Exhibit 99.1

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG

2010 GLOBAL LOSS TRIANGLES

Global Loss Development Triangle Cautionary Language

     This report is for informational purposes only and is current only as of December 31, 2010. Allied World Assurance Company Holdings, AG (“Allied World”, the “Company”, “we”, “us” or “our”) is under no obligation (and expressly disclaims any such obligation) to update or revise this report, whether as a result of new information, future events or otherwise. Nothing contained in this report is or should be relied upon as a promise or representation as to the future. Although the loss development patterns disclosed in this report are an important factor in the process used to estimate loss reserve requirements, they are not the only factors considered in establishing reserves. The process for establishing reserves is subject to considerable variability and requires the use of informed estimates and judgments. Important details, such as specific loss development expectations for particular contracts, years or events, cannot be developed solely by analyzing the information provided in this report. In addition to analyzing loss development data, management incorporates additional information into the reserving process, such as pricing for insurance and reinsurance products as well as current market conditions. Readers must keep these and other qualifications more fully described in this report in mind when reviewing this information. Information presented in this report may differ materially from that reported in the Company’s financial statements prepared in accordance with accounting principles generally accepted in the United States due to differences in foreign exchange rates, exclusions, the impact of premium adjustments and other adjustments. This report is a supplement to the Company’s financial disclosures and represents the second publishing of our Global Loss Triangles. This report should be read in conjunction with the Company’s most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and other documents on file with the U.S. Securities and Exchange Commission (the “SEC”). This report shall not be incorporated by reference into any on the Company’s filings under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended.

Cautionary Statement Regarding Forward-Looking Statements

     Any forward-looking statements made in this report reflect the Company’s current views with respect to future events and financial performance and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Such statements involve risks and uncertainties, which may cause actual results to differ materially from those set forth in these statements. For example, the Company’s forward-looking statements could be affected by pricing and policy term trends; increased competition; the impact of acts of terrorism and acts of war; greater frequency or severity of unpredictable catastrophic events; negative rating agency actions; the adequacy of our loss reserves; the Company or its subsidiaries becoming subject to significant income taxes in the United States or elsewhere; changes in regulations or tax laws; changes in the availability, cost or quality of reinsurance or retrocessional coverage; adverse general economic conditions; and judicial, legislative, political and other governmental developments, as well as management’s response to these factors, and other factors identified in the Company’s filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date on which they are made. The Company is under no obligation (and expressly disclaims any such obligation) to update or revise any forward-looking statement that may be made from time to time, whether as a result of new information, future developments or otherwise.

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
2010 GLOBAL LOSS TRIANGLES

Table of Contents

		Page
I. EXECUTIVE SUMMARY			1
— Overview			1
— Limitations of the Reserving Processes			3
— Treaty Year Projections			5
II. RECONCILIATION OF GLOBAL LOSS TRIANGLES TO DECEMBER 31, 2010 FINANCIAL STATEMENTS			6
III. GLOBAL LOSS TRIANGLES			7
— Basis of Presentation			7
— Description of Data Presented			8
— Large Losses			8
— GLT Class Details			9
— Property Insurance (Gross of Ceded Reinsurance)			12
— General Casualty Insurance (Gross of Ceded Reinsurance)			13
— Professional Liability Lines Insurance (Gross of Ceded Reinsurance)			14
— Healthcare Insurance (Gross of Ceded Reinsurance)			15
— Property Insurance (Net of Ceded Reinsurance)			16
— General Casualty Insurance (Net of Ceded Reinsurance)			17
— Professional Liability Lines Insurance (Net of Ceded Reinsurance)			18
— Healthcare Insurance (Net of Ceded Reinsurance)			19
— Property Catastrophe Reinsurance (Gross of Ceded Reinsurance)			20
— Property Other Reinsurance (Gross of Ceded Reinsurance)			21
— General Casualty Reinsurance (Gross of Ceded Reinsurance)			22
— Professional Liability Lines Reinsurance (Gross of Ceded Reinsurance)			23
— Other Reinsurance (Gross of Ceded Reinsurance)			24
— Property Catastrophe Reinsurance (Net of Ceded Reinsurance)			25
— Property Other Reinsurance (Net of Ceded Reinsurance)			26
— General Casualty Reinsurance (Net of Ceded Reinsurance)			27
— Professional Liability Lines Reinsurance (Net of Ceded Reinsurance)			28
— Other Reinsurance (Net of Ceded Reinsurance)			29
— Insurance (Gross of Ceded Reinsurance) Premium/Loss Summary			30
— Insurance (Net of Ceded Reinsurance) Premium/Loss Summary			31
— Reinsurance (Gross of Ceded Reinsurance) Premium/Loss Summary			32
— Reinsurance (Net of Ceded Reinsurance) Premium/Loss Summary			33
IV. SELECTED EXCERPTS FROM ALLIED WORLD’S 2010 10-K DISCLOSURE			34
V. GLOSSARY			39

I. EXECUTIVE SUMMARY

     Overview

     A critical component of financial reporting for insurance and reinsurance companies is to accurately estimate potential losses and associated loss expenses on risks that have been insured or reinsured. This report is Allied World’s release of its Global Loss Triangles (“GLTs”) as of December 31, 2010. For your convenience, we have included a glossary beginning on page 39 of selected insurance and reinsurance terms.

