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USD ($)

USD ($) / shares
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   &lt;!-- Begin Block Tagged Note 12 - us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock--&gt;
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       &lt;b&gt;&lt;font style="font-family: 'Times New Roman', Times"&gt;12.&amp;#160;&amp;#160;&lt;/font&gt;&lt;/b&gt;
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       &lt;td&gt;
       &lt;b&gt;&lt;font style="font-family: 'Times New Roman', Times"&gt;Share
       Based Payments&lt;/font&gt;&lt;/b&gt;
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   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       The Company has issued options and other equity incentives under
       four arrangements: investor options, employee awards,
       non-employee director awards and the employee share purchase
       plans. When options are exercised or other equity awards have
       vested, new shares are issued as the Company does not currently
       hold treasury shares. The Company applies a fair value based
       measurement method and an estimate of future forfeitures in the
       calculation of the compensation costs of stock options and
       restricted share units.
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   &lt;div align="left" style="margin-top: 6pt; margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       &lt;i&gt;Investor Options.&lt;/i&gt;&amp;#160;&amp;#160;The investor options were
       issued on June&amp;#160;21, 2002 to Wellington Investment Holdings
       (Jersey) Limited (&amp;#8220;Wellington Investment&amp;#8221;) and members
       of Syndicate 2020 who were not corporate members of Syndicate
       2020. The options conferred to the members of Syndicate 2020 are
       held for their benefit by Appleby Services (Bermuda) Ltd.
       (formerly Appleby Trust (Bermuda) Limited) (&amp;#8220;Names&amp;#8217;
       Trustee&amp;#8221;). The subscription price payable under the options
       is initially &amp;#163;10 and increases by 5% per annum, less any
       dividends paid. Option holders are not entitled to participate
       in any dividends prior to exercise and would not rank as a
       creditor in the event of liquidation. If not exercised, the
       options will expire on June&amp;#160;21, 2012. During the three
       months ended March&amp;#160;31, 2011, the Names&amp;#8217; Trustee
       exercised 539,823 options on a cash and cashless basis (2010
       &amp;#8212;&amp;#160;3,221 options).
   &lt;/div&gt;
   &lt;div style="margin-top: 6pt; font-size: 1pt"&gt;&amp;#160;
   &lt;/div&gt;
   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       &lt;i&gt;Employee and Non-Executive Director
       Awards.&lt;/i&gt;&amp;#160;&amp;#160;Employee options and other awards are
       granted under the Aspen 2003&amp;#160;Share Incentive Plan and
       non-executive director awards are granted under the 2006 Stock
       Option Plan for Non-Employee Directors.
   &lt;/div&gt;
   &lt;div style="margin-top: 6pt; font-size: 1pt"&gt;&amp;#160;
   &lt;/div&gt;
   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       Stock options are granted with an exercise price equivalent to
       the fair value of the share on the grant date. The weighted
       average value at grant date is determined using the
       Black-Scholes option pricing model. Stock options typically vest
       over a three-year period with a ten-year contract period (except
       for options granted in 2007 which have a
       &lt;font style="white-space: nowrap"&gt;7-year&lt;/font&gt;
       exercise period) with vesting dependent on time and performance
       conditions established at the time of grant. No options were
       granted in the three months ended March&amp;#160;31, 2011
       (2010&amp;#160;&amp;#8212; Nil); 9,208 options were exercised during the
       three months ended March&amp;#160;31, 2011 (2010&amp;#160;&amp;#8212;
       374,961). Compensation costs credited against income in respect
       of employee options for the three months ended March&amp;#160;31,
       2011 were $Nil (2010&amp;#160;&amp;#8212; charges of $0.3&amp;#160;million).
   &lt;/div&gt;
   &lt;div style="margin-top: 6pt; font-size: 1pt"&gt;&amp;#160;
   &lt;/div&gt;
   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       Restricted share units (&amp;#8220;RSU&amp;#8217;s&amp;#8221;) to employees
       vest equally over a two or three-year period. Some of the grants
       vest at year-end, while some other grants vest on the
       anniversary of the date of grant or when the Compensation
       Committee of the Board agrees to deliver them. The fair value of
       the restricted share units is based on the closing price on the
       date of the grant. The fair value is expensed through the income
       statement evenly over the vesting period. During the three
       months ended March&amp;#160;31, 2011, the Company granted to
       employees 105,234 restricted share units (2010&amp;#160;&amp;#8212;
       32,754). In the case of non-employee directors, one-twelfth of
       the RSU&amp;#8217;s vest on each one month anniversary of the date of
       grant, with 100% of the RSU&amp;#8217;s becoming vested on the first
       anniversary of the date of grant. On February&amp;#160;3, 2011 (with
       a grant date of February&amp;#160;9, 2011), the Board of Directors
       approved a total of 23,408 RSU&amp;#8217;s for the non-employee
       directors (February&amp;#160;11, 2010&amp;#160;&amp;#8212; 28,640) and 16,722
       RSU&amp;#8217;s to the Chairman (February&amp;#160;11, 2010&amp;#160;&amp;#8212;
       17,902). Compensation costs charged against income in respect of
       restricted share units for the three months ended March&amp;#160;31,
       2011 were $2.5&amp;#160;million (2010&amp;#160;&amp;#8212; $0.8&amp;#160;million).
   &lt;/div&gt;
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   &lt;/div&gt;
