Reserves for Losses and Loss Expenses

Loss reserves included in the Company’s financial statements represent management’s best estimates based upon an actuarially derived point estimate and other considerations. The Company uses a variety of actuarial techniques and methods to derive an actuarial point estimate for each operating unit. These methods include paid loss development, incurred loss development, paid and incurred Bornhuetter-Ferguson methods and frequency and severity methods. In circumstances where one actuarial method is considered more credible than the others, that method is used to set the point estimate. The actuarial point estimate may also be based on a judgmental weighting of estimates produced from each of the methods considered. Industry loss experience is used to supplement the Company’s own data in selecting “tail factors” in areas where the Company’s own data is limited. The actuarial data is analyzed by line of business, coverage and accident or policy year, as appropriate, for each operating unit.

The establishment of the actuarially derived loss reserve point estimate also includes consideration of qualitative factors that may affect the ultimate losses. These qualitative considerations include, among others, the impact of re-underwriting initiatives, changes in the mix of business, changes in distribution sources and changes in policy terms and conditions.

The key assumptions used to arrive at the best estimate of loss reserves are the expected loss ratios, rate of loss cost inflation, and reported and paid loss emergence patterns. Expected loss ratios represent management’s expectation of losses at the time the business is priced and written, before any actual claims experience has emerged. This expectation is a significant determinant of the estimate of loss reserves for recently written business where there is little paid or incurred loss data to consider. Expected loss ratios are generally derived from historical loss ratios adjusted for the impact of rate changes, loss cost trends and known changes in the type of risks underwritten. Expected loss ratios are estimated for each key line of business within each operating unit. Expected loss cost inflation is particularly important for the long-tail lines, such as excess casualty, and claims with a high medical component, such as workers’ compensation. Reported and paid loss emergence patterns are used to project current reported or paid loss amounts to their ultimate settlement value. Loss development factors are based on the historical emergence patterns of paid and incurred losses, and are derived from the Company’s own experience and industry data. The paid loss emergence pattern is also significant to excess and assumed workers’ compensation reserves because those reserves are discounted to their estimated present value based upon such estimated payout patterns.

Loss frequency and severity are measures of loss activity that are considered in determining the key assumptions described in our discussion of loss and loss expense reserves, including expected loss ratios, rate of loss cost inflation and reported and paid loss emergence patterns. Loss frequency is a measure of the number of claims per unit of insured exposure, and loss severity is a measure of the average size of claims. Factors affecting loss frequency include the effectiveness of loss controls and safety programs and changes in economic activity or weather patterns. Factors affecting loss severity include changes in policy limits, retentions, rate of inflation and judicial interpretations.

Another factor affecting estimates of loss frequency and severity is the loss reporting lag, which is the period of time between the occurrence of a loss and the date the loss is reported to the Company. The length of the loss reporting lag affects our ability to accurately predict loss frequency (loss frequencies are more predictable for lines with short reporting lags) as well as the amount of reserves needed for incurred but not reported losses (less IBNR is required for lines with short reporting lags). As a result, loss reserves for lines with short reporting lags are likely to have less variation from initial loss estimates. For lines with short reporting lags, which include commercial automobile, primary workers’ compensation, other liability (claims-made) and property business, the key assumption is the loss emergence pattern used to project ultimate loss estimates from known losses paid or reported to date. For lines of business with long reporting lags, which include other liability (occurrence), products liability, excess workers’ compensation and liability reinsurance, the key assumption is the expected loss ratio since there is often little paid or incurred loss data to consider. Historically, the Company has experienced less variation from its initial loss estimates for lines of businesses with short reporting lags than for lines of business with long reporting lags.

The key assumptions used in calculating the most recent estimate of the loss reserves are reviewed each quarter and adjusted, to the extent necessary, to reflect the latest reported loss data, current trends and other factors observed.

A claim may be defined as an event, as a claimant (number of parties claiming damages from an event) or by exposure type (e.g., an event may give rise to two parties, each claiming loss for bodily injury and property damage).

The most commonly used claim count method is by event. Most of the Company's operating units use the number of events to define and quantify the number of claims. However, in certain lines of business, where it is common for multiple parties to claim damages arising from a single event, an operating unit may quantify claims on the basis of the number of separate parties involved in an event. This may be the case with businesses writing substantial automobile or transportation exposure.

