EXHIBIT 99.1

Endurance Specialty Holdings Ltd.

2010 Loss Development Triangles

2010 Loss Development Triangle Cautionary Language

This report is for informational purposes only and is current as of December 31, 2010. We are under no obligation and do not expect to update or revise this report, whether as a result of new information, future events or otherwise, even when such new data has been reflected in the Company’s filings with the U.S. Security and Exchange Commission (the “SEC”) or otherwise. 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 information, 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. This report should be read in conjunction with other documents filed by Endurance Specialty Holdings Ltd. (“Endurance” or the “Company”) with the SEC, including the most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q.

Safe Harbor for Forward-Looking Statements

Some of the statements in this report may include forward-looking statements which reflect management’s current views with respect to future events and financial performance. Such statements may include forward-looking statements with respect to the Company in general and the insurance and reinsurance business segments specifically, both as to underwriting and investment matters. Statements which include the words “expect,” “intend,” “plan,” “believe,” “project,” “anticipate,” “seek,” “will,” and similar statements of a future or forward-looking nature identify forward-looking statements in this report for purposes of the U.S. federal securities laws or otherwise. The Company intends these forward-looking statements to be covered by the safe harbor provisions for forward-looking statements in the Private Securities Litigation Reform Act of 1995.

All forward-looking statements address matters that involve risks and uncertainties. Accordingly, there are or may be important factors that could cause actual results to differ from those indicated in the forward-looking statements in this report. These factors include, but are not limited to, (i) changes in the size of the claims payable by Endurance relating to natural catastrophes, (ii) greater frequency or severity of claims and loss activity than Endurance’s underwriting, reserving or investment practices anticipate based upon historical experience or industry data, (iii) trends in rates for property and casualty insurance and reinsurance, (iv) changes in the judicial, legislative or regulatory environments in which Endurance operates, (v) changes in general economic conditions, including foreign currency exchange rates, inflation and other factors and (vi) the other factors described in the Company’s most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q.

Forward-looking statements speak only as of the date on which they are made, and the Company undertakes no obligation publicly to update or revise any forward-looking statement, whether as a result of new information, future developments or otherwise.

ENDURANCE SPECIALTY HOLDINGS LTD.

2010 GLOBAL LOSS TRIANGLES

Table of Contents

Section		Page
I. Introduction			1
II. Observations on Data Presented			3
III. Data Compilation and Definitions			5
IV. Triangle Class Details			12
V. Overview of Reserving Methodology			17
VI. Reconciliations			20
VII. Data and Exhibits (Summary Exhibits and Triangles)
Consolidated Total		Exhibit 1
Insurance Segment
High Attaching Excess of Loss Casualty		Exhibit 2
United States Sourced Casualty		Exhibit 3
Workers’ Compensation		Exhibit 4
Agriculture and Other Specialty		Exhibit 5
International Sourced Property		Exhibit 6
United States Sourced Property		Exhibit 7
Reinsurance Segment
Casualty Directors and Officers		Exhibit 8
Casualty Motor		Exhibit 9
Casualty Other		Exhibit 10
Workers’ Compensation		Exhibit 11
Agriculture and Other Specialty		Exhibit 12
Short Tail Marine and Aerospace		Exhibit 13
Short Tail Property		Exhibit 14
Short Tail Surety		Exhibit 15
Consolidated Workers’ Compensation		Exhibit 16
Insurance Long Tail		Exhibit 17
Insurance Other		Exhibit 18
Insurance Short Tail		Exhibit 19
Reinsurance Long Tail		Exhibit 20
Reinsurance Other		Exhibit 21
Reinsurance Short Tail		Exhibit 22
Insurance Segment		Exhibit 23
Reinsurance Segment		Exhibit 24

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

I. INTRODUCTION

This report provides additional information on the loss development characteristics of Endurance Specialty Holdings Ltd. and its consolidated subsidiaries (“Endurance” or the “Company”) as of December 31, 2010. This report provides greater detail on Endurance’s reserves by showing global loss triangles for gross paid and reported loss and loss adjustment expenses (“LAE”) by accident year at annual evaluation dates. The most recent evaluation is as of December 31, 2010. In addition, accident year summary exhibits are provided which further highlight the gross, ceded, and net results by business segment and triangle classes as of December 31, 2010. These summaries include: earned premiums, paid loss and allocated loss adjustment expenses (“ALAE”); cases outstanding losses; additional case reserves; incurred but not reported losses (“IBNR”); unallocated loss adjustment expenses reserve (“ULAE”); and the ultimate loss & LAE ratios as of December 31, 2010 on an inception to date basis. Section II of this document offers general observations on the data presented in both the triangles and the summary exhibits, while Section III provides a discussion of the means used to compile the data, as well as definitions for many of the terms used in this report. A more detailed description of the business underlying the triangle information is found in Section IV of this report. Section V of this report contains a summary description of management’s loss reserving methodology.

The inherent uncertainty associated with the estimation of loss and LAE reserves remains a significant balance sheet risk for all property-casualty specialty insurance and reinsurance companies, including Endurance. Management believes the triangles and corresponding accident year summary exhibits along with the narrative in this report provide additional insight into the loss development characteristics of Endurance’s diversified businesses.

The process of establishing and periodically adjusting loss and LAE reserves is an inherently complex process containing numerous management judgments related to the segmentation of data, methodologies utilized and their associated parameters, along with the weights applied to the various techniques used in the reserving process. Actuarial determinations of unpaid future losses and LAE are subject to potential errors of estimation, which could be significant, due to the fact that the ultimate disposition of claims incurred prior to the date of such estimation, whether reported to Endurance or not, is subject to the outcome of events that have not yet occurred. Likewise, any estimate of future costs associated with claims settlement is subject to the inherent limitation on the ability to predict the course of future events. Consequently, it should be expected that the actual emergence of the ultimate loss and LAE will vary, perhaps considerably, from any prior estimate. Readers should also review additional reserve disclosures and company risk factors that are provided in the Company’s most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q filed with the SEC.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Readers of this report are strongly advised against projecting ultimate losses and LAE for Endurance directly from the loss development triangles in this report, as these calculations rarely take into account fully the true underlying nature of the liabilities. The fourteen triangle classes

we have selected are the compilation of over 200 discrete reserving groups within Endurance that represent different geographies, pricing environments, legislative climates, and policy forms.

Also, depending upon which actuarial reserving method is utilized, the presence or absence of large catastrophe losses and how they are treated may have a significant impact on the estimated ultimate loss and LAE. In addition, changes to the premium volume, mix of business and the underlying exposures within a class may have significant effects on the resulting ultimate loss estimates and overall reserve levels. Without incorporating this critical information, the results derived from a direct extrapolation of the loss development triangles in this report have the potential of being materially misleading.

