line item that includes gain (loss) recognized in net income (loss) Three months ended March 31, 2024 2023 Relating to investment portfolio: Foreign exchange forward contracts Net investment gains (losses) $ 795 $ (947) Relating to underwriting portfolio: Foreign exchange forward contracts Foreign exchange (losses) gains (2,015) 11,250 Total $ (1,220) $ 10,303

RESERVE FOR LOSSES AND LOSS E_2

RESERVE FOR LOSSES AND LOSS EXPENSES (Tables)	3 Months Ended
	Mar. 31, 2024
Insurance [Abstract]
Summary of Reconciliation of Beginning and Ending Gross Reserve for Losses and Loss Expenses and Net Reserve for Unpaid Losses and Loss Expenses	The following table presents a reconciliation of the Company's beginning and ending gross reserve for losses and loss expenses and net reserve for unpaid losses and loss expenses: Three months ended March 31, 2024 2023 Gross reserve for losses and loss expenses, beginning of period $ 16,434,018 $ 15,168,863 Less reinsurance recoverable on unpaid losses and loss expenses, beginning of period (6,323,083) (5,831,172) Net reserve for unpaid losses and loss expenses, beginning of period 10,110,935 9,337,691 Net incurred losses and loss expenses related to: Current year 728,671 724,680 Prior years — (4,038) 728,671 720,642 Net paid losses and loss expenses related to: Current year (50,724) (38,662) Prior years (612,571) (574,538) (663,295) (613,200) Foreign exchange and other (48,602) 46,094 Net reserve for unpaid losses and loss expenses, end of period 10,127,709 9,491,227 Reinsurance recoverable on unpaid losses and loss expenses, end of period 6,503,188 5,823,417 Gross reserve for losses and loss expenses, end of period $ 16,630,897 $ 15,314,644
Summary of Prior Year Loss Development	The following table presents net prior year reserve development by segment: Three months ended March 31, 2024 2023 Favorable (Adverse) Favorable (Adverse) Insurance $ — $ 1,041 Reinsurance — 2,997 Total $ — $ 4,038 Prior year reserve development by line of business was as follows: Three months ended March 31, 2024 2023 Favorable (Adverse) Favorable (Adverse) Property $ 8,011 $ 5,900 Accident and health — (304) Marine and aviation (8,011) 13,221 Cyber — 8,452 Professional lines — (12,594) Credit and political risk — 4,519 Liability — (18,153) Total $ — $ 1,041 Prior year reserve development by line of business was as follows: Three months ended March 31, 2024 2023 Favorable Favorable Accident and health $ — $ 6,988 Agriculture — 11,891 Marine and aviation — (250) Professional lines — (3,225) Credit and surety — (546) Motor — (17,122) Liability — (32,853) Run-off lines Catastrophe — 31,058 Property — 6,883 Engineering — 173 Total run-off lines — 38,114 Total $ — $ 2,997

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Summary of Basic and Diluted Earnings Per Common Share	The following table presents a comparison of earnings per common share and earnings per diluted common share: Three months ended March 31, 2024 2023 Earnings per common share Net income $ 395,459 $ 180,097 Less: Preferred share dividends 7,563 7,563 Net income available to common shareholders $ 387,896 $ 172,534 Weighted average common shares outstanding 84,879 84,864 Earnings per common share $ 4.57 $ 2.03 Earnings per diluted common share Net income available to common shareholders $ 387,896 $ 172,534 Weighted average common shares outstanding 84,879 84,864 Share-based compensation plans 814 989 Weighted average diluted common shares outstanding 85,693 85,853 Earnings per diluted common share $ 4.53 $ 2.01 Weighted average anti-dilutive shares excluded from the dilutive computation 748 805

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Additional Information Related to Share-based Compensation	The following table provides details of the significant inputs used in the Monte Carlo simulation model: Three months ended March 31, 2024 2023 (1) 2023 (2) Expected volatility 26.00% 36.24% 29.30% Expected term (in years) 3.0 3.0 1.0 Expected dividend yield n/a n/a n/a Risk-free interest rate 4.06% 3.79% 4.61% n/a - not applicable (1) Performance restricted stock units granted in the ordinary course of business (2) Performance restricted stock units granted in the three months ended March 31, 2023 in relation to senior leadership transition The following table provides additional information related to share-based compensation: Three months ended March 31, 2024 2023 Share-based compensation expense $ 13,671 $ 12,526 Tax benefits associated with share-based compensation expense $ 2,763 $ 2,647 Fair value of restricted stock units vested (1) $ 41,156 $ 50,714 Unrecognized share-based compensation expense $ 92,556 $ 108,882 Expected weighted average period associated with the recognition of unrecognized share-based compensation expense 2.9 years 2.8 years (1) Fair value is based on the closing price of the Company's common shares on the vest date.
Summary of Share-Settled Restricted Stock Units	The following table provides an activity summary of the Company's share-settled restricted stock units for the three months ended March 31, 2024: Share-Settled Performance Share-Settled Service Number of restricted stock units Weighted Number of restricted stock units Weighted average Non-vested restricted stock units - beginning of period 144 $ 65.69 1,855 $ 55.21 Granted 104 65.77 696 59.34 Vested — — (682) 54.67 Forfeited — — (78) 55.29 Non-vested restricted stock units - end of period 248 $ 65.73 1,791 $ 57.02

SHAREHOLDERS' EQUITY (Tables)

SHAREHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Summary of Common Shares Issued and Outstanding	The following table presents changes in common shares issued and outstanding: Three months ended March 31, 2024 2023 Shares issued, balance at beginning of period 176,580 176,580 Shares issued — — Total shares issued at end of period 176,580 176,580 Treasury shares, balance at beginning of period (91,294) (91,912) Shares repurchased (1,281) (262) Shares reissued 682 777 Total treasury shares at end of period (91,893) (91,397) Total shares outstanding 84,687 85,183
Summary of Share Repurchases	The following table presents common shares repurchased from shares held in Treasury: Three months ended March 31, 2024 2023 In the open market: (1) Total shares 1,048 — Total cost $ 61,607 $ — Average price per share (2) $ 58.79 $ — From employees: (3) Total shares 233 262 Total cost $ 14,121 $ 15,945 Average price per share (2) $ 60.70 $ 60.82 Total shares repurchased: Total shares 1,281 262 Total cost $ 75,728 $ 15,945 Average price per share (2) $ 59.13 $ 60.82 (1) Shares are repurchased pursuant to the Company's Board-authorized share repurchase program announced in December 2023, effective January 1, 2024 through to December 31, 2024. (2) Calculated using whole numbers. (3) Shares are repurchased from employees to satisfy personal withholding tax liabilities that arise on the vesting of share-settled restricted stock units.
Summary of Dividends Declared and Paid	The following table presents dividends declared and paid related to the Company's common and preferred shares: Per share data Dividends declared Dividends paid in period of declaration Dividends paid in period following declaration Three months ended March 31, 2024 Common shares $ 0.44 $ — $ 0.44 Series E preferred shares $ 34.38 $ — $ 34.38 Three months ended March 31, 2023 Common shares $ 0.44 $ — $ 0.44 Series E preferred shares $ 34.38 $ — $ 34.38

