The Company's loss reserving process begins with the collection and analysis of paid and incurred claim data for each of the Company's segments. The segmental data is disaggregated by reserve class and further disaggregated by underwriting year and accident year. Underwriting year or accident year information is used to analyze the Company's business and to estimate reserves for losses and loss expenses. Reserve classes are selected to ensure that the underlying contracts have homogeneous loss development characteristics, while remaining large enough to make the estimation of trends credible. The Company's reserve classes are reviewed on a regular basis and adjusted over time as the Company's business evolves. The paid and incurred claim data, in addition to industry benchmarks, serves as a key input to many of the methods employed by the Company's actuaries. The relative weights assigned to the Company's historical loss data versus industry data vary based on a number of factors including the Company's historical track record and the development profile for the reserve class being evaluated (refer to 'Claim Tail Analysis' and 'Net Incurred and Paid Claims Development Tables By Accident Year' below for further details).

Insurance segment

Reserve class and tail

Property and other

Marine

Aviation

Credit and political risk

Professional lines

Liability

Short

Short/Medium

Medium

Long

Reported lines of business

Property

Marine

Terrorism

Aviation

Credit and political risk

Professional lines

Liability

Accident and health

Discontinued lines - Novae

Reinsurance segment

Reserve class and tail

Property and other

Credit and surety

Professional lines

Motor

Liability

Short

Medium

Long

Reported lines of business

Catastrophe

Property

Credit and surety

Professional lines

Motor

Liability

Engineering

Agriculture

Marine and aviation

Accident and health

Discontinued lines - Novae

Multiple actuarial methods are available to estimate ultimate losses. Each method has its own assumptions and its own advantages and disadvantages, with no single estimation method being better than the others in all situations and no one set of assumption variables being meaningful for all reserve classes. The relative strengths and weaknesses of the particular estimation methods when applied to a particular group of claims can also change over time.

•Expected Loss Ratio Method ("ELR Method"): This method estimates ultimate losses for an accident year or underwriting year by applying an expected loss ratio to the earned or written premium for that year. Generally, expected loss ratios are based on one or more of (a) an analysis of historical loss experience to date, (b) pricing information and (c) industry data, adjusted as appropriate, to reflect changes in rates, loss and exposure trends, and terms and conditions. This method is insensitive to actual incurred losses for the accident year or underwriting year in question and is, therefore, often useful in the early stages of development when very few losses have been incurred. Conversely, the lack of sensitivity to incurred/paid losses for the accident year or underwriting year in question means that this method is usually inappropriate in later stages of an accident year or underwriting year’s development.

•Loss Development Method (also referred to as the "Chain Ladder Method" or "Link Ratio Method"): This method assumes that the losses incurred/paid for each accident year or underwriting year at a particular development stage follow a relatively similar pattern. It assumes that on average, every accident year or underwriting year will display the same percentage of ultimate losses incurred/paid at the same point in time after the inception of that year. The percentages incurred/paid are established for each development stage (e.g. 12 months, 24 months, etc.) after examining averages from historical loss development data and/or external industry benchmark information. Ultimate losses are then estimated by multiplying the actual incurred/paid losses by the reciprocal of the established incurred/paid percentage. The strengths of this method are that it reacts to loss emergence/payments and that it makes full use of historical claim emergence/payment experience. However, this method has weaknesses when the underlying assumption of stable loss development/payment patterns is not valid. This could be the consequence of changes in business mix, claim inflation trends or claim reporting practices and/or the presence of large claims, among other things. Furthermore, this method tends to produce volatile estimates of ultimate losses where there is volatility in the underlying incurred/paid patterns. In

•Bornhuetter-Ferguson Method ("BF Method"): This method can be seen as a combination of the ELR and Loss Development Methods, under which the Loss Development Method is given progressively more weight as an accident year or underwriting year matures. The main advantage of the BF Method is that it provides a more stable estimate of ultimate losses than the Loss Development Method at earlier stages of development, while remaining more responsive to emerging loss development than the ELR Method. In addition, the BF Method allows for the incorporation of external market information through the use of expected loss ratios, whereas the Loss Development Method does not incorporate such information.

As part of the loss reserving process, the Company's actuaries employ the estimation method(s) that they believe will produce the most reliable estimate of ultimate losses, at that particular evaluation date, for each reserve class and accident year or underwriting year combination. Often, this is a blend (i.e. weighted average) of the results of two or more appropriate actuarial methods. These ultimate loss estimates are generally utilized to evaluate the adequacy of ultimate loss estimates for previous accident or underwriting years, established in the prior reporting period. For the initial estimate of the current accident or underwriting year, the available claim data is typically insufficient to produce a reliable estimate of ultimate losses. As a result, initial estimates for an accident or underwriting year are generally based on the ELR Method for longer tailed lines and a BF Method for shorter tailed lines. The initial ELR for each reserve class is established collaboratively by the Company's actuaries, underwriters and management at the start of the year as part of the planning process, taking into consideration prior accident years’ or underwriting years' experience and industry benchmarks, adjusted after considering factors such as loss and exposure trends, rate differences, changes in contract terms and conditions, business mix changes and other known differences between the current year and prior accident or underwriting years. The initial expected loss ratios for a given accident or underwriting year may be modified over time if the underlying assumptions, such as loss development or premium rate changes, differ from the original assumptions.

In earlier years, significant reliance was placed on industry benchmarks in establishing expected loss ratios and selecting loss development patterns. Over time, more reliance has been placed on historical loss experience in establishing these ratios and selecting these patterns where the Company believes the weight of its experience has become sufficiently credible for consideration. The weight given to the Company's experience differs for each of the three claim tail classes (refer to 'Claim Tail Analysis' below for further details). In establishing expected loss ratios for the insurance segment, consideration is given to a number of other factors, including exposure trends, rate adequacy on new and renewal business, ceded reinsurance costs, changes in claims emergence and underwriters’ view of terms and conditions in the market environment. For the reinsurance segment, expected loss ratios are based on a contract-by-contract review, which considers information provided by clients together with estimates provided by underwriters and actuaries about the impact of changes in pricing, terms and conditions and coverage. Market experience of some classes of business as compiled and analyzed by an independent actuarial firm has also been considered, as appropriate.