The triangles and summary exhibits are provided for both the Insurance and Reinsurance segments of the Company. In addition, while analysis, reviews and reporting of reserves focuses primarily on the loss reserve development classes within each business segment, the information provided in the triangles in this report has been expanded to capture some of the additional differences in reporting that naturally occur within these lines of business. For ease of comparison, a reconciliation of the information presented in this report to our five reserve development tails and two segments is provided. The losses in these exhibits and triangles represent the Company’s December 31, 2010 gross, ceded and net loss and LAE reserves in their entirety, although these amounts have been adjusted for changes in foreign currency. A reconciliation to select data from the Company’s financial statements prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) is included in Section VI of this document.

As discussed more fully in Section III, the accident year losses in these exhibits and triangles are adjusted for changes in calendar year earned premium adjustments and foreign exchange movements. Because of these adjustments, which we would expect to continue, future versions of this information will not tie directly to the data included in this report.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

II. OBSERVATIONS ON DATA PRESENTED

Based on the data as of December 31, 2010 presented in this report, we believe the following general observations are noteworthy:

	•		As of December 31, 2010, 72% of Endurance’s gross loss and LAE reserves arise from Long Tail lines of business, which by their nature contain a significant amount of uncertainty. Of the 72% of Endurance’s gross Long Tail loss and LAE reserves, 45% are generated from the Company’s Insurance segment and 27% from the Reinsurance segment.
	•		On an inception to date basis, 64% and 36% of gross (net of FCIC) earned premium arises from the Reinsurance and Insurance segments, respectively. Correspondingly, on a gross basis 49% and 51% of loss and LAE reserves arise from the Reinsurance and Insurance segments, respectively. On a net basis, 52% and 48% of the loss and LAE reserves arise from the Reinsurance and Insurance segments, respectively.
	•		Additional Case Reserves (“ACRs”) amount to 10% of reported case reserves. Within Endurance’s Reinsurance Long Tail lines of business, this amount is approximately 37% of the reported case reserves.
	•		IBNR reserves for Endurance’s Long Tail lines of business represent 74% of the total gross reserves within the Long Tail lines of business, indicating an IBNR to case outstanding ratio of over three to one. Within the Insurance Long Tail business, IBNR reserves represent approximately 76% of the total gross reserves. Within the Reinsurance Long Tail business, IBNR reserves represent approximately 71% of the total gross reserves.
	•		On an inception to date basis, the Short Tail and Other Specialty reserve categories have contributed approximately 65% to the overall total favorable development. Insurance and Reinsurance Long Tail reserve categories contributed to the remaining 35%. A majority of this Long Tail favorable development came from accident years 2006 and prior and from Reinsurance Professional and Insurance High Attaching Excess of Loss claims-made business.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

			The Reinsurance and Insurance segments have contributed approximately 51% and 49% to the total inception to date prior year favorable reserve development, respectively.
	•		Endurance’s overall inception to date gross ultimate loss and LAE ratio (net of FCIC) of 59% is comprised of a 64% loss ratio for the Insurance segment and a 57% loss ratio for the Reinsurance segment.
	•		As discussed in the preceding section, accident year losses and triangles are adjusted for changes in calendar year earned premium adjustments and foreign exchange movements. Therefore, this version of Endurance’s Global Loss Triangles does not tie to the previous version. For example, inception to date gross earned premium as of December 31, 2009 is $33 million less in this report than our 2009 Global Loss Triangles. Of this difference, approximately $34 million is due to changes in foreign exchange rates between year end 2009 and year end 2010.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

III. DATA COMPILATION AND DEFINITIONS

Numerous data elements were extracted to prepare this report. The Global Loss Triangles and summary exhibits are presented on an accident year (or report year where applicable) basis. While underwriting or policy year statistics may also provide useful information for analysis purposes, management believes the accident/report year presentation better highlights the true loss activity that occurs at Endurance within a given calendar year. We note that the accident year presentation of triangles requires the utilization of assumptions and allocation procedures with respect to certain lines of business underwritten by Endurance (bordereaux allocation). This is primarily as a result of not receiving sufficient information from ceding companies in certain lines of business that prevents the allocation of claims to specific accident years with certainty. Although we attempt to keep the allocations reasonable and accurate as possible, to the extent our assumptions and allocation procedures differ from actual historical loss development patterns, the actual loss development may differ materially from the loss development included in this report.

Data Presented

The data presented in the accident year triangle and summary exhibits is as follows:

•

Triangles

	•		Paid loss and LAE
	•		Case incurred loss & LAE (including ACRs)
	•		Ultimate loss and LAE
	•		Earned Premium
	•		Ultimate loss and LAE ratio
	•		Ultimate loss and LAE emergence

•

Summary Exhibits

	•		Gross premium, paid losses, reserves (case outstanding, ACRs, IBNR, ULAE)
	•		Ceded premium, paid losses, reserves (case outstanding, ACRs, IBNR, ULAE)
	•		Net premium, paid losses, reserves (case outstanding, ACRs, IBNR, ULAE)

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Basis of Presentation

Information presented herein may differ materially from that reported in Endurance’s financial statements prepared in accordance with GAAP due to differences in foreign currency exchange rates, exclusion of the FCIC cessions, the impact of premium adjustments and other data adjustments.

All amounts are presented in thousands of U.S. dollars and reflect the conversion from the original currency of the underlying business if not denominated in U.S. dollars (“USD”). Foreign currency denominated losses and premiums are converted based on exchange rates at the dates of the transactions to the currency of the legal underwriting entity, which are either USD or British Pounds (“GBP”). Endurance’s reporting currency is USD. Fluctuations in currency exchange rates can cause material shifts in loss development. To eliminate distortions caused by such fluctuations, data in the triangles have been restated using the year end 2010 rate of exchange of 1.566 USD to GBP.

Some (re)insurance contracts and policies contain provisions resulting in a variation of the premium or acquisition expenses as a result of loss experience under the contract or policy. Within the analysis, estimated reinstatement premiums are included in the premium totals. In addition, premium adjustments with respect to paid losses are reflected in the triangles but adjustments to premium resulting from future expected claims settlements are not.

Inter-company reinsurance transactions have not been reflected in the triangles. The summary exhibits also include ceded (third party) and net schedules.

The loss development triangles are presented on the basis of applying reinsurance accounting to all Endurance’s business and do not reflect any adjustments that may be required for financial reporting purposes to comply with Accounting Standards Certification Topic 340 Subtopic 30 “Other Assets and Deferred Cost Insurance Contracts that do not Transfer Risk” as highlighted in the reconciliation to GAAP reserves in Section VI of this document.