OTHER COMPREHENSIVE INCOME (L_2

OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Summary of Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss)	The following table presents the tax effects allocated to each component of other comprehensive income (loss): 2024 2023 Before tax amount Income tax (expense) benefit Net of tax amount Before tax amount Income tax (expense) benefit Net of tax amount Three months ended March 31, Available for sale investments: Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has not been recognized $ (76,408) $ 16,349 $ (60,059) $ 153,851 $ (19,284) $ 134,567 Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has been recognized (434) 16 (418) 14,950 (1,328) 13,622 Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss) 24,879 (1,464) 23,415 44,121 (3,371) 40,750 Unrealized gains (losses) arising during the period, net of reclassification adjustment (51,963) 14,901 (37,062) 212,922 (23,983) 188,939 Foreign currency translation adjustment (8,951) — (8,951) (535) — (535) Total other comprehensive income (loss), net of tax $ (60,914) $ 14,901 $ (46,013) $ 212,387 $ (23,983) $ 188,404
Summary of Reclassifications Out of AOCI Into Net Income Available to Common Shareholders	The following table presents details of amounts reclassified from accumulated other comprehensive income (loss) ("AOCI") to net income (loss): Amount reclassified from AOCI (1) AOCI Components Consolidated statement of operations line item that includes reclassification adjustment Three months ended March 31, 2024 2023 Unrealized gains (losses) on available for sale investments Other realized gains (losses) $ (24,871) $ (44,121) Impairment losses (8) — Total before tax (24,879) (44,121) Income tax (expense) benefit 1,464 3,371 Net of tax $ (23,415) $ (40,750) (1) Amounts in parentheses are charges to net income (loss).

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Analysis of Income Tax Expense (Benefit) and Tax Assets	The following table provides an analysis of income tax expense (benefit): Three months ended March 31, 2024 2023 Current income tax expense (benefit) U.S. $ 21,498 $ 10,905 Europe 5,528 3,174 Bermuda — 199 Deferred income tax expense (benefit) U.S. 2,745 70 Europe 8,280 1,548 Bermuda (162,705) — Total income tax expense (benefit) $ (124,654) $ 15,896
Schedule of Distribution of Income Before Income Taxes and Reconciliation of Income Tax Rate To Effective Tax Rate	The following table presents the distribution of income before income taxes between domestic and foreign jurisdictions and a reconciliation of the actual income tax rate to the amount computed by applying the effective tax rate of 0% under Bermuda law to income before income taxes: Three months ended March 31, 2024 2023 Income before income taxes Bermuda (domestic) $ 83,231 $ 106,604 Foreign 187,574 89,388 Total income before income taxes $ 270,805 $ 195,992 Reconciliation of effective tax rate (% of income before income taxes) Expected tax rate — % — % Foreign taxes at local expected rates: U.S. 9.2 % 5.4 % Europe 5.0 % 3.2 % Valuation allowance (0.7 %) (1.8 %) Bermuda Economic Transition Adjustment (60.1 %) — % Other 0.6 % 1.3 % Actual tax rate (46.0 %) 8.1 %

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	2
Segment Information [Line Items]
Net premiums earned	$ 1,258,041	$ 1,230,199
Other insurance related income	8,340	577
Net losses and loss expenses	(728,671)	(720,642)
Acquisition costs	(254,254)	(230,373)
Underwriting-related general and administrative expenses and corporate expenses	(163,373)	(166,811)
Net investment income	167,383	133,771
Foreign exchange (losses) gains	23,552	(8,710)
Interest expense and financing costs	(17,147)	(16,894)
Reorganization expenses	(12,299)	0
Amortization of intangible assets	(2,729)	(2,729)
Income before income taxes and interest in income (loss) of equity method investments	269,636	198,198
Income tax (expense) benefit	124,654	(15,896)
Interest in income (loss) of equity method investments	1,169	(2,205)
Net income	395,459	180,097
Preferred share dividends	7,563	7,563
Net income available to common shareholders	387,896	172,534
Operating Segments
Segment Information [Line Items]
Gross premiums written	2,654,427	2,381,976
Net premiums written	1,722,073	1,608,356
Net premiums earned	1,258,041	1,230,199
Other insurance related income	8,340	577
Net losses and loss expenses	(728,671)	(720,642)
Acquisition costs	(254,254)	(230,373)
Underwriting-related general and administrative expenses and corporate expenses	(137,793)	(140,395)
Underwriting income	$ 145,663	$ 139,366
Net losses and loss expenses ratio (as a percent)	57.90%	58.60%
Acquisition cost ratio (as a percent)	20.20%	18.70%
General and administrative expense ratio (as a percent)	13%	13.60%
Combined ratio (as a percent)	91.10%	90.90%
Goodwill and intangible assets	$ 284,956	$ 295,872
Operating Segments | Insurance
Segment Information [Line Items]
Gross premiums written	1,574,505	1,415,612
Net premiums written	1,022,354	882,576
Net premiums earned	917,946	816,456
Other insurance related income	21	54
Net losses and loss expenses	(496,864)	(449,467)
Acquisition costs	(176,029)	(147,058)
Underwriting-related general and administrative expenses and corporate expenses	(122,087)	(116,630)
Underwriting income	$ 122,987	$ 103,355
Net losses and loss expenses ratio (as a percent)	54.10%	55.10%
Acquisition cost ratio (as a percent)	19.20%	18%
General and administrative expense ratio (as a percent)	13.30%	14.20%
Combined ratio (as a percent)	86.60%	87.30%
Goodwill and intangible assets	$ 284,956	$ 295,872
Operating Segments | Reinsurance
Segment Information [Line Items]
Gross premiums written	1,079,922	966,364
Net premiums written	699,719	725,780
Net premiums earned	340,095	413,743
Other insurance related income	8,319	523
Net losses and loss expenses	(231,807)	(271,175)
Acquisition costs	(78,225)	(83,315)
Underwriting-related general and administrative expenses and corporate expenses	(15,706)	(23,765)
Underwriting income	$ 22,676	$ 36,011
Net losses and loss expenses ratio (as a percent)	68.20%	65.50%
Acquisition cost ratio (as a percent)	23%	20.10%
General and administrative expense ratio (as a percent)	4.60%	5.80%
Combined ratio (as a percent)	95.80%	91.40%
Goodwill and intangible assets	$ 0	$ 0
Segment Reconciling Items
Segment Information [Line Items]
Net investment income	167,383	133,771
Net investment gains (losses)	(9,207)	(20,190)
Foreign exchange (losses) gains	23,552	(8,710)
Interest expense and financing costs	(17,147)	(16,894)
Reorganization expenses	(12,299)	0
Amortization of intangible assets	(2,729)	(2,729)
Corporate expenses
Segment Information [Line Items]
Underwriting-related general and administrative expenses and corporate expenses	$ (25,580)	$ (26,416)

INVESTMENTS - Fixed Maturities

INVESTMENTS - Fixed Maturities Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Available for sale
Amortized cost	$ 12,714,210	$ 12,634,254
Allowance for expected credit losses	(4,237)	(10,759)	$ (12,645)	$ (11,733)
Gross unrealized gains	51,727	91,762
Gross unrealized losses	(492,390)	(480,515)
Fair value	12,269,310	12,234,742
U.S. government and agency
Available for sale
Amortized cost	2,649,595	3,049,445
Allowance for expected credit losses	0	0
Gross unrealized gains	1,590	13,211
Gross unrealized losses	(57,468)	(55,128)
Fair value	2,593,717	3,007,528
Non-U.S. government
Available for sale
Amortized cost	757,162	729,761
Allowance for expected credit losses	(17)	(30)
Gross unrealized gains	4,851	13,089
Gross unrealized losses	(23,798)	(18,861)
Fair value	738,198	723,959
Corporate debt
Available for sale
Amortized cost	5,095,372	4,651,654
Allowance for expected credit losses	(3,973)	(10,438)
Gross unrealized gains	37,431	49,434
Gross unrealized losses	(212,892)	(216,478)
Fair value	4,915,938	4,474,172
Agency RMBS
Available for sale
Amortized cost	1,684,869	1,706,204
Allowance for expected credit losses	0	0
Gross unrealized gains	4,273	11,495
Gross unrealized losses	(103,522)	(83,038)
Fair value	1,585,620	1,634,661
CMBS
Available for sale
Amortized cost	870,433	897,553
Allowance for expected credit losses	0	0
Gross unrealized gains	545	551
Gross unrealized losses	(50,585)	(58,408)
Fair value	820,393	839,696
Non-agency RMBS
Available for sale
Amortized cost	152,322	165,910
Allowance for expected credit losses	(198)	(194)
Gross unrealized gains	518	713
Gross unrealized losses	(12,650)	(13,033)
Fair value	139,992	153,396
ABS
Available for sale
Amortized cost	1,336,681	1,265,187
Allowance for expected credit losses	(49)	(50)
Gross unrealized gains	2,148	2,855
Gross unrealized losses	(20,875)	(25,021)
Fair value	1,317,905	1,242,971
Municipals
Available for sale
Amortized cost	167,776	168,540
Allowance for expected credit losses	0	(47)
Gross unrealized gains	371	414
Gross unrealized losses	(10,600)	(10,548)
Fair value	$ 157,547	$ 158,359

