The Company believes the most significant accounting judgment made by management is its estimate of claims and claim expense reserves. Claims and claim expense reserves represent estimates, including actuarial and statistical projections at a given point in time, of the ultimate settlement and administration costs for unpaid claims and claim expenses arising from the insurance and reinsurance contracts the Company sells. The Company establishes its claims and claim expense reserves by taking claims reported to the Company by insureds and ceding companies, but which have not yet been paid (“case reserves”), adding estimates for the anticipated cost of claims incurred but not yet reported to the Company, or incurred but not enough reported to the Company (collectively referred to as “IBNR”) and, if deemed necessary, adding costs for additional case reserves which represent the Company’s estimates for claims related to specific contracts previously reported to the Company which it believes may not be adequately estimated by the client as of that date, or adequately covered in the application of IBNR. The Company’s reserving committee, which includes members of the Company’s senior management, reviews, discusses, and assesses the reasonableness and adequacy of the reserving estimates included in our audited financial statements.

Activity in the liability for unpaid claims and claim expenses is summarized as follows:




Year ended December 31,	2019			2018			2017
Net reserves as of beginning of period	$	3,704,050		$	3,493,778		$	2,568,730
Net incurred related to:
Current year	2,123,876			1,390,767			1,902,424
Prior years	(26,855		)	(270,749		)	(40,996		)
Total net incurred	2,097,021			1,120,018			1,861,428
Net paid related to:
Current year	265,649			391,061			450,527
Prior years	832,405			503,708			524,298
Total net paid	1,098,054			894,769			974,825
Amounts acquired (1)	1,858,775			—			—
Foreign exchange (2)	31,260			(14,977		)	38,445
Net reserves as of end of period	6,593,052			3,704,050			3,493,778
Reinsurance recoverable as of end of period	2,791,297			2,372,221			1,586,630
Gross reserves as of end of period	$	9,384,349		$	6,076,271		$	5,080,408

The Company’s reserving methodology for each line of business uses a loss reserving process that calculates a point estimate for its ultimate settlement and administration costs for claims and claim expenses. The Company does not calculate a range of estimates and does not discount any of its reserves for claims and claim expenses. The Company uses this point estimate, along with paid claims and case reserves, to record its best estimate of additional case reserves and IBNR in its consolidated financial statements. Under GAAP, the Company is not permitted to establish estimates for catastrophe claims and claim expense reserves until an event occurs that gives rise to a loss.

Reserving for reinsurance claims involves other uncertainties, such as the dependence on information from ceding companies, the time lag inherent in reporting information from the primary insurer to the Company or to the Company’s ceding companies, and differing reserving practices among ceding companies. The information received from ceding companies is typically in the form of bordereaux, broker notifications of loss and/or discussions with ceding companies or their brokers. This information may be received on a monthly, quarterly or transactional basis and normally includes paid claims and estimates of case reserves. The Company sometimes also receives an estimate or provision for IBNR. This information is often updated and adjusted from time to time during the loss settlement period as new data or facts in respect of initial claims, client accounts, industry or event trends may be reported or emerge in addition to changes in applicable statutory and case laws.

The Company’s estimates of losses from large events are based on factors including currently available information derived from claims information from certain customers and brokers, industry assessments of losses from the events, proprietary models, and the terms and conditions of the Company’s contracts. The uncertainty of the Company’s estimates for large events is also impacted by the preliminary nature of the information available, the magnitude and relative infrequency of the events, the expected duration of the respective claims development period, inadequacies in the data provided to the relevant date by industry participants and the potential for further reporting lags or insufficiencies; and in certain large events, significant uncertainty as to the form of the claims and legal issues, under the relevant terms of insurance and reinsurance contracts. In addition, a significant portion of the net claims and claim expenses associated with certain large events can be concentrated with a few large clients and therefore the loss estimates for these events may vary significantly based on the claims experience of those clients. The contingent nature of business interruption and other exposures will also impact losses in a meaningful way, which may give rise to significant complexity in respect of claims handling, claims adjustment and other coverage issues,