Claim counts for assumed reinsurance will vary based on whether the business is written on a facultative or treaty basis. Further variability as respects treaty claim counts may be reflective of the nature of the treaty, line of business coverage, and type of participation such as quota share or excess of loss contracts. Accordingly, the claim counts have been excluded from the below Reinsurance segment tables due to this variability.

The claim count information set forth in the tables presented below may not provide an accurate reflection of ultimate loss payouts by product line.

The following tables present undiscounted incurred and paid claims development as of December 31, 2016, net of reinsurance, as well as cumulative claim frequency and the total of incurred but not reported liabilities (IBNR). The information about incurred and paid claims development for the years ended December 31, 2007 to 2015 is presented as supplementary information. To enhance the comparability of the loss development data, the Company has removed the impact of foreign exchange rate movements by using the December 31, 2016 exchange rate for all periods. In addition, the Company’s UK and European insurance business has been included in the Insurance segment tables below (excluding primary and excess workers' compensation) for accident years 2012 through 2016, since underwriting year information was only available prior to 2012.

Insurance

Other Liability

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR		Cumulative Number of Reported Claims
2007	$	888,917	$	846,759	$	799,566	$	759,028	$	726,338	$	712,995	$	693,669	$	668,914	$	663,122	$	662,889	$	30,457	26
2008	—		843,528		812,048		755,595		717,985		698,709		689,571		662,644		653,088		654,908		40,213		26
2009	—		—		699,630		664,619		632,324		605,497		595,643		567,578		563,317		558,566		41,517		23
2010	—		—		—		620,030		623,798		598,926		597,272		583,916		580,882		579,538		51,702		23
2011	—		—		—		—		676,275		681,815		666,887		665,885		660,412		655,443		65,108		24
2012	—		—		—		—		—		704,519		712,889		711,727		716,617		723,961		93,444		25
2013	—		—		—		—		—		—		754,543		797,759		788,498		790,734		143,155		26
2014	—		—		—		—		—		—		—		850,243		850,666		851,724		282,056		26
2015	—		—		—		—		—		—		—		—		953,822		992,128		546,566		24
2016	—		—		—		—		—		—		—		—		—		1,020,972		770,954		18
Total																			$	7,490,863



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	46,993	$	126,938	$	233,194	$	332,348	$	414,621	$	477,050	$	528,583	$	564,049	$	589,270	$	609,568
2008	—		48,699		139,809		252,214		356,362		445,060		505,829		539,166		569,020		588,965
2009	—		—		45,461		124,901		217,471		314,994		388,508		432,622		474,893		489,453
2010	—		—		—		46,868		132,654		252,518		340,262		421,217		466,048		494,381
2011	—		—		—		—		50,702		146,070		271,011		384,107		475,650		527,270
2012	—		—		—		—		—		59,669		162,543		304,171		422,269		517,386
2013	—		—		—		—		—		—		64,535		191,902		335,206		476,662
2014	—		—		—		—		—		—		—		79,801		192,893		342,933
2015	—		—		—		—		—		—		—		—		83,378		208,837
2016	—		—		—		—		—		—		—		—		—		65,599
Total																			$	4,321,054
	Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																		120,276
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	3,290,085

Primary Workers' Compensation

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR		Cumulative Number of Reported Claims
2007	$	383,641	$	362,843	$	311,511	$	303,788	$	297,208	$	347,731	$	347,596	$	348,335	$	348,327	$	350,731	$	10,478	48
2008	—		377,794		347,423		345,605		345,413		388,558		388,472		389,343		391,788		393,932		11,623		46
2009	—		—		327,537		332,303		326,766		387,503		392,791		394,303		392,287		395,288		13,128		41
2010	—		—		—		358,734		361,808		411,527		420,604		426,622		429,952		429,762		23,233		42
2011	—		—		—		—		419,364		444,887		457,134		470,026		472,087		474,076		29,589		43
2012	—		—		—		—		—		501,681		501,810		503,956		503,863		509,167		44,568		44
2013	—		—		—		—		—		—		552,570		547,295		546,995		543,293		63,271		48
2014	—		—		—		—		—		—		—		639,436		637,307		627,862		110,364		51
2015	—		—		—		—		—		—		—		—		712,800		690,656		214,854		52
2016	—		—		—		—		—		—		—		—		—		702,761		339,257		49
Total																			$	5,117,528



