Lerach Coughlin Stoia Geller Rudman & Robbins LLP Files Class Action Suit against Aon Corp.

SAN DIEGO--(BUSINESS WIRE)--Oct. 25, 2004--Lerach Coughlin Stoia Geller Rudman & Robbins LLP ("Lerach Coughlin") (http://www.lerachlaw.com/cases/aoncorp/) today announced that a class action has been commenced in the United States District Court for the Northern District of Illinois on behalf of purchasers of Aon Corp. ("AON") (NYSE:AOC) publicly traded securities during the period between October 31, 2002 and October 18, 2004 (the "Class Period").

If you wish to serve as lead plaintiff, you must move the Court no later than 60 days from today. If you wish to discuss this action or have any questions concerning this notice or your rights or interests, please contact plaintiff's counsel, William Lerach or Darren Robbins of Lerach Coughlin at 800-449-4900 or via e-mail at [e-mail]. If you are a member of this class, you can view a copy of the complaint as filed or join this class action online at http://www.lerachlaw.com/cases/aoncorp/. Any member of the purported class may move the Court to serve as lead plaintiff through counsel of their choice, or may choose to do nothing and remain an absent class member.

The complaint charges Aon and certain of its officers and directors with violations of the Securities Exchange Act of 1934. Aon, through its various subsidiaries worldwide, serves its clients through three operating segments: Risk and Insurance Brokerage Services, Consulting and Insurance Underwriting.

The complaint alleges that Aon and its top officers violated the federal securities laws by disseminating false and misleading statements concerning the Company's results and operations. The true facts, which were known by each of the defendants but concealed from the investing public during the Class Period, were as follows: (a) that the Company was receiving illegal and concealed "contingent commissions" pursuant to illegal "contingent commission agreements"; (b) that by concealing these "contingent commissions" and such "contingent commission agreements," the defendants violated applicable principles of fiduciary law, subjecting the Company to enormous fines and penalties totaling potentially tens -- if not hundreds -- of millions of dollars; and (c) that as a result, Company's prior reported revenue and income was grossly overstated.

On October 14, 2004, New York Attorney General Eliot Spitzer announced he had charged several of the nation's largest insurance companies and the largest broker with bid rigging and pay-offs that he claimed violated fraud and competition laws. Upon revelation of these illegal acts, the Company's shares fell to $23.03, a loss of 16%. Then on October 19, 2004, The Wall Street Journal published an article on Spitzer's investigation of Aon which stated that the reinsurance business, or insurance policies for insurance companies, was the focus of the probe, because Spitzer suspected Aon's insurance-buying clients may not have received the best deal. On these revelations, the Company's shares fell again, from $21.20 to $19.20, a drop of 9%.

Plaintiff seeks to recover damages on behalf of all purchasers of Aon publicly traded securities during the Class Period (the "Class"). The plaintiff is represented by Lerach Coughlin, which has expertise in prosecuting investor class actions and extensive experience in actions involving financial fraud.

Lerach Coughlin, a 140-lawyer firm with offices in San Diego, San Francisco, Los Angeles, New York, Boca Raton, Washington, D.C., Houston, Philadelphia and Seattle, is active in major litigations pending in federal and state courts throughout the United States and has taken a leading role in many important actions on behalf of defrauded investors, consumers, and companies, as well as victims of human rights violations. Lerach Coughlin lawyers have been responsible for more than $20 billion in aggregate recoveries. The Lerach Coughlin Web site (http://www.lerachlaw.com) has more information about the firm.