INVESTMENTS - Contractual Matur

INVESTMENTS - Contractual Maturities (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Amortized cost
Due in one year or less	$ 435,592,000	$ 474,557,000
Due after one year through five years	5,891,599,000	5,902,571,000
Due after five years through ten years	2,164,623,000	2,064,619,000
Due after ten years	178,091,000	157,653,000
Total fixed maturities with a single maturity date	8,669,905,000	8,599,400,000
Amortized cost, total	12,714,210,000	12,634,254,000
Fair value
Due in one year or less	427,428,000	463,789,000
Due after one year through five years	5,759,009,000	5,790,493,000
Due after five years through ten years	2,046,280,000	1,954,449,000
Due after ten years	172,683,000	155,287,000
Total fixed maturities with a single maturity date	8,405,400,000	8,364,018,000
Fair value, total	$ 12,269,310,000	$ 12,234,742,000
% of Total fair value
Due in one year or less	3.60%	3.60%
Due after one year through five years (as a percent)	46.90%	47.30%
Due after five years through ten years (as a percent)	16.70%	16%
Due after ten years (as a percent)	1.40%	1.30%
Fixed maturities with a single maturity date (as a percent)	68.60%	68.20%
Total (as a percent)	100%	100%
Agency RMBS
Amortized cost
Fixed maturities without a single maturity date	$ 1,684,869,000	$ 1,706,204,000
Amortized cost, total	1,684,869,000	1,706,204,000
Fair value
Fixed maturities without a single maturity date	1,585,620,000	1,634,661,000
Fair value, total	$ 1,585,620,000	$ 1,634,661,000
% of Total fair value
Fixed maturities without a single maturity date (as a percent)	12.90%	13.40%
CMBS
Amortized cost
Fixed maturities without a single maturity date	$ 870,433,000	$ 897,553,000
Amortized cost, total	870,433,000	897,553,000
Fair value
Fixed maturities without a single maturity date	820,393,000	839,696,000
Fair value, total	$ 820,393,000	$ 839,696,000
% of Total fair value
Fixed maturities without a single maturity date (as a percent)	6.70%	6.90%
Non-agency RMBS
Amortized cost
Fixed maturities without a single maturity date	$ 152,322,000	$ 165,910,000
Amortized cost, total	152,322,000	165,910,000
Fair value
Fixed maturities without a single maturity date	139,992,000	153,396,000
Fair value, total	$ 139,992,000	$ 153,396,000
% of Total fair value
Fixed maturities without a single maturity date (as a percent)	1.10%	1.30%
ABS
Amortized cost
Fixed maturities without a single maturity date	$ 1,336,681,000	$ 1,265,187,000
Amortized cost, total	1,336,681,000	1,265,187,000
Fair value
Fixed maturities without a single maturity date	1,317,905,000	1,242,971,000
Fair value, total	$ 1,317,905,000	$ 1,242,971,000
% of Total fair value
Fixed maturities without a single maturity date (as a percent)	10.70%	10.20%
Held-to-maturity securities without a single maturity date	$ 593,000,000	$ 591,000,000
Corporate debt
Amortized cost
Amortized cost, total	5,095,372,000	4,651,654,000
Fair value
Fair value, total	4,915,938,000	4,474,172,000
% of Total fair value
Held-to-maturity securities with maturity after one year through three years	17,000,000	0
Held-to-maturity securities with maturity after three years through ten years	$ 83,000,000	$ 95,000,000

INVESTMENTS - Gross Unrealized

INVESTMENTS - Gross Unrealized Losses (Details) $ in Thousands	Mar. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Fixed maturities, available for sale
Fair value
12 months or greater	$ 5,353,809	$ 6,293,107
Less than 12 months	3,673,152	1,617,343
Total	9,026,961	7,910,450
Unrealized losses
12 months or greater	(450,397)	(453,997)
Less than 12 months	(41,993)	(26,518)
Total	$ (492,390)	$ (480,515)
Number of securities in unrealized loss position | security	4,138	3,535
Number of securities in a continuous unrealized loss position | security	3,004	3,212
Fixed maturities, available for sale | Below Investment Grade or Not Rated
Unrealized losses
Total	$ (11,000)	$ (13,000)
U.S. government and agency
Fair value
12 months or greater	657,958	846,503
Less than 12 months	1,669,439	867,733
Total	2,327,397	1,714,236
Unrealized losses
12 months or greater	(40,409)	(42,465)
Less than 12 months	(17,059)	(12,663)
Total	(57,468)	(55,128)
Non-U.S. government
Fair value
12 months or greater	224,688	233,038
Less than 12 months	274,043	115,112
Total	498,731	348,150
Unrealized losses
12 months or greater	(20,529)	(18,178)
Less than 12 months	(3,269)	(683)
Total	(23,798)	(18,861)
Corporate debt
Fair value
12 months or greater	2,337,348	2,623,304
Less than 12 months	862,666	240,813
Total	3,200,014	2,864,117
Unrealized losses
12 months or greater	(202,913)	(210,512)
Less than 12 months	(9,979)	(5,966)
Total	(212,892)	(216,478)
Agency RMBS
Fair value
12 months or greater	810,334	778,656
Less than 12 months	414,071	218,606
Total	1,224,405	997,262
Unrealized losses
12 months or greater	(96,973)	(80,070)
Less than 12 months	(6,549)	(2,968)
Total	(103,522)	(83,038)
CMBS
Fair value
12 months or greater	665,150	703,411
Less than 12 months	86,723	75,242
Total	751,873	778,653
Unrealized losses
12 months or greater	(47,233)	(54,856)
Less than 12 months	(3,352)	(3,552)
Total	(50,585)	(58,408)
Non-agency RMBS
Fair value
12 months or greater	86,352	98,483
Less than 12 months	15,966	10,017
Total	102,318	108,500
Unrealized losses
12 months or greater	(12,562)	(13,013)
Less than 12 months	(88)	(20)
Total	(12,650)	(13,033)
ABS
Fair value
12 months or greater	447,941	879,743
Less than 12 months	343,163	83,582
Total	791,104	963,325
Unrealized losses
12 months or greater	(19,575)	(24,747)
Less than 12 months	(1,300)	(274)
Total	(20,875)	(25,021)
Municipals
Fair value
12 months or greater	124,038	129,969
Less than 12 months	7,081	6,238
Total	131,119	136,207
Unrealized losses
12 months or greater	(10,203)	(10,156)
Less than 12 months	(397)	(392)
Total	$ (10,600)	$ (10,548)

