London - May 4, 2004 - Stephen Cross has been appointed to the position of Chief Executive Officer of Aon Captive Services Group (ACSG), Aon's captive management and risk finance consulting operations.
Mr Cross, who was previously Chief Operating Officer for ACSG and joined the company in 1990, takes over the position from Philip Stamp who continues in his role as Chairman of ACSG.

Commenting on the appointment, Philip Stamp, said: "Stephen has demonstrated exceptional leadership skills in helping to maintain the growth of Aon Captive Services Group as a world leader in the captive management and alternative risk transfer arena, and I congratulate him on his well earned appointment as Chief Executive Officer."

In addition, ACSG has announced the promotion of Bill Harris and Ken MacDonald to Joint Chief Operating Officers of ACSG, with responsibility for the ACSG captive management /ART and risk finance consulting activities in the Americas and Europe/Asia respectively. Both will report directly to Stephen Cross.

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About Aon

Aon Corporation (www.aon.com) is a leading provider of risk management services, insurance and reinsurance brokerage, human capital and management consulting, and specialty insurance underwriting. The company employs approximately 53,000 professionals in its 600 offices in more than 120 countries. Backed by broad resources, industry knowledge and technical expertise, Aon professionals help a wide range of clients develop effective risk management and workforce productivity solutions.

This press release contains certain statements relating to future results, which are forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from either historical or anticipated results, depending on a variety of factors. Potential factors that could impact results include the general economic conditions in different countries around the world, fluctuations in global equity and fixed income markets, exchange rates, rating agency actions, pension funding, ultimate paid claims may be different from actuarial estimates and actuarial estimates may change over time, changes in commercial property and casualty markets and commercial premium rates, the competitive environment, the actual costs of resolution of contingent liabilities and other loss contingencies, the heightened level of potential errors and omissions liability arising from placements of complex policies and sophisticated reinsurance arrangements in an insurance market in which insurer reserves are under pressure, and the timing and resolution of related insurance and reinsurance issues relating to the events of September 11, 2001. Further information concerning the Company and its business, including factors that potentially could materially affect the Companys financial results, are contained in the Companys filings with the Securities and Exchange Commission.