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	85,962	$	176,184	$	223,380	$	251,437	$	265,770	$	292,764	$	303,058	$	309,988	$	315,309	$	319,350
2008	—		94,385		203,079		261,867		296,667		320,169		335,030		344,892		352,539		360,799
2009	—		—		93,647		197,736		257,972		297,619		318,349		333,793		344,771		352,516
2010	—		—		—		107,742		214,034		281,280		320,154		344,631		362,078		374,013
2011	—		—		—		—		106,157		236,207		309,509		355,909		385,759		408,304
2012	—		—		—		—		—		115,536		255,063		339,560		387,368		419,588
2013	—		—		—		—		—		—		117,900		277,538		363,028		414,216
2014	—		—		—		—		—		—		—		148,405		319,743		412,716
2015	—		—		—		—		—		—		—		—		139,320		323,879
2016	—		—		—		—		—		—		—		—		—		143,066
Total																			$	3,528,447
			Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																138,281
			Reserves for loss and loss adjustment expenses, net of reinsurance																$	1,727,362

Excess Workers' Compensation

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR		Cumulative Number of Reported Claims
2007	$	241,493	$	242,094	$	246,499	$	262,171	$	259,181	$	254,748	$	254,806	$	250,170	$	251,356	$	243,758	$	40,607	2
2008	—		243,067		240,528		211,624		202,419		197,321		195,385		193,395		194,302		183,802		52,994		1
2009	—		—		228,830		214,506		220,124		210,273		202,239		190,439		193,697		189,646		54,310		1
2010	—		—		—		182,028		178,317		171,925		163,365		147,043		153,430		149,806		47,030		1
2011	—		—		—		—		128,301		146,493		150,551		139,251		138,775		137,265		45,151		1
2012	—		—		—		—		—		98,799		101,663		112,477		117,066		115,583		34,805		1
2013	—		—		—		—		—		—		75,214		54,171		50,448		46,028		28,016		1
2014	—		—		—		—		—		—		—		68,521		66,854		59,903		37,366		1
2015	—		—		—		—		—		—		—		—		74,777		61,574		45,861		—
2016	—		—		—		—		—		—		—		—		—		76,184		62,033		—
Total																			$	1,263,549



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	2,420	$	10,422	$	18,713	$	27,445	$	39,212	$	49,129	$	61,962	$	72,674	$	80,770	$	87,356
2008	—		2,464		2,942		6,302		9,907		14,489		25,063		34,418		39,257		48,042
2009	—		—		5,298		8,893		12,444		18,338		25,925		32,419		39,200		45,963
2010	—		—		—		3,227		4,700		4,916		7,938		11,745		15,871		20,799
2011	—		—		—		—		3,015		5,051		9,991		18,995		27,399		32,008
2012	—		—		—		—		—		715		7,421		19,184		24,120		28,055
2013	—		—		—		—		—		—		279		679		2,159		3,013
2014	—		—		—		—		—		—		—		377		2,277		4,266
2015	—		—		—		—		—		—		—		—		2,069		2,484
2016	—		—		—		—		—		—		—		—		—		2,501
Total																			$	274,487
	Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																		734,713
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	1,723,774

Professional Liability

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR		Cumulative Number of Reported Claims
2007	$	98,534	$	98,272	$	105,191	$	104,445	$	102,807	$	103,607	$	99,723	$	99,193	$	97,571	$	98,461	$	595	2
2008	—		113,171		119,953		116,539		111,452		110,268		107,760		107,320		109,242		108,507		1,857		2
2009	—		—		134,978		139,340		145,638		148,992		148,108		150,545		150,875		153,574		2,523		3
2010	—		—		—		147,564		165,875		179,478		178,079		176,843		172,683		174,969		3,689		4
2011	—		—		—		—		180,080		165,439		187,213		190,411		177,401		173,777		8,319		5
2012	—		—		—		—		—		236,681		240,210		263,640		250,074		238,086		23,185		8
2013	—		—		—		—		—		—		266,538		245,925		242,639		247,687		36,873		8
2014	—		—		—		—		—		—		—		252,167		246,068		255,700		75,613		9
2015	—		—		—		—		—		—		—		—		259,368		256,432		121,119		9
2016	—		—		—		—		—		—		—		—		—		311,042		232,577		9
Total																			$	2,018,235