Short-tail business generally includes exposures for which losses are usually known and paid within a relatively short period of time after the underlying loss event has occurred. Short-tail business includes the underlying exposures in the property and other, marine, and aviation reserve classes in the insurance segment, and the underlying exposures in the property and other reserve class in the reinsurance segment.

The key actuarial assumptions for short-tail business in early accident years were primarily developed with reference to industry benchmarks for expected loss ratios and loss development patterns. As the Company's historical loss experience amassed, it gained credibility and became relevant for consideration in establishing these key actuarial assumptions. As a result, the Company gradually increased the weighting assigned to its historical loss experience in selecting the expected loss ratios and loss development patterns utilized to establish estimates of ultimate losses for an accident year. Due to the relatively short reporting and settlement patterns for short-tail business, more weight is generally placed on experience-based methods and other qualitative considerations in establishing reserves for recent and more mature accident years. The majority of development for an accident year or underwriting year is expected to be recognized in the subsequent one to three years.

For the Company's earliest accident and underwriting years, initial key actuarial expected loss ratio and loss development assumptions were established utilizing industry benchmarks. Due to the longer claim tail, the length of time required to develop credible loss history for use in the reserve process is greater for medium-tail business than for short-tail business.

In contrast to short and medium-tail business, the claim tail for long-tail business is expected to be notably longer, as claims are often reported and ultimately paid or settled years, or even decades, after the related loss events occur. Long-tail business consists primarily of insurance and reinsurance liability reserve classes and reinsurance motor reserve class.

As a general rule, estimates of accident year or underwriting year ultimate losses for long-tail business are notably more uncertain than those for short and medium-tail business. To date, key actuarial assumptions for long-tail business have been derived from a combination of industry benchmarks supplemented with Company historical loss experience. While industry benchmarks that the Company believes reflect the nature and coverage of its business are considered, actual loss experience may differ from the benchmarks based on industry averages. Due to the length of the development tail for this business, reserve estimates for most accident years and underwriting years are predominantly based on the BF Method or ELR Method and the consideration of qualitative factors.

The Company cannot estimate losses from widespread catastrophic events, such as hurricanes and earthquakes, using the traditional actuarial methods described above. The magnitude and complexity of losses associated with 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. As a result, actual losses for these events may ultimately differ materially from current estimates.

Net reserves for losses and loss expenses related to the COVID-19 pandemic represents the Company's best estimate of losses and loss expenses that have been incurred at December 31, 2020. The determination of net reserves for losses and loss expenses is based on the Company's ground-up assessment of coverage from individual contracts and treaties across all lines of business, and includes a review of modeling analyses and market information, where appropriate. In addition, the Company considers information received from clients, brokers and loss adjusters together with global shelter-in-place orders and the outcomes of recent court judgments, including the UK Supreme Court ruling.

The estimate of net reserves for losses and loss expenses related to the COVID-19 pandemic is subject to significant uncertainty. This uncertainty is driven by the inherent difficulty in making assumptions around the impact of the COVID-19 pandemic due to the lack of comparable events, the ongoing nature of the event, and its far-reaching impacts on world-wide economies and the health of the population. These assumptions include:

While the Company believes its estimate of net reserves for losses and loss expenses is adequate for losses and loss expenses that have been incurred at December 31, 2020 based on current facts and circumstances, the Company continues to monitor the appropriateness of these assumptions as new information comes to light and adjustments are made to the estimate of ultimate losses related to the COVID-19 pandemic if there are developments that are different from previous expectations. Adjustments are recorded in the period in which they are identified. Actual losses for this event may ultimately differ materially from the Company's current estimates.

The estimate of net reserves for losses and loss expenses related to catastrophes other than the COVID-19 pandemic represent the Company's best estimate of losses and loss expenses that have been incurred at December 31, 2020.The determination of these net reserves for losses and loss expenses is estimated by management after a catastrophe occurs by completing an in-depth analysis of individual contracts which may potentially have been impacted by the catastrophic event. This in-depth analysis may rely on several sources of information including:

While the Company believes its estimate of net reserves for losses and loss expenses is adequate for losses and loss expenses that have been incurred at December 31, 2020 based on current facts and circumstances, the Company monitors changes in paid and incurred losses in relation to each significant catastrophe in subsequent reporting periods and adjustments are made to estimates of ultimate losses for each event if there are developments that are different from previous expectations. Adjustments are recorded in the period in which they are identified. Actual losses for these events may ultimately differ materially from the Company's current estimates.

The Company's loss reserving process involves the collaboration of its underwriting, claims, actuarial, legal, ceded reinsurance and finance departments, includes various segmental committee meetings and culminates with the approval of a single point best estimate by the Company's Group Reserving Committee, which comprises senior management. In selecting this best estimate, management considers actuarial estimates and applies informed judgment regarding qualitative factors that may not be fully captured in these actuarial estimates. Such factors include, but are not limited to, the timing of the

emergence of claims, volume and complexity of claims, social and judicial trends, potential severity of individual claims and the extent of Company historical loss data versus industry information. While these qualitative factors are considered in arriving at the point estimate, no specific provisions for qualitative factors are established.



Year ended December 31,	2020		2019		2018

Gross reserve for losses and loss expenses, beginning of year	$	12,752,081	$	12,280,769	$	12,997,553
Less reinsurance recoverable on unpaid losses, beginning of year	(3,877,756)		(3,501,669)		(3,159,514)
Net reserve for unpaid losses and loss expenses, beginning of year	8,874,325		8,779,100		9,838,039

Net incurred losses and loss expenses related to:
Current year	3,297,161		3,123,698		3,389,949
Prior years	(15,909)		(78,900)		(199,662)
	3,281,252		3,044,798		3,190,287
Net paid losses and loss expenses related to:
Current year	(571,442)		(598,988)		(724,199)
Prior years	(2,365,959)		(2,371,637)		(2,368,615)
	(2,937,401)		(2,970,625)		(3,092,814)

Foreign exchange and other	211,949		21,052		(1,156,412)

Net reserve for unpaid losses and loss expenses, end of year	9,430,125		8,874,325		8,779,100
Reinsurance recoverable on unpaid losses, end of year	4,496,641		3,877,756		3,501,669
Gross reserve for losses and loss expenses, end of year	$	13,926,766	$	12,752,081	$	12,280,769

The Company writes business with loss experience generally characterized as low frequency and high severity in nature, which can result in volatility in its financial results. During 2020, 2019 and 2018, the Company recognized catastrophe and weather-related losses, net of reinstatement premiums, of $774 million, $336 million and $430 million.