INVESTMENTS - Fixed Maturitie_2

INVESTMENTS - Fixed Maturities Held to Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Held to maturity
Amortized cost	$ 693,042	$ 686,296
Allowance for expected credit losses	0	0
Net carrying value	693,042	686,296
Gross unrealized gains	447	303
Gross unrealized losses	(9,763)	(10,748)
Fair value	683,726	675,851
Corporate debt
Held to maturity
Amortized cost	100,217	95,200
Allowance for expected credit losses	0	0
Net carrying value	100,217	95,200
Gross unrealized gains	177	298
Gross unrealized losses	(9,360)	(8,827)
Fair value	91,034	86,671
ABS
Held to maturity
Amortized cost	592,825	591,096
Allowance for expected credit losses	0	0
Net carrying value	592,825	591,096
Gross unrealized gains	270	5
Gross unrealized losses	(403)	(1,921)
Fair value	$ 592,692	$ 589,180

INVESTMENTS - Equity Securities

INVESTMENTS - Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Cost	$ 545,538	$ 543,833
Gross unrealized gains	102,247	110,296
Gross unrealized losses	(65,607)	(65,618)
Fair value	582,178	588,511
Common stocks
Debt and Equity Securities, FV-NI [Line Items]
Cost	2,843	2,843
Gross unrealized gains	25	101
Gross unrealized losses	(416)	(398)
Fair value	2,452	2,546
Preferred stocks
Debt and Equity Securities, FV-NI [Line Items]
Cost	5,654	5,496
Gross unrealized gains	161	218
Gross unrealized losses	(113)	(113)
Fair value	5,702	5,601
Exchange-traded funds
Debt and Equity Securities, FV-NI [Line Items]
Cost	188,548	182,989
Gross unrealized gains	99,734	105,858
Gross unrealized losses	(1,116)	(1,572)
Fair value	287,166	287,275
Bond mutual funds
Debt and Equity Securities, FV-NI [Line Items]
Cost	348,493	352,505
Gross unrealized gains	2,327	4,119
Gross unrealized losses	(63,962)	(63,535)
Fair value	$ 286,858	$ 293,089

INVESTMENTS - Mortgage Loans (D

INVESTMENTS - Mortgage Loans (Details)	Mar. 31, 2024 USD ($) loan	Dec. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)
Mortgage loans, held for investment:
Commercial	$ 617,817,000	$ 616,368,000
Allowance for expected credit losses	(8,113,000)	(6,220,000)
Total mortgage loans, held for investment	$ 609,704,000	$ 610,148,000
Commercial (as a percent)	101%	101%
Allowance for expected credit losses (as a percent)	(1.00%)	(1.00%)
Total mortgage loans, held-for investment (as a percent)	100%	100%
Weighted average debt service coverage ratios	1.9		1.9
Weighted average loan-to-value ratios (as a percent)	71%		71%
Commercial mortgage loans, past due amount	$ 0		$ 0
Number of collateral dependent loan | loan	3

INVESTMENTS - Other Investments

INVESTMENTS - Other Investments (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($) fund	Dec. 31, 2023 USD ($)
Other Investments [Line Items]
Other investments, at fair value	$ 934,724	$ 949,413
Percentage of total fair value (as a percent)	100%	100%
Multi-strategy funds
Other Investments [Line Items]
Other investments, at fair value	$ 24,950	$ 24,619
Percentage of total fair value (as a percent)	3%	3%
Multi-strategy funds | Lockup Redemption Restriction
Other Investments [Line Items]
Fair value of other investments subject to redemption restrictions	$ 0	$ 0
Multi-strategy funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 28,000	$ 28,000
Multi-strategy funds | Minimum
Other Investments [Line Items]
Redemption notice period	60 days	60 days
Multi-strategy funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	2 years
Multi-strategy funds | Maximum
Other Investments [Line Items]
Redemption notice period	90 days	90 days
Direct lending funds
Other Investments [Line Items]
Other investments, at fair value	$ 168,987	$ 192,270
Percentage of total fair value (as a percent)	18%	20%
Redemption notice period	90 days	90 days
Direct lending funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 190,000	$ 192,000
Optional extension of investment term	3 years
Direct lending funds | Quarterly Redemption
Other Investments [Line Items]
Other investments, at fair value	$ 13,000	17,000
Number of funds | fund	1
Direct lending funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	4 years
Direct lending funds | Maximum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	10 years
Private equity funds
Other Investments [Line Items]
Other investments, at fair value	$ 309,399	$ 301,712
Percentage of total fair value (as a percent)	33%	32%
Private equity funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 134,000	$ 145,000
Investment term	6 years
Real estate funds
Other Investments [Line Items]
Other investments, at fair value	$ 309,545	$ 317,325
Percentage of total fair value (as a percent)	33%	33%
Real estate funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 105,000	$ 107,000
Real estate funds | Quarterly Redemption
Other Investments [Line Items]
Other investments, at fair value	$ 64,000	66,000
Number of funds | fund	1
Real estate funds | Annual Redemption
Other Investments [Line Items]
Other investments, at fair value	$ 24,000	$ 25,000
Number of funds | fund	1
Real estate funds | Minimum
Other Investments [Line Items]
Redemption notice period	45 days	45 days
Real estate funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	2 years
Real estate funds | Maximum
Other Investments [Line Items]
Redemption notice period	90 days	90 days
CLO-Equities
Other Investments [Line Items]
Other investments, at fair value	$ 4,986	$ 5,300
Percentage of total fair value (as a percent)	0%	1%
Other privately held investments
Other Investments [Line Items]
Other investments, at fair value	$ 116,857	$ 108,187
Percentage of total fair value (as a percent)	13%	11%
Private Company Investment Funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 23,000	$ 30,000
Number of funds | fund	3
Private Company Investment Funds | Other Redemption Restriction | Investment Funds, Term, Period One
Other Investments [Line Items]
Investment term	5 years
Number of funds | fund	2
Private Company Investment Funds | Other Redemption Restriction | Investment Funds, Term, Period Two
Other Investments [Line Items]
Investment term	10 years
Number of funds | fund	1

INVESTMENTS - Equity Method Inv

INVESTMENTS - Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 6,791	$ 0
Monarch Point Re (ISAC) Ltd. and Monarch Point Re (ISA 2023) Ltd
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments			$ 22,000
Equity method investment, ownership percentage (as a percent)			18%
Monarch Point Re (ISA 2024) Ltd., (Monarch Point Re (ISAC) Ltd., Monarch Point Re (ISA 2023) Ltd. and Monarch Point Re (ISA 2024) Ltd
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 7,000
Equity method investment, ownership percentage (as a percent)	18%
Harrington Reinsurance Holdings Limited
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments				$ 108,000
Equity method investment, ownership percentage (as a percent)				19%
Equity method investment, difference between carrying amount and underlying equity				$ 5,000

INVESTMENTS - Variable Interest

INVESTMENTS - Variable Interest Entities (Details)	Mar. 31, 2024
Limited partnership
Debt Securities, Available-for-sale [Line Items]
Percentage of investment composition (as a percent)	74%

INVESTMENTS - Net Investment In

INVESTMENTS - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Gross investment income	$ 174,085	$ 141,261
Investment expenses	(6,702)	(7,490)
Net investment income	167,383	133,771
Fixed maturities
Net Investment Income [Line Items]
Gross investment income	139,396	118,262
Other investments
Net Investment Income [Line Items]
Gross investment income	5,673	486
Equity securities
Net Investment Income [Line Items]
Gross investment income	2,762	2,455
Mortgage loans
Net Investment Income [Line Items]
Gross investment income	9,130	8,386
Cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income	13,661	10,012
Short-term investments
Net Investment Income [Line Items]
Gross investment income	$ 3,463	$ 1,660

