Reserves For Losses And Loss Expenses (Tables)

12 Months Ended

Dec. 31, 2023

Insurance [Abstract]

Loss and loss expenses incurred, net of reinsurance, and cumulative paid claims and claim adjustment expenses, net of reinsurance

Insurance

Other Liability

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited																				IBNR		Cumulative Number of Reported Claims
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	846,005	$	847,308	$	845,254	$	849,657	$	862,568	$	868,639	$	863,890	$	862,440	$	863,636	$	863,342	$	28,447	28
2015			949,853		985,529		960,136		963,237		965,497		975,534		982,145		1,011,753		1,018,418		42,923		28
2016					1,017,074		1,010,016		1,019,067		1,030,490		1,044,563		1,060,478		1,092,036		1,134,162		80,989		28
2017							1,065,837		1,099,566		1,121,979		1,138,821		1,178,596		1,249,086		1,267,359		95,118		28
2018									1,104,011		1,131,672		1,121,429		1,156,233		1,232,803		1,299,691		141,108		28
2019											1,240,667		1,237,516		1,237,950		1,294,768		1,371,217		205,380		29
2020													1,339,702		1,212,875		1,158,966		1,167,753		317,212		23
2021															1,534,634		1,390,800		1,347,336		537,640		25
2022																	1,823,703		1,830,125		1,116,619		25
2023																			2,120,365		1,815,051		19
Total																			$	13,419,768

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	78,811	$	190,637	$	337,870	$	479,657	$	593,577	$	679,351	$	729,573	$	759,003	$	782,462	$	810,687
2015			82,664		210,421		381,682		537,415		675,274		756,353		814,964		873,489		928,793
2016					69,404		208,851		389,988		558,176		676,957		766,774		871,252		955,951
2017							79,937		255,591		453,073		638,879		774,674		930,529		1,048,203
2018									86,788		264,261		435,711		615,688		806,757		986,108
2019											88,173		275,315		471,186		704,851		909,617
2020													72,203		224,991		423,186		621,085
2021															76,568		267,564		492,271
2022																	93,477		356,621
2023																			92,758
Total																			$	7,202,094
	Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																		154,001
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	6,371,675

Workers' Compensation

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited																				IBNR		Cumulative Number of Reported Claims
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	639,436	$	637,307	$	627,767	$	617,242	$	615,435	$	604,030	$	600,194	$	602,000	$	598,977	$	589,283	$	12,555	57
2015			712,800		690,525		650,997		641,169		626,432		620,741		617,478		612,687		603,732		18,013		58
2016					702,716		696,339		684,700		660,520		651,278		657,972		654,385		641,549		19,823		58
2017							762,093		733,505		689,622		673,216		683,880		682,153		675,871		22,933		58
2018									778,964		724,697		715,055		724,056		721,170		715,018		27,179		56
2019											784,281		721,018		732,762		734,034		722,456		39,081		54
2020													725,245		716,430		704,008		668,222		36,045		42
2021															742,687		701,703		667,517		67,127		46
2022																	772,620		745,218		153,476		46
2023																			784,906		352,511		43
Total																			$	6,813,772

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	148,405	$	319,743	$	412,611	$	471,235	$	503,915	$	521,141	$	531,475	$	538,914	$	547,894	$	553,739
2015			139,320		323,744		421,734		477,541		512,933		531,512		544,849		557,215		564,658
2016					142,998		338,835		446,072		504,850		537,861		558,934		572,669		584,330
2017							153,456		362,299		468,817		525,753		559,198		583,258		603,006
2018									171,006		397,464		508,546		574,889		613,675		642,292
2019											184,715		397,376		515,914		581,003		618,324
2020													172,478		380,454		485,203		548,585
2021															172,729		384,867		490,648
2022																	180,982		408,929
2023																			195,204
Total																			$	5,209,715
			Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																208,451
			Reserves for loss and loss adjustment expenses, net of reinsurance																$	1,812,508

Professional Liability

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited																				IBNR		Cumulative Number of Reported Claims
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	252,473	$	245,854	$	258,874	$	242,903	$	238,388	$	257,205	$	256,157	$	255,527	$	254,514	$	256,527	$	10,067	7
2015			259,122		257,634		274,233		275,604		291,157		282,452		282,806		286,950		286,320		13,275		8
2016					310,140		324,043		360,778		401,569		438,761		468,154		463,625		449,678		15,850		9
2017							333,255		332,317		338,526		377,209		384,107		393,054		401,661		45,095		10
2018									335,128		322,297		333,413		359,493		382,239		397,593		81,991		10
2019											336,397		332,426		345,548		354,121		362,983		89,944		11
2020													394,304		375,559		337,796		313,386		100,150		11
2021															525,389		471,456		446,596		215,820		11
2022																	649,725		586,327		405,848		11
2023																			648,231		509,380		12
Total																			$	4,149,302