The Company reevaluates its actuarial reserving techniques on a periodic basis. Typically, the quarterly review procedures include reviewing paid and reported claims in the most recent reporting period, reviewing the development of paid and reported claims from prior periods, and reviewing the Company’s overall experience by underwriting year and in the aggregate. The Company monitors its expected ultimate claims and claim expense ratios and expected claims reporting assumptions on a quarterly basis and compares them to its actual experience. These actuarial assumptions are generally reviewed annually, based on input from the Company’s actuaries, underwriters, claims personnel and finance professionals, although adjustments may be made more frequently if needed. Assumption changes are made to adjust for changes in the pricing and terms of coverage the Company provides, changes in industry results for similar business, as well as its actual experience to the extent the Company has enough data to rely on its own experience. If the Company determines that adjustments to an earlier estimate are appropriate, such adjustments are recorded in the period in which they are identified.

The information provided herein about incurred and paid accident year claims development for the years ended prior to December 31, 2019 on a consolidated basis and by segment is presented as supplementary information. The Company has applied a retrospective approach with respect to its acquisitions, presenting all relevant historical information for all periods presented. In addition, included in the incurred claims and claim expenses and cumulated paid claims and claim expenses tables below is a reconciling item that represents the unamortized balance of fair value adjustments recorded in connection with the acquisitions of Platinum and TMR, respectively, to reflect an increase in net claims and claim expenses due to the addition of a market based risk margin that represented the cost of capital required by a market participant to assume the net claims and claim expenses of Platinum and TMR, partially offset by a decrease from discounting in connection with the acquisitions of Platinum and TMR, to reflect the time value of money.




	Incurred claims and claim expenses, net of reinsurance
	For the year ended December 31,																					At December 31, 2019
Accident Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019			IBNR and ACR
	(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)
2010	$	1,131,892	$	1,105,041	$	1,048,747	$	1,033,341	$	1,045,727	$	1,037,725	$	1,045,490	$	1,043,565	$	1,015,540	$	1,052,931		$	60,342
2011	—		1,989,024		1,926,506		1,827,258		1,768,793		1,738,452		1,698,378		1,683,614		1,678,015		1,664,869			55,191
2012	—		—		1,138,018		1,021,668		958,139		927,438		891,981		894,168		901,049		907,212			48,297
2013	—		—		—		912,545		861,093		810,934		761,033		737,158		718,563		699,767			43,792
2014	—		—		—		—		1,024,813		997,906		990,050		966,802		948,264		953,904			114,985
2015	—		—		—		—		—		1,171,023		1,156,856		1,175,927		1,145,983		1,133,632			131,005
2016	—		—		—		—		—		—		1,401,451		1,458,767		1,432,001		1,426,575			251,952
2017	—		—		—		—		—		—		—		2,940,713		2,724,795		2,632,396			731,975
2018	—		—		—		—		—		—		—		—		2,198,980		2,338,291			940,346
2019	—		—		—		—		—		—		—		—		—		2,280,044			1,764,899
Total																			$	15,089,621		$	4,142,784

	Cumulative paid claims and claim expenses, net of reinsurance
	For the year ended December 31,
Accident Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019
	(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)
2010	$	146,890	$	334,347	$	518,162	$	603,060	$	670,935	$	746,454	$	859,745	$	892,480	$	912,776	$	928,552
2011	—		311,906		728,464		1,143,829		1,330,492		1,449,060		1,493,174		1,530,030		1,550,195		1,565,359
2012	—		—		267,764		416,808		522,264		596,634		647,618		721,942		752,614		783,106
2013	—		—		—		131,829		340,652		434,508		496,380		554,686		587,978		615,463
2014	—		—		—		—		230,826		432,761		554,398		630,417		691,774		741,844
2015	—		—		—		—		—		262,085		495,119		662,001		781,622		879,950
2016	—		—		—		—		—		—		286,317		623,440		826,502		971,424
2017	—		—		—		—		—		—		—		745,098		1,067,481		1,371,477
2018	—		—		—		—		—		—		—		—		587,619		804,566
2019	—		—		—		—		—		—		—		—		—		284,842
Total																			$	8,946,583
Outstanding liabilities from accident year 2009 and prior, net of reinsurance																			270,317
Claims and claim expenses, net of reinsurance, from the Company's former Bermuda-based insurance operations																			229
Adjustment for unallocated claim expenses																			51,876
Unamortized fair value adjustments recorded in connection with acquisitions																			(69,219		)
Liability for claims and claim expense, net of reinsurance, associated with RenaissanceRe UK																			196,811
Liability for claims and claim expenses, net of reinsurance																			$	6,593,052