INVESTMENTS - Net Investment Ga

INVESTMENTS - Net Investment Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Gross realized investment gains
Fixed maturities and short-term investments	$ 14,399	$ 12,370
Equity securities	30,626	1,517
Gross realized investment gains	45,025	13,887
Gross realized investment losses
Fixed maturities and short-term investments	(43,932)	(53,649)
Equity securities	(7,712)	(396)
Gross realized investment losses	(51,644)	(54,045)
(Increase) decrease in allowance for expected credit losses, fixed maturities, available for sale	6,522	(911)
(Increase) decrease in allowance for expected credit losses, mortgage loans	(1,858)	(1,900)
Impairment losses	(8)	0
Change in fair value of investment derivatives	795	(947)
Net unrealized gains (losses) on equity securities	(8,039)	23,726
Total net investment gains (losses)	$ (9,207)	$ (20,190)

INVESTMENTS - Summary of Allowa

INVESTMENTS - Summary of Allowance for Expected Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 10,759	$ 11,733
Expected credit losses on securities where credit losses were not previously recognized	31	613
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	(1,553)	919
Impairments of securities which the Company intends to sell or more likely than not will be required to sell	0	0
Securities sold/redeemed/matured	(5,000)	(620)
Balance at end of period	$ 4,237	$ 12,645

INVESTMENTS - Reverse Repurchas

INVESTMENTS - Reverse Repurchase Agreements (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Value of reverse repurchase agreements	$ 53	$ 12
Minimum required collateral for reverse repurchase agreements, expressed as a percentage of loan principal (as a percent)	102%

FAIR VALUE MEASUREMENTS - Finan

FAIR VALUE MEASUREMENTS - Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Fixed maturities, available for sale	$ 12,269,310	$ 12,234,742
Equity securities	582,178	588,511
Other investments	934,724	949,413
Short-term investments	75,879	17,216
Derivative instruments (refer to Note 5)	1,232	4,424
Total Assets	13,863,323	13,794,306
Liabilities
Derivative instruments	2,282	10,165
Total Liabilities	2,282	10,165
U.S. government and agency
Assets
Fixed maturities, available for sale	2,593,717	3,007,528
Non-U.S. government
Assets
Fixed maturities, available for sale	738,198	723,959
Corporate debt
Assets
Fixed maturities, available for sale	4,915,938	4,474,172
Agency RMBS
Assets
Fixed maturities, available for sale	1,585,620	1,634,661
CMBS
Assets
Fixed maturities, available for sale	820,393	839,696
Non-agency RMBS
Assets
Fixed maturities, available for sale	139,992	153,396
ABS
Assets
Fixed maturities, available for sale	1,317,905	1,242,971
Municipals
Assets
Fixed maturities, available for sale	157,547	158,359
Common stocks
Assets
Equity securities	2,452	2,546
Preferred stocks
Assets
Equity securities	5,702	5,601
Exchange-traded funds
Assets
Equity securities	287,166	287,275
Bond mutual funds
Assets
Equity securities	286,858	293,089
Multi-strategy funds
Assets
Other investments	24,950	24,619
Direct lending funds
Assets
Other investments	168,987	192,270
Private equity funds
Assets
Other investments	309,399	301,712
Real estate funds
Assets
Other investments	309,545	317,325
CLO-Equities
Assets
Other investments	4,986	5,300
Other privately held investments
Assets
Other investments	116,857	108,187
Quoted prices in active markets for identical assets (Level 1)
Assets
Fixed maturities, available for sale	2,576,715	2,989,612
Equity securities	289,620	289,822
Other investments	0	0
Short-term investments	0	0
Derivative instruments (refer to Note 5)	0	0
Total Assets	2,866,335	3,279,434
Liabilities
Derivative instruments	0	0
Total Liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) | U.S. government and agency
Assets
Fixed maturities, available for sale	2,576,715	2,989,612
Quoted prices in active markets for identical assets (Level 1) | Non-U.S. government
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | Corporate debt
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | Agency RMBS
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | CMBS
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | Non-agency RMBS
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | ABS
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | Municipals
Assets
Fixed maturities, available for sale	0	0
Quoted prices in active markets for identical assets (Level 1) | Common stocks
Assets
Equity securities	2,452	2,546
Quoted prices in active markets for identical assets (Level 1) | Preferred stocks
Assets
Equity securities	2	1
Quoted prices in active markets for identical assets (Level 1) | Exchange-traded funds
Assets
Equity securities	287,166	287,275
Quoted prices in active markets for identical assets (Level 1) | Bond mutual funds
Assets
Equity securities	0	0
Quoted prices in active markets for identical assets (Level 1) | Multi-strategy funds
Assets
Other investments	0	0
Quoted prices in active markets for identical assets (Level 1) | Direct lending funds
Assets
Other investments	0	0
Quoted prices in active markets for identical assets (Level 1) | Private equity funds
Assets
Other investments	0	0
Quoted prices in active markets for identical assets (Level 1) | Real estate funds
Assets
Other investments	0	0
Quoted prices in active markets for identical assets (Level 1) | CLO-Equities
Assets
Other investments	0	0
Quoted prices in active markets for identical assets (Level 1) | Other privately held investments
Assets
Other investments	0	0
Significant other observable inputs (Level 2)
Assets
Fixed maturities, available for sale	9,566,120	9,109,377
Equity securities	292,558	298,689
Other investments	0	0
Short-term investments	75,879	17,216
Derivative instruments (refer to Note 5)	1,232	4,424
Total Assets	9,935,789	9,429,706
Liabilities
Derivative instruments	2,282	10,165
Total Liabilities	2,282	10,165
Significant other observable inputs (Level 2) | U.S. government and agency
Assets
Fixed maturities, available for sale	17,002	17,916
Significant other observable inputs (Level 2) | Non-U.S. government
Assets
Fixed maturities, available for sale	738,198	723,959
Significant other observable inputs (Level 2) | Corporate debt
Assets
Fixed maturities, available for sale	4,789,463	4,338,419
Significant other observable inputs (Level 2) | Agency RMBS
Assets
Fixed maturities, available for sale	1,585,620	1,634,661
Significant other observable inputs (Level 2) | CMBS
Assets
Fixed maturities, available for sale	820,393	839,696
Significant other observable inputs (Level 2) | Non-agency RMBS
Assets
Fixed maturities, available for sale	139,992	153,396
Significant other observable inputs (Level 2) | ABS
Assets
Fixed maturities, available for sale	1,317,905	1,242,971
Significant other observable inputs (Level 2) | Municipals
Assets
Fixed maturities, available for sale	157,547	158,359
Significant other observable inputs (Level 2) | Common stocks
Assets
Equity securities	0	0
Significant other observable inputs (Level 2) | Preferred stocks
Assets
Equity securities	5,700	5,600
Significant other observable inputs (Level 2) | Exchange-traded funds
Assets
Equity securities	0	0
Significant other observable inputs (Level 2) | Bond mutual funds
Assets
Equity securities	286,858	293,089
Significant other observable inputs (Level 2) | Multi-strategy funds
Assets
Other investments	0	0
Significant other observable inputs (Level 2) | Direct lending funds
Assets
Other investments	0	0
Significant other observable inputs (Level 2) | Private equity funds
Assets
Other investments	0	0
Significant other observable inputs (Level 2) | Real estate funds
Assets
Other investments	0	0
Significant other observable inputs (Level 2) | CLO-Equities
Assets
Other investments	0	0
Significant other observable inputs (Level 2) | Other privately held investments
Assets
Other investments	0	0
Significant unobservable inputs (Level 3)
Assets
Fixed maturities, available for sale	126,475	135,753
Equity securities	0	0
Other investments	101,241	92,589
Short-term investments	0	0
Derivative instruments (refer to Note 5)	0	0
Total Assets	227,716	228,342
Liabilities
Derivative instruments	0	0
Total Liabilities	0	0
Significant unobservable inputs (Level 3) | U.S. government and agency
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | Non-U.S. government
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | Corporate debt
Assets
Fixed maturities, available for sale	126,475	135,753
Significant unobservable inputs (Level 3) | Agency RMBS
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | CMBS
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | Non-agency RMBS
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | ABS
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | Municipals
Assets
Fixed maturities, available for sale	0	0
Significant unobservable inputs (Level 3) | Common stocks
Assets
Equity securities	0	0
Significant unobservable inputs (Level 3) | Preferred stocks
Assets
Equity securities	0	0
Significant unobservable inputs (Level 3) | Exchange-traded funds
Assets
Equity securities	0	0
Significant unobservable inputs (Level 3) | Bond mutual funds
Assets
Equity securities	0	0
Significant unobservable inputs (Level 3) | Multi-strategy funds
Assets
Other investments	0	0
Significant unobservable inputs (Level 3) | Direct lending funds
Assets
Other investments	0	0
Significant unobservable inputs (Level 3) | Private equity funds
Assets
Other investments	0	0
Significant unobservable inputs (Level 3) | Real estate funds
Assets
Other investments	0	0
Significant unobservable inputs (Level 3) | CLO-Equities
Assets
Other investments	4,986	5,300
Significant unobservable inputs (Level 3) | Other privately held investments
Assets
Other investments	96,255	87,289
Fair value based on NAV practical expedient
Assets
Other investments	833,483	856,824
Total Assets	833,483	856,824
Fair value based on NAV practical expedient | Multi-strategy funds
Assets
Other investments	24,950	24,619
Fair value based on NAV practical expedient | Direct lending funds
Assets
Other investments	168,987	192,270
Fair value based on NAV practical expedient | Private equity funds
Assets
Other investments	309,399	301,712
Fair value based on NAV practical expedient | Real estate funds
Assets
Other investments	309,545	317,325
Fair value based on NAV practical expedient | Other privately held investments
Assets
Other investments	$ 20,602	$ 20,898