Earned Premium

The earned premium triangle includes the calendar year changes in accident year earned premium due to premium adjustments. For financial reporting purposes, the premium adjustments are recognized in the calendar year they were determined. For actuarial reserving purposes, these premium adjustments are allocated to the accident year or years based on the initial policy or treaty to which the adjustment belongs. For example, if a premium adjustment is recognized in calendar year 2010 from a policy written and exposures earned in 2005, the additional premium is recognized in the 2010 calendar year for financial reporting purposes. However, for reserving purposes, the premium is allocated to the years in which the premium for the 2005 treaty was originally earned. As a result, the information provided herein may differ materially from that presented in Endurance’s financial statements.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Ultimate Loss and LAE Ratio

The ultimate loss and LAE ratio triangle shows the year to year changes in the ratio of all expected settlement amounts, whether paid or reserved, together with any associated settlement expenses to earned premium. The ultimate loss and LAE ratio is presented to show the relationship between management’s best estimate of expected ultimate losses and LAE and the associated premiums that were received by Endurance to assume the risks related to those losses. Ultimate losses and LAE within an accident year are subject to many factors that impact the recorded value of such losses (such as favorable/adverse claims emergence, frequency/severity trends, inflation, methodology changes, foreign exchange fluctuations, and premium adjustments from prior accident periods). Since Endurance distributes earned premium from premium adjustments to the appropriate accident year in its reserving process, one will see changes in booked ultimate losses solely due to these premium changes. Because of this phenomenon, the triangle of ultimate loss & LAE ratios can be very useful as it essentially removes the effect of changes in premium from the loss estimates. At any point (maturity) in the triangle, management’s best estimate of booked ultimate loss and LAE estimate is the product of the corresponding accident year earned premium and ultimate loss and LAE ratio.

Ultimate Loss and LAE

The triangle of ultimate loss and LAE is derived by multiplying the most recent accident year earned premium (the last diagonal of the earned premium triangle) by the historical accident year ultimate loss and LAE ratio as presented in their respective triangles. For example, using the consolidated triangles, the ultimate loss and LAE amount for accident year 2004 at 12 months maturity ($1,102 million) is derived by multiplying the ultimate loss and LAE ratio for accident year 2004 at 12 months maturity (67%) by the latest earned premium for accident year 2004 ($1,645 million) at 72 months maturity. This presentation removes the effect of premium adjustments from the development of ultimate losses, and provides a better picture of the changes occurring to the true accident year ultimate loss and LAE. Reconciliation to Endurance’s GAAP financial statements is included in Section VI of this report.

Ultimate Loss Emergence

The triangle of ultimate loss emergence is calculated by taking the difference of corresponding cells in the ultimate loss and LAE triangle. For example, using the consolidated triangles, the change in ultimate loss at the 12 month maturity for the 2006 accident year is derived by subtracting the ultimate loss & LAE at the 12 month maturity for the 2006 accident year from the ultimate loss & LAE at the 24 month maturity for the same accident year. The full calendar year emergence is represented by the total of any given diagonal (excluding the loss emergence within the first 12 months of an accident year), and is also shown as an additional row at the bottom of the triangle.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Global Loss Triangle Classes

Triangles are provided in 15 classes, six for the Insurance segment, and eight for the Reinsurance segment and a combined Insurance and Reinsurance workers’ compensation class. The classes are based on the loss development characteristics for the lines of business represented by the exposures in a given triangle class (motor, workers compensation, directors & officers, etc.), as well as differences in the underlying business as evidenced by the separate Insurance casualty classes. It is important to note that for the Reinsurance classes, there is no differentiation between proportional and non-proportional business that could have different loss emergence patterns. The combined Insurance and Reinsurance workers’ compensation class is included as the current insurance workers’ compensation business was transitioned from a proportional reinsurance treaty to insurance in 2006. The 15 triangle classes included in this report are listed below.

Insurance Segment Loss Triangle Classes

	•		High Attaching Excess of Loss Casualty (Insurance Long Tail)
	•		United States Sourced Casualty (Insurance Long Tail)
	•		Workers’ Compensation (Insurance Long Tail)
	•		Agriculture and Other Specialty (Insurance Other Specialty)
	•		International Sourced Property (Insurance Short Tail)
	•		United States Sourced Property (Insurance Short Tail)

Reinsurance Segment Loss Triangle Classes

	•		Casualty Directors and Officers (Reinsurance Long Tail)
	•		Casualty Motor (Reinsurance Long Tail)
	•		Casualty Other (Reinsurance Long Tail)
	•		Workers’ Compensation (Reinsurance Long Tail)
	•		Agriculture and Other Specialty (Reinsurance Other Specialty)
	•		Short Tail Marine and Aerospace (Reinsurance Long Tail)
	•		Short Tail Property (Reinsurance Short Tail)
	•		Short Tail Surety (Reinsurance Short Tail)

Combined Insurance and Reinsurance Loss Triangle Class

•

Workers’ Compensation (Insurance and Reinsurance Long Tail)

Further detail of the types of business contained in each class is provided in Section IV of this document. In the upper left hand label of each triangle (excluding the one combined triangle class), a mapping of that triangle’s classes to the reserve categories disclosed in the Company’s Annual Report on Form 10-K is included. In addition, Section VII includes a mapping of the lines of business within the Company’s segments to the associated triangle class.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Accident Year Loss Allocation

Many proportional reinsurance contracts are submitted using quarterly bordereau reporting by underwriting year with a supplemental listing of large losses. As a result, a two step allocation process was utilized to allocate these losses to accident year. The first step is to identify large losses and place them in the corresponding accident year as reported on a large loss listing. The second step is to allocate the remaining losses to particular accident years based on selected payment and reporting patterns applied to the earning of the underlying exposures, which in many instances is premium. To the extent management’s assumptions and allocation procedures differ from actual historical loss development patterns, the actual loss development may differ materially from the loss development included in this report.

Large Losses and Other Adjustments

The triangles are unadjusted with respect to large losses and catastrophic losses, including losses related to the 2004, 2005, and 2008 hurricanes. The loss amounts are gross of any retrocession recoveries. The premium data is gross of any retrocession recoveries and includes any reinstatement premiums associated with the loss events.

Business Not Included

Cessions to the FCIC within the Insurance Agriculture & Other Specialty class have been excluded from the analysis. No other business has been excluded from the analysis.

Discounting

The losses and IBNR stated in the triangles do not include a provision to reflect the time value of money.

Maturity of Triangle Periods

Since Endurance was formed in late 2001, underwriting data is available only for periods beginning 2001 or subsequent. For many lines of business, even less data is available as those lines were added more recently. For the business lines with sparse or limited data presented, there is an additional amount of uncertainty in the estimated ultimate loss and LAE and actual loss experience could differ materially from the estimated ultimate loss amount.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Definitions

To assist the reader, several key definitions are highlighted below.

Accident Year means the year in which the event occurred that triggered a claim to Endurance. All years referred to are years ending December 31^st.

Additional Case Reserves or ACRs are amounts that are held in addition to Case Reserves that result from Endurance’s claims professionals determining that the established Case Reserves (which are often established by cedents or third parties) are expected to be insufficient to meet the expected future settlement amounts.

Additional Event Reserves are amounts that are held in respect of known events that are expected to give rise to future settlements but at the time of being established, not enough is known to allocate them to specific (re)-insureds.