On December 15, 2019, the Company entered into a quota share retrocessional agreement with Harrington Re, a related party, which was deemed to have met the established criteria for retroactive reinsurance accounting. The Company recognized reinsurance recoverable on unpaid losses of $59 million related to this reinsurance agreement. This transaction was conducted at market rates consistent with negotiated arms-length contracts.

On April 16, 2018, the Company entered into a quota share retrocessional agreement with Harrington Re, a related party, which was deemed to have met the established criteria for retroactive reinsurance accounting. The Company recognized reinsurance recoverable on unpaid losses of $108 million related to this reinsurance agreement. This transaction was conducted at market rates consistent with negotiated arms-length contracts.

AXIS Managing Agency Ltd., the managing agent of Syndicate 2007 entered into an agreement for the Reinsurance to Close ("RITC") of the 2015 and prior years of account of Syndicate 2007, with an effective date of January 1, 2018. This agreement was accounted for as a novation reinsurance contract. At December 31, 2018, foreign exchange and other included a reduction in reserves for losses and loss expenses of $819 million related to this transaction.

At December 31, 2020, net reserve 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 the COVID-19 pandemic, Hurricanes Laura, Sally, Zeta and Delta, the Midwest derecho and wildfires across the West Coast of the United States in 2020, Japanese Typhoons Hagibis, Faxai and Tapah, Hurricane Dorian and the Australia Wildfires in 2019 and Hurricanes Michael and Florence, California Wildfires and Typhoon Jebi in 2018. As a result, actual losses for these events may ultimately differ materially from current estimates.


	Favorable (Adverse)		Favorable (Adverse)		Favorable (Adverse)
Years ended December 31,	2020		2019		2018

Property and other	$	46,791	$	11,042	$	64,781
Marine	16,780		33,260		17,913
Aviation	6,416		3,741		(2,938)
Credit and political risk	(745)		18,810		3,609
Professional lines	(35,661)		11,721		31,687
Liability	(24,644)		(25,272)		(22,246)
Total	$	8,937	$	53,302	$	92,806

•$36 million of net adverse prior year reserve development on professional lines business primarily due to reserve strengthening within the European professional indemnity and financial institutions books of business and the commercial management solutions book of business mainly related to the 2018 and 2019 accident years and an increase in the loss estimate attributable to a specific large claim related to the 2009 accident year.

•$25 million of net adverse prior year reserve development on liability business primarily due to reserve strengthening within the U.S. excess casualty and U.S. primary casualty books of business mainly driven by the higher frequency and severity of auto claims and the higher frequency of general liability claims mainly related to the 2015 and 2017 accident years.

•$30 million of net adverse prior year reserve development on liability business due to reserve strengthening within the U.S. casualty, the U.S. multiline/regional and the European books of business mainly related to the 2016 to 2019 accident years and an increase in the loss estimate attributable to a specific large claim related to the 2009 accident year.

•$6 million of net adverse prior year reserve development on property and other business primarily due to an increase in the loss estimate attributable to a specific large claim within the marine and aviation line of business related to the 2019 accident year, reserve strengthening within the engineering line of business mainly related to the 2016 to 2018 accident years, partially offset by net favorable prior year reserve development within the property line of business due to better than expected loss emergence attributable to the 2019 catastrophe events.

The following tables present net incurred and paid claims development by accident year, total incurred-but-not-reported liabilities plus expected development on reported claims, cumulative reported claims frequency and average annual percentage payout of incurred claims by age for each reserve class. The loss development tables are presented on an accident year basis for the insurance and reinsurance segments. The Company does not discount reserves for losses and loss expenses.

Non-U.S. dollar denominated loss data is converted to U.S. dollar at the rates of exchange in effect at the balance sheet date for material underlying currencies. Fluctuations in foreign currency exchange rates may cause material shifts in loss development. Reserves for losses and loss expenses disclosed in the consolidated balance sheets are also remeasured using the rates of exchange in effect at the balance sheet date.

There are many considerations in establishing net reserves for losses and loss expenses and an attempt to evaluate net reserves for losses and loss expenses using solely the data presented in these tables could be misleading. The Company cautions against mechanical application of standard actuarial methodologies to project ultimate losses using data presented in this disclosure.

The reporting of cumulative claims frequency for the reserve classes within the insurance segment has been measured by counting the number of unique claim references including claim references assigned to nil and nominal case reserves. Claim references are grouped by claimant by loss event for each reserve class. For certain insurance facilities and business produced by managing general agents where underlying data is reported to the Company in an aggregated format, the information necessary to provide cumulative claims frequency is not available therefore reporting of claims frequency is deemed to be impracticable.

The property line of business provides physical loss or damage, business interruption and machinery breakdown cover for virtually all types of property, including commercial buildings, residential premises, construction projects and onshore energy installations. This line of business includes primary and excess risks, some of which are catastrophe-exposed.

The accident and health line of business includes accidental death, travel insurance and specialty health products for employer and affinity groups. A large increase in reported claims related to the accident and health line of business was observed from 2012. In addition, an increase in limited benefits medical business written in 2017 resulted in a significant increase in reported claims observed in that year.


Insurance property and other
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims		Cumulative number of reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	347,569	$	325,274	$	304,702	$	284,201	$	281,155	$	279,964	$	280,395	$	278,688	$	277,792	$	277,515	$	(231)	6,367
2012			393,170		403,254		385,068		364,667		360,525		354,801		353,971		343,934		343,619		(21)		29,942
2013					310,601		300,682		273,775		269,831		269,490		279,922		276,229		275,712		1,135		53,204
2014							362,684		357,885		347,227		331,142		330,011		328,404		323,736		4,334		62,371
2015									280,489		273,606		262,733		258,190		255,319		257,419		1,763		48,469
2016											355,771		384,230		375,260		362,103		356,016		3,427		93,792
2017													911,274		838,640		824,039		813,005		(5,501)		698,289
2018															742,601		775,861		754,741		10,217		731,142
2019																	454,386		448,467		11,186		659,908
2020																			733,794		308,515		524,539
																	Total		$	4,584,024