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	5,162	$	43,314	$	68,764	$	88,053	$	95,829	$	99,370	$	98,384	$	98,539	$	96,916	$	97,846
2008	—		9,998		37,818		66,167		85,588		96,585		97,796		100,352		105,299		106,381
2009	—		—		12,608		52,597		85,929		117,738		127,798		138,947		144,024		144,792
2010	—		—		—		14,844		58,946		108,627		129,823		144,541		160,666		165,084
2011	—		—		—		—		18,804		62,513		103,200		134,785		151,026		159,193
2012	—		—		—		—		—		21,524		86,356		127,980		159,061		189,796
2013	—		—		—		—		—		—		23,550		63,927		119,553		176,103
2014	—		—		—		—		—		—		—		19,391		83,672		134,726
2015	—		—		—		—		—		—		—		—		20,496		85,348
2016	—		—		—		—		—		—		—		—		—		28,789
Total																			$	1,288,059
	Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																		7,173
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	737,349

Commercial Automobile

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR		Cumulative Number of Reported Claims
2007	$	438,263	$	425,645	$	431,903	$	424,158	$	427,800	$	427,918	$	426,200	$	425,576	$	426,314	$	426,769	$	307	49
2008	—		432,629		444,941		430,453		427,088		425,600		422,999		422,309		423,258		421,829		361		50
2009	—		—		362,302		345,139		340,962		335,851		337,922		336,861		334,654		335,091		895		39
2010	—		—		—		310,591		320,302		330,432		329,109		333,028		331,865		330,586		1,193		38
2011	—		—		—		—		314,038		322,724		330,125		335,024		343,701		341,200		2,567		38
2012	—		—		—		—		—		314,309		326,831		342,588		355,609		355,461		5,014		34
2013	—		—		—		—		—		—		327,514		349,136		368,894		366,843		18,768		34
2014	—		—		—		—		—		—		—		363,968		385,345		394,998		28,672		36
2015	—		—		—		—		—		—		—		—		389,914		390,590		58,001		39
2016	—		—		—		—		—		—		—		—		—		387,499		124,075		35
Total																			$	3,750,866



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	167,894	$	259,300	$	328,600	$	375,101	$	405,204	$	415,228	$	421,192	$	423,046	$	424,954	$	425,081
2008	—		175,402		270,421		334,078		377,643		402,882		413,411		417,598		420,553		420,596
2009	—		—		136,433		209,553		257,326		291,925		312,903		328,845		331,484		333,144
2010	—		—		—		136,029		208,790		263,639		295,355		313,262		324,997		326,804
2011	—		—		—		—		135,350		211,756		262,685		296,370		321,814		333,987
2012	—		—		—		—		—		136,844		215,214		273,446		312,342		335,806
2013	—		—		—		—		—		—		142,929		218,596		267,253		312,952
2014	—		—		—		—		—		—		—		155,615		237,766		306,594
2015	—		—		—		—		—		—		—		—		160,239		242,031
2016	—		—		—		—		—		—		—		—		—		156,545
Total																			$	3,193,540
			Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																2,157
			Reserves for loss and loss adjustment expenses, net of reinsurance																$	559,482