Allocated Loss Adjustment Expense or ALAE is an estimate of the associated external expenses to be incurred in settling a claim. ALAE includes the costs of third party loss assessors or legal experts.

Case Incurred Loss and ALAE is the sum of Paid Losses and ALAE, plus Case Reserves and any Additional Case Reserves.

Case Reserves are amounts set aside in relation to claims that have been made but not yet been paid and represent an assessment of the remaining amount to be paid in respect of each notified claim.

Ceded Claims are those amounts Endurance received or expects to receive from third party reinsurers to whom Endurance ceded premiums.

Ceded Premiums are those premiums paid by Endurance to third party reinsurers.

Diagonals in the triangle from bottom left to top right represent evaluation dates. For example, the last diagonal in our published triangles shows the position of each Accident Year as at December 31, 2010.

Earned Premium is the amount of policy premiums allocated between Accident Years in accordance with the assumed incidence of risk which results from insurance and reinsurance contracts that do not all commence at the start of a given Accident Year.

FCIC is the U.S. Federal Crop Insurance Corporation, the government reinsurer of multi-peril crop insurance underwritten by Endurance’s agriculture insurance subsidiary.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Gross Premiums and Gross Losses are shown before the impact of any third party outwards reinsurance that Endurance purchases including catastrophe bonds.

IBNR means incurred but not reported reserve, or a reserve amount held to cover expected future settlements in relation to all claims that have occurred but have not yet been reported to Endurance. This includes a reserve provision for claims which may have already occurred and expected development (upward or downward) in existing Case Reserves and Additional Case Reserves. Endurance’s process for establishing IBNR is discussed further in Section V of this document.

Loss Adjustment Expense or LAE is expense incurred in settling the claim. LAE includes the costs of third party loss assessors or legal experts and the cost of internal time necessary to settle a claim. LAE is the sum of ALAE and ULAE.

Maturity is measured in months from the start of the Accident Year.

Net means the retained portion of premiums written or losses paid and incurred. Net Premium equals Gross Premium less Ceded Premium and Net Losses equals Gross Losses less Ceded Claims.

Paid Losses are claim amounts paid to insureds or ceding companies.

Report Year / Claims Made Year refers to the year in which a claim is reported to Endurance. All years referred to are years ending December 31^st.

Triangle is a cross tabulation of data usually showing financial quantities in respect of periods of exposure (e.g. Accident Years), each evaluated at regular intervals (maturities).

Unallocated Loss Adjustment Expense or ULAE is an assessment of the internal expenses required to settle the current claims.

Ultimate Loss and LAE are the total of all expected settlement amounts, whether paid or reserved together with any associated settlement expenses and is the estimated total amount of loss at the measurement date. For the purposes of this report, Ultimate Loss & LAE is calculated by adding: Paid Loss ALAE, Case Reserves, Additional Case Reserves, IBNR (inclusive of Additional Event Reserves), and ULAE.

Ultimate Loss and LAE Ratio is the ratio of Ultimate Loss and LAE amounts to Earned Premium, which shows the relationship between expected losses and the associated premiums that are received related to those losses.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

IV. TRIANGLE CLASS DETAILS

a) Insurance Long Tail — High Attaching Excess of Loss Casualty

The high attaching excess of loss casualty triangle class represents the commercial casualty insurance business underwritten out of Endurance’s Bermuda operating subsidiary. This triangle class comprises three of Endurance’s lines of business.

Healthcare Liability Insurance — third party excess liability coverage for hospitals in the United States written on both a direct insurance basis and as reinsurance to captive insurance companies. Clients are predominantly multi-hospital systems, academic medical centers and specialty hospitals such as pediatric hospitals. Clients typically assume a large portion of their own risk, practice strong clinical risk management and claims management, and purchase large limits.

Excess Casualty Insurance — third-party liability coverage for a wide range of industry groups. Clients are typically Fortune 1000 companies in a variety of industries, including but not limited to: chemical manufacturers; medical products; pharmaceuticals; construction, including home builders and owner controlled insurance programs; transportation, including commuter and freight rail, and trucking; premises exposures; and manufacturing.

Professional Lines Insurance — management liability and professional liability coverage for all industry groups underwritten on a direct insurance or facultative reinsurance basis. Clients are U.S. and international commercial and financial institutions. The products in this business line include directors & officers liability (except managed care), errors & omissions, employment practices liability and fiduciary liability for commercial and financial institutions.

For Excess Casualty and Professional Lines Insurance, during 2010 Endurance has purchased and utilized a greater amount of third party reinsurance to limit its retention to within its risk tolerances.

b) Insurance Long Tail — United States Sourced Casualty

The United States sourced casualty class comprises U.S. commercial liability insurance underwritten by certain of Endurance’s U.S. insurance operating subsidiaries, which commenced operations in 2005. The largest product in this triangle class based upon gross earned premium is excess casualty, with the remainder comprising primary casualty, pollution liability, healthcare liability, directors & officers’ liability, and miscellaneous errors & omissions liability.

Endurance’s excess casualty product targets clients, typically below the Fortune 500 level, that include contractors, manufacturers, real estate, financial institutions, transportation, and public entities. Participations are generally on the second or third excess of loss layers.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

The primary casualty product typically insures commercial exposures for smaller clients representing more benign general liability and auto exposures.

The pollution liability business provides general liability, contractor’s pollution liability, and professional liability coverage for environmental engineers and contractors throughout the United States. A smaller portion of this book provides site pollution coverage.

Endurance’s errors and omissions product includes primary and excess coverage of insurance related services, real estate related services, technology services, general consulting services and media services.

For all of the above listed businesses, Endurance utilizes third party reinsurance to limit its retention to within its risk tolerances.

c) Insurance Long Tail — Workers’ Compensation

The workers’ compensation triangle class is primarily ground up workers’ compensation insurance in niche markets in the United States. Target clients are small businesses that are written through local production sources utilizing web-based systems. Experience in this class is a combination of insurance and reinsurance, as in 2006 we converted the business from reinsurance to insurance. However, we have separated the insurance and reinsurance triangles to allow segment based analysis. Since late 2005, the exposures in this triangle class primarily arise from California and consist predominantly of ground up workers’ compensation coverage provided to small and medium size businesses.

The Company exited the California workers’ compensation business during the first quarter of 2009.

d) Insurance Other Specialty — Agriculture and Other Specialty

The agriculture and other specialty insurance triangle class is comprised of multiple peril crop insurance (a business that interacts heavily with the U.S. federal government’s crop reinsurance program), crop hail, livestock risk protection and other agriculture risk management products. The protections offered provide coverage for yield and revenue losses resulting from weather related perils such as drought and hail as well as losses stemming from commodity price movements. The majority of this triangle class is multi-peril crop insurance.

e) Insurance Short Tail — International Sourced Property

The international sourced property triangle class includes the commercial property insurance and facultative reinsurance business underwritten by Endurance’s Bermuda and U.K. operating subsidiaries. This triangle class was initially composed of business written by Endurance’s Bermuda subsidiary, which focused on underwriting U.S. clients that required multiple insurers and reinsurers to accommodate their insurance needs. More recently it included business written by the U.K. branch.