     We establish a reserve for losses and loss expenses to cover our estimated liability for the payment of all losses and loss expenses incurred with respect to earned premiums on the policies and treaties that we write. This reserve is a balance sheet liability representing estimates of losses and loss expenses we are required to pay for insured or reinsured claims that have occurred as of or before the balance sheet date.

     The process of establishing loss reserves can be complex and is subject to considerable variability as it requires the use of judgment regarding numerous items, including future litigation trends, future inflation trends, new laws and regulations, attachment points and timing of payments. Actuarial estimates of these reserves are subject to potential errors of estimation, which could be significant, as they are based upon the outcomes of future events. The estimates are even more difficult for a company such as Allied World, as many of our casualty lines of business have relatively high attachment points (often exceeding $100 million) and relatively high net limits (with $25 million being a typical maximum). Those characteristics make some of our casualty lines subject to claims that are very low in frequency (the number of actual claims), but very high in severity (the average claim size). The combination of low frequency and high severity exacerbates the difficulty in establishing loss reserves for Allied World. Loss reserves may vary considerably from prior estimates. We caution that an attempt to evaluate our loss reserves using exclusively the data presented in this report could be misleading.

     The reserve for losses and loss expenses is comprised of two main elements: outstanding loss reserves, also known as “case reserves,” and reserves for losses incurred but not reported (“IBNR”). Outstanding loss reserves relate to known claims and represent management’s best estimate of the likely loss settlement cost. Thus, there is a significant amount of estimation involved in determining the likely loss payment. IBNR reserves require judgment because they relate primarily to unreported events that, based on industry information, management’s experience and actuarial evaluation, can reasonably be expected to have occurred and are reasonably likely to result in a loss to the Company. IBNR reserves also relate to estimated development of reported events that based on industry information, management’s experience and actuarial evaluation, can reasonably be expected to reach our attachment point and are reasonably likely to result in a loss to the Company.

     IBNR is the estimated liability for (1) claims that have occurred but have not yet been reported as well as (2) changes in the values of claims that have been reported to us but are not yet settled. Each claim is settled individually based upon its merits and it is not unusual for a

claim to take years after being reported to settle, especially if legal action is involved. As a result, reserves for losses and loss expenses include significant estimates for IBNR reserves.

     The reserve for IBNR is estimated by management for each line of business based on various factors, including underwriters’ expectations about loss experience, actuarial analysis, comparisons with the results of industry benchmarks and loss experience to date. The reserve for IBNR is calculated as the ultimate amount of losses and loss expenses less cumulative paid losses and loss expenses and case reserves. Our actuaries employ generally accepted actuarial methodologies to determine estimated ultimate loss reserves.

     When estimating IBNR reserves, we segregate the Company’s insurance and reinsurance loss and exposure data into over 70 classes in total. Within each class, the business is further segregated by treaty year, accident year or report year. Professional liability and healthcare lines of business are reviewed on a report year basis due to the claims-made nature of the underlying contracts. Our general casualty insurance business is a mixture of claims-made and loss-occurring contracts. Since the Company’s formation in November 2001, 57% of our gross earned premiums and 55% of our net earned premiums have been associated with occurrence policies for our general casualty insurance business.

     Generally, initial actuarial estimates of IBNR reserves not related to a single event (such as a catastrophe) are based upon the expected loss ratio method applied to each class of business. Actual paid losses and case reserves are subtracted from the expected ultimate losses to derive the IBNR reserves. The initial expected loss ratio used in the expected loss ratio method involve managerial judgments and are based upon historical information for the class of business, which includes historic loss ratios, market conditions, changes in pricing, policy terms and conditions, peer analysis, underwriting changes, changes in claims emergence and other factors that may influence expected ultimate losses. Over time, the actuarial estimates for our non-property lines of business generally become a blend of the Bornhuetter-Ferguson reported loss method (the “B-F method”) and the expected loss ratio method. The B-F method incorporates actual reported loss data and expected unreported losses, which is a function of the initial expected loss ratio and the expected loss emergence pattern, to determine an estimate of ultimate losses. The B-F method is often appropriate for lines of business where there is limited actual loss data and/or a relatively less stable pattern of loss emergence. For additional details on the B-F method, see “IV. Selected Excerpts from Allied World’s 2010 10-K Disclosure — Expected Loss Ratio Method” and “— B-F Method.”

     These actuarial methods may be inappropriate for lines of business with very low frequency and high severity and in certain specific situations, such as catastrophe losses. In such situations, specific knowledge of the open claims, the underlying exposures, ceded reinsurance, litigation trends, the types of coverages involved and the changes in the frequency or severity of the claim may be used to establish reserves.