Short-tail lines

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR		Cumulative Number of Reported Claims
2007	$	358,317	$	337,419	$	325,658	$	324,765	$	324,052	$	327,882	$	329,293	$	328,659	$	327,996	$	327,951	$	991	21
2008	—		428,243		415,554		402,911		396,055		393,943		393,913		393,137		392,457		392,782		1,202		23
2009	—		—		368,106		354,134		344,157		332,782		332,621		328,711		327,465		327,199		1,129		19
2010	—		—		—		404,551		387,712		374,214		370,705		360,614		360,616		360,786		1,555		19
2011	—		—		—		—		505,432		488,681		477,675		473,186		470,593		465,856		2,359		22
2012	—		—		—		—		—		555,079		560,110		556,418		550,656		546,259		8,173		41
2013	—		—		—		—		—		—		588,182		598,549		588,285		588,399		10,793		51
2014	—		—		—		—		—		—		—		710,961		718,422		705,706		22,492		60
2015	—		—		—		—		—		—		—		—		752,486		774,801		56,787		62
2016	—		—		—		—		—		—		—		—		—		817,059		179,583		48
Total																			$	5,306,798



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	185,994	$	282,504	$	301,059	$	309,544	$	314,535	$	318,691	$	323,904	$	324,788	$	325,521	$	326,959
2008	—		248,653		353,632		369,446		380,158		379,494		385,350		386,792		388,068		390,626
2009	—		—		214,062		296,125		311,568		313,052		318,138		318,775		320,701		323,248
2010	—		—		—		248,944		333,807		346,598		356,044		349,611		353,594		356,838
2011	—		—		—		—		307,397		425,522		446,687		451,135		456,707		461,039
2012	—		—		—		—		—		284,916		462,315		514,064		524,678		532,900
2013	—		—		—		—		—		—		316,170		492,780		542,173		564,813
2014	—		—		—		—		—		—		—		374,214		601,225		652,405
2015	—		—		—		—		—		—		—		—		397,084		645,601
2016	—		—		—		—		—		—		—		—		—		447,240
Total																			$	4,701,669
	Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																		3,099
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	608,228

Reinsurance

Casualty

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR
2007	$	370,597	$	350,646	$	343,561	$	333,549	$	313,240	$	326,388	$	318,062	$	330,451	$	330,322	$	329,635	$	9,329
2008	—		289,826		273,071		257,676		246,116		237,149		235,122		240,631		241,337		240,434		7,806
2009	—		—		266,204		260,300		254,200		240,722		241,181		236,095		226,141		227,923		11,383
2010	—		—		—		236,460		236,246		228,052		223,537		213,384		200,288		196,105		18,259
2011	—		—		—		—		239,562		247,663		243,468		241,309		247,739		244,833		27,815
2012	—		—		—		—		—		291,395		295,673		282,343		273,152		281,961		53,802
2013	—		—		—		—		—		—		300,906		259,110		264,625		275,901		72,629
2014	—		—		—		—		—		—		—		311,776		307,849		306,791		119,679
2015	—		—		—		—		—		—		—		—		250,976		224,777		115,419
2016	—		—		—		—		—		—		—		—		—		234,392		173,456
Total																			$	2,562,752



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	6,580	$	34,100	$	82,716	$	151,243	$	192,654	$	234,173	$	249,420	$	265,680	$	279,051	$	295,987
2008	—		9,675		30,151		64,589		102,511		135,642		157,689		175,813		190,494		207,257
2009	—		—		20,535		51,270		81,594		116,544		146,140		171,526		182,913		196,395
2010	—		—		—		16,049		41,463		72,274		101,312		122,709		140,946		155,603
2011	—		—		—		—		15,670		47,500		88,490		123,450		152,163		175,933
2012	—		—		—		—		—		20,749		55,884		97,666		134,122		171,102
2013	—		—		—		—		—		—		28,154		61,692		106,396		143,071
2014	—		—		—		—		—		—		—		20,394		66,656		114,334
2015	—		—		—		—		—		—		—		—		17,259		51,082
2016	—		—		—		—		—		—		—		—		—		23,741
Total																			$	1,534,505
	Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																		257,239
			Reserves for loss and loss adjustment expenses, net of reinsurance																$	1,285,485

Property

(In thousands)