Insurance property and other
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	83,511	$	191,823	$	248,346	$	270,636	$	269,626	$	269,423	$	270,104	$	270,546	$	270,516	$	270,507
2012			77,794		214,771		279,588		302,638		310,171		315,391		315,466		317,574		317,803
2013					76,179		199,930		238,808		249,852		260,895		263,930		265,749		269,598
2014							133,451		261,155		308,010		315,212		319,414		320,597		317,306
2015									100,483		204,862		229,901		244,205		244,916		251,758
2016											126,232		294,777		335,173		343,839		345,188
2017													256,136		634,649		751,394		781,152
2018															292,977		592,507		693,287
2019																	197,703		330,268
2020																			219,395
Total																			3,796,262

All outstanding liabilities before 2011, net of reinsurance																			7,141

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	794,903

This reserve class includes the marine line of business which provides cover for traditional marine classes, including offshore energy, renewable offshore energy, cargo, liability, recreational marine, fine art, specie, and hull and war. Offshore energy coverage includes physical damage, business interruption, operators extra expense and liability coverage for all aspects of offshore upstream energy, from exploration and construction through the operation and distribution phases. The complex nature of claims arising under marine policies tends to result in reporting and payment patterns that are longer than those of the property and other reserve class. Exposure to natural perils such as windstorm and earthquake can result in volatility.


Insurance marine
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims		Cumulative number of reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	90,960	$	79,215	$	73,257	$	66,351	$	66,320	$	66,560	$	68,860	$	69,555	$	68,861	$	67,054	$	(1,250)	3,830
2012			89,889		83,431		69,484		71,663		72,708		75,326		73,581		63,067		66,026		7,249		4,135
2013					80,641		102,110		97,660		98,759		83,984		83,594		82,622		81,774		846		2,354
2014							59,786		44,936		49,238		44,979		46,705		48,470		42,221		(2,231)		2,166
2015									160,793		142,383		138,704		131,483		118,861		123,836		7,507		2,231
2016											86,464		78,953		76,805		71,694		70,491		3,300		2,857
2017													207,378		172,077		160,919		158,812		13,932		4,005
2018															186,550		194,257		183,415		34,579		4,370
2019																	170,489		168,318		47,064		4,475
2020																			170,763		107,624		3,558
																	Total		$	1,132,710


Insurance marine
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	26,467	$	44,483	$	55,329	$	58,465	$	60,340	$	61,063	$	65,512	$	67,560	$	68,051	$	68,022
2012			10,752		38,820		45,197		50,028		50,865		53,309		55,387		56,524		56,689
2013					19,577		44,931		56,126		64,497		67,196		78,245		78,396		79,683
2014							6,365		15,418		27,529		27,462		36,681		41,788		42,945
2015									21,467		55,425		109,431		112,390		113,818		115,391
2016											12,498		31,890		57,552		63,829		64,645
2017													14,634		68,709		92,848		117,253
2018															27,218		87,150		117,629
2019																	36,354		76,175
2020																			38,433
Total																			776,865

All outstanding liabilities before 2011, net of reinsurance																			6,786

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	362,631

This reserve class includes the aviation line of business which provides cover for hull and liability, and specific war cover primarily for passenger airlines but also for cargo operations, general aviation operations, airports, aviation authorities, security firms and product manufacturers. The claims reporting pattern varies by insurance coverage provided. Losses arising from war or terrorism and damage to hulls of aircraft are generally reported quickly compared with liability claims which involve passengers and third parties and generally exhibit longer reporting and payment patterns. To date, the claims reported to the Company have predominantly related to damage to hulls, therefore, reporting and payment patterns have typically exhibited a relatively short tail.


Insurance aviation
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims		Cumulative number of reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	17,727	$	15,407	$	12,799	$	9,576	$	8,447	$	7,301	$	7,259	$	7,217	$	6,976	$	6,582	$	56	4,203
2012			12,808		10,705		10,832		8,752		7,804		7,747		7,635		7,428		7,346		59		2,859
2013					15,657		16,349		15,234		15,278		15,615		15,502		16,793		16,700		149		3,020
2014							20,438		23,050		24,373		21,818		21,876		19,118		17,370		58		3,534
2015									29,796		28,534		29,877		29,613		27,557		28,038		86		4,155
2016											29,194		33,553		33,728		31,796		32,525		812		4,091
2017													56,102		62,643		67,644		70,029		(1,046)		4,347
2018															58,340		64,250		62,696		3,262		4,405
2019																	44,653		42,786		5,387		2,785
2020																			37,092		22,625		1,297
																	Total		$	321,164


Insurance aviation
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	639	$	2,834	$	4,527	$	5,047	$	5,584	$	5,836	$	6,057	$	6,199	$	6,244	$	6,252
2012			958		2,872		4,166		5,966		6,863		7,087		7,201		7,136		7,134
2013					4,402		7,339		9,767		11,474		13,585		14,195		14,516		15,976
2014							3,990		8,035		11,711		13,871		14,509		14,874		15,044
2015									8,092		16,182		20,990		23,253		24,716		26,026
2016											10,424		19,310		26,311		27,879		29,117
2017													21,458		40,811		51,512		59,895
2018															21,544		40,713		48,088
2019																	18,465		29,808
2020																			6,311
Total																			243,651

All outstanding liabilities before 2011, net of reinsurance																			6,511

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	84,024

This reserve class includes the credit and political risk line of business which provides credit and political risk insurance products for banks, commodity traders, corporations and multilateral and export credit agencies. Cover is provided for a range of risks including sovereign default, credit default, political violence, currency inconvertibility and non-transfer, expropriation, aircraft non-repossession and contract frustration due to political events.

The credit insurance coverage is primarily for lenders seeking to mitigate the risk of non-payment from their borrowers. In order to claim compensation under a credit insurance contract, the insured (most often a bank) cannot assign, without the Company's prior agreement, the insured contract (most often a loan) to any third party and is normally obliged to hold a material portion of insured asset on their books, unhedged and uninsured. Claims for this business tend to be characterized by their severity risk, as opposed to their frequency risk. Claim reporting and payment patterns are anticipated to be volatile. Under the notification provisions of credit insurance policies issued by the Company, it anticipates being advised of an insured event within a relatively short time period. Consequently, the Company generally estimates ultimate losses based on a contract-by-contract analysis which considers the contracts’ terms, the facts and circumstances of underlying loss events and qualitative input from claims managers.