   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       The fair value of performance share awards is based on the value
       of the average of the high and low of the share price on the
       date of the grant less a deduction for expected dividends which
       would not accrue during the vesting period. Performance shares
       vest over a three or four-year period with shares eligible for
       vesting dependent on the achievement of performance targets at
       the end of specified periods as established at the time of
       grant. Compensation costs credited against income in the three
       months ended March&amp;#160;31, 2011 in respect of performance
       shares were a credit of $0.1&amp;#160;million (2010&amp;#160;&amp;#8212;
       charge of $3.2&amp;#160;million).
   &lt;/div&gt;
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   &lt;/div&gt;
   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       &lt;i&gt;2011 Performance Shares.&lt;/i&gt;&amp;#160;&amp;#160;On February 3 and 4,
       2011, the Compensation Committee approved the grant of 853,223
       performance shares with a grant date of February&amp;#160;9, 2011
       and an additional grant of 31,669 performance shares was made on
       March&amp;#160;21, 2011 (February&amp;#160;11, 2010&amp;#160;&amp;#8212;
       720,098). The performance shares will be subject to a three-year
       vesting period with a separate annual Return on Equity
       (&amp;#8220;ROE&amp;#8221;) test for each year. One-third of the grant
       will be eligible for vesting each year based on a formula, and
       will only be issuable at the end of the three-year period. If
       the ROE achieved in 2011 is less than 6%, then the portion of
       the performance shares subject to the vesting conditions in such
       year will be forfeited (i.e. 33.33% of the initial grant). If
       the ROE achieved in 2011 is between 6% and 11%, then the
       percentage of the performance shares eligible for vesting will
       be between 10% and 100% on a straight-line basis. If the ROE
       achieved in 2011 is between 11% and 21%, then the percentage of
       the performance shares eligible for vesting will be between 100%
       and 200% on a straight-line basis. The Compensation Committee
       will determine the vesting conditions for the 2012 and 2013
       portions of the
   grant in such years taking into consideration the market
       conditions and the Company&amp;#8217;s business plans at the
       commencement of the years concerned. Notwithstanding the vesting
       criteria for each given year, if in any given year, the shares
       eligible for vesting are greater than 100% for the portion of
       such year&amp;#8217;s grant and the average ROE over such year and
       the preceding year is less than the average of the minimum
       vesting thresholds for such year and the preceding year, then
       only 100% (and no more) of the shares that are eligible for
       vesting in such year shall vest. If the average ROE over the two
       years is greater than the average of the minimum vesting
       thresholds for such year and the preceding year, then there will
       be no diminution in vesting and the shares eligible for vesting
       in such year will vest in accordance with the vesting schedule
       without regard to the average ROE over the two-year period.
   &lt;/div&gt;
   &lt;div style="margin-top: 6pt; font-size: 1pt"&gt;&amp;#160;
   &lt;/div&gt;
   &lt;div align="left" style="margin-left: 0%; margin-right: 0%; text-indent: 4%; font-size: 11pt; font-family: 'Times New Roman', Times; color: #000000; background: transparent"&gt;
       &lt;i&gt;Employee Share Purchase Plans.&lt;/i&gt;&amp;#160;&amp;#160;On
       April&amp;#160;30, 2008, the shareholders of the Company approved
       the Employee Share Purchase Plan (the &amp;#8220;ESPP&amp;#8221;), the
       2008&amp;#160;Sharesave Scheme and the International Employee Share
       Purchase Plan, which are implemented by a series of consecutive
       offering periods as determined by the Board. In respect of the
       ESPP, employees can save up to $500 per month over a two-year
       period, at the end of which they will be eligible to purchase
       Company shares at a discounted price. In respect of the
       2008&amp;#160;Sharesave Scheme, employees can save up to &amp;#163;250
       per month over a three-year period, at the end of which they
       will be eligible to purchase Company shares at a discounted
       price. The purchase price will be eighty-five percent (85%) of
       the fair market value of a share on the offering date which may
       be adjusted upon changes in capitalization of the Company. Under
       the plan, 21,479&amp;#160;shares were issued during the three months
       ended March&amp;#160;31, 2011 (2010&amp;#160;&amp;#8212; Nil). Compensation
       costs charged against income in the three months ended
       March&amp;#160;31, 2011 in respect of the ESPP were
       $0.2&amp;#160;million (2010&amp;#160;&amp;#8212; $0.4&amp;#160;million).
   &lt;/div&gt;
   &lt;/div&gt;
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   &lt;!-- Begin Block Tagged Note</NonNumericTextHeader><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>us-types:textBlockItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>Disclosure of compensation-related costs for share-based compensation which may include disclosure of policies, compensation plan details, allocation of stock compensation, incentive distributions, share-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef
 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 123R
 -Paragraph 64, 65, A240

Reference 2: http://www.xbrl.org/2003/role/presentationRef
 -Publisher AICPA
 -Name Statement of Position (SOP)
 -Number 93-6
 -Paragraph 53

Reference 3: http://www.xbrl.org/2003/role/presentationRef
 -Publisher SEC
 -Name Staff Accounting Bulletin (SAB)
 -Number Topic 14

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