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	19,318	$	83,246	$	137,931	$	175,230	$	198,176	$	214,915	$	226,323	$	235,581	$	238,277	$	243,397
2015			20,319		85,169		139,396		187,007		215,821		232,506		239,514		246,501		258,988
2016					28,503		102,232		201,167		254,994		297,088		357,094		405,052		412,645
2017							36,450		96,179		162,660		242,929		261,033		306,535		329,303
2018									28,108		99,540		155,102		198,546		244,068		283,639
2019											31,635		97,302		147,767		200,259		235,124
2020													27,996		80,180		128,869		169,000
2021															28,542		85,886		153,063
2022																	33,417		90,594
2023																			41,064
Total																			$	2,216,817
	Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																		38,814
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	1,971,299

Auto

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited																				IBNR		Cumulative Number of Reported Claims
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	363,882	$	385,214	$	417,539	$	415,490	$	412,929	$	412,757	$	408,304	$	407,435	$	408,816	$	408,743	$	291	47
2015			389,529		416,251		422,344		430,503		431,514		429,950		427,079		428,898		428,339		1,013		53
2016					430,132		429,762		441,051		442,122		438,917		438,616		440,412		442,164		2,410		52
2017							430,445		428,420		430,205		434,186		440,004		444,483		445,263		3,148		47
2018									442,701		462,657		479,085		494,442		521,794		530,374		6,234		45
2019											483,120		488,379		504,901		530,967		548,688		11,878		45
2020													523,739		428,761		442,165		469,184		16,227		30
2021															614,422		596,810		632,918		54,629		38
2022																	792,553		825,359		192,025		44
2023																			916,722		444,715		40
Total																			$	5,647,754

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	155,553	$	237,622	$	327,548	$	364,768	$	393,428	$	401,368	$	404,067	$	405,061	$	405,817	$	407,212
2015			159,932		264,377		324,175		369,223		396,832		410,275		416,060		419,891		421,749
2016					183,777		278,289		340,319		389,233		408,676		419,203		427,662		433,882
2017							180,494		267,309		326,851		371,755		401,846		419,548		431,165
2018									180,110		281,564		350,212		412,985		463,232		498,094
2019											185,289		290,194		374,545		440,449		495,111
2020													142,816		228,358		308,452		374,990
2021															180,860		319,941		429,419
2022																	253,206		428,621
2023																			277,634
Total																			$	4,197,877
			Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																2,953
			Reserves for loss and loss adjustment expenses, net of reinsurance																$	1,452,830

Short-tail lines

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited																				IBNR		Cumulative Number of Reported Claims
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	697,102	$	701,133	$	658,437	$	656,704	$	657,637	$	657,968	$	660,388	$	658,600	$	656,931	$	656,326	$	1,483	30
2015			737,494		725,927		722,556		721,082		713,225		711,665		709,937		710,266		714,974		2,044		32
2016					771,829		775,358		762,449		757,010		751,510		753,926		752,541		752,960		3,288		34
2017							752,865		753,274		747,521		746,878		746,475		747,710		746,406		4,267		42
2018									759,748		748,859		746,183		744,467		742,212		741,264		7,835		48
2019											721,072		701,168		690,928		684,606		684,707		14,592		43
2020													900,816		904,545		922,258		926,379		7,624		38
2021															828,347		832,240		815,228		24,478		36
2022																	945,041		928,562		54,776		36
2023																			1,075,325		286,870		27
Total																			$	8,042,131

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	369,514	$	590,511	$	608,396	$	626,751	$	641,861	$	649,068	$	651,560	$	652,054	$	652,379	$	652,449
2015			392,762		608,056		663,402		685,314		694,780		700,569		707,271		707,447		716,682
2016					416,513		669,738		711,238		726,462		731,552		738,302		739,143		744,157
2017							445,208		689,587		718,436		730,584		734,415		741,582		746,917
2018									414,833		661,607		708,101		725,027		725,128		730,199
2019											404,870		615,748		645,251		657,699		665,789
2020													460,351		784,553		845,590		900,682
2021															405,461		698,030		754,448
2022																	472,020		799,125
2023																			565,586
Total																			$	7,276,034
	Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																		5,171
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	771,268

Reinsurance & Monoline Excess

Casualty

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023		IBNR
2014	$	319,818	$	319,210	$	318,559	$	330,354	$	324,470	$	323,855	$	335,560	$	336,622	$	341,244	$	343,235	$	13,680
2015			259,244		231,574		230,136		252,249		293,032		303,053		304,503		308,986		313,327		16,235
2016					240,868		252,786		245,317		267,808		301,629		301,242		310,273		309,126		19,483
2017							231,313		220,878		238,916		261,438		281,132		298,284		314,895		28,441
2018									221,393		210,492		230,817		246,861		261,004		292,927		37,287
2019											236,517		230,620		239,206		240,879		272,393		52,998
2020													299,888		293,574		290,037		313,904		103,742
2021															360,399		347,054		344,272		190,749
2022																	447,231		437,358		325,597
2023																			449,816		396,340
Total																			$	3,391,253