Insurance credit and political risk
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims		Cumulative number of reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	58,154	$	48,665	$	47,706	$	48,361	$	48,333	$	45,036	$	33,609	$	27,904	$	27,904	$	27,754	$	118	4
2012			32,602		15,672		12,435		12,447		10,323		47		199		199		199		155		4
2013					26,439		25,684		9,759		9,880		14,942		14,067		12,377		12,739		4,432		2
2014							38,825		70,713		67,109		68,324		69,589		71,275		70,747		2,123		6
2015									30,329		30,368		27,524		26,012		25,930		24,851		1,542		2
2016											47,736		43,746		41,256		41,826		25,612		2,061		1
2017													48,086		33,524		26,552		18,744		8,163		3
2018															45,047		34,116		32,740		12,279		1
2019																	51,638		80,181		23,821		14
2020																			60,501		48,752		24
																	Total		$	354,068


Insurance credit and political risk
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	32,788	$	37,205	$	27,636	$	27,636	$	27,636	$	27,636	$	27,636	$	27,636	$	27,636	$	27,636
2012			—		—		—		—		40		42		44		44		44
2013					745		2,235		3,726		5,216		11,769		13,828		13,828		13,828
2014							1,924		39,952		61,108		57,858		57,858		64,051		70,224
2015									—		23,309		23,309		23,309		23,309		23,309
2016											—		23,551		23,551		23,551		23,551
2017													396		4,305		9,615		12,103
2018															5,751		14,095		16,152
2019																	16,260		46,797
2020																			9,823
Total																			243,467

All outstanding liabilities before 2011, net of reinsurance																			(3,957)

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	106,644

This reserve class includes the professional lines line of business which provides directors’ and officers’ liability, errors and omissions liability, employment practices liability, fiduciary liability, crime, professional indemnity, cyber and privacy insurance, medical malpractice and other financial insurance related covers for commercial enterprises, financial institutions, not-for-profit organizations and other professional service providers. This reserve class also includes discontinued lines - Novae specifically the financial institutions and professional indemnity lines of business that Novae exited or placed into run-off in the first quarter of 2017. This business is predominantly written on a claims-made basis. Typically, this reserve class is anticipated to exhibit medium to long tail claim reporting and payment patterns.

With respect to key actuarial assumptions, the Company relies on its loss experience when establishing expected loss ratios and selecting loss development patterns. Loss reporting patterns for professional lines business tend to be volatile, causing instability in actuarial indications based on incurred loss data until an accident year or underwriting year matures. Consequently, initial reserves for losses and loss expenses for an accident year or underwriting year are generally based on an ELR Method and the consideration of relevant qualitative factors. As accident years and underwriting years mature, the Company increasingly gives more weight to methods that reflect its experience until its selections are based almost exclusively on experience-based methods. The Company evaluates the appropriateness of the transition to experience-based methods at the reserve class level, commencing this transition when it believes that its incurred loss development is sufficient to produce meaningful actuarial indications. The rate at which the Company transitions fully to sole reliance on experience-based methods can vary by reserve class and by year, depending on its assessment of the stability and relevance of such indications. For some professional lines in the insurance segment, the Company also relies on the evaluation of the open claim inventory in addition to the commonly employed actuarial methods when establishing reserves.


Insurance professional lines
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims		Cumulative number of reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	314,835	$	316,639	$	335,265	$	327,971	$	331,903	$	344,964	$	353,336	$	353,862	$	351,191	$	345,862	$	22,156	7,239
2012			330,010		377,296		378,793		377,895		365,291		367,369		355,893		353,860		335,671		22,818		8,334
2013					385,460		399,136		400,434		367,072		356,643		358,938		336,933		340,078		41,955		9,457
2014							414,720		413,840		423,998		394,748		374,397		356,930		350,182		63,136		9,825
2015									379,378		379,036		384,477		359,619		346,488		329,502		54,530		10,493
2016											351,055		353,679		360,116		361,799		372,198		76,612		11,836
2017													396,543		403,257		439,134		435,827		154,318		13,670
2018															365,577		378,822		432,338		196,909		16,453
2019																	407,043		429,729		248,218		16,369
2020																			439,054		384,984		9,284
																	Total		$	3,810,441


Insurance professional lines
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	7,464	$	33,058	$	74,932	$	109,183	$	166,417	$	239,092	$	284,246	$	295,434	$	303,147	$	318,439
2012			7,830		41,586		100,608		185,091		231,960		255,108		274,615		282,970		299,719
2013					17,732		73,347		130,341		176,846		214,481		244,566		265,346		278,086
2014							23,616		71,224		131,018		193,659		225,591		244,832		254,655
2015									20,376		67,994		138,369		170,331		204,480		243,519
2016											15,924		71,316		147,958		193,151		235,346
2017													21,039		72,501		140,047		207,157
2018															21,346		83,623		156,052
2019																	28,265		99,594
2020																			26,489
Total																			2,119,056

All outstanding liabilities before 2011, net of reinsurance																			94,767

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	1,786,152

This reserve class includes the liability line of business which primarily targets primary and low to mid-level excess and umbrella commercial liability risks in the U.S. wholesale markets in addition to primary and excess of loss employers, public and products liability business predominately in the U.K. This reserve class also includes discontinued lines - Novae specifically the international liability line of business that Novae exited or placed into run-off in the fourth quarter of 2016. Target industry sectors include construction, manufacturing, transportation and trucking and other services. The delay between the writing of a contract, notification and subsequent settlement of a claim in respect of that contract results in claim reporting and payment patterns that are typically long-tail in nature. A consequence of the claim development tail is that this line of business is particularly exposed, among a number of uncertainties, to the potential for unanticipated levels of claim inflation relative to that assumed when the contracts were written. Factors influencing claim inflation on this class can include, but are not limited to, underlying economic and medical inflation, judicial inflation, mass tort and changing social trends.