Loss and Loss Expenses Incurred, Net of Reinsurance																					As of December 31, 2016
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR
2007	$	21,645	$	19,073	$	17,366	$	15,093	$	15,459	$	15,258	$	15,191	$	15,211	$	15,210	$	15,265	(28	)
2008	—		23,896		21,055		19,597		19,449		18,879		19,498		18,952		18,968		19,061		66
2009	—		—		26,917		25,118		25,424		24,160		24,071		23,824		23,704		23,246		60
2010	—		—		—		39,792		37,397		36,802		36,489		36,915		36,860		36,956		33
2011	—		—		—		—		66,860		69,441		69,084		70,320		69,494		69,418		152
2012	—		—		—		—		—		73,551		69,515		64,989		65,526		64,170		545
2013	—		—		—		—		—		—		125,131		97,153		100,897		99,513		1,312
2014	—		—		—		—		—		—		—		102,644		86,848		88,592		1,552
2015	—		—		—		—		—		—		—		—		115,942		106,965		5,887
2016	—		—		—		—		—		—		—		—		—		158,664		43,516
Total																			$	681,850



Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
	Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	2,387	$	9,609	$	12,014	$	13,755	$	13,924	$	14,383	$	14,948	$	14,970	$	15,054	$	15,125
2008	—		7,275		13,993		16,620		17,670		18,111		18,591		18,816		18,839		18,940
2009	—		—		8,256		17,216		21,384		22,510		23,159		23,026		23,053		23,009
2010	—		—		—		19,859		29,231		33,656		34,632		35,442		35,764		36,285
2011	—		—		—		—		27,164		51,216		63,560		66,012		67,301		67,940
2012	—		—		—		—		—		11,908		42,504		52,640		58,760		60,917
2013	—		—		—		—		—		—		34,625		69,056		85,182		91,192
2014	—		—		—		—		—		—		—		36,723		61,966		74,695
2015	—		—		—		—		—		—		—		—		51,982		81,565
2016	—		—		—		—		—		—		—		—		—		72,976
Total																			$	542,644
	Reserves for loss and loss adjustment expenses before 2007, net of reinsurance																		557
	Reserves for loss and loss adjustment expenses, net of reinsurance																		$	139,763

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



(In thousands)		December 31, 2016
Undiscounted reserves for loss and loss expenses, net of reinsurance:
	Other liability	$	3,290,085
	Primary workers' compensation	1,727,362
	Excess workers' compensation	1,723,774
	Professional liability	737,349
	Commercial automobile	559,482
	Short-tail lines	608,228
	Other	158,269
	Insurance	8,804,549
	Casualty	1,285,485
	Property	139,763
	Reinsurance	1,425,248
Total undiscounted reserves for loss and loss expenses, net of reinsurance		$	10,229,797



(In thousands)		December 31, 2016
Due from reinsurers on unpaid claims:
	Other liability	$	362,047
	Primary workers' compensation	585,861
	Excess workers' compensation	55,154
	Professional liability	278,460
	Commercial automobile	7,286
	Short-tail lines	210,859
	Other	32,468
	Insurance	1,532,135
	Casualty	65,314
	Property	9,481
	Reinsurance	74,795
Total due from reinsurers on unpaid claims		$	1,606,930



(In thousands)		December 31, 2016
Loss reserve discount:
	Other liability	$	—
	Primary workers' compensation	(6,367		)
	Excess workers' compensation	(582,384		)
	Professional liability	—
	Commercial automobile	—
	Short-tail lines	—
	Other	—
	Insurance	(588,751		)
	Casualty	(50,781		)
	Property	—
	Reinsurance	(50,781		)
Total loss reserve discount		$	(639,532	)
Total gross reserves for loss and loss expenses		$	11,197,195

The following is supplementary information regarding average historical claims duration as of December 31, 2016:



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	7.9	%	14.0	%	18.1	%	16.4	%	13.4	%	8.4	%	6.3	%	4.2	%	3.4	%	3.1	%
Primary workers' compensation	22.8	%	27.0	%	15.2	%	9.2	%	5.6	%	4.8	%	2.7	%	2.0	%	1.8	%	1.2	%
Excess workers' compensation	1.8	%	2.0	%	3.4	%	3.3	%	3.9	%	3.9	%	4.3	%	3.5	%	4.1	%	2.7	%
Professional liability	8.5	%	26.1	%	23.2	%	17.8	%	9.2	%	5.2	%	1.8	%	1.7	%	1.0	%	0.9	%
Commercial automobile	40.1	%	21.6	%	15.5	%	10.6	%	6.5	%	3.3	%	0.9	%	0.5	%	0.2	%	—	%
Short-tail lines	58.5	%	28.5	%	6.0	%	2.2	%	0.6	%	1.0	%	0.9	%	0.5	%	0.4	%	0.4	%

