London – 17 March 2005 –  The global aviation industry saw the lowest level of losses in its history in 2004 although concerns in the insurance industry over the severity of claims are growing, according to Aon’s 2004 Airline Insurance Market Review*. An average of 22 total losses per year during the 1990s decreased to just 15 in 2004. Though there were fewer losses, the total loss amount of US$1billion showed a moderate increase from the figure recorded in 2003. While the introduction of safety initiatives are clearly reducing the number of incidents, the cumulative cost of those incidents to the insurance industry is on the increase.

Despite fears over the growing cost of claims, the airline insurance market remained buoyant with an average premium reduction of 7% achieved in 2004 by the world’s airlines as insurers competed for business. Market capacity continued to be adequate despite the departure of one underwriting syndicate in 2004 and the outlook for the 2005 renewals is stable provided there is no significant change in the level of losses.

Commenting on the report, Steve Doyle, Manager of Aon’s Aviation and Aerospace Global Practice Group, said: “While 2004 was the safest year on record in the aviation industry, the actual severity of claims made has shown an increase on the previous year. This factor is clearly of concern to the insurance industry, though we expect market conditions in 2005 to remain stable barring any significant change in the level of losses.

“2005 will also see the first insurance policy placed for the Airbus A380, which in itself will represent peak exposures in both hull value and seating capacity in a single aircraft. It will be interesting to see how the insurance market responds to this challenge,” said Doyle.

*Copies of Aon’s 2004 Airline Insurance Market Review are available on request by emailing aviation&aerospace@aon.co.uk

Notes to Editors

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 48,000 professionals in its 500 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, resolution of pending regulatory investigations and related issues, including those related to compensation arrangements with underwriters, 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, and 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.  Further information concerning the Company and its business, including factors that potentially could materially affect the Company’s financial results, is contained in the Company’s filings with the Securities and Exchange Commission.

Aon Limited is authorized and regulated by the Financial Service Authority in respect of insurance mediation activities only.