Insurance liability
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims		Cumulative number of reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	72,584	$	75,329	$	83,925	$	87,771	$	85,792	$	84,079	$	82,313	$	82,658	$	85,037	$	85,085	$	12,780	3,691
2012			70,883		71,711		74,136		71,475		68,659		75,698		72,728		67,239		64,543		14,803		3,312
2013					93,238		95,315		95,181		88,248		93,688		95,989		91,949		89,908		11,899		3,693
2014							107,161		124,368		129,828		130,688		132,034		131,490		132,596		18,701		5,087
2015									128,438		127,423		137,718		165,202		182,959		188,296		34,876		6,351
2016											124,331		130,249		129,069		127,691		120,442		36,430		7,262
2017													167,648		167,673		183,746		200,362		47,636		8,542
2018															169,557		167,564		190,741		78,563		8,255
2019																	192,320		193,686		109,765		7,119
2020																			225,025		204,825		3,977
																	Total		$	1,490,684


Insurance liability
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	2,761	$	10,540	$	20,190	$	38,377	$	46,074	$	54,996	$	60,261	$	62,151	$	67,114	$	72,023
2012			1,631		5,515		15,412		30,146		37,140		42,741		46,541		48,035		48,317
2013					2,364		23,287		33,326		42,056		60,011		66,970		71,989		73,320
2014							1,419		18,665		49,861		71,609		84,389		93,589		103,063
2015									5,440		22,441		39,718		92,753		120,357		141,062
2016											6,333		23,326		36,404		56,497		66,437
2017													5,481		29,687		59,432		116,232
2018															9,554		35,056		72,604
2019																	7,900		40,047
2020																			8,156
Total																			741,261

All outstanding liabilities before 2011, net of reinsurance																			53,506

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	802,929

The presentation of net incurred and paid claims development tables by accident year for the reinsurance segment is challenging due to the need to allocate loss information related to proportional treaties to the appropriate accident years. Information related to proportional treaty reinsurance contracts is generally submitted to the Company using quarterly bordereau reporting by underwriting year, with a supplemental listing of large losses. Large losses can be allocated to the corresponding accident years accurately. The remaining losses can generally only be allocated to accident years based on estimated premiums earned and loss reporting patterns. To the extent management’s assumptions and allocation procedures differ from the actual loss development patterns, the actual loss development may differ materially from the net incurred and paid claims development presented in the tables below.

The catastrophe line of business provides protection for most catastrophic losses that are covered in the underlying insurance policies written by the Company's cedants. The underlying policies principally cover property-related exposures but other exposures including workers compensation and personal accident are also covered. The principal perils covered by policies in this portfolio include hurricane and windstorm, earthquake, flood, tornado, hail and fire. In some instances, terrorism may be a covered peril or the only peril. This business is written on a proportional and an excess of loss basis.

The property line of business provides protection for property damage and related losses resulting from natural and man-made perils that are covered in underlying personal and commercial lines insurance policies written by the Company's cedants. The predominant exposure is to property damage, but other risks, including business interruption and other non-property losses, may also be covered when arising from a covered peril. The most significant perils covered by policies in this portfolio include windstorm, tornado and earthquake, but other perils such as freezes, riots, floods, industrial explosions, fires, hail and a number of other loss events are also included. This business is written on a proportional and excess of loss basis.

The agriculture line of business provides protection for risks associated with the production of food and fiber on a global basis for primary insurance companies writing multi-peril crop insurance, crop hail, and named peril covers, as well as custom risk transfer mechanisms for agricultural dependent industries with exposures to crop yield and/or price deviations. This business is written on a proportional and aggregate stop loss reinsurance basis.

The engineering line of business provides protection for all types of construction risks and risks associated with erection, testing and commissioning of machinery and plants during the construction stage. This line of business also includes coverage for losses arising from operational failures of machinery, plant and equipment, and electronic equipment as well as business interruption. The Company decided to exit this line of business in 2020.

The marine and aviation line of business includes specialty marine classes such as cargo, hull, pleasure craft, marine liability, inland marine and offshore energy. The principal perils covered by policies in this portfolio include physical loss, damage and/or liability arising from natural perils of the seas or land, man-made events including fire and explosion, stranding/sinking/salvage, pollution, shipowners and maritime employers liability. This business is written on a non-proportional and proportional basis. Aviation provides cover for airline, aerospace and general aviation exposures. This business is written on a proportional and non-proportional basis.


Reinsurance property and other
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	1,147,558	$	1,156,022	$	1,156,008	$	1,113,395	$	1,096,469	$	1,070,969	$	1,069,295	$	1,070,875	$	1,072,109	$	1,068,938	$	4,016
2012			558,114		526,700		511,157		480,467		464,567		459,625		461,000		457,777		457,372		747
2013					583,687		567,292		536,423		516,164		510,134		509,582		506,213		505,548		738
2014							544,212		565,279		539,285		526,767		524,785		524,099		521,230		39,729
2015									481,328		470,515		465,427		459,819		455,873		461,382		6,756
2016											623,624		644,393		630,447		626,868		628,910		2,351
2017													1,101,428		1,080,866		1,098,312		1,106,201		47,451
2018															889,102		1,020,689		1,025,683		68,161
2019																	966,716		977,194		183,064
2020																			855,632		442,418
																	Total		$	7,608,090


Reinsurance property and other
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	261,198	$	605,668	$	817,211	$	919,965	$	950,247	$	1,024,187	$	1,039,375	$	1,042,203	$	1,048,430	$	1,052,937
2012			123,594		296,496		369,726		392,448		407,161		416,897		418,995		431,573		437,895
2013					107,883		328,273		446,221		477,155		487,161		488,626		489,337		494,554
2014							102,394		355,383		438,269		456,267		462,510		467,589		469,836
2015									71,438		268,037		372,981		405,736		418,506		429,278
2016											128,439		381,965		527,359		570,973		592,463
2017													251,905		720,708		860,241		929,367
2018															196,512		654,299		798,684
2019																	161,854		593,715
2020																			184,340
Total																			5,983,069

All outstanding liabilities before 2011, net of reinsurance																			14,996

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	1,640,017

This reserve class includes the credit and surety line of business which provides reinsurance of trade credit insurance products and includes proportional and excess of loss structures. The underlying insurance indemnifies sellers of goods and services in the event of a payment default by the buyer of those goods and services. Surety reinsurance provides protection for losses arising from a broad array of surety bonds issued by insurers to satisfy regulatory demands or contract obligations in a variety of jurisdictions around the world. The Company also provides mortgage reinsurance to mortgage guaranty insurers and U.S. government sponsored entities for losses related to credit risk transfer into the private sector.