Reinsurance
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years	1		2		3		4		5		6		7		8		9		10
Casualty	7.2	%	12.3	%	15.2	%	15.3	%	12.5	%	10.4	%	6.2	%	5.7	%	5.5	%	5.1	%
Property	37.2	%	35.5	%	15.4	%	6.2	%	2.3	%	1.3	%	1.6	%	—	%	0.5	%	0.5	%

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



(In thousands)	2016			2015			2014
Net reserves at beginning of year	$	9,244,872		$	8,970,641		$	8,683,797
Net provision for losses and loss expenses:
Claims occurring during the current year (1)	3,826,620			3,653,561			3,495,825
Decrease in estimates for claims occurring in prior years (2)	(29,904		)	(46,713		)	(75,764		)
Loss reserve discount accretion (3)	49,084			49,422			70,506
Total	3,845,800			3,656,270			3,490,567
Net payments for claims:
Current year	1,052,452			914,637			898,944
Prior year	2,401,722			2,342,378			2,216,283
Total	3,454,174			3,257,015			3,115,227
Foreign currency translation	(46,233		)	(125,024		)	(88,496		)
Net reserves at end of year	9,590,265			9,244,872			8,970,641
Ceded reserve at end of year	1,606,930			1,424,278			1,399,060
Gross reserves at end of year	$	11,197,195		$	10,669,150		$	10,369,701

_______________________________________


(1)	Claims occurring during the current year are net of loss reserve discounts of $18,929,000, $20,357,000 and $21,306,000 in 2016, 2015, and 2014 , respectively.


(2)	The decrease 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 $59,175,000, $64,971,000 and $116,866,000 in 2016, 2015 and 2014, respectively.


(3)	In 2014, the Company entered into a commutation agreement that resulted in a reduction in prior year workers' compensation reserves of $30 million on an undiscounted basis and $12 million on a discounted basis.

Favorable prior year development (net of additional and return premiums) was $59 million in 2016.

Insurance - Reserves for the Insurance segment developed favorably by $53 million in 2016. The favorable development was primarily related to workers' compensation business, and was partially offset by unfavorable development for medical professional liability business.

For workers' compensation, the favorable development was related to both primary and excess business and to many accident years, including those prior to 2007. During 2016, reported workers' compensation losses continued to be below our expectations at most of our operating units. Loss frequency and severity trends continued to be better than the assumptions underlying our previous reserve estimates. Loss severity trends also benefited from our continued investment in medical case management services and from our preferred provider networks. The long term trend of declining workers' compensation frequency can be attributed to improved workplace safety.

For medical professional liability business, unfavorable development was primarily related to a class of business that has been discontinued. The adverse development for that business stemmed mainly from accident years 2010 through 2015.

Reinsurance - Reserves for the Reinsurance segment developed favorably by $6 million in 2016. The favorable development was primarily related to direct facultative reinsurance business and to accident years 2008 through 2014.

Favorable prior year development (net of additional and return premiums) was $63 million in 2015.

Insurance - Reserves for the Insurance segment developed favorably by $52 million in 2015. The favorable development was primarily related to workers' compensation, other liability business and commercial property, and was partially offset by unfavorable development for commercial automobile liability business and professional indemnity business.

For workers' compensation, the favorable development was related to both primary and excess business and to many accident years, including those prior to 2006. In 2015, reported workers' compensation losses were below our expectations for many of our operating units. In addition, overall loss frequency and severity trends emerged better than the assumptions underlying our previous reserve estimates. The long term trend of declining workers' compensation claim frequency continued in 2015. The improvement is attributable to better workplace safety and to benign medical severity trends as we continue to invest in medical case management services and higher usage of preferred provider networks.

For other liability business, favorable development was concentrated in accident years 2007 through 2013. The favorable development was primarily related to our excess and surplus lines casualty business that has benefited from a persistent improvement in claim frequency trends over the past several years.

For commercial property business, favorable development was attributable to accident years 2012 through 2014 and was driven by favorable frequency and severity trends on property business written in Lloyd's.