The Company exited the UK property insurance market during the first quarter of 2009.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

f) Insurance Short Tail — United States Sourced Property

The United States sourced property triangle class comprises commercial property insurance underwritten by certain of Endurance’s U.S. operating subsidiaries, which commenced operations in 2005. All of the business written in this class is significantly hedged by third party reinsurance.

The products offered in this triangle class are named peril catastrophe protection and difference in conditions coverage for earthquake and flood for all usual commercial occupancies and throughout the United States. Typical risks that are written have multiple layers of coverage provided by multiple insurance carriers.

This triangle class also contains a comparatively small component of commercial property all-risk coverage that includes wind exposed risks.

In addition, the triangle class includes habitational property risks across the U.S. with a focus in the Northeast.

g) Reinsurance Long Tail — Casualty Directors and Officers

The casualty directors and officers triangle class contains predominantly U.S. directors’ and officers’ liability and related products, written almost exclusively on a claims made basis. Business in this triangle class is written on either an excess of loss or a proportional basis. All business is placed through the broker market.

h) Reinsurance Long Tail — Casualty Motor

The casualty motor triangle class comprises treaty reinsurance of U.S. and international cedents underwriting motor business. The international business is comprised largely of proportional protections covering both property and third party exposures. The U.S. business is a mix of proportional and excess of loss coverages, where the exposure is predominantly liability.

i) Reinsurance Long Tail — Casualty Other

The casualty other triangle class comprises our treaty casualty products (other than the products included in the casualty motor or casualty directors and officers triangle classes) underwritten by the Company’s Bermuda, U.K., and U.S. subsidiaries and its Zurich, and Singapore branches.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

This triangle class includes third party liability exposures from ceding companies on a treaty basis and comprises most casualty exposures including, general liability, public liability, products liability, umbrella and clash, warranty, medical malpractice liability, lawyers errors and omissions, miscellaneous errors and omissions, excess casualty and political risk. This triangle class includes both frequency and severity-exposed contracts covering risk underwritten on both an occurrence and claims made basis.

j) Reinsurance Long Tail — Workers’ Compensation

For a description of workers’ compensation, please see “Insurance Long Tail — Workers’ Compensation” in c) above.

k) Reinsurance Other Specialty — Agriculture & Other Specialty

The agriculture & other specialty triangle class predominantly consists of U.S. agricultural reinsurance, but also includes personal accident reinsurance underwritten by the Company’s U.K., Bermuda and U.S. subsidiaries and its Singapore and Zurich branches.

Endurance’s agriculture products specialize in risks associated with the production of food and fiber on a global basis underwritten through traditional treaty reinsurance, proportional and aggregate stop loss, as well as custom risk transfer mechanisms. The protections offered provide coverage for yield and revenue losses resulting from weather related perils such as drought and hail as well as losses stemming from commodity price movements. The majority of the business is multi-peril crop insurance, a unique business that interacts heavily with the U.S. federal government’s crop reinsurance program.

Endurance’s other specialty lines include personal accident products such as accidental death, medical and disability coverages underwritten on a treaty and facultative reinsurance basis. Endurance’s personal accident products provide per person and catastrophe protection, for life insurance companies and other specialty risk underwriters.

l) Reinsurance Other — Short Tail Marine & Aerospace

Endurance’s aerospace products in this triangle class include proportional and non-proportional treaty reinsurance for airline hull and liability, aircraft manufacturers’ products liability and general aviation risks. Endurance also includes in this triangle class proportional treaty reinsurance for satellite launch and in-orbit coverage.

The marine products in this triangle class contain a wide range of marine and energy business underwritten on both a proportional and non-proportional basis from Bermuda, the U.S., the U.K., and the Zurich and Singapore branches. Initially the underwritings were dominated by onshore energy business underwritten from Bermuda. The development of the marine and energy team in the U.K. and U.S. led to the consolidation of the global energy book in the U.K. and the growth in European hull, cargo and marine liability classes, along with specialty classes such as marine and aviation hull war. In 2006, Endurance exited the offshore energy business and significantly curtailed underwriting of onshore energy risks. Since 2007, a modest amount of onshore energy risks have been underwritten within the property portfolio.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

m) Reinsurance Short Tail — Short Tail Property

The short tail property triangle class contains international and U.S. property catastrophe business and workers compensation catastrophe business underwritten in Bermuda and per risk excess of loss and proportional treaty business underwritten in the U.S. and U.K. subsidiaries and the Singapore and Zurich branches.

Endurance’s property catastrophe reinsurance reinsures ceding company clients’ exposures to catastrophic events such as tropical cyclones including hurricanes and typhoons, earthquakes and tsunamis, floods, thunderstorms including tornados and hailstorms, fire, as well as terror attacks on a treaty basis. Coverage typically applies only when a catastrophic event impacts more than one risk or insured. Endurance has established a worldwide portfolio of reinsurance contracts, including coverage in the Americas, Europe, Africa, Asia, and Oceania. Endurance reinsures predominantly on an indemnity excess of loss basis, although Endurance also provides pro rata coverage for certain types of events primarily related to catastrophes. In addition, coverage can be based on either an industry loss or physical trigger basis.

Endurance’s Workers’ compensation catastrophe reinsurance consists of the reinsurance of U.S. workers’ compensation writers against multi-life events. The major exposures are earthquake and transport related losses.

Endurance’s property per risk treaty reinsurance covers portfolios of individual property risks such as buildings, contents, equipment and business interruption that are protected by primary insurers. These risks are assumed on a treaty basis. Endurance underwrites personal, commercial and industrial lines, but the years shown in this report are predominantly commercial and industrial exposures. Endurance underwrites this business primarily from the U.S. and the U.K. Endurance underwrites pro rata of primary, pro rata of excess and traditional excess of loss business. All excess of loss agreements have risk limits in place and, with a limited number of exceptions; all treaties either have occurrence limits or limited reinstatement rights.

n) Reinsurance Short Tail — Short Tail Surety

Endurance underwrites surety reinsurance on both a proportional and excess of loss basis. The business in the short tail surety triangle class focuses primarily on reinsurance of surety and fidelity lines of business. The surety reinsurance products are underwritten by Endurance’s U.S. reinsurance operating subsidiary and are largely comprised of U.S. programs established on either a direct or brokered basis. Endurance’s business partners in connection with these products include national account writers, regional companies and specialty operations.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

V. OVERVIEW OF RESERVING METHODOLOGY

In order to estimate Endurance’s reserve for losses and loss expenses, management uses information either (i) developed from internal or independent external sources, or (ii) pricing information created by Endurance or provided to Endurance by insureds and brokers at the time individual contracts and policies are bound. In addition, management uses commercially available risk analysis models, contract by contract review by our underwriting teams and to a limited extent, overall market share assumptions to estimate our loss and loss expense reserves related to specific loss events. When the applicable information has been obtained, Endurance uses a variety of actuarial methods to estimate the ultimate losses and loss expenses incurred by Endurance in connection with business it has underwritten and thus, the applicable reserve for losses and loss expenses.