Initial and most recent underwriting year loss projections are generally based on the ELR Method, with consideration given to qualitative factors. Given that there is a quicker and more stable reporting pattern for trade credit and mortgage business, the Company generally commences the transition to experience-based methods sooner for these lines of business than for surety business.


Reinsurance credit and surety
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	124,676	$	113,314	$	111,684	$	119,067	$	117,020	$	108,220	$	106,414	$	105,776	$	102,612	$	100,503	$	1,102
2012			164,496		154,131		156,952		153,928		145,254		136,944		133,199		130,049		127,775		2,141
2013					168,742		158,105		149,059		145,059		140,569		128,951		128,982		131,791		2,600
2014							139,551		140,462		147,688		143,931		132,014		130,638		126,854		3,602
2015									164,357		172,064		166,901		162,359		142,908		143,946		4,697
2016											145,370		145,838		153,816		127,556		119,640		3,335
2017													142,334		137,372		131,559		122,789		4,399
2018															114,691		125,256		120,639		30,189
2019																	77,203		72,559		17,807
2020																			77,143		39,026
																	Total		$	1,143,639


Reinsurance credit and surety
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	22,714	$	56,811	$	75,122	$	83,199	$	87,860	$	90,181	$	92,557	$	94,208	$	95,042	$	95,734
2012			50,749		88,745		103,866		109,765		113,340		115,187		116,559		118,514		118,948
2013					32,786		79,432		94,952		101,765		109,528		111,532		116,501		118,730
2014							35,910		63,361		89,356		98,712		106,341		110,768		111,316
2015									33,105		84,626		103,810		121,482		123,365		127,130
2016											42,410		75,646		95,624		105,444		106,658
2017													37,531		76,621		94,020		106,016
2018															39,333		71,157		76,834
2019																	19,535		33,521
2020																			25,366
Total																			920,253

All outstanding liabilities before 2011, net of reinsurance																			20,223

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	243,609

This reserve class includes the professional line of business which provides protection for directors' and officers' liability, employment practices liability, medical malpractice, professional indemnity, environmental liability, cyber, and miscellaneous errors and omissions insurance risks. The underlying business is predominantly written on a claims-made basis. This business is written on a proportional and excess of loss basis. Typically, this reserve class is anticipated to exhibit medium to long-tail claim reporting and payment patterns.

With respect to key actuarial assumptions, the Company relies on its loss experience when establishing expected loss ratios and selecting loss development patterns. Loss reporting patterns for professional lines business tend to be volatile, causing instability in actuarial indications based on incurred loss data until an underwriting year matures. Consequently, initial reserves for losses and loss expenses for an underwriting year are generally based on the ELR Method and the consideration of relevant qualitative factors. As underwriting years mature, the Company increasingly gives more weight to methods that reflect its experience until its selections are based almost exclusively on experience-based methods. The Company evaluates the appropriateness of the transition to experience-based methods at the reserve class level, commencing this transition when it believes that its incurred loss development is sufficient to produce meaningful actuarial indications. The rate at which the Company transitions fully to sole reliance on experience-based methods can vary by reserve class and by year, depending on its assessment of the stability and relevance of such indications.


Reinsurance professional lines
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	202,330	$	202,548	$	203,632	$	212,362	$	209,993	$	209,133	$	201,175	$	178,046	$	167,553	$	163,620	$	8,396
2012			210,543		217,148		222,578		224,912		223,661		213,805		215,159		207,936		204,530		10,839
2013					210,173		215,431		216,716		215,064		214,668		207,425		183,035		170,614		17,670
2014							220,070		220,132		220,120		220,167		234,567		231,153		230,034		21,710
2015									212,683		213,076		215,362		226,092		233,056		230,331		37,004
2016											195,753		196,922		200,808		229,187		257,160		55,800
2017													156,074		157,025		163,474		180,501		64,159
2018															148,348		151,299		158,552		86,571
2019																	141,702		142,176		101,309
2020																			141,457		123,152
																	Total		$	1,878,975


Reinsurance professional lines
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	1,510	$	11,836	$	30,342	$	57,404	$	85,065	$	103,322	$	120,088	$	130,411	$	136,934	$	138,436
2012			780		10,453		29,747		53,827		86,240		107,641		132,392		146,517		156,191
2013					1,069		12,132		30,676		65,218		81,967		105,398		123,927		129,296
2014							2,020		13,089		48,957		74,799		109,581		147,649		159,457
2015									3,134		13,507		41,600		79,330		112,228		132,417
2016											1,786		20,646		52,820		95,727		125,847
2017													2,815		15,082		40,082		63,183
2018															272		2,702		31,594
2019																	377		13,843
2020																			3,824
Total																			954,088

All outstanding liabilities before 2011, net of reinsurance																			65,680

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	990,567

This reserve class includes the motor line of business which provides protection to insurers for motor liability and motor property damage losses arising from any one occurrence. A loss occurrence can involve one or many claimants where the ceding insurer aggregates the claims from the occurrence. This reserve class also includes discontinued lines - Novae specifically the motor reinsurance line of business that Novae exited or placed into run-off in the first quarter of 2017. The Company offers traditional proportional and non-proportional reinsurance as well as structured solutions predominantly relating to European exposures.

The business written on a proportional basis has expanded significantly since 2010 and now represents the majority of the premium in this line of business. Most of the premium relates to a relatively small number of large United Kingdom ("U.K.") quota share reinsurance treaty contracts. The motor proportional class generally has a significantly shorter reported and payment pattern, relative to the motor non-proportional class.

The motor non-proportional business consists of standard excess of loss contracts written for cedants in several European countries with most of the premium related to two major markets, U.K. and France. Since 2009/2010, an increasing number of large bodily injury settlements in the U.K. market were settled using indexed annuities (Periodical Payment Orders "PPOs"). This led to a materially longer development tail on the older accident years for the U.K. non-proportional motor book. This also resulted in the inclusion of capitalization clauses on a number of U.K. motor treaties which allow reinsurers to settle claims arising under PPOs with a lump sum payment, to help mitigate the lengthening of the development tail on more recent accident years.

