(Bloomberg) ? New York Attorney General Eliot Spitzer said his next move may be to pursue insurance companies implicated in his bid-rigging lawsuit against broker Marsh & McLennan Cos.

"The natural progression here is that we continue to inquire about not only other brokers but also carriers," Spitzer said in an interview. "Several carriers are listed in the underlying complaint that we filed against Marsh Mac as having participated."

Spitzer said in his October 14 suit that Marsh, the world's largest insurance brokerage, colluded with American International Group Inc., ACE Ltd., Hartford Financial Services Group Ltd. and Munich Re to rig bids for clients. He sued only Marsh and declined to say yesterday what companies he may target next. Three employees of American International and ACE have pleaded guilty.

Shares of dozens of insurers and brokers have fallen this month on expectations Spitzer will bring more accusations against the industry as he widens his investigation. Marsh has lost $9.3 billion of market value since the suit was filed and replaced its chief executive this week to meet Spitzer's demands.

Insurers have come forward in the past two weeks with details about their own internal investigations, Spitzer said.

"There has been a more rapid flow of information to my office because carriers and brokers and others are now coming in saying `here's what we have found,"' Spitzer said. "I'd like to think we always know a little bit more than they do, but I'm never going to tell them exactly what we know because part of this process is ensuring they are being entirely open and full."

American International spokesman Joe Norton and ACE spokeswoman Rhonda Barnat declined to comment. Terese Rosenthal, a spokeswoman for Munich Re in the US, and Hartford Financial spokesman Josh King said their companies were cooperating with Spitzer's investigation.

Spitzer gave the interview at the Waldorf Astoria hotel in New York, where he was attending a $750-a-plate annual gala benefiting Montefiore Medical Center, where he formerly served as a trustee. Spitzer attended the event with his parents and gave a short speech.

Executives of American International occupied a table at the gala, held in the grand ballroom of the Waldorf. Before speaking, Spitzer joked with the audience about the investigation, saying "I just want you to know that based on the distribution of applause, I know where the insurance executives are sitting."

Spitzer all but demanded Jeffrey Greenberg's resignation as Marsh's chief executive officer by refusing to negotiate with the company's management and urging the board to look "long and hard" at executive leadership. Spitzer in the interview that said Marsh attempted to mislead him during the investigation.

"What we were met with was a denial, obfuscation, and in my view, misleading comments about both their practices and facts," Spitzer said. "It is up to me to make determinations about the nature of the individuals and the trustworthiness of individuals and leadership with whom I will negotiate. And that is the determination I made and obviously now we are on a different footing with the company, and that is as it should be."

Michael Cherkasky, Spitzer's boss when he was a prosecutor with the Manhattan District Attorney's office more than a decade ago, replaced Greenberg. Spitzer said the company is now "reacting appropriately" as it eliminates commissions charged to insurers that were the focus of his complaint.

Marsh's two biggest competitors, Aon Corp. and Willis Group Holdings Ltd., have also scrapped the fees.

Shares of American International rose $1.19 to $61.21 in New York Stock Exchange composite trading, and are down 8.6 percent since Spitzer's suit.

Hartford fell 32 cents to $58.74 and ACE rose 88 cents to $37.98. Munich Re rose 75 cents to 76.65 euros in Frankfurt.

"We're pursuing a wide range of issues because our concern is that the law is abided by and that there be a marketplace with real competition," Spitzer said. Cooperation from companies might help them avoid a suit like the one against Marsh, the attorney general said. Any settlement would include explicit disclosure of improper or illegal activity, he said. "A settlement that is in the shadows and obscured by a lack of understanding doesn't help," he said.

Spitzer said he was mindful of the impact his office's investigations have had on the companies being probed.

"Of course we worry about the impact of the loss of market cap, the loss of portfolio value, the loss of jobs," he said. "