FAIR VALUE MEASUREMENTS - Signi

FAIR VALUE MEASUREMENTS - Significant Unobservable Inputs (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 934,724	$ 949,413
Fixed maturities, available for sale	12,269,310	12,234,742
Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	101,241	92,589
Fixed maturities, available for sale	126,475	$ 135,753
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 4,986
Estimated maturity date	4 years
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date	4 years
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Default rate
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.045
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Default rate | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.045
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Loss severity rate
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.500
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Loss severity rate | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.500
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Collateral spread
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.030
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Discounted cash flow | Collateral spread | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.030
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 18,728
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date	1 year
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date	0 years
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity date	2 years
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Default rate
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.005
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Default rate | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.005
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Discount rate
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.060
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Discount rate | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.060
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Loss absorption yield
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.010
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Discounted cash flow | Loss absorption yield | Weighted average
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input (as a percent)	0.010
Significant unobservable inputs (Level 3) | Other investments - Other privately held investments | Valuation, Market Approach
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 78,000

FAIR VALUE MEASUREMENTS - Chang

FAIR VALUE MEASUREMENTS - Changes in Level 3 for Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	$ 228,342	$ 260,278
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	894	740
Included in OCI	(495)	1,183
Purchases	11,469	23,369
Sales	0	0
Settlements/ distributions	(12,494)	(9,171)
Closing balance	227,716	276,399
Change in unrealized investment gains/(losses)	1,728	747
Fixed maturities, available for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	135,753	119,104
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(834)	(7)
Included in OCI	(495)	1,183
Purchases	4,231	18,910
Sales	0	0
Settlements/ distributions	(12,180)	(8,763)
Closing balance	126,475	130,427
Change in unrealized investment gains/(losses)	0	0
Fixed maturities, available for sale | Corporate debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	135,753	119,104
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(834)	(7)
Included in OCI	(495)	1,183
Purchases	4,231	18,910
Sales	0	0
Settlements/ distributions	(12,180)	(8,763)
Closing balance	126,475	130,427
Change in unrealized investment gains/(losses)	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	92,589	141,174
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	1,728	747
Included in OCI	0	0
Purchases	7,238	4,459
Sales	0	0
Settlements/ distributions	(314)	(408)
Closing balance	101,241	145,972
Change in unrealized investment gains/(losses)	1,728	747
Other investments | CLO-Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	5,300	5,016
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	0	411
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(314)	(408)
Closing balance	4,986	5,019
Change in unrealized investment gains/(losses)	0	411
Other investments | Other privately held investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	87,289	136,158
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	1,728	336
Included in OCI	0	0
Purchases	7,238	4,459
Sales	0	0
Settlements/ distributions	0	0
Closing balance	96,255	140,953
Change in unrealized investment gains/(losses)	$ 1,728	$ 336

FAIR VALUE MEASUREMENTS - Fin_2

FAIR VALUE MEASUREMENTS - Financial Instruments Disclosed, But Not Carried, at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fixed maturities, held to maturity, amortized cost	$ 693,042	$ 686,296
Fixed maturities, held to maturity, fair value	683,726	675,851
Federal Home Loan Bank advances	85,790	85,790
Federal Home Loan Bank advances, fair value	86,000	86,000
Reported value measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	1,314,000	1,314,000
Estimate of fair value measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	$ 1,204,000	$ 1,198,000

DERIVATIVE INSTRUMENTS - Schedu

DERIVATIVE INSTRUMENTS - Schedule of Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative asset fair value	$ 1,232	$ 4,424
Derivative liability fair value	$ 2,282	$ 10,165
Derivative asset, statement of financial position [Extensible Enumeration]	Other assets	Other assets
Derivative liability, statement of financial position [Extensible Enumeration]	Other liabilities	Other liabilities
Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative asset fair value	$ 1,232	$ 4,424
Derivative liability fair value	2,282	10,165
Not Designated as Hedging Instruments | Relating to investment portfolio: | Foreign exchange forward contracts
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	110,733	49,307
Derivative asset fair value	204	66
Derivative liability fair value	2	274
Not Designated as Hedging Instruments | Relating to underwriting portfolio: | Foreign exchange forward contracts
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	1,547,244	1,347,559
Derivative asset fair value	1,028	4,358
Derivative liability fair value	$ 2,280	$ 9,891

DERIVATIVE INSTRUMENTS - Offset

DERIVATIVE INSTRUMENTS - Offsetting Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative assets
Gross amounts	$ 4,516	$ 8,708
Gross amounts offset	(3,284)	(4,284)
Net amounts	1,232	4,424
Derivative liabilities
Gross amounts	5,566	14,449
Gross amounts offset	(3,284)	(4,284)
Net amounts	$ 2,282	$ 10,165

DERIVATIVE INSTRUMENTS - Gains

DERIVATIVE INSTRUMENTS - Gains (Losses) on Derivatives Recognized in Net Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	$ (1,220)	$ 10,303
Relating to investment portfolio: | Foreign exchange forward contracts | Net investment gains (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	795	(947)
Relating to underwriting portfolio: | Foreign exchange forward contracts | Foreign exchange (losses) gains
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	$ (2,015)	$ 11,250