In 2017, the U.K. Ministry of Justice announced a decrease in the discount rate to be used to calculate lump sum awards in U.K. bodily injury cases, known as the Ogden Rate. Effective March 20, 2017, the Ogden rate changed from plus 2.5% to minus 0.75%. This resulted in a trend toward a lower number of claims settlements using PPOs and an increase in projected ultimate losses, particularly related to recent accident years.


Reinsurance motor
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	164,847	$	169,341	$	173,561	$	179,943	$	176,048	$	166,869	$	155,648	$	150,105	$	142,017	$	139,182	$	17,768
2012			188,256		179,151		166,747		158,734		153,524		143,492		140,251		131,573		131,937		13,920
2013					172,316		171,275		158,838		148,804		145,148		141,827		132,624		129,238		12,486
2014							192,457		196,133		191,121		187,883		183,197		179,646		175,871		6,713
2015									233,605		231,712		235,796		237,299		225,413		223,532		11,590
2016											257,429		279,115		281,659		270,554		261,473		11,999
2017													379,810		396,370		377,292		378,976		37,506
2018															375,513		378,515		391,410		55,538
2019																	354,221		354,568		79,778
2020																			221,276		152,472
																	Total		$	2,407,463


Reinsurance motor
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	24,346	$	49,721	$	65,351	$	76,441	$	83,615	$	89,952	$	94,893	$	95,946	$	98,020	$	100,394
2012			29,851		55,800		71,305		81,695		88,535		92,812		95,269		96,508		98,316
2013					34,780		56,692		71,790		82,510		88,589		94,498		97,715		100,213
2014							44,432		78,589		99,642		108,374		119,252		129,566		139,456
2015									59,120		98,431		120,135		138,317		155,110		169,838
2016											62,171		110,605		136,449		155,493		175,311
2017													73,759		141,599		174,770		209,888
2018															85,701		150,276		200,801
2019																	91,189		159,461
2020																			25,631
Total																			1,379,309

All outstanding liabilities before 2011, net of reinsurance																			233,087

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	1,261,241

This reserve class includes the liability line of business which provides protection to insurers of admitted casualty business, excess and surplus lines casualty business and specialty casualty programs. The primary focus of the underlying business is general liability, workers' compensation, auto liability and excess casualty. This reserve class includes discontinued lines - Novae specifically the general liability reinsurance line of business that Novae exited or placed into run-off in the first quarter of 2017.

Claim reporting and payment patterns are typically long-tail in nature and, therefore, subject to increased uncertainty surrounding future loss development. In particular, claims can be subject to inflation from a number of sources including, but not limited to, economic and medical inflation, judicial inflation mass tort and changing social trends.


Reinsurance liability
	Incurred claims and allocated claim adjustment expenses, net of reinsurance																				At December 31, 2020
	For the years ended December 31,																				Total of incurred-but-not-reported liabilities plus expected development on reported claims
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	174,639	$	174,227	$	175,605	$	193,629	$	200,328	$	197,061	$	196,289	$	194,372	$	191,594	$	193,320	$	6,656
2012			168,766		164,844		169,091		173,932		175,105		172,431		165,296		159,163		161,267		10,642
2013					173,637		177,377		184,048		186,062		185,681		178,529		157,813		156,342		16,314
2014							201,352		204,684		206,463		202,487		201,313		199,173		189,296		28,929
2015									216,431		216,838		217,784		217,535		215,250		215,178		48,999
2016											242,579		248,194		253,506		256,767		267,235		73,124
2017													278,204		273,664		281,677		290,621		95,966
2018															267,162		272,102		277,824		127,342
2019																	265,317		275,090		186,427
2020																			283,901		239,574
																	Total		$	2,310,074


Reinsurance liability
	Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance
	For the years ended December 31,
Accident year	2011 unaudited		2012 unaudited		2013 unaudited		2014 unaudited		2015 unaudited		2016 unaudited		2017 unaudited		2018 unaudited		2019 unaudited		2020
2011	$	5,202	$	21,305	$	40,027	$	70,339	$	92,760	$	112,649	$	123,781	$	136,200	$	142,173	$	150,790
2012			3,545		12,812		28,426		58,881		78,405		101,391		115,874		126,298		134,789
2013					5,977		22,262		52,364		69,100		88,334		102,678		113,217		123,774
2014							7,112		28,700		48,503		70,400		89,760		110,511		131,002
2015									7,274		27,476		54,640		81,010		109,349		131,327
2016											11,886		37,831		69,903		112,434		143,917
2017													12,448		42,218		78,830		121,535
2018															19,369		50,223		85,671
2019																	19,334		45,511
2020																			16,948
Total																			1,085,264

All outstanding liabilities before 2011, net of reinsurance																			95,411

Liabilities for claims and claim adjustment expenses, net of reinsurance																			$	1,320,221


Reconciliation of the disclosure of incurred and paid claims development to the liability for unpaid claims and claim adjustment expenses

	At December 31, 2020
	Net outstanding liabilities		Reinsurance recoverable on unpaid claims		Gross outstanding liabilities

Insurance segment
Property and other	$	794,903	$	508,225	$	1,303,128
Marine	362,631		162,396		525,027
Aviation	84,024		64,252		148,276
Credit and political risk	106,644		51,667		158,311
Professional lines	1,786,152		1,227,183		3,013,335
Liability	802,929		1,182,644		1,985,573
Total insurance segment	3,937,283		3,196,367		7,133,650

Reinsurance segment
Property and other	1,640,017		497,211		2,137,228
Credit and surety	243,609		70,143		313,752
Professional lines	990,567		186,245		1,176,812
Motor	1,261,241		228,453		1,489,694
Liability	1,320,221		318,222		1,638,443
Total reinsurance segment	5,455,655		1,300,274		6,755,929


Total	$	9,392,938	$	4,496,641	13,889,579
Unallocated claims adjustment expenses					140,245
Foreign exchange and other(1)					49,072
(Ceded)/assumed reserves related to retroactive transactions					(152,130)

Total liability for unpaid claims and claims adjustment expense					$	13,926,766

(1) Non-U.S. dollar denominated loss data is converted to U.S dollar at the rates of exchange in effect at the balance sheet date for material underlying currencies. Fluctuations in currency exchange rates may cause material shifts in loss development. Reserves for losses and loss expenses disclosed in the consolidated balance sheets are also remeasured using rates of exchange in effect at the balance sheet date.