Marsh & McLennan Cos., the world’s largest insurance brokerage, agreed to pay $850 million to settle New York Attorney General Eliot Spitzer’s accusations that it rigged bids and took kickbacks from insurers. It is the largest settlement yet obtained by the crusading attorney general and 2006 Democratic gubernatorial candidate.

The settlement is to be used solely to reimburse Marsh clients, Mr. Spitzer said in a statement today. Marsh apologized that some employees had “unlawfully deceived” customers. At the same time, it wouldn’t admit or deny any claim in Mr. Spitzer’s Oct. 14 suit. The accord, which exceeds Bank of America Corp.’s $675 million settlement over improper mutual-fund trading, may be the first of many in the $2.4 trillion insurance industry, according to Bloomberg News.

Chief Executive Officer Michael Cherkasky, 54, is relying on the agreement to help hold onto clients and employees after Spitzer accused the broker of staging sham bids and steering clients to insurers that paid hidden fees. Shares of New York based Marsh have fallen 30 percent since the suit.

Under the agreement, Marsh will pay $255 million a year for two years, then $170 million for two more. The company will dole out the biggest sum, $131 million, in California, where it does the most business, Mr. Cherkasky said. New York clients will receive $95 million, the second biggest amount.