While management does not at this time include an explicit or implicit provision for uncertainty in its reserve for losses and loss expenses, certain of Endurance’s business lines are by their nature subject to additional uncertainties, including Endurance’s casualty, property, catastrophe, aerospace and surety and other specialty lines in the Reinsurance business segment and Endurance’s casualty and professional lines in the Insurance business segment, which are discussed in detail below. In addition, Endurance’s Reinsurance business segment is subject to additional factors which add to the uncertainty of estimating loss and loss expense reserves. Time lags in the reporting of losses can also introduce further ambiguity to the process of estimating loss and loss expense reserves.

Certain aspects of Endurance’s casualty line in the Reinsurance business segment and the casualty and professional lines in the Insurance business segment complicate the process of estimating loss reserves. These include the lack of long-term historical data for losses of the same type intended to be covered by the policies and contracts written by Endurance, and the expectation that a portion of losses in excess of Endurance’s attachment levels in many of its contracts will be low in frequency and high in severity, limiting the usefulness of claims experience of other insurers and reinsurers for similar claims. In addition, the portion of Endurance’s casualty line in its Insurance business segment that is underwritten in Bermuda includes policy forms that vary from more traditional policy forms. The primary difference in the casualty policy form used by Endurance’s Bermuda subsidiary from more traditional policy forms relates to the coverage being provided on an occurrence reported basis instead of the typical occurrence or claims-made basis used in traditional policy forms. The occurrence reported policy forms typically cover occurrences causing unexpected and unintended personal injury or property damage to third parties arising from events or conditions that commence at or subsequent to an inception date and prior to the expiration of the policy, provided that proper notice is given during the term of the policy or the discovery period.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

The inherent uncertainty of estimating Endurance’s loss and loss expense reserves for its Reinsurance business segment increases principally due to:

	(i)		the lag in time between the time claims are reported to the ceding company and the time they are reported through one or more reinsurance broker intermediaries to Endurance;
	(ii)		the differing reserving practices among ceding companies;
	(iii)		the diversity of loss development patterns among different types of reinsurance treaties or contracts; and
	(iv)		Endurance’s need to rely on its ceding companies for loss information.

In addition to the factors creating uncertainty in Endurance’s estimate of loss and loss expense reserves, Endurance’s estimated reserve for losses and loss expenses can change over time because of unexpected changes in the external environment. Potential changing external factors include:

	•		changes in the inflation rate for goods and services related to the covered damages;
	•		changes in the general economic environment that could cause unanticipated changes in claim frequency or severity;
	•		changes in the litigation environment regarding the representation of plaintiffs and potential plaintiffs;
	•		changes in the judicial and/or arbitration environment regarding the interpretation of policy and contract provisions relating to the determination of coverage and/or the amount of damages awarded for certain types of claims;
	•		changes in the social environment regarding the general attitude of juries in the determination of liability and damages;
	•		changes in the legislative environment regarding the definition of damages;
	•		new types of injuries caused by new types of injurious activities or exposures; and
	•		in the case of assumed reinsurance, changes in ceding company case reserving and reporting patterns.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Endurance’s estimates of reserves for losses and loss expenses can also change over time because of changes in internal company operations. Potential changing internal factors include:

	•		alterations in claims handling procedures;
	•		growth in new lines of business where exposure and loss development patterns are not well established; or
	•		changes in the quality of risk selection or pricing in the underwriting process.

Due to the inherent complexity of the assumptions used in establishing Endurance’s loss and loss expense reserve estimates, final claim settlements made by Endurance may vary significantly from the present estimates, particularly when those settlements may not occur until well into the future.

For a more detailed discussion of the Company’s reserving methodology and an analysis of the potential variability in reserves for losses and loss expenses, please see the Company’s most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q as filed with the SEC.

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

VI. RECONCILIATIONS

Reconciliation of Unpaid Loss and LAE

The following table reconciles the reserves for losses and loss expenses as of December 31, 2010 as reported in Endurance’s financial statements prepared in accordance with GAAP to the reserves for losses and loss expenses published in the triangles (all amounts in millions, on a gross basis).

Consolidated triangles unpaid loss and LAE		$	3,325.4
FCIC related Agriculture Insurance Reserves			27.0
Deposit accounting reserves			(31.9	)
F/X and Other			(0.6	)
Adjusted unpaid loss and LAE		$	3,319.9
Reserves for losses and loss expenses Per 12/31/10 GAAP Financial Statements		$	3,319.9

Reconciliation of Earned Premium

The following table reconciles the calendar year 2010 earned premium as of December 31, 2010 as reported in Endurance’s financial statements prepared in accordance with GAAP to the earned premium published in the triangles (all amounts in millions, on a gross basis). Prior diagonals were reconciled in our previously disclosed 2009 Loss Development Triangles. Differences between the 2010 and 2009 versions are mainly due to foreign exchange movements.

Consolidated triangles earned premium		$	1,876.0
FCIC related Agriculture Insurance Premium			159.5
Impact of contracts subject to deposit accounting			2.2
Miscellaneous adjustments (including F/X)			5.6
Adjusted 2010 Earned Premium		$	2,043.4
2010 Earned Premium per Financial Statements		$	2,043.4

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Reconciliation of Calendar Year Loss Emergence

The following table reconciles the calendar year 2010 development of losses and loss adjustment expenses as of December 31, 2010 as reported in Endurance’s financial statements prepared in accordance with GAAP to the development of losses and loss adjustment expenses published in the triangles (all amounts in millions). Prior diagonals were reconciled in our previously disclosed 2009 Loss Development Triangles. Differences between the 2010 and 2009 versions are mainly due to foreign exchange movements.

Development per Triangles		$	127.6
Impact of ceded, Including FCIC related impact for Agriculture Insurance			(3.8	)
Impact of contracts subject to deposit accounting			0.7
Miscellaneous, including F/X			2.3
Adjusted development		$	126.8
Development per Financial Statements		$	126.8

Endurance Specialty Holdings Ltd.
2010 Global Loss Triangles

Reconciliation of Triangle Classes to Lines of Business

The following tables reconcile the lines of business of Endurance as of December 31, 2010 as reported in Endurance’s financial statements prepared in accordance with GAAP to the reserving classes published in the triangles.