RESERVE FOR LOSSES AND LOSS E_3

RESERVE FOR LOSSES AND LOSS EXPENSES - Reserve Roll-Forward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserve for losses and loss expenses, beginning of period	$ 16,434,018	$ 15,168,863
Less reinsurance recoverable on unpaid losses and loss expenses, beginning of period	(6,323,083)	(5,831,172)
Net reserve for unpaid losses and loss expenses, beginning of period	10,110,935	9,337,691
Net incurred losses and loss expenses related to:
Current year	728,671	724,680
Prior years	0	(4,038)
Net incurred losses and loss expenses	728,671	720,642
Net paid losses and loss expenses related to:
Current year	(50,724)	(38,662)
Prior years	(612,571)	(574,538)
Net paid losses and loss expenses	(663,295)	(613,200)
Foreign exchange and other	(48,602)	46,094
Net reserve for unpaid losses and loss expenses, end of period	10,127,709	9,491,227
Reinsurance recoverable on unpaid losses and loss expenses, end of period	6,503,188	5,823,417
Gross reserve for losses and loss expenses, end of period	$ 16,630,897	$ 15,314,644

RESERVE FOR LOSSES AND LOSS E_4

RESERVE FOR LOSSES AND LOSS EXPENSES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net loss and loss expenses	$ 728,671	$ 724,680
Catastrophe and Weather-related Events
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net loss and loss expenses	$ 20,000	$ 38,000

RESERVE FOR LOSSES AND LOSS E_5

RESERVE FOR LOSSES AND LOSS EXPENSES - Prior Year Development (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years - net favorable (adverse) effect	$ 0	$ 4,038
Insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years - net favorable (adverse) effect	0	1,041
Reinsurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years - net favorable (adverse) effect	$ 0	$ 2,997

RESERVE FOR LOSSES AND LOSS E_6

RESERVE FOR LOSSES AND LOSS EXPENSES - Prior Year Reserve Development By Segment and Line of Business (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	$ 0	$ 4,038
Insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	1,041
Insurance | Property
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	8,011	5,900
Insurance | Accident and health
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(304)
Insurance | Marine and aviation
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	(8,011)	13,221
Insurance | Cyber
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	8,452
Insurance | Professional lines
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(12,594)
Insurance | Credit and political risk
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	4,519
Insurance | Liability
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(18,153)
Reinsurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	2,997
Reinsurance | Run-Off Lines
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	38,114
Reinsurance | Property | Run-Off Lines
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	6,883
Reinsurance | Accident and health
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	6,988
Reinsurance | Marine and aviation
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(250)
Reinsurance | Professional lines
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(3,225)
Reinsurance | Liability
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(32,853)
Reinsurance | Agriculture
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	11,891
Reinsurance | Credit and surety
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(546)
Reinsurance | Motor
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	(17,122)
Reinsurance | Catastrophe | Run-Off Lines
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	0	31,058
Reinsurance | Engineering | Run-Off Lines
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net favorable (adverse) prior year reserve development	$ 0	$ 173

EARNINGS PER COMMON SHARE (Deta

EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings per common share
Net income	$ 395,459	$ 180,097
Less: Preferred share dividends	7,563	7,563
Net income available to common shareholders	$ 387,896	$ 172,534
Weighted average common shares outstanding (in shares)	84,879	84,864
Earnings per common share (in usd per share)	$ 4.57	$ 2.03
Earnings per diluted common share
Net income available to common shareholders	$ 387,896	$ 172,534
Weighted average common shares outstanding (in shares)	84,879	84,864
Share-based compensation plans (in shares)	814	989
Weighted average diluted common shares outstanding (in shares)	85,693	85,853
Earnings per diluted common share (in usd per share)	$ 4.53	$ 2.01
Weighted average anti-dilutive shares excluded from the dilutive computation (in shares)	748	805

SHARE-BASED COMPENSATION - Narr

SHARE-BASED COMPENSATION - Narrative (Details) - d	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Trading days proceeding performance period	30	10
Senior Leadership
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Trading days proceeding performance period		10
Performance Vesting Restricted Stock Units | Market condition
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Vesting period	3 years
Performance Vesting Restricted Stock Units | Market condition | Minimum
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Vesting as a percentage of target (percent)	0%
Performance Vesting Restricted Stock Units | Market condition | Maximum
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Vesting as a percentage of target (percent)	200%
Performance Vesting Restricted Stock Units | Performance condition
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Vesting period	3 years
Performance Vesting Restricted Stock Units | Performance condition | Minimum
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Vesting as a percentage of target (percent)	0%
Performance Vesting Restricted Stock Units | Performance condition | Maximum
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Vesting as a percentage of target (percent)	200%

SHARE-BASED COMPENSATION - Valu

SHARE-BASED COMPENSATION - Valuation Assumptions (Details) - Performance Vesting Restricted Stock Units	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Expected volatility (as a percent)	26%	36.24%
Expected term (in years)	3 years	3 years
Risk-free interest rate (as a percent)	4.06%	3.79%
Senior Leadership
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Expected volatility (as a percent)		29.30%
Expected term (in years)		1 year
Risk-free interest rate (as a percent)		4.61%

SHARE-BASED COMPENSATION - Rest

SHARE-BASED COMPENSATION - Restricted Stock Unit Awards by Type (Details) - Share Settled shares in Thousands	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Performance Vesting Restricted Stock Units
Number of restricted stock units
Nonvested restricted stock units - beginning of period (in shares) | shares	144
Granted (in shares) | shares	104
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
Nonvested restricted stock units - end of period (in shares) | shares	248
Weighted  average grant date fair value
Nonvested restricted stock units - beginning of period (in usd per share) | $ / shares	$ 65.69
Granted (in usd per share) | $ / shares	65.77
Vested (in usd per share) | $ / shares	0
Forfeited (in usd per share) | $ / shares	0
Nonvested restricted stock units - end of period (in usd per share) | $ / shares	$ 65.73
Restricted Stock Units (RSUs)
Number of restricted stock units
Nonvested restricted stock units - beginning of period (in shares) | shares	1,855
Granted (in shares) | shares	696
Vested (in shares) | shares	(682)
Forfeited (in shares) | shares	(78)
Nonvested restricted stock units - end of period (in shares) | shares	1,791
Weighted  average grant date fair value
Nonvested restricted stock units - beginning of period (in usd per share) | $ / shares	$ 55.21
Granted (in usd per share) | $ / shares	59.34
Vested (in usd per share) | $ / shares	54.67
Forfeited (in usd per share) | $ / shares	55.29
Nonvested restricted stock units - end of period (in usd per share) | $ / shares	$ 57.02

SHARE-BASED COMPENSATION - Sche

SHARE-BASED COMPENSATION - Schedule of Additional Information Related to Share-based Compensation (Details) - Restricted Stock Units (RSUs) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Share based compensation expense	$ 13,671	$ 12,526
Tax benefits associated with share-based compensation expense	2,763	2,647
Fair value of restricted stock units vested	41,156	50,714
Unrecognized share-based compensation expense	$ 92,556	$ 108,882
Expected weighted average period associated with the recognition of unrecognized share-based compensation expense	2 years 10 months 24 days	2 years 9 months 18 days

SHAREHOLDERS' EQUITY - Common S

SHAREHOLDERS' EQUITY - Common Shares Issued and Outstanding (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, balance at beginning of period (in shares)	176,580
Total shares issued at end of period (in shares)	176,580
Treasury shares, balance at beginning of period (in shares)	(91,294)
Total treasury shares at end of period (in shares)	(91,893)
Total shares outstanding (in shares)	84,687		85,286
Common shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, balance at beginning of period (in shares)	176,580	176,580
Shares issued (in shares)	0	0
Total shares issued at end of period (in shares)	176,580	176,580
Treasury shares, balance at beginning of period (in shares)	(91,294)	(91,912)
Shares repurchased (in shares)	(1,281)	(262)
Share reissued (in shares)	682	777
Total treasury shares at end of period (in shares)	(91,893)	(91,397)
Total shares outstanding (in shares)	84,687	85,183