For commercial automobile business, adverse development was primarily related to large losses for long-haul trucking business and to accident years 2011 through 2014. The higher loss cost trends for the commercial automobile industry are attributable, in part, to the increase in miles driven as the economy improved and fuel prices declined over the past several years.

For Professional indemnity business in the U.K., adverse development was primarily for accident years 2006 through 2013.

Reinsurance - Reserves for the Reinsurance segment developed favorably by $11 million in 2015. The favorable development was primarily related to direct facultative reinsurance business and to accident years 2005 through 2013. Loss reserves developed favorably for umbrella business and for other liability coverage for contractors.

Favorable prior year development (net of additional and return premiums) was $85 million in 2014.

Insurance - For the Insurance segment, favorable development in 2014 of $69 million was driven principally by other liability business for accident years 2006 through 2010, primarily related to our excess and surplus lines casualty business. Reported losses during these years continued to be below our initial expectations at the time the business was written, largely as a result of persistent improvement in claim frequency trends (i.e., number of reported claims per unit of exposure). As these accident years have matured, the weighting of actuarial methods has shifted from methods based on initial expected losses to methods based on actual reported losses. We believe the favorable claim frequency trends we have seen during this time period are due to changes in the mix of business written and to the general slowdown in the economy. Commercial automobile reported unfavorable development primarily as a result of large losses for long-haul trucking business in 2012 and 2013. The favorable development was also offset by adverse reserve development driven primarily by unexpected large losses from accident years 2009-2012 in the professional indemnity line of business in the United Kingdom.

Reinsurance - For the Reinsurance segment, favorable reserve development in 2014 of $16 million was driven primarily by assumed professional liability excess of loss and umbrella treaty business, as well as direct facultative business. This was partially offset by adverse development on brokerage facultative business caused by completed operations losses associated with construction projects in accident years prior to 2009.

Environmental and Asbestos — To date, known environmental and asbestos claims have not had a material impact on the Company’s operations, because its subsidiaries generally did not insure large industrial companies that are subject to significant environmental or asbestos exposures prior to 1986 when an absolute exclusion was incorporated into standard policy language.

The Company’s net reserves for losses and loss expenses relating to asbestos and environmental claims on policies written before adoption of the absolute exclusion was $31 million at December 31, 2016 and $33 million at December 31, 2015. The estimation of these liabilities is subject to significantly greater than normal variation and uncertainty because it is difficult to make an actuarial estimate of these liabilities due to the absence of a generally accepted actuarial methodology for these exposures and the potential effect of significant unresolved legal matters, including coverage issues, as well as the cost of litigating the legal issues. Additionally, the determination of ultimate damages and the final allocation of such damages to financially responsible parties are highly uncertain.

Discounting — The Company discounts its liabilities for certain workers’ compensation reserves. The amount of workers’ compensation reserves that were discounted was $1.907 million million and $2.308 million at December 31, 2016 and December 31, 2015, respectively. The aggregate net discount for those reserves, after reflecting the effects of ceded reinsurance, was $640 million and $699 million at December 31, 2016 and 2015, respectively. At December 31, 2016, discount rates by year ranged from 2.0% to 6.5%, with a weighted average discount rate of 3.9%.

Substantially all of discounted workers’ compensation reserves (97% of total discounted reserves at December 31, 2016) are excess workers’ compensation reserves. In order to properly match loss expenses with income earned on investment securities supporting the liabilities, reserves for excess workers’ compensation business are discounted using risk-free discount rates determined by reference to the U.S. Treasury yield curve. These rates are determined annually based on the weighted average rate for the period. Once established, no adjustments are made to the discount rate for that period, and any increases or decreases in loss reserves in subsequent years are discounted at the same rate, without regard to when any such adjustments are recognized. The expected loss and loss expense payout patterns subject to discounting are derived from the Company’s loss payout experience.

The Company also discounts reserves for certain other long-duration workers’ compensation reserves (representing approximately 3% of total discounted reserves at December 31, 2016), including reserves for quota share reinsurance and reserves related to losses regarding occupational lung disease. These reserves are discounted at statutory rates permitted by the Department of Insurance of the State of Delaware.