Lines of Business

Healthcare

Workers’

Professional

Property

Casualty

Agriculture

Liability

Compensation

Lines

Triangle Class — Insurance Segment

Other Specialty

X

High Attaching Excess of Loss Casualty

X

X

X

US Sourced Casualty

X

International Sourced Property

X

US Sourced Property

X

Workers’ Compensation

X

		Lines of Business
										Surety and
								Aerospace		Other
		Property		Casualty		Catastrophe		and Marine		Specialty
Triangle Class — Reinsurance Segment
Other Specialty										X
Casualty Other				X
Casualty Directors & Officers				X
Casualty Motor				X
Short Tail Marine and Aerospace								X
Short Tail Property		X				X
Short Tail Surety										X
Workers’ Compensation				X

Valuation Date: December 31, 2010		ENDURANCE SPECIALTY HOLDINGS LTD.
Values in Thousands USD (1.56565 USD/GBP)		ACCIDENT YEAR GLOBAL DEVELOPMENT TRIANGLES
Consolidated Total
Consolidated Total

ITD SUMMARY

Gross

Accident		Earned				Paid Loss				Case Reserves				Additional												Ultimate Loss				Ultimate Loss
Year		Premium				& ALAE				& ALAE				Case Reserves				IBNR				ULAE				& LAE				& LAE Ratio
2001			1,320				335				0				—				11				0				346				26	%
2002			461,595				121,360				5,890				5,260				21,623				492				154,624				33	%
2003			1,243,575				364,398				30,986				5,062				82,284				1,775				484,505				39	%
2004			1,645,060				631,776				31,557				5,262				113,413				2,254				784,262				48	%
2005			1,801,089				1,492,212				93,610				15,038				145,740				3,915				1,750,515				97	%
2006			1,897,993				544,385				71,653				7,049				190,585				4,560				818,232				43	%
2007			1,765,108				557,618				117,430				18,167				233,912				6,560				933,688				53	%
2008			1,979,568				841,853				192,257				18,380				298,262				9,273				1,360,025				69	%
2009			1,876,769				536,900				147,549				12,164				414,379				11,965				1,122,959				60	%
2010			1,874,307				215,324				243,790				9,012				736,622				17,653				1,222,401				65	%
			14,546,382				5,306,160				934,724				95,395				2,236,830				58,448				8,631,558				59	%
Ceded
Accident		Earned				Paid Loss				Case Reserves				Additional												Ultimate Loss				Ultimate Loss
Year		Premium				& ALAE				& ALAE				Case Reserves				IBNR				ULAE				& LAE				& LAE Ratio
2001			—				—				—				—				—				—				—				0	%
2002			26,341				(178	)			(1	)			—				—				—				(179	)			-1	%
2003			9,751				1,241				30				—				8				—				1,279				13	%
2004			11,251				9,703				93				—				35				—				9,832				87	%
2005			28,589				13,902				409				—				2,027				—				16,338				57	%
2006			117,325				12,088				3,610				107				9,283				—				25,088				21	%
2007			197,091				23,666				3,496				—				20,559				—				47,721				24	%
2008			229,068				53,377				3,864				—				30,383				—				87,624				38	%
2009			223,662				61,192				11,596				—				45,659				—				118,500				53	%
2010			138,793				1,272				8,313				—				68,837				—				78,422				57	%
			981,871				176,263				31,410				107				176,790				—				384,625				39	%
Net
Accident		Earned				Paid Loss				Case Reserves				Additional												Ultimate Loss				Ultimate Loss
Year		Premium				& ALAE				& ALAE				Case Reserves				IBNR				ULAE				& LAE				& LAE Ratio
2001			1,320				335				0				—				11				0				346				26	%
2002			435,254				121,538				5,891				5,260				21,623				492				154,803				36	%
2003			1,233,824				363,157				30,956				5,062				82,276				1,775				483,226				39	%
2004			1,633,809				622,073				31,463				5,262				113,378				2,254				774,430				47	%
2005			1,772,500				1,478,310				93,201				15,038				143,713				3,915				1,734,177				98	%
2006			1,780,667				532,296				68,043				6,942				181,302				4,560				793,144				45	%
2007			1,568,017				533,952				113,934				18,167				213,353				6,560				885,967				57	%
2008			1,750,500				788,476				188,393				18,380				267,879				9,273				1,272,402				73	%
2009			1,653,107				475,708				135,954				12,164				368,721				11,965				1,004,458				61	%
2010			1,735,514				214,052				235,477				9,012				667,785				17,653				1,143,979				66	%
			13,564,510				5,129,897				903,314				95,288				2,060,040				58,448				8,246,933				61	%

Insurance — Agriculture gross is net of FCIC cession

Valuation Date: December 31, 2010		ENDURANCE SPECIALTY HOLDINGS LTD.
Values in Thousands USD (1.56565 USD/GBP)		ACCIDENT YEAR GLOBAL DEVELOPMENT TRIANGLES
Consolidated Total
Consolidated Total

GROSS BASIS

Paid Loss & ALAE		12				24				36				48				60				72				84				96				108				120
2001															311				282				288				247				295				314				335
2002			4,698				48,863				66,637				74,143				99,434				101,698				110,528				118,944				121,360
2003			53,684				155,011				213,853				251,160				293,871				320,001				336,714				364,398
2004			128,198				364,925				463,570				538,085				580,538				613,986				631,776
2005			298,708				868,484				1,191,953				1,349,995				1,443,950				1,492,212
2006			65,218				307,732				411,871				493,654				544,385
2007			72,087				317,291				415,666				557,618
2008			336,472				702,442				841,853
2009			270,036				536,900
2010			215,324
Case Incurred Loss
& ALAE (incl ACRs)		12				24				36				48				60				72				84				96				108				120
2001															375				297				297				251				295				314				335
2002			50,590				99,037				102,167				127,912				144,750				141,179				139,392				137,096				132,510
2003			164,980				280,033				315,287				347,427				373,371				386,560				399,842				400,446
2004			330,126				567,780				619,042				642,992				665,423				672,618				668,595
2005			961,335				1,448,453				1,532,227				1,592,205				1,626,168				1,600,861
2006			203,202				462,322				531,705				587,114				623,087
2007			205,897				503,509				624,293				693,216
2008			719,113				895,805				1,052,490
2009			514,718				696,614
2010			468,126
Ultimate Loss
& LAE		12				24				36				48				60				72				84				96				108				120
2001															398				322				319				277				320				327				346
2002			240,986				209,589				182,226				195,485				189,737				182,093				178,718				167,169				154,624
2003			737,614				629,812				557,110				539,177				529,284				514,231				503,247				484,505
2004			1,101,909				999,593				913,277				883,926				851,689				830,065				784,262
2005			1,823,806				1,883,484				1,853,918				1,822,396				1,805,039				1,750,515
2006			1,002,353				920,348				870,474				841,311				818,232
2007			975,655				967,530				959,688				933,688
2008			1,392,059				1,314,638				1,360,025
2009			1,115,282				1,122,959
2010			1,222,401

Diagonals as of 12/31
Insurance — Agriculture gross is net of FCIC cession

Valuation Date: December 31, 2010		ENDURANCE SPECIALTY HOLDINGS LTD.
Values in Thousands USD (1.56565 USD/GBP)		ACCIDENT YEAR GLOBAL DEVELOPMENT TRIANGLES
Consolidated Total
Consolidated Total

