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Aon’s Redomestication Transaction Statement
Aon’s redomestication transaction on April 2, 2012 resulted in gain recognition for US taxpayers who were shareholders of Aon stock. The gain is computed as the difference between cost basis and fair market value at the time of the transaction. The Internal Revenue Service considers fair market value (FMV) as the price at which property would change hands between a willing buyer and a willing seller in an arm’s length transaction. The FMV of a publicly traded security is the current price at which it trades in the open market.

Aon computed the fair market value as $49.08 per share. Aon computed this amount as the opening price in the market on April 2, 2012. This value was filed with the Internal Revenue Service on publicly available Form 8806, Information Return for Acquisition of Control or Substantial Changes in Capital Structure. Aon’s method of calculation of FMV is not the sole method; other methods of computing fair market value may be available and acceptable. Please consult your tax advisor for further information.

For U.S. tax purposes, the holding period of any Aon UK shares received by US shareholders should be unaffected by the redomestication transaction provided that US shareholders held their Aon stock as a capital asset. What this means is that regardless of whether shareholders are in a gain or loss position, shareholders’ holding period in Aon UK shares received in the redomestication transaction should include the period during which the shareholders held Aon Delaware shares. If a shareholder does not hold Aon stock as a capital asset, or is uncertain if the Aon stock is held as a capital asset, please consult a tax advisor for further assistance.