     Multiple estimates of ultimate losses using a variety of actuarial methods are calculated for many of our classes of business for each year of loss experience. Our actuaries review each class of business and each year of loss experience and determine the most appropriate point estimate based upon the characteristics of the particular class of business and other relevant

factors as described above. Once our actuaries make their determination of the most appropriate point estimate for each class of business and for each year of loss experience, both gross and net of reinsurance, this information is aggregated and presented to management for consideration in establishing the recorded reserves for losses and loss expenses.

     Limitations of the Reserving Processes

     Reserving actuaries, especially in personal lines and mid-market commercial lines companies, often employ standard actuarial loss development methods to project ultimate losses from triangles of paid and reported losses. These methods rely on an assumption that losses develop consistently from one year to the next, and for the expected loss ratio and B-F methods, on the assumption that an initial expected loss ratio and expected emergence pattern can be accurately selected. However, Allied World writes complex lines of business, including excess casualty insurance and reinsurance, which often do not have the consistent patterns of reported losses that personal lines and mid-market commercial lines companies do.

     Projections of ultimate losses require a significant amount of estimation and judgment based on a variety of factors. We strongly caution against any assumption that standard loss projection techniques applied mechanically can alone be used to estimate ultimate losses for our data as the outcome of such a simplistic approach would lead to misleading results and inaccurate conclusions. Reasons to avoid simplistic projections include:

	•		Allied World has only been in existence since November 2001 and many of our GLTs lack sufficient actuarial credibility to project ultimate losses and do not have the history to accurately estimate the development of losses beyond nine years.
	•		Allied World acquired Darwin Professional Underwriters, Inc. and its subsidiaries (“Darwin”) in October 2008. The loss triangles from Darwin have been merged into Allied World’s GLTs. However, it is likely that the historical loss emergence patterns from the Darwin business are substantially different from the historical loss patterns of the business written by Allied World due to different attachment point profiles, different policy forms (nearly all Darwin policies are claims-made) and differing claims department philosophies.
	•		As many of our casualty lines can have relatively low frequency and relatively high severity losses, the absence or emergence of only a few losses can distort our paid and reported GLTs.
	•		Our U.S. direct insurance business has been generally growing faster than our international direct insurance business. The difference in the business mix between these two insurance businesses and the lower attachment point profile of the U.S. business can cause historical loss development not to be appropriate for future loss development.

	•		Some of our largest reinsurance treaties have special characteristics, such as loss corridors, annual aggregate deductibles or swing-rated premiums that cannot be considered in a simplistic aggregate projection.
	•		We have had changes in our underwriting philosophy over time, exiting or paring back some classes of business and in other classes changing coverage terms and conditions.
	•		Losses develop differently for different classes of business. The aim of the GLTs contained herein is to present our loss development experience in an informative format, while protecting proprietary Company information. Accordingly, we do not show our 70+ reserving classes, but rather have aggregated them into nine classes, which represent different geographies, pricing environments, legislative climates and policy forms and which will not be as homogeneous as our actual reserving classes would be if reported individually.
	•		Paid loss development patterns are considerably longer than the corresponding reported loss development patterns and can produce for many of our classes of business extremely volatile indications, particularly within the first several years of development.
	•		For several classes of business, pricing conditions have changed in recent years. The extrapolation of losses and loss expense ratios from prior periods to current periods would not be appropriate.

     In addition to these factors, the global credit crisis and the effects of inflation (as discussed in more detail below) could adversely impact our ultimate losses and cause our projections and judgments regarding our expected loss reserves to differ materially from the ultimate losses we may incur.

     Global Credit Crisis — Worldwide financial and housing markets have experienced extreme volatility and disruption in recent years. As a result of the global credit crisis, the following reserving classes have been impacted:

	•		direct insurance professional liability lines (primarily the 2007 and 2008 report years), and
	•		reinsurance professional liability lines (primarily the 2006 through 2008 treaty years).

     There continue to be relatively high levels of uncertainty around the ultimate losses for the years referenced. This is mainly attributable to the higher volume of reported claims and the higher proportion of open claims for these years compared to earlier years at the same stage of development. In addition, these reported claims have caused higher reported losses and ALAE ratios for these years compared to earlier years at similar stages of development. As a result, the ultimate loss development patterns on these years may differ from prior years. The uncertainty is

increased by the fact that we have relatively high average attachment points for many of these potential credit crisis-related claims for our direct insurance business and by the fact that we often provide D&O side A cover, for which we are required to provide coverage to directors and officer for claims alleging negligence or malfeasance if such claims are not indemnified by the insured.

     Our reserves for these lines of business are based on a detailed analysis of all open claims that considers attachment points, exposed limits, coverage provided and litigation trends as well as quarterly, in-depth discussions with members of our claims department and underwriting staff.

     Inflation — Losses and loss expense reserves can be impacted by social and judicial inflation. Higher than expected inflation can negatively impact the costs of claims as it may cause an increase in frequency (the number of actual claims) and severity (the average claim size). Though our reserving techniques factor in inflation through the use of expected loss ratios derived from our pricing models, which consider the effects of inflation, and through the use of industry loss development patterns that go back as far as 1984, losses and loss expense reserves can be impacted by unexpected changes in inflation rates. We do not explicitly account for excessive inflation in our reserves.