GROSS BASIS

Ultimate Loss
& LAE Ratio		12				24				36				48				60				72				84				96				108				120
2001															30.1	%			24.4	%			24.2	%			21.0	%			24.2	%			24.7	%			26.2	%
2002			52.2	%			45.4	%			39.5	%			42.3	%			41.1	%			39.4	%			38.7	%			36.2	%			33.5	%
2003			59.3	%			50.6	%			44.8	%			43.4	%			42.6	%			41.4	%			40.5	%			39.0	%
2004			67.0	%			60.8	%			55.5	%			53.7	%			51.8	%			50.5	%			47.7	%
2005			101.3	%			104.6	%			102.9	%			101.2	%			100.2	%			97.2	%
2006			52.8	%			48.5	%			45.9	%			44.3	%			43.1	%
2007			55.3	%			54.8	%			54.4	%			52.9	%
2008			70.3	%			66.4	%			68.7	%
2009			59.4	%			59.8	%
2010			65.2	%
Earned Premium		12				24				36				48				60				72				84				96				108				120
2001															1,342				1,320				1,320				1,320				1,320				1,320				1,320
2002			393,472				453,262				458,016				469,255				463,084				462,934				461,490				461,663				461,595
2003			1,228,581				1,240,801				1,242,823				1,241,298				1,242,459				1,243,079				1,243,527				1,243,575
2004			1,613,651				1,635,916				1,639,207				1,641,574				1,642,354				1,644,015				1,645,060
2005			1,782,230				1,798,544				1,802,227				1,803,572				1,805,178				1,801,089
2006			1,852,872				1,889,007				1,895,982				1,898,861				1,897,993
2007			1,765,968				1,768,539				1,763,965				1,765,108
2008			1,979,529				1,979,750				1,979,568
2009			1,872,072				1,876,769
2010			1,874,307

Loss Emergence		@ 12				12 - 24				24 - 36				36 - 48				48 - 60				60 - 72				72 - 84				84 - 96				96 - 108				108 - 120				Total Development
2001															398				(75	)			(3	)			(42	)			43				7				20				346
2002			240,986				(31,397	)			(27,364	)			13,259				(5,747	)			(7,644	)			(3,375	)			(11,549	)			(12,544	)							(86,362	)
2003			737,614				(107,801	)			(72,702	)			(17,933	)			(9,893	)			(15,053	)			(10,984	)			(18,742	)											(253,109	)
2004			1,101,909				(102,315	)			(86,317	)			(29,351	)			(32,236	)			(21,624	)			(45,803	)															(317,647	)
2005			1,823,806				59,678				(29,566	)			(31,522	)			(17,358	)			(54,524	)																			(73,291	)
2006			1,002,353				(82,005	)			(49,874	)			(29,163	)			(23,079	)																							(184,120	)
2007			975,655				(8,124	)			(7,843	)			(26,000	)																											(41,967	)
2008			1,392,059				(77,421	)			45,387																																(32,034	)
2009			1,115,282				7,677																																				7,677
2010			1,222,401
Calendar Year		CY 2001				CY 2002				CY 2003				CY 2004				CY 2005				CY 2006				CY 2007				CY 2008				CY 2009				CY 2010				Total Development
			N/A				N/A				(31,397	)			(134,768	)			(161,833	)			(50,322	)			(158,502	)			(140,142	)			(175,935	)			(127,608	)			(980,506	)

Diagonals as of 12/31
Insurance — Agriculture gross is net of FCIC cession

Valuation Date: December 31, 2010		ENDURANCE SPECIALTY HOLDINGS LTD.
Values in Thousands USD (1.56565 USD/GBP)		ACCIDENT YEAR GLOBAL DEVELOPMENT TRIANGLES
Insurance Long Tail
High Attaching Excess of Loss Casualty

ITD SUMMARY

Gross

Accident		Earned				Paid Loss				Case Reserves				Additional												Ultimate Loss				Ultimate Loss
Year		Premium				& ALAE				& ALAE				Case Reserves				IBNR				ULAE				& LAE				& LAE Ratio
2001			70				—				—				—				10				0				10				15	%
2002			43,745				—				—				—				5,387				81				5,468				12	%
2003			174,168				3,472				3,256				—				22,917				393				30,037				17	%
2004			235,163				9,168				49				—				40,440				607				50,265				21	%
2005			258,385				22,530				25,097				—				63,365				1,327				112,319				43	%
2006			266,845				35,497				38				—				80,930				1,215				117,679				44	%
2007			244,895				79,706				27,763				—				102,598				1,955				212,022				87	%
2008			219,929				25,014				50,417				500				119,206				2,552				197,689				90	%
2009			226,426				127				35,682				—				139,289				2,625				177,723				78	%
2010			223,557				44				25,500				—				165,453				2,864				193,861				87	%
			1,893,186				175,559				167,803				500				739,594				13,618				1,097,074				58	%
Ceded
Accident		Earned				Paid Loss				Case Reserves				Additional												Ultimate Loss				Ultimate Loss
Year		Premium				& ALAE				& ALAE				Case Reserves				IBNR				ULAE				& LAE				& LAE Ratio
2001			—				—				—				—				—				—				—				0	%
2002			—				—				—				—				—				—				—				0	%
2003			509				—				—				—				—				—				—				0	%
2004			446				38				—				—				11				—				49				11	%
2005			470				—				—				—				44				—				44				9	%
2006			170				—				—				—				93				—				93				55	%
2007			3,728				—				—				—				1,970				—				1,970				53	%
2008			5,526				—				—				—				3,227				—				3,227				58	%
2009			15,073				47				4,474				—				4,733				—				9,254				61	%
2010			23,505				19				7,488				—				25,602				—				33,109				141	%
			49,426				104				11,961				—				35,681				—				47,746				97	%
Net
Accident		Earned				Paid Loss				Case Reserves				Additional												Ultimate Loss				Ultimate Loss
Year		Premium				& ALAE				& ALAE				Case Reserves				IBNR				ULAE				& LAE				& LAE Ratio
2001			70				—				—				—				10				0				10				15	%
2002			43,745				—				—				—				5,387				81				5,468				12	%
2003			173,660				3,472				3,256				—				22,917				393				30,037				17	%
2004			234,717				9,130				49				—				40,429				607				50,216				21	%
2005			257,915				22,530				25,097				—				63,321				1,327				112,275				44	%
2006			266,676				35,497				38				—				80,836				1,215				117,585				44	%
2007			241,168				79,706				27,763				—				100,628				1,955				210,053				87	%
2008			214,403				25,014				50,417				500				115,979				2,552				194,462				91	%
2009			211,353				80				31,208				—				134,556				2,625				168,469				80	%
2010			200,053				26				18,012				—				139,850				2,864				160,753				80	%
			1,843,759				175,455				155,841				500				703,913				13,618				1,049,328				57	%