Anti-trust charges against some of the world's leading insurers and brokers have been dropped in the US.

A federal judge says a class action brought against companies such as AIG, The Hartford Group, Liberty Mutual and American Re, Willis and Marsh & McLennan failed to provide enough evidence to suggest a price-fixing conspiracy between brokers and insurers.

It is the third time Chief Judge Garrett E Brown has dismissed the application. He agreed with the defendants' motion to dismiss in April, but gave the wide group of individual plaintiffs another chance to make their case.

In finally throwing out the case, he found the alleged conspiracy - in which brokers were said to arrange uncompetitive quotes so their clients would stay with a preferred insurer - to be devoid of a factual basis.

"Plaintiffs have not shown that the insurer defendants colluded among themselves in the broker-centred conspiracies."

The anti-trust class action follows investigations into alleged bid-rigging practices that were conducted by then New York Attorney-General Eliot Spitzer.

The companies still face class action suits from aggrieved policyholders under Racketeer Influenced and Corrupt Organisations legislation. There are also state-sponsored actions to consider, including the suit filed by Ohio Attorney-General Mark Dann on August 27.