Previously, Aspen excluded net unrealized investment and foreign exchange gains from the definition of average equity for this purpose. Aspen has made this change to bring its definition of Operating ROE into line with that used by the majority of Aspen’s market peers and because Aspen believes it better represents the performance relative to total ordinary shareholders’ accumulated investment in the business and retained earnings. See page 2 of Aspen’s financial supplement for the effect of this change on previously reported Operating ROE.
(2) Operating Income is a non-GAAP financial measure. Operating income is an internal performance measure used by Aspen in the management of its operations and represents after-tax operational results excluding, as applicable, after-tax net realized and unrealized capital gains or losses, including realized and unrealized gains or losses on interest rate swaps, and after-tax net foreign exchange gains or losses including net realized and unrealized gains and losses from foreign exchange contracts.
Aspen excludes these items from its calculation of operating income because the amount of these gains or losses is heavily influenced by, and fluctuates in part, according to the availability of market opportunities. Aspen believes these amounts are largely independent of its business and underwriting process and including them would distort the analysis of trends in its operations. In addition to presenting net income determined in accordance with GAAP, Aspen believes that showing operating income enables investors, analysts, rating agencies and other users of its financial information to more easily analyze Aspen's results of operations in a manner similar to how management analyzes Aspen's underlying business performance. Operating income should not be viewed as a substitute for GAAP net income. Please see above and page 26 of Aspen's financial supplement for a reconciliation of operating income to net income. Aspen’s financial supplement can be obtained from the Investor Relations section of Aspen's website at www.aspen.co.
(3) Diluted Book Value per Ordinary Share is a non-GAAP financial measure. Aspen has included diluted book value per ordinary share as it illustrates the effect on basic book value per share of dilutive securities thereby providing a better benchmark for comparison with other companies. Diluted book value per share is calculated using the treasury stock method, defined on page 24 of Aspen’s financial supplement, which can be obtained from the Investor Relations section of Aspen’s website at www.aspen.co.(4) Diluted Operating Earnings per Share and Basic Operating Earnings per Share are non-GAAP financial measures. Aspen believes that the presentation of diluted operating earnings per share and basic operating earnings per share supports meaningful comparison from period to period and the analysis of normal business operations. Diluted operating earnings per share and basic operating earnings per share are calculated by dividing operating income by the diluted or basic weighted average number of shares outstanding for the period. See page 26 for a reconciliation of diluted and basic operating earnings per share to basic earnings per share. Aspen’s financial supplement can be obtained from the Investor Relations section of Aspen’s website at www.aspen.co. Other (1) Provision of ASU 2010-26. In the current quarter, Aspen adopted the provision of ASU 2010-26, “Accounting for Costs Associated with Acquiring or Renewing Insurance Contracts.” Under the standard, Aspen is required to expense the proportion of its general and administrative deferred acquisition costs not directly related to successful business acquisition. The application of this standard has resulted in a net $16.0 million write down of deferred acquisition costs through retained earnings brought forward and the restatement of our quarterly balance sheets from December 31, 2010 to December 31, 2011. (2) Catastrophe Load included in our guidance is an estimate of the average annual aggregate loss before reinsurance and tax from natural catastrophe events based on 50,000 simulations of our internal capital model which, in relation to its catastrophe modeling components, is based on a combination of catastrophe models selected by Aspen to best fit its current understanding of the world wide natural catastrophe perils to which Aspen has known exposures. It does not include losses from non-natural catastrophe events such as terrorism or industrial accidents. This load is attributed and then released quarter by quarter based on historic claims patterns. For example, there is a higher proportion allocated to the third quarter due to the historical frequency of US Wind events in this period. As an organization, Aspen monitors its current catastrophe losses to date against expected and updates the projected numbers accordingly based on this experience.