     Treaty Year Projections

     Data organized by treaty year assigns claims and premiums to the year in which the assumed reinsurance contract incepted. As such, a treaty year may cover claims spanning several accident years. This has two primary implications for estimating ultimate loss reserves. First, the payment and reporting patterns are generally slower to develop than for the data presented by accident year or report year. This means that it is even more critical that premium-based reserving methods, such as the expected loss ratio method or the B-F method, are used for the more recent years rather than loss development methods that can be distorted by small movements in actual paid or reported loss activity due to the application of large loss development factors. Second, treaty years for which premium is not fully earned require an adjustment to the indicated reserves to reflect only the portion of the ultimate treaty year losses that are associated with losses that have occurred prior to the evaluation date. This is typically done by developing an ultimate loss ratio estimate for the full treaty year and applying this loss ratio to the earned premiums from the treaty year.

II. RECONCILIATION OF GLOBAL LOSS TRIANGLES TO DECEMBER 31, 2010 FINANCIAL STATEMENTS

     The tables below provide a reconciliation of our presented GLTs to our audited financial statements as of and for the year ended December 31, 2009 and 2010, respectively.

(Expressed in U.S. dollars in thousands)

Paid Losses and Paid LAE in 2009 Calendar Year

Consolidated GLTs — net paid losses and ALAE1		$	391,719
Paid losses and paid ALAE from excluded catastrophes			51,281
Paid ULAE			14,903
Foreign exchange and other			318
Paid losses and paid LAE in 2009 calendar year per 10-K		$	458,221
Paid Losses and Paid LAE in 2010 Calendar Year
Consolidated GLTs — net paid losses and ALAE1		$	525,004
Paid losses and paid ALAE from excluded catastrophes			51,835
Paid ULAE			19,219
Foreign exchange and other			677
Paid losses and paid LAE in 2010 calendar year per 10-K		$	596,734
Incurred Losses and Incurred LAE in 2009 Calendar Year
Consolidated GLTs — net reported losses and ALAE1		$	496,443
Reported losses and reported ALAE from excluded catastrophes			18,614
Reported ULAE			14,903
Change in IBNR			69,886
Foreign exchange and other			4,214
Incurred losses and incurred LAE in 2009 calendar year per 10-K		$	604,060
Incurred Losses and Incurred LAE in 2010 Calendar Year
Consolidated GLTs — net reported losses and ALAE1		$	611,369
Reported losses and reported ALAE from excluded catastrophes			46,642
Reported ULAE			19,219
Change in IBNR			34,929
Foreign exchange and other			(4,276	)
Incurred losses and incurred LAE in 2010 calendar year per 10-K		$	707,883

III. GLOBAL LOSS TRIANGLES

     Basis of Presentation

     For the basis of this presentation, we have split our data into nine classes of GLTs, four for our direct insurance business and five for our reinsurance business. They are listed below:

	Direct Insurance Business					Reinsurance Business
	•	Property				•	Property Catastrophe
	•	General Casualty				•	Property Other
	•	Professional Liability Lines				•	General Casualty
	•	Healthcare				•	Professional Liability Lines
						•	Other Reinsurance

•

Our direct insurance general casualty business contains a mix of claims-made, occurrence-reported and occurrence policy forms.

General Casualty
Distribution of Gross Premiums Written
Underwriting						Occurrence-
Year		Claims-Made				Reported				Occurrence				Total
2002			20.3	%			26.1	%			53.6	%			100.0	%
2003			16.6	%			30.0	%			53.4	%			100.0	%
2004			20.3	%			30.7	%			49.0	%			100.0	%
2005			14.4	%			35.2	%			50.4	%			100.0	%
2006			16.1	%			32.3	%			51.6	%			100.0	%
2007			16.5	%			35.5	%			48.0	%			100.0	%
2008			16.3	%			29.8	%			54.0	%			100.0	%
2009			11.1	%			21.6	%			67.2	%			100.0	%
2010			8.9	%			23.8	%			67.3	%			100.0	%
Total			16.4	%			30.3	%			53.3	%			100.0	%

	•		Our reinsurance business classified as “other reinsurance” includes accident and health, workers’ compensation catastrophe coverage, motor business, aviation and marine.
	•		Our reinsurance business is presented separately from our direct insurance business as we show the reinsurance classes on a treaty year basis. Many reinsurance treaties do not provide sufficient detail to split losses and loss adjustment expenses accurately by accident year or report year.

	•		Our nine classes were selected to create categories which were relatively homogeneous yet were not so small as to have insufficient actuarial credibility.
	•		Our GLTs are presented in thousands of U.S. dollars, reflecting conversions from local currencies based upon the date on which the transactions were entered into the Company’s systems.