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	21,302	$	68,906	$	115,585	$	154,811	$	197,644	$	227,038	$	251,736	$	271,062	$	283,876	$	296,469
2015			17,876		48,371		91,016		141,073		178,280		204,981		233,281		250,504		266,497
2016					19,884		61,710		100,074		140,104		171,465		205,052		224,739		241,884
2017							16,457		40,013		69,190		123,404		147,049		174,745		207,378
2018									11,056		40,884		77,371		109,290		141,309		182,326
2019											14,544		39,035		63,945		94,735		142,501
2020													20,746		49,637		81,710		137,043
2021															10,910		43,791		89,076
2022																	11,574		45,625
2023																			10,603
Total																			$	1,619,402
	Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																		402,281
			Reserves for loss and loss adjustment expenses, net of reinsurance																$	2,174,132

Monoline Excess

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023		IBNR
2014	$	63,465	$	57,558	$	49,478	$	45,758	$	41,671	$	42,541	$	42,618	$	40,652	$	35,707	$	32,185	$	3,400
2015			69,977		57,897		50,099		45,115		39,682		39,781		36,774		30,104		27,590		4,664
2016					72,657		70,281		71,404		64,957		65,485		65,222		61,432		53,304		6,192
2017							76,701		80,508		70,749		71,025		66,795		62,647		55,713		9,442
2018									77,820		72,505		71,448		66,180		57,847		50,744		12,964
2019											78,929		77,482		76,242		73,978		66,071		12,977
2020													84,354		83,468		80,452		72,376		26,582
2021															98,110		87,980		77,220		31,581
2022																	98,923		76,725		35,307
2023																			110,446		73,881
Total																			$	622,374

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	358	$	1,729	$	3,354	$	4,175	$	5,808	$	7,595	$	11,154	$	11,938	$	13,491	$	14,632
2015			2,069		2,481		3,272		4,099		4,416		5,083		5,421		6,457		6,844
2016					2,498		4,783		5,573		5,928		7,685		9,883		11,819		13,569
2017							6,282		12,810		15,356		17,327		18,375		19,275		21,275
2018									6,141		8,230		9,368		10,359		12,414		13,583
2019											6,241		10,884		12,728		15,436		18,836
2020													4,869		8,699		10,471		12,869
2021															4,586		6,026		8,872
2022																	5,898		10,564
2023																			6,390
Total																			$	127,434
	Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																		576,491
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	1,071,431

Property

(In thousands)

Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2023
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023		IBNR
2014	$	113,055	$	96,586	$	97,261	$	99,973	$	99,200	$	98,846	$	99,244	$	97,308	$	96,648	$	96,135	$	344
2015			127,315		117,503		131,722		130,389		129,472		131,133		130,697		131,393		131,947		1,007
2016					167,998		174,440		181,595		180,816		186,086		184,053		185,133		186,176		1,303
2017							206,666		200,487		199,481		198,039		191,941		192,458		193,551		1,452
2018									108,348		112,133		103,192		105,165		103,015		101,498		1,898
2019											103,316		77,255		82,036		81,192		81,157		2,479
2020													114,645		117,885		116,786		121,417		4,291
2021															133,989		146,726		144,429		13,709
2022																	167,223		167,351		30,362
2023																			137,685		60,458
Total																			$	1,361,346

Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2014		2015		2016		2017		2018		2019		2020		2021		2022		2023
2014	$	38,734	$	66,816	$	82,113	$	88,240	$	91,376	$	93,087	$	94,552	$	95,186	$	95,620	$	94,996
2015			53,435		89,120		109,053		118,615		122,630		125,494		126,895		128,037		128,947
2016					78,887		133,478		157,341		168,433		175,867		177,961		182,300		184,208
2017							72,114		141,390		171,736		179,799		182,680		185,895		188,497
2018									33,972		65,071		82,327		87,789		94,931		96,262
2019											23,129		54,709		68,693		71,264		73,234
2020													26,606		65,563		86,885		95,643
2021															15,245		71,800		109,179
2022																	25,515		91,718
2023																			24,737
Total																			$	1,087,421
	Reserves for loss and loss adjustment expenses before 2014, net of reinsurance																		1,472
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	275,397

Reconciliation of net incurred and paid claims development to reserves for loss and loss adjustment expenses

The reconciliation of the net incurred and paid claims development tables to the reserves for losses and loss expenses in the consolidated balance sheet is as follows:

(In thousands)		December 31, 2023
Undiscounted reserves for loss and loss expenses, net of reinsurance:
	Other liability	$	6,371,675
	Workers' compensation	1,812,508
	Professional liability	1,971,299
	Auto	1,452,830
	Short-tail lines	771,268
	Other	151,204
	Insurance	12,530,784
	Casualty	2,174,132
	Monoline excess	1,071,431
	Property	275,397
	Reinsurance & Monoline Excess	3,520,960
Total undiscounted reserves for loss and loss expenses, net of reinsurance		$	16,051,744

(In thousands)		December 31, 2023
Due from reinsurers on unpaid claims:
	Other liability	$	951,773
	Workers' compensation	189,182
	Professional liability	1,138,129
	Auto	81,334
	Short-tail lines	379,621
	Other	127,581
	Insurance	2,867,620
	Casualty	116,198
	Monoline excess	40,467
	Property	53,547
	Reinsurance & Monoline Excess	210,212
Total due from reinsurers on unpaid claims		$	3,077,832

(In thousands)		December 31, 2023
Loss reserve discount:
	Other liability	$	—
	Workers' compensation	(12,193)
	Professional liability	—
	Auto	—
	Short-tail lines	—
	Other	—
	Insurance	(12,193)
	Casualty	(72,503)
	Monoline excess	(305,228)
	Property	—
	Reinsurance & Monoline Excess	(377,731)
Total loss reserve discount		$	(389,924)
Total gross reserves for loss and loss expenses		$	18,739,652

Supplementary information regarding average historical claims duration

The following is supplementary information regarding average historical claims duration as of December 31, 2023:

Insurance
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years	1		2		3		4		5		6		7		8		9		10
Other liability	6.4	%	13.4	%	15.8	%	15.6	%	12.9	%	10.4	%	7.5	%	5.5	%	4.1	%	3.3	%
Workers' compensation	24.4	%	30.6	%	16.0	%	9.2	%	5.3	%	3.4	%	2.3	%	1.7	%	1.4	%	1.0	%
Professional liability	7.3	%	17.1	%	17.2	%	14.5	%	9.0	%	9.4	%	5.8	%	2.6	%	4.0	%	2.0	%
Auto	34.5	%	20.6	%	15.8	%	11.3	%	7.3	%	3.6	%	1.6	%	0.8	%	0.3	%	0.3	%
Short-tail lines	54.4	%	33.4	%	5.5	%	2.8	%	1.0	%	0.9	%	0.5	%	0.3	%	0.4	%	0.3	%
Reinsurance & Monoline Excess
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years	1		2		3		4		5		6		7		8		9		10
Casualty	4.7	%	10.0	%	11.7	%	13.9	%	11.7	%	10.1	%	8.2	%	5.6	%	4.4	%	3.7	%
Monoline excess	7.2	%	5.1	%	3.1	%	2.7	%	3.4	%	3.2	%	4.9	%	3.2	%	3.1	%	3.5	%
Property	28.8	%	33.5	%	17.1	%	5.6	%	3.5	%	1.6	%	1.6	%	0.6	%	0.2	%	—	%

Reconciliation of beginning and ending reserve balance

The table below provides a reconciliation of the beginning and ending reserve balances:

(In thousands)	2023		2022		2021
Net reserves at beginning of year	$	14,248,879	$	12,848,362	$	11,620,393
Net provision for losses and loss expenses:
Claims occurring during the current year (1)	6,311,780		5,774,713		4,921,191
Increase in estimates for claims occurring in prior years (2)	29,681		54,511		863
Loss reserve discount accretion	30,681		32,526		31,906
Total	6,372,142		5,861,750		4,953,960
Net payments for claims:
Current year	1,217,078		1,068,577		887,896
Prior year	3,764,532		3,279,333		2,777,798
Total	4,981,610		4,347,910		3,665,694
Foreign currency translation	22,409		(113,323)		(60,297)
Net reserves at end of year	15,661,820		14,248,879		12,848,362
Ceded reserve at end of year	3,077,832		2,762,344		2,542,526
Gross reserves at end of year	$	18,739,652	$	17,011,223	$	15,390,888
Net change in premiums and losses occurring in prior years:
Increase in estimates for claims occurring in prior years (2)	$	(29,681)	$	(54,511)	$	(863)
Retrospective premium adjustments for claims occurring in prior years (3)	10,782		18,106		7,510
Net premium and reserve development on prior years	$	(18,899)	$	(36,405)	$	6,647

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(1)Claims occurring during the current year are net of loss reserve discounts of $47 million, $35 million and $21 million in 2023, 2022, and 2021, respectively.

(2)The change in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years decreased by $13 million in 2023, increased by $16 million in 2022, and decreased by $19 million in 2021.

(3)For certain retrospectively rated insurance polices and reinsurance agreements, changes in loss and loss expenses for prior years are offset by additional or return premiums.