Within the Property segment, the Company principally writes property catastrophe excess of loss reinsurance contracts to insure insurance and reinsurance companies against natural and man-made catastrophes. Under these contracts, the Company indemnifies an insurer or reinsurer when its aggregate paid claims and claim expenses from a single occurrence of a covered peril exceeds the attachment point specified in the contract, up to an amount per loss specified in the contract. The Company's most significant exposure is to losses from hurricanes, earthquakes and other windstorms, although the Company is also exposed to claims arising from other catastrophes, such as tsunamis, winter storms, freezes, floods, fires, tornadoes, explosions and acts of terrorism. The Company's predominant exposure under such coverage is to property damage. However, other risks, including business interruption and other non-property losses,

Coverage can also vary from “all property” perils to limited coverage on selected perils, such as “earthquake only” coverage. The Company also enters into retrocessional contracts that provide property catastrophe coverage to other reinsurers or retrocedants. This coverage is generally in the form of excess of loss retrocessional contracts and may cover all perils and exposures on a worldwide basis or be limited in scope to selected geographic areas, perils and/or exposures. The exposures the Company assumes from retrocessional business can change within a contract term as the underwriters of a retrocedant may alter their book of business after the retrocessional coverage has been bound. The Company also offers dual trigger reinsurance contracts which require the Company to pay claims based on claims incurred by insurers and reinsurers in addition to the estimate of insured industry losses as reported by referenced statistical reporting agencies.

Also included in the Property segment is property per risk, property (re)insurance, binding facilities and regional U.S. multi-line reinsurance. The Company's predominant exposure under such coverage is to property damage. However, other risks, including business interruption and other non-property losses, may also be covered when arising from a covered peril. The Company's coverages are offered on either a worldwide basis or are limited to selected geographic areas. The exposures assumed from retrocessional business can change within a contract term as the underwriters of a retrocedant may alter their book of business after the retrocessional coverage has been bound. The Company offers these products principally through proportional coverage. In a proportional reinsurance arrangement (also referred to as quota share reinsurance or pro rata reinsurance), the reinsurer shares a proportional part of the original premiums and losses of the reinsured.

Claims and claim expenses in the Company's Property segment are generally characterized by loss events of low frequency and high severity. Initial reporting of paid and incurred claims in general, tends to be relatively prompt. The Company considers this business “short-tail” as compared to the reporting of claims for “long-tail” products, which tends to be slower. However, the timing of claims payment and reporting also varies depending on various factors, including: whether the claims arise under reinsurance of primary insurance companies or reinsurance of other reinsurance companies; the nature of the events (e.g., hurricanes, earthquakes or terrorism); the geographic area involved; post-event inflation which may cause the cost to repair damaged property to increase significantly from current estimates, or for property claims to remain open for a longer period of time, due to limitations on the supply of building materials, labor and other resources; complex policy coverage and other legal issues; and the quality of each client’s claims management and reserving practices. Management’s judgments regarding these factors are reflected in the Company's reserve for claims and claim expenses.

Reserving for most of the Company's Property segment generally does not involve the use of traditional actuarial techniques. Rather, claims and claim expense reserves are estimated by management after a catastrophe occurs by completing an in-depth analysis of the individual contracts which may potentially be impacted by the catastrophic event. The in-depth analysis generally involves: 1) estimating the size of insured industry losses from the catastrophic event; 2) reviewing reinsurance contract portfolios to identify contracts which are exposed to the catastrophic event; 3) reviewing information reported by customers and brokers; 4) discussing the event with customers and brokers; and 5) estimating the ultimate expected cost to settle all claims and administrative costs arising from the catastrophic event on a contract-by-contract basis and in aggregate for the event. Once an event has occurred, during the then current reporting period, the Company records its best estimate of the ultimate expected cost to settle all claims arising from the event. The Company's estimate of claims and claim expense reserves is then determined by deducting cumulative paid losses from its estimate of the ultimate expected loss for an event. The Company’s estimate of IBNR is determined by deducting cumulative paid losses, case reserves and additional case reserves from its estimate of the ultimate expected loss for an event. Once the Company receives a valid notice of loss or payment request under a catastrophe reinsurance contract, it is generally able to process and pay such claims promptly.

For smaller events including localized severe weather events such as windstorms, hail, ice, snow, flooding, freezing and tornadoes, which are not necessarily prominent, public occurrences, the Company initially places greater reliance on catastrophe bulletins published by statistical reporting agencies to assist in determining what events occurred during the reporting period than the Company does for large events. This includes reviewing catastrophe bulletins published by Property Claim Services (“PCS”) for U.S. catastrophes. The Company sets its initial estimates of reserves for claims and claim expenses for these smaller events based on a combination of its historical market share for these types of losses and the estimate of the total insured industry property losses as reported by statistical reporting agencies, although management may make significant adjustments based on the Company's current exposure to the geographic region involved as well as the size of the loss and the peril involved. This approach supplements the Company's approach for estimating losses for larger catastrophes, which as discussed above, includes discussions with brokers and ceding companies and reviewing individual contracts impacted by the event. Approximately one year from the date of loss for these small events, the Company typically estimates IBNR for these events by using the paid Bornhuetter-Ferguson actuarial method. The loss development factors for the paid Bornhuetter-Ferguson actuarial method are selected based on a review of the Company's historical experience. There were no significant changes to the Company's paid loss development factors over the last three years.

In general, reserves for the Company's more recent reinsured catastrophic events are subject to greater uncertainty and, therefore, greater potential variability, and are likely to experience material changes from one period to the next. This is due to the uncertainty as to the size of the industry losses from the event, uncertainty as to which contracts have been exposed to the catastrophic event, uncertainty due to complex legal and coverage issues that can arise out of large or complex catastrophic events, and uncertainty as to the magnitude of claims incurred by the Company's customers. As the Company's claims age, more information becomes available and the Company believes its estimates become more certain.




	Incurred claims and claim expenses, net of reinsurance
	For the year ended December 31,																					At December 31, 2019
Accident Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019			IBNR and ACR
	(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)
2010	$	720,159	$	681,287	$	636,962	$	657,719	$	691,473	$	696,844	$	706,258	$	708,343	$	681,435	$	731,179		$	50,422
2011	—		1,559,069		1,491,770		1,422,659		1,393,110		1,369,567		1,338,187		1,333,982		1,321,137		1,302,141			24,335
2012	—		—		559,946		429,425		395,203		375,098		356,310		344,535		336,719		331,865			12,351
2013	—		—		—		317,258		287,694		265,570		240,945		228,622		224,748		222,939			1,092
2014	—		—		—		—		306,731		283,608		270,618		265,820		264,754		265,229			4,554
2015	—		—		—		—		—		368,766		334,572		317,865		307,088		301,733			11,672
2016	—		—		—		—		—		—		445,532		458,525		443,135		432,269			53,990
2017	—		—		—		—		—		—		—		1,640,129		1,446,566		1,348,260			295,210
2018	—		—		—		—		—		—		—		—		945,829		1,054,884			273,477
2019	—		—		—		—		—		—		—		—		—		1,000,190			719,847
Total																			$	6,990,689		$	1,446,950

	Cumulative paid claims and claim expenses, net of reinsurance
	For the year ended December 31,
Accident Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019
	(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)
2010	$	104,859	$	230,552	$	345,574	$	401,977	$	450,624	$	481,489	$	581,160	$	595,131	$	612,013	$	623,231
2011	—		262,987		590,346		965,668		1,121,374		1,207,136		1,230,503		1,252,204		1,257,516		1,264,414
2012	—		—		165,850		205,567		253,699		280,195		291,027		305,627		308,822		313,976
2013	—		—		—		80,083		155,459		191,181		206,376		213,351		216,176		219,231
2014	—		—		—		—		106,618		184,140		222,509		234,144		241,139		247,663
2015	—		—		—		—		—		126,831		215,134		249,182		268,545		279,165
2016	—		—		—		—		—		—		119,908		258,355		324,296		350,646
2017	—		—		—		—		—		—		—		534,097		660,491		824,443
2018	—		—		—		—		—		—		—		—		432,201		450,125
2019	—		—		—		—		—		—		—		—		—		159,585
Total																			$	4,732,479
Outstanding liabilities from accident year 2009 and prior, net of reinsurance																			4,283
Adjustment for unallocated claim expenses																			19,339
Unamortized fair value adjustments recorded in connection with acquisitions																			(10,606		)
Liability for claims and claim expense, net of reinsurance, associated with RenaissanceRe UK																			17,536
Liability for claims and claim expenses, net of reinsurance																			$	2,288,762

The Company has accepted a wide range of proportional risks, facilitating the Company's efforts to expand its product offerings. While the Company remains focused on underwriting discipline, and seeks to remain focused on opportunities amenable to stochastic representation and supported by strong data and analytics, the Company's expanded casualty and specialty product suite, may pose new, unmodelled or unforeseen risks for which the Company may not be adequately compensated and may also result in a higher level of attritional claims and claim expenses and the potential for reserve development, either adverse or favorable.

The Company's processes and methodologies in respect of loss estimation for the coverages offered through its Casualty and Specialty segment differ from those used for its Property segment. For example, the Company's casualty and specialty coverages are more likely to be impacted by factors such as long-term inflation and changes in the social and legal environment, which the Company believes gives rise to greater uncertainty in its reserves for claims and claim expenses. Moreover, in many lines of business the Company does not have the benefit of a significant amount of its own historical experience and may have little or no related corporate reserving history in many of its newer or growing lines of business. The Company believes this makes its Casualty and Specialty segment reserving subject to greater uncertainty than its Property segment.

The Company calculates multiple point estimates for claims and claim expense reserves using a variety of actuarial reserving techniques for many, but not all, of its classes of business for each underwriting year within the Casualty and Specialty segment. The Company does not believe that these multiple point estimates are, or should be considered, a range. Rather, the Company considers each class of business and determines the most appropriate point estimate for each underwriting year based on the characteristics of the particular class including: (1) loss development patterns derived from historical data; (2) the credibility of the selected loss development pattern; (3) the stability of the loss development patterns; (4) how developed the underwriting year is; and (5) the observed loss development of other underwriting years for the same class. The Company also considers other relevant factors, including: (1) historical ultimate loss ratios; (2) the presence of individual large losses; and (3) known occurrences that have not yet resulted in reported losses. The Company makes determinations of the most appropriate point estimate of loss for each class based on an evaluation of relevant information and do not ascribe any particular portion of the estimate to a particular factor or consideration. In addition, the Company believes that a review of individual contract information improves the loss estimates for some classes of business.

For classes of business and underwriting years where the Company has limited historical claims experience, estimates of ultimate losses that are not related to a specific event are generally initially determined based on the loss ratio method applied to each underwriting year and to each class of business. Unless the Company has credible claims experience or unfavorable development, it generally selects an ultimate loss based on its initial view of the loss. The selected ultimate losses are determined by multiplying the initial expected loss ratio by the earned premium. The initial expected loss ratios are key inputs that involve management judgment and are based on a variety of factors, including: (1) contract by contract expected loss ratios developed during the Company’s pricing process; (2) historical loss ratios and combined ratios adjusted for rate change and trend; and (3) industry benchmarks for similar business. These judgments take into account management’s view of past, current and future factors that may influence ultimate losses, including: (1) market conditions; (2) changes in the business underwritten; (3) changes in timing of the emergence of claims; and (4) other factors that may influence ultimate loss ratios and losses.

The determination of when reported losses are sufficient and credible to warrant selection of an ultimate loss ratio different from the initial expected loss ratios also requires judgment. The Company generally makes adjustments for reported loss experience indicating unfavorable variances from initial expected loss ratios sooner than reported loss experience indicating favorable variances. This is because the reporting of losses in excess of expectations tends to have greater credibility than an absence or lower than expected level of reported losses. Over time, as a greater number of claims are reported and the credibility of

The Bornhuetter-Ferguson method allows for greater weight to be applied to expected results in periods where little or no actual experience is available, and, hence, is less susceptible to the potential pitfall of being excessively swayed by one year or one quarter of actual paid and/or reported loss data, compared to the chain ladder actuarial method. The Bornhuetter-Ferguson method uses the initial expected loss ratio to estimate IBNR, and it assumes that past experience is not fully representative of the future. As the Company’s reserves for claims and claim expenses age, and actual claims experience becomes available, this method places less weight on expected experience and places more weight on actual experience. This experience, which represents the difference between expected reported claims and actual reported claims, is reflected in the respective reporting period as a change in estimate. The utilization of the Bornhuetter-Ferguson method requires the Company to estimate an expected ultimate claims and claim expense ratio and select an expected loss reporting pattern. The Company selects its estimates of the expected ultimate claims and claim expense ratios as described above and selects its expected loss reporting patterns by utilizing actuarial analysis, including management’s judgment, and historical patterns of paid losses and reporting of case reserves to the Company, as well as industry loss development patterns. The estimated expected claims and claim expense ratio may be modified to the extent that reported losses at a given point in time differ from what would be expected based on the selected loss reporting pattern.

The reported chain ladder actuarial method utilizes actual reported losses and a loss development pattern to determine an estimate of ultimate losses that is independent of the initial expected ultimate loss ratio and earned premium. The Company believes this technique is most appropriate when there are a large number of reported losses with significant statistical credibility and a relatively stable loss development pattern. Information that may cause future loss development patterns to differ from historical loss development patterns is considered and reflected in the Company’s selected loss development patterns as appropriate. For certain reinsurance contracts, historical loss development patterns may be developed from ceding company data or other sources.




	Incurred claims and claim expenses, net of reinsurance
	For the year ended December 31,																					At December 31, 2019
Accident Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019			IBNR and ACR
	(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)
2010	$	411,733	$	423,754	$	411,785	$	375,622	$	354,254	$	340,881	$	339,232	$	335,222	$	334,105	$	321,752		$	9,920
2011	—		429,955		434,736		404,599		375,683		368,885		360,191		349,632		356,878		362,728			30,856
2012	—		—		578,072		592,243		562,936		552,340		535,671		549,633		564,330		575,347			35,946
2013	—		—		—		595,287		573,399		545,364		520,088		508,536		493,815		476,828			42,700
2014	—		—		—		—		718,082		714,298		719,432		700,982		683,510		688,675			110,431
2015	—		—		—		—		—		802,257		822,284		858,062		838,895		831,899			119,333
2016	—		—		—		—		—		—		955,919		1,000,242		988,866		994,306			197,962
2017	—		—		—		—		—		—		—		1,300,584		1,278,229		1,284,136			436,765
2018	—		—		—		—		—		—		—		—		1,253,151		1,283,407			666,869
2019	—		—		—		—		—		—		—		—		—		1,279,854			1,045,052
Total																			$	8,098,932		$	2,695,834

	Cumulative paid claims and claim expenses, net of reinsurance
	For the year ended December 31,
Accident Year	2010		2011		2012		2013		2014		2015		2016		2017		2018		2019
	(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)		(unaudited)
2010	$	42,031	$	103,795	$	172,588	$	201,083	$	220,311	$	264,965	$	278,585	$	297,349	$	300,763	$	305,321
2011	—		48,919		138,118		178,161		209,118		241,924		262,671		277,826		292,679		300,945
2012	—		—		101,914		211,241		268,565		316,439		356,591		416,315		443,792		469,130
2013	—		—		—		51,746		185,193		243,327		290,004		341,335		371,802		396,232
2014	—		—		—		—		124,208		248,621		331,889		396,273		450,635		494,181
2015	—		—		—		—		—		135,254		279,985		412,819		513,077		600,785
2016	—		—		—		—		—		—		166,409		365,085		502,206		620,778
2017	—		—		—		—		—		—		—		211,001		406,990		547,034
2018	—		—		—		—		—		—		—		—		155,418		354,441
2019	—		—		—		—		—		—		—		—		—		125,257
Total																			$	4,214,104
Outstanding liabilities from accident year 2009 and prior, net of reinsurance																			266,034
Adjustment for unallocated claim expenses																			32,537
Unamortized fair value adjustments recorded in connection with acquisitions																			(58,613		)
Liability for claims and claim expense, net of reinsurance, associated with RenaissanceRe UK																			179,275
Liability for claims and claim expenses, net of reinsurance																			$	4,304,061

The Company’s estimates of claims and claim expense reserves are not precise in that, among other things, they are based on predictions of future developments and estimates of future trends and other variable factors. Some, but not all, of the Company’s reserves are further subject to the uncertainty inherent in actuarial methodologies and estimates. Because a reserve estimate is simply an insurer’s estimate at a point in time of its ultimate liability, and because there are numerous factors that affect reserves and claims payments that cannot be determined with certainty in advance, the Company’s ultimate payments will vary, perhaps materially, from its estimates of reserves. If the Company determines in a subsequent period that adjustments to its previously established reserves are appropriate, such adjustments are recorded in the

The following tables detail the development of the Company’s liability for unpaid claims and claim expenses for its Property segment, allocated between large and small catastrophe net claims and claim expenses and attritional net claims and claim expenses, included in the other line item:




Year ended December 31,	2019
	(Favorable) adverse development
Catastrophe net claims and claim expenses
Large catastrophe events
2017 Large Loss Events	$	(101,572	)
New Zealand Earthquake (2011)	(7,497		)
Tohoku Earthquake and Tsunami (2011)	(5,198		)
New Zealand Earthquake (2010)	47,071
2018 Large Loss Events	81,555
Other	(31,916		)
Total large catastrophe events	(17,557		)
Small catastrophe events and attritional loss movements
Other small catastrophe events and attritional loss movements	5,379
Total small catastrophe events and attritional loss movements	5,379
Total catastrophe and attritional net claims and claim expenses	(12,178		)
Actuarial assumption changes	9,245
Total net favorable development of prior accident years net claims and claim expenses	$	(2,933	)

assumption changes principally related to the Company’s other property class of business. Included in net favorable development of prior accident years net claims and claim expenses from large catastrophe events was $101.6 million of net decreases in the estimated ultimate losses associated with Hurricanes Harvey, Irma and Maria, the Mexico City Earthquake, the wildfires in California during the fourth quarter of 2017 and certain losses associated with aggregate loss contracts (collectively, the “2017 Large Loss Events”), partially offset by $81.6 million of net increases in the estimated ultimate losses associated with Typhoons Jebi, Mangkhut and Trami, Hurricane Florence, the wildfires in California during the third and fourth quarters of 2018, Hurricane Michael and certain losses associated with aggregate loss contracts (collectively, the “2018 Large Loss Events”) and $47.1 million of net increases in the estimated ultimate losses associated with the 2010 New Zealand Earthquake.




Year ended December 31,	2018
	(Favorable) adverse development
Catastrophe net claims and claim expenses
Large catastrophe events
2017 Large Loss Events	$	(172,512	)
Other	(9,517		)
Total large catastrophe events	(182,029		)
Small catastrophe events and attritional loss movements
Other small catastrophe events and attritional loss movements	(33,579		)
Total small catastrophe events and attritional loss movements	(33,579		)
Total catastrophe and attritional net claims and claim expenses	(215,608		)
Actuarial assumption changes	(5,682		)
Total net favorable development of prior accident years net claims and claim expenses	$	(221,290	)

The net favorable development of prior accident years net claims and claim expenses within the Company’s Property segment in 2018 of $221.3 million was comprised of net favorable development of $182.0 million related to large catastrophe events, net favorable development of $33.6 million related to small catastrophe events and attritional loss movements and $5.7 million of net favorable development associated with actuarial assumption changes. Included in net favorable development of prior accident years net claims and claim expenses from large events was $172.5 million of net decreases in the estimated ultimate losses associated with the 2017 Large Loss Events. The Company’s Property segment also experienced net favorable development of $33.6 million associated with a number of other small catastrophe events as well as attritional loss movements related to lines of business where the Company principally estimates net claims and claim expenses using traditional actuarial methods.




Year ended December 31,	2017
	(Favorable) adverse development
Catastrophe net claims and claim expenses
Large catastrophe events
Storm Sandy (2012)	$	(4,395	)
April and May U.S. Tornadoes (2011)	(4,177		)
New Zealand Earthquake (2010)	4,061
New Zealand Earthquake (2011)	5,807
Other	(8,936		)
Total large catastrophe events	(7,640		)
Small catastrophe events and attritional loss movements
Tianjin Explosion (2015)	(8,002		)
Fort McMurray Wildfire (2016)	(6,364		)
Other small catastrophe events and attritional loss movements	(24,432		)
Total small catastrophe events and attritional loss movements	(38,798		)
Total catastrophe and attritional net claims and claim expenses	(46,438		)
Actuarial assumption changes	842
Total net favorable development of prior accident years net claims and claim expenses	$	(45,596	)

The net favorable development of prior accident years net claims and claim expenses within the Company’s Property segment in 2017 of $45.6 million was comprised of net favorable development of $7.6 million related to large catastrophe events, net favorable development of $38.8 million related to small catastrophe events and attritional loss movements and $0.8 million of adverse development associated with actuarial assumption changes. Included in net favorable development of prior accident years net claims and claim expenses from large events was a number of relatively small net decreases in the estimated ultimate losses associated with a number of events from prior accident years. Included in net favorable development of prior accident years net claims and claims expenses from small events and attritional loss movements was a reduction in the estimated ultimate losses associated with a number of small catastrophes and attritional loss movements of $24.4 million, the 2015 Tianjin Explosion of $8.0 million and the 2016 Fort McMurray Wildfire of $6.4 million.

The following table details the development of the Company’s liability for unpaid claims and claim expenses for its Casualty and Specialty segment:




Year ended December 31,	2019			2018			2017
	(Favorable) adverse development			(Favorable) adverse development			(Favorable) adverse development
Actuarial methods - actual reported claims less than expected claims	$	(52,796	)	$	(41,476	)	$	(24,836	)
Ogden Rate change	—			—			33,481
Actuarial assumption changes	28,914			(7,786		)	(2,462		)
Total net (favorable) adverse development of prior accident years net claims and claim expenses	$	(23,882	)	$	(49,262	)	$	6,183

The net adverse development of prior accident years net claims and claim expenses within the Company’s Casualty and Specialty segment in 2017 of $6.2 million was driven by $33.5 million of adverse development associated with the change in the discount rate used to calculate lump sum awards in U.K. bodily injury cases (the “Ogden Rate”), from 2.5%, to minus 0.75%. Notwithstanding the impact of the Ogden Rate change was $24.8 million of net favorable development in 2017 related to actual reported losses coming in lower than expected on attritional net claims and claim expenses across a number of lines of business and $2.5 million of net favorable development associated with actuarial assumption changes.

Each of the Company’s reportable segments are broadly considered to be assumed reinsurance, where multiple claims are often aggregated, perhaps multiple times through retrocessional reinsurance, before ultimately being ceded to the Company. In addition, the nature, size, terms and conditions of contracts entered into by the Company changes from one accident year to the next and the quantum of contractual or policy limits, and accordingly the potential amount of claims and claim expenses associated with a reported claim, can range from nominal, to significant. These factors can impact the amount and timing of the claims and claim expenses to be recorded and accordingly, developing claim frequency information is highly subjective and is not prepared or utilized for internal purposes. In addition, the Company does not have direct access to claim frequency information underlying certain of its proportional contracts given the nature

Net claims and claim expenses incurred were reduced by $Nil during 2019 (2018 – $0.2 million, 2017 – $0.2 million) related to income earned on assumed reinsurance contracts that were classified as deposit contracts with underwriting risk only. Other income was increased by $1.3 million during 2019 (2018 – $11.2 million, 2017 – $3.7 million) related to premiums and losses incurred on assumed reinsurance contracts that were classified as deposit contracts with timing risk only. Aggregate deposit liabilities of $9.0 million are included in reinsurance balances payable at December 31, 2019 (2018 – $10.3 million) and aggregate deposit assets of $Nil are included in other assets at December 31, 2019 (2018 – $Nil) associated with these contracts.