     Description of Data Presented

     For each class of business, earned premiums are presented both gross and net of external reinsurance, with intercompany reinsurance transactions not being reflected in the GLTs. For classes of business within our reinsurance segment, these premiums are presented on a treaty year basis. For all other classes of business, the net earned premiums are presented on a calendar year basis. GLTs which show cumulative paid losses and ALAE, gross and net of reinsurance, are presented for each class of business. Finally, we present GLTs of cumulative net reported losses and ALAE (paid plus case reserves) for each class of business. For the reinsurance segment’s classes of business, the GLTs are presented on a treaty year basis. For direct insurance business, property classes of business are presented on an accident year basis. Our general casualty classes of business are a blend of policies where losses can be triggered by either report date or accident date, so the paid and reported losses are a blend of report year and accident year data. The remaining casualty classes of business, including professional liability and healthcare, are presented on a report year basis. These conventions match the standard industry reserving practices for reinsurance and direct insurance, respectively.

     Case reserves for Allied World’s reinsurance classes are generally established based upon reports received from ceding companies as we generally “follow their fortunes.” Additional case reserves may be established by Allied World to reflect our estimated ultimate cost of a loss. Any such additional case reserves have been included in the presented reinsurance GLTs.

     The premiums in our reinsurance segment are often based upon estimates by the ceding companies. At the end of the treaty year, these estimates will be replaced by actual premiums. In addition, some of our reinsurance treaties may have premiums that are swing-rated subject to reinstatement premiums. The presented premium data is subject to future adjustments, either upwards or downwards, based upon these factors.

     Large Losses

     Loss development associated with the following three groups of catastrophic losses have been excluded from the GLTs for all lines except for property catastrophe: (1) 2004 hurricanes, (2) 2005 hurricanes, (3) 2008 hurricanes and (4) 2010 Chile Earthquake. These events have been excluded from the GLTs due to their magnitude in order to avoid distortions in the development factors and indicated reserve levels. Reserves for these events are not based on aggregate development statistics, but rather on ground-up, exposure-based assessments reflecting information provided by insureds and cedents on an insurance policy-by-policy and reinsurance contract-by-contract basis. Separate information is provided on these catastrophic events including gross and net paid losses, reported losses and IBNR as of December 31, 2010.

     GLT Class Details

     Insurance Lines of Business

     Property — Our property insurance GLTs are shown on both a gross and net of reinsurance basis (see pages 12 and 16). The vast majority of the ceded reinsurance we have purchased for our direct property class of business is written as quota share reinsurance, with a smaller portion written as facultative reinsurance. We have not removed losses associated with recoveries from any catastrophe covers as we have excluded major catastrophes already from the data. The major catastrophes removed from our property insurance GLTs, as well as from our “property other reinsurance” and our “other reinsurance” GLTs discussed below, include:

	•		2004 — Hurricanes/Tropical Storms Charlie, Frances, Jeanne and Ivan;
	•		2005 — Hurricanes/Tropical Storms Katrina, Rita and Wilma;
	•		2008 — Hurricanes/Tropical Storms Gustav and Ike; and
	•		2010 — Chilean Earthquake.

     It should be noted that we removed all property losses associated with these events, even after such storms may have weakened and moved inland. For our property insurance GLTs, the total amounts excluded from these storms are as follows:

		Gross								Net of Reinsurance
		Paid				Reported				Paid				Reported
		(Dollars in Millions)								(Dollars in Millions)
2004 Events		$	166.6			$	169.0			$	146.2			$	148.3
2005 Events		$	454.7			$	458.1			$	189.2			$	190.8
2008 Events		$	90.5			$	99.8			$	57.3			$	64.7
2010 Events		$	42.9			$	65.3			$	36.6			$	50.9

     Our property book of business has shifted over time. Over the last several years, we have de-emphasized energy classes of business, which included such industry classes as mining, chemical plants, pulp and paper manufacturing and refiners. In addition, our Bermuda property book of business (which is included in the property insurance GLTs) has evolved from largely being a primary insurance account based book of business to where we now write many accounts on an excess basis. Our European property business (which is also included in the property insurance GLTs) has shifted away from accounts with higher relative frequency in the past 36 months.

     General Casualty — Our general casualty insurance GLTs are shown on both a gross and net of reinsurance basis (see pages 13 and 17). Our Bermuda and European casualty books of business are comprised largely of Fortune 1000-type accounts with generally high attachment points with medians between $80 million and $100 million. Historically, about 55% to 57% of the earned premiums have come from occurrence policies. This percentage grew to 65% to 67% in 2010 as our business mix has shifted to more occurrence business as we expanded our U.S. underwriting platform. The vast majority of the ceded reinsurance we have purchased for the

casualty class of business has been either quota share reinsurance or surplus treaty reinsurance. The general casualty book has changed over time, with pharmaceutical and energy classes being de-emphasized in Bermuda and with the business underwritten in the United States (which generally has a lower attachment point profile) shrinking in the 2005-2007 calendar years and growing in the 2008-2010 calendar years.

     Professional Liability Lines — Our professional liability lines insurance GLTs are shown on both a gross and net of reinsurance basis (see pages 14 and 18). Professional liability lines include directors and officers liability, errors & omissions liability, D&O side A cover, employment practices liability insurance and fiduciary liability business. Similar to our casualty lines of business, our Bermuda and European professional liability lines are comprised largely of Fortune 1000 and FTSE 1000-type accounts with generally high attachment points with medians between $80 million and $100 million. It is not uncommon for the Company to “ventilate” an account, which means the Company underwrites two excess layers with differing attachment points. Our U.S. professional liability book has a very different profile, with a portion of the business underwritten on a primary basis for smaller, non-Fortune 1000 accounts. Common classes include insurance agencies, psychologists/counselors and smaller law firms. Our professional liability lines book of business is written on claims-made and occurrence-reported basis and virtually none of this business is written on an occurrence basis (regardless of where it is written).