SHAREHOLDERS' EQUITY - Treasury

SHAREHOLDERS' EQUITY - Treasury Shares (Details) - Common shares - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Treasury Shares [Line Items]
Total shares (in shares)	1,281	262
Total cost	$ 75,728	$ 15,945
Average price per share (in usd per share)	$ 59.13	$ 60.82
In the open market
Treasury Shares [Line Items]
Total shares (in shares)	1,048	0
Total cost	$ 61,607	$ 0
Average price per share (in usd per share)	$ 58.79	$ 0
From employees
Treasury Shares [Line Items]
Total shares (in shares)	233	262
Total cost	$ 14,121	$ 15,945
Average price per share (in usd per share)	$ 60.70	$ 60.82

SHAREHOLDERS' EQUITY - Dividend

SHAREHOLDERS' EQUITY - Dividends (Details) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Common shares
Class of Stock [Line Items]
Dividends declared, common shares (in usd per share)	$ 0.44	$ 0.44
Dividends paid in period of declaration, common shares (in usd per share)	0	0
Dividends paid in period following declaration (in usd per share)	0.44	0.44
Series E preferred shares
Class of Stock [Line Items]
Dividends declared, preferred shares (in usd per share)	34.38	34.38
Dividends paid in period of declaration, preferred shares (in usd per share)	0	0
Dividends paid in period following declaration (in usd per share)	$ 34.38	$ 34.38

DEBT AND FINANCING ARRANGEMEN_2

DEBT AND FINANCING ARRANGEMENTS (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 26, 2024	Mar. 25, 2024
Line of Credit Facility [Line Items]
Loan advances made	$ 345,065	$ 305,222
Letter of Credit | LOC Facility
Line of Credit Facility [Line Items]
Line of credit facility			$ 300,000	$ 500,000
Third Party Reinsurer | Related Party
Line of Credit Facility [Line Items]
Non-cash repayment of advance		31,000
Third Party Reinsurer | Loan Agreement With Third Party Reinsurer | Related Party
Line of Credit Facility [Line Items]
Non-cash repayment of advance	25,000	82,000
Loan advances made	$ 55,000	80,000
Commitment to advance amounts to reinsurer		$ 26,000

FEDERAL HOME LOAN BANK ADVANC_2

FEDERAL HOME LOAN BANK ADVANCES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Advance from Federal Home Loan Bank
Federal Home Loan Bank advances	$ 85,790		$ 85,790
Federal Home Loan Bank of Chicago
Advance from Federal Home Loan Bank
FHLB program, admitted assets, actual	3,000,000		3,000,000
FHLB program, maximum borrowing capacity	759,000		759,000
Federal Home Loan Bank advances	86,000		86,000
Interest expense on FHLB borrowings	1,000	$ 1,000
FHLB program, investments pledged as security	$ 90,000		$ 95,000
Federal Home Loan Bank of Chicago | Minimum
Advance from Federal Home Loan Bank
FHLB advances, interest rate (as a percent)	5.60%		5.60%
Federal Home Loan Bank of Chicago | Maximum
Advance from Federal Home Loan Bank
FHLB advances, interest rate (as a percent)	5.70%		5.90%

OTHER COMPREHENSIVE INCOME (L_3

OTHER COMPREHENSIVE INCOME (LOSS) - Tax Effects of Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Before tax amount
Unrealized gains (losses) arising during the period, net of reclassification adjustment	$ (51,963)	$ 212,922
Foreign currency translation adjustment	(8,951)	(535)
Total other comprehensive income (loss), before tax	(60,914)	212,387
Income tax (expense) benefit
Unrealized gains (losses) arising during the period, net of reclassification adjustment	14,901	(23,983)
Foreign currency translation adjustment	0	0
Income tax (expense) benefit	14,901	(23,983)
Net of tax amount
Unrealized gains (losses) arising during the period, net of reclassification adjustment	(37,062)	188,939
Foreign currency translation adjustment	(8,951)	(535)
Total other comprehensive income (loss), net of tax	(46,013)	188,404
Available for sale investments
Before tax amount
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	24,879	44,121
Income tax (expense) benefit
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	(1,464)	(3,371)
Net of tax amount
Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss)	23,415	40,750
Unrealized gains (losses) arising during the period, net of reclassification adjustment	(37,062)	188,939
Available for sale investments | Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has been recognized
Before tax amount
Unrealized gains (losses) arising during the period	(76,408)	153,851
Income tax (expense) benefit
Unrealized gains (losses) arising during the period	16,349	(19,284)
Net of tax amount
Unrealized gains (losses) arising during the period	(60,059)	134,567
Available for sale investments | Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has not been recognized
Before tax amount
Unrealized gains (losses) arising during the period	(434)	14,950
Income tax (expense) benefit
Unrealized gains (losses) arising during the period	16	(1,328)
Net of tax amount
Unrealized gains (losses) arising during the period	$ (418)	$ 13,622

OTHER COMPREHENSIVE INCOME (L_4

OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications Out of AOCI Into Net Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]
Impairment losses	$ (8)	$ 0
Income before income taxes and interest in income (loss) of equity method investments	269,636	198,198
Income tax (expense) benefit	124,654	(15,896)
Net income	395,459	180,097
Unrealized gains (losses) on available for sale investments | Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]
Other realized gains (losses)	(24,871)	(44,121)
Impairment losses	(8)	0
Income before income taxes and interest in income (loss) of equity method investments	(24,879)	(44,121)
Income tax (expense) benefit	1,464	3,371
Net income	$ (23,415)	$ (40,750)

REORGANIZATION EXPENSES (Detail

REORGANIZATION EXPENSES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restructuring and Related Activities [Abstract]
Reorganization expenses	$ 12,299	$ 0

Income Taxes - Schedule of Anal

Income Taxes - Schedule of Analysis of Income Tax Expense (Benefit) and Tax Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred income tax expense (benefit)	$ (163,000)
Total income tax expense (benefit)	(124,654)	$ 15,896
U.S. | Foreign Tax Authority
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Current income tax expense (benefit)	21,498	10,905
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred income tax expense (benefit)	2,745	70
Europe | Foreign Tax Authority
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Current income tax expense (benefit)	5,528	3,174
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred income tax expense (benefit)	8,280	1,548
Bermuda | Bermuda Taxing Authority
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Current income tax expense (benefit)	0	199
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred income tax expense (benefit)	$ (162,705)	$ 0

Income Taxes - Schedule of Dist

Income Taxes - Schedule of Distribution of Income Before Income Taxes and Reconciliation of Income Tax Rate To Effective Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income before income taxes
Bermuda (domestic)	$ 83,231	$ 106,604
Foreign	187,574	89,388
Income before income taxes and interest in income (loss) of equity method investments	$ 270,805	$ 195,992
Reconciliation of effective tax rate (% of income before income taxes)
Expected tax rate	0%	0%
Valuation allowance	(0.70%)	(1.80%)
Bermuda Economic Transition Adjustment	(0.601)	0
Other	0.60%	1.30%
Actual tax rate	(46.00%)	8.10%
U.S. | Foreign Tax Authority
Reconciliation of effective tax rate (% of income before income taxes)
Foreign taxes at local expected rates:	9.20%	5.40%
Europe | Foreign Tax Authority
Reconciliation of effective tax rate (% of income before income taxes)
Foreign taxes at local expected rates:	5%	3.20%