Regardless of whether or not the US Federal Government authorizes an extension to TRIA (Terrorism Risk Insurance Act) beyond the end of this year, terrorism remains a very real threat and should not be ignored. According to Aon's 2005 Terrorism Risk Map, presented at the RIMS annual conference today, terrorist activity is making the world a riskier place in which to do business. The map assesses the level and nature of terrorist threat around the world and is the third in an annual series.

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This year 31 countries have received higher terrorism risk ratings than last year, almost half (48%) of which are in Western Europe. Among these, the Netherlands, Germany, Belgium and Denmark have all been marked as higher risk because of increased Islamic extremist activity. The most recent manifestation of this was the murder of filmmaker Theo Van Gogh in November 2004 by a Dutch Moroccan Islamic extremist.

The US rating of 'elevated' remains unchanged from last year. In fact, 27 terrorist incidents (albeit minor) occurred in the US during 2004. Similarly, fears that Islamic extremists might stage attacks to try to influence the UK general election on 5 May also reinforce the UK's risk rating.

The Terrorism Risk Map shows that participation in the US-led Iraq coalition has increased terrorism risk in countries such as Australia, Poland and Estonia. There is concern that Al-Qaida and other international terrorist organizations could take advantage of anti-western sentiment and launch terrorist attacks in these countries in future. Businesses which originate from these countries should also be aware of threats to their operations and personnel abroad as evidenced by incidents such as the terrorist attack on the Australian embassy in Indonesia, the recent bombing of a British theater and school in Qatar and the thwarted plot to blow up the Italian embassy in Lebanon.

"Terrorism is not a new threat and many international businesses have to date been rightly pre-occupied with the risks facing their operations in the Middle East, Africa and the Gulf. Although companies do need to be aware of the global picture, the 2005 map highlights the need for vigilance in so called 'safer' European countries," commented Paul Bassett, executive director in Aon's Crisis Management division.

"Companies must acquire as much knowledge as possible about the risks they face and their exposure to those risks in order to minimize the human and financial impact of such attacks. Businesses can then assess how best to allocate their expenditure on insurance and counter terrorism risk management procedures effectively," he added.

Efforts by the insurance market to press the US Federal Government for reauthorization of TRIA are intensifying as the deadline for its expiration draws nearer. With the uncertainty surrounding TRIA, Aon is urging its clients to join the lobbying. "But, more importantly," says Aaron Davis, vice president of Aon' s Property Syndication Group in the US, "if TRIA does expire at the end of this year the aggregate capacity of the stand-alone terrorism market is going to come under severe strain. Businesses need to explore alternative options for mitigating and transferring their terrorism risks now."

   For further information contact:
   Sally Coode-Bate             Al Orendorff
   Aon Press Office (UK)        Aon Press Office (US)
   +44 (0)207 505 7478          312 381 3153
   Cell phone: +44 7718 104991  Cell phone:  773.209.3113
   sally.coode-bate@aon.co.uk   Al_Orendorff@aon.com


  Notes to editors:

In addition to the Terrorism Risk Map, Aon has also released an update to the Terrorism Risk Management & Risk Transfer Market Overview originally published in December 2004. The update provides a current snapshot of the state of the terrorism insurance market and describes the metrics risk control and other issues surrounding it.

About Aon:

Aon Corporation (NYSE: AOC)( http://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 related to future results, or states our intentions, beliefs and expectations or predictions for the future 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: general economic conditions in different countries in which we do business around the world, changes in global equity and fixed income markets that could affect the return on invested assets, fluctuations in exchange and interest rates that could influence revenue and expense, rating agency actions that could affect our ability to borrow funds, funding of our various pension plans, changes in the competitive environment, changes in commercial property and casualty markets and commercial premium rates that could impact revenues, changes in revenues and earnings due to the elimination of contingent commissions, other uncertainties surrounding a new compensation model, the impact of regulatory investigations brought by state attorneys general and state insurance regulators related to our compensation arrangements with underwriters and related issues, the impact of class actions and individual lawsuits including derivative actions and claims under ERISA, the cost of resolution of other contingent liabilities and loss contingencies, and the difference in ultimate paid claims in our underwriting companies from actuarial estimates.

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.

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SOURCE: Aon Corporation

CONTACT: Sally Coode-Bate, Aon Press Office (UK), +44 (0)207 505 7478,
Cell phone, +44 7718 104991, or sally.coode-bate@aon.co.uk , or Al Orendorff,
Aon Press Office (US), +1-312-381-3153, Cell phone, +1-773-209-3113,
Al_Orendorff@aon.com , both of Aon Corporation

Web site: http://www.aon.com/