     Healthcare — Our healthcare insurance GLTs are shown on both a gross and net of reinsurance basis (see pages 15 and 19). Our healthcare book of business is written on a claims-made and occurrence-reported basis and has virtually no business written on occurrence policy forms. The Bermuda healthcare group writes gross lines of up to $25 million, with average attachment points of around $45 million. This business is largely comprised of large hospitals, but does include managed care organizations and healthcare systems. The U.S. healthcare business has a much lower attachment point profile than the international book of business, with much of the U.S. business being written on a primary basis. It includes smaller hospitals and hospital systems, managed care organizations and medical facilities such as home care providers, specialized surgery and rehabilitation centers, and outpatient clinics. Our Bermuda business has also begun to write accounts on a primary basis, although typically over a large deductible.

     Reinsurance Lines of Business

     Property Catastrophe — Our property catastrophe reinsurance GLTs are shown on both a gross and net of reinsurance basis (see pages 20 and 25). This business is excess-of-loss property catastrophe reinsurance. Typically, it has a relatively short tail.

     Property Other — Our property other reinsurance GLTs are shown on both a gross and net of reinsurance basis (see pages 21 and 26). This line contains our entire property reinsurance book of business, excluding property catastrophe coverages, and is written as either excess-of-loss reinsurance or quota share reinsurance.

     General Casualty — Our general casualty reinsurance GLTs are shown on both a gross and net of reinsurance basis (see pages 22 and 27). This business is essentially comprised of any

business that does not fit into the other casualty classes. It is largely umbrella casualty business that contains some workers’ compensation business. This business can be written as either excess-of-loss reinsurance or quota share reinsurance.

     Professional Liability Lines — Our professional liability lines reinsurance GLTs are shown on both a gross and net of reinsurance basis (see pages 23 and 28). This business is largely written on a claims-made basis. Lines of business include employment practices liability insurance, medical malpractice, directors and officers, errors and omissions and miscellaneous professional classes and transactional risk liability. Some of our larger treaties can have complex structures, including swing-rated premiums, loss corridors and annual aggregate deductibles. This business is written as either excess-of-loss reinsurance or quota share reinsurance.

     Other Reinsurance — Our other reinsurance GLTs are shown on both a gross and net of reinsurance basis (see pages 24 and 29). This business is a mixture of miscellaneous lines including accident and health (which is predominantly catastrophe driven), workers’ compensation catastrophe, aviation and marine. Virtually all of the losses are associated with aviation and marine treaties. The marine treaties were impacted by various hurricanes (specifically Ivan, Katrina, Rita, Ike and Gustav) which went through the Gulf of Mexico. All of our marine and aviation treaties have been written as quota share reinsurance.

     For our other reinsurance GLTs, the total amounts excluded from the 2004, 2005, 2008 and 2010 events discussed above are as follows:

		Gross								Net of Reinsurance
		Paid				Reported				Paid				Reported
		(Dollars in Millions)								(Dollars in Millions)
2004 Events		$	38.2			$	40.8			$	38.2			$	40.8
2005 Events		$	91.5			$	95.0			$	84.5			$	88.0
2008 Events		$	0.7			$	5.3			$	0.7			$	5.3
2010 Events		$	0.1			$	0.8			$	0.1			$	0.8

December 2010 Global Loss Triangles — Insurance Segment
Excluding large losses
U.S. dollars in thousands

Property Insurance (Gross of Ceded Reinsurance)

Cumulative Paid Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			2,584				29,354				46,287				51,590				56,582				56,687				56,776				56,675				56,700
2003			50,572				136,299				198,801				217,328				218,048				217,531				221,698				221,688
2004			38,251				153,141				203,006				217,517				229,272				232,078				234,064
2005			91,198				228,634				308,207				354,186				366,824				365,367
2006			30,040				103,621				172,546				201,132				208,659
2007			43,151				129,076				169,655				186,261
2008			75,528				155,973				198,875
2009			24,044				64,420
2010			44,677

Reported Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			18,005				55,432				58,559				59,169				57,437				56,848				57,987				56,707				56,700
2003			146,467				208,054				228,434				232,111				227,106				224,146				222,856				222,651
2004			132,453				223,857				246,725				247,912				245,057				240,018				238,280
2005			223,945				353,412				382,622				383,966				381,922				370,203
2006			157,140				225,124				235,681				222,453				219,524
2007			189,533				227,570				227,509				220,583
2008			263,049				265,851				240,547
2009			89,871				89,436
2010			114,273

Reported Loss & ALAE Ratio to Earned Premium (excluding IBNR)

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			9	%			28	%			30	%			30	%			29	%			29	%			30	%			29	%			29	%
2003			30	%			43	%			47	%			48	%			47	%			46	%			46	%			46	%
2004			23	%			40	%			44	%			44	%			43	%			42	%			42	%
2005			47	%			74	%			80	%			81	%			80	%			78	%
2006			36	%			51	%			53	%			50	%			50	%
2007			45	%			54	%			54	%			52	%
2008			74	%			74	%			67	%
2009			33	%			33	%
2010			49	%

Accident		Earned				Loss & ALAE																								Ult. L&ALAE
Year		Premium				Paid				Reported				Case O/S				IBNR				Unpaid				Ultimate				Ratio
2002			195,890				56,700				56,700				—				0				0				56,700				28.9	%
2003			483,719				221,688				222,651				963				240				1,203				222,891				46.1	%
2004			565,327				234,064				238,280				4,216				1,859				6,074				240,138				42.5	%
2005			476,481				365,367				370,203				4,836				690				5,526				370,893				77.8	%
2006			441,138				208,659				219,524				10,865				1,779				12,644				221,303				50.2	%
2007			423,468				186,261				220,583				34,321				9,222				43,543				229,804				54.3	%
2008			357,588				198,875				240,547				41,671				26,618				68,290				267,165				74.7	%
2009			272,873				64,420				89,436				25,017				33,898				58,915				123,334				45.2	%
2010			231,398				44,677				114,273				69,596				60,704				130,300				174,977				75.6	%
Total			3,447,882				1,580,711				1,772,196				191,485				135,010				326,495				1,907,206				55.3	%

December 2010 Global Loss Triangles — Insurance Segment

U.S. dollars in thousands

General Casualty Insurance (Gross of Ceded Reinsurance)

Cumulative Paid Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			0				0				185				464				2,848				4,691				5,591				6,574				7,802
2003			0				461				16,019				18,500				29,401				55,140				57,458				57,463
2004			0				21				90				634				5,507				8,516				19,470
2005			15				26,548				31,396				63,544				65,785				118,117
2006			—				274				2,591				34,249				84,696
2007			107				7,235				9,707				13,553
2008			1,319				8,351				26,339
2009			309				8,308
2010			1,046

Reported Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			1,429				617				989				552				6,299				15,616				16,506				17,369				23,360
2003			23				13,124				25,852				33,579				58,980				59,141				57,667				57,575
2004			1,007				540				816				915				7,822				24,831				25,154
2005			30,852				109,619				113,339				119,923				124,573				124,781
2006			165				30,097				39,318				90,005				92,725
2007			4,131				15,419				15,970				32,500
2008			8,193				26,768				52,114
2009			1,876				35,210
2010			70,070

Reported Loss & ALAE Ratio to Earned Premium (excluding IBNR)

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			2	%			1	%			1	%			1	%			7	%			18	%			19	%			20	%			27	%
2003			0	%			5	%			10	%			13	%			23	%			23	%			22	%			22	%
2004			0	%			0	%			0	%			0	%			2	%			7	%			8	%
2005			10	%			37	%			38	%			40	%			42	%			42	%
2006			0	%			11	%			14	%			33	%			34	%
2007			2	%			6	%			6	%			12	%
2008			3	%			11	%			21	%
2009			1	%			13	%
2010			24	%

Accident		Earned				Loss & ALAE																								Ult. L&ALAE
Year		Premium				Paid				Reported				Case O/S				IBNR				Unpaid				Ultimate				Ratio
2002			88,051				7,802				23,360				15,559				10,972				26,530				34,332				39.0	%
2003			257,017				57,463				57,575				112				40,996				41,108				98,571				38.4	%
2004			332,389				19,470				25,154				5,684				64,723				70,407				89,877				27.0	%
2005			297,511				118,117				124,781				6,664				109,598				116,262				234,379				78.8	%
2006			275,405				84,696				92,725				8,029				137,357				145,386				230,082				83.5	%
2007			264,680				13,553				32,500				18,947				146,457				165,404				178,957				67.6	%
2008			243,673				26,339				52,114				25,774				166,732				192,507				218,846				89.8	%
2009			265,068				8,308				35,210				26,902				165,754				192,656				200,964				75.8	%
2010			290,500				1,046				70,070				69,024				193,494				262,518				263,564				90.7	%
Total			2,314,293				336,794				513,490				176,697				1,036,082				1,212,778				1,549,572				67.0	%

December 2010 Global Loss Triangles — Insurance Segment

U.S. dollars in thousands

Professional Liability Lines Insurance (Gross of Ceded Reinsurance)

Cumulative Paid Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			—				10				61				5,225				13,909				45,884				59,860				59,930				59,944
2003			20				80				603				802				6,002				16,936				17,238				26,397
2004			15				683				7,406				29,477				30,403				39,004				48,452
2005			95				3,328				7,370				23,528				24,320				44,267
2006			296				6,850				44,815				59,330				88,030
2007			1,401				12,296				41,300				66,932
2008			2,750				22,943				46,619
2009			6,061				31,918
2010			9,674

Reported Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			—				2,010				7,062				23,775				28,000				47,706				60,648				59,930				59,944
2003			60				243				858				6,255				33,468				41,460				44,712				42,038
2004			434				1,692				8,106				32,701				55,437				55,592				61,361
2005			3,931				15,625				48,363				51,426				50,281				58,062
2006			41,225				52,944				92,820				120,819				133,885
2007			11,223				47,137				111,589				143,583
2008			17,483				86,164				125,901
2009			20,787				62,090
2010			30,916

Reported Loss & ALAE Ratio to Earned Premium (excluding IBNR)

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			0	%			3	%			12	%			40	%			47	%			80	%			102	%			101	%			101	%
2003			0	%			0	%			0	%			3	%			14	%			17	%			19	%			18	%
2004			0	%			1	%			3	%			10	%			17	%			17	%			19	%
2005			1	%			4	%			14	%			15	%			14	%			16	%
2006			10	%			13	%			23	%			31	%			34	%
2007			3	%			11	%			26	%			33	%
2008			4	%			19	%			28	%
2009			4	%			12	%
2010			7	%

Accident		Earned				Loss & ALAE																								Ult. L&ALAE
Year		Premium				Paid				Reported				Case O/S				IBNR				Unpaid				Ultimate				Ratio
2002			59,558				59,944				59,944				—				4,369				4,369				64,313				108.0	%
2003			237,656				26,397				42,038				15,641				23,662				39,302				65,700				27.6	%
2004			321,801				48,452				61,361				12,909				35,678				48,587				97,039				30.2	%
2005			352,174				44,267				58,062				13,794				58,613				72,408				116,675				33.1	%
2006			395,104				88,030				133,885				45,855				144,081				189,936				277,966				70.4	%
2007			431,009				66,932				143,583				76,651				159,035				235,687				302,618				70.2	%
2008			457,068				46,619				125,901				79,282				191,566				270,848				317,467				69.5	%
2009			512,438				31,918				62,090				30,172				303,869				334,041				365,959				71.4	%
2010			475,222				9,674				30,916				21,242				302,118				323,360				333,035				70.1	%
Total			3,242,029				422,233				717,780				295,547				1,222,991				1,518,538				1,940,771				59.9	%

December 2010 Global Loss Triangles — Insurance Segment

U.S. dollars in thousands

Healthcare Insurance (Gross of Ceded Reinsurance)

Cumulative Paid Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			—				835				2,158				3,209				5,533				8,008				8,020				8,023				8,026
2003			1				4,202				11,148				13,777				14,724				18,198				18,756				20,074
2004			2				852				5,892				9,738				12,694				13,229				13,379
2005			277				2,861				4,941				10,255				11,122				11,692
2006			381				4,009				5,864				12,839				16,034
2007			944				7,190				17,307				20,125
2008			793				9,776				18,440
2009			6,586				16,657
2010			2,168

Reported Loss & ALAE

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			130				1,351				5,450				8,985				8,910				8,444				8,121				8,086				8,046
2003			345				11,153				20,246				20,723				20,529				23,625				23,160				23,420
2004			1,849				6,406				12,190				14,720				14,999				16,045				15,928
2005			5,566				11,649				15,497				14,435				13,384				13,710
2006			5,666				11,753				13,222				17,022				19,082
2007			3,773				15,281				24,537				37,172
2008			3,801				19,115				33,200
2009			10,999				29,590
2010			11,846

Reported Loss & ALAE Ratio to Earned Premium (excluding IBNR)

Accident		Months of Development
Year		12				24				36				48				60				72				84				96				108
2002			0	%			3	%			14	%			23	%			22	%			21	%			20	%			20	%			20	%
2003			0	%			15	%			27	%			27	%			27	%			31	%			30	%			31	%
2004			2	%			5	%			10	%			12	%			12	%			13	%			13	%
2005			4	%			9	%			11	%			11	%			10	%			10	%
2006			4	%			8	%			9	%			11	%			13	%
2007			3	%			10	%			17	%			25	%
2008			2	%			11	%			19	%
2009			6	%			15	%
2010			5	%

Accident		Earned				Loss & ALAE																								Ult. L&ALAE
Year		Premium				Paid				Reported				Case O/S				IBNR				Unpaid				Ultimate				Ratio
2002			39,904				8,026				8,046				20				2,856				2,876				10,902				27.3	%
2003			76,140				20,074				23,420				3,346				7,668				11,014				31,088				40.8	%
2004			120,800				13,379				15,928				2,549				14,222				16,771				30,150				25.0	%
2005			136,577				11,692				13,710				2,019				18,957				20,976				32,667				23.9	%
2006			150,401				16,034				19,082				3,048				31,388				34,436				50,470				33.6	%
2007			147,720				20,125				37,172				17,047				38,091				55,138				75,263				50.9	%
2008			170,600				18,440				33,200				14,760				58,217				72,977				91,417				53.6	%
2009			197,314				16,657				29,590				12,933				80,969				93,903				110,560				56.0	%
2010			222,171				2,168				11,846				9,678				120,889				130,567				132,735				59.7	%
Total			1,261,627				126,596				191,996				65,400				373,257				438,657				565,252				44.8	%