The lawsuit accuses the carriers of the companies in an “unlawful conspiracy to allocate customers, divide markets and restrain competition” for casualty insurance policies for businesses in Ohio between January 2001 and late 2004.
Mike Kachel, spokesperson for Marsh & McLennan, stated that the company has already settled claims brought by most of its clients and intends to “vigorously” defend itself against the lawsuit.
There was no comment by AIG, the world's largest insurer.
The lawsuit is the result of a three-year investigation by Mr. Dann, and accuses Marsh & McLennan of conspiring to artificially inflate prices while feigning competition.
Other defendants include ACE Ltd, Chubb Corp. and Hartford Financial Services Group Inc. The companies could not be reached for comment late Monday.
Zurich American Insurance Co, a subsidiary of Swiss insurance company Zurich Financial Services Group, entered a $7 million settlement with Ohio in October 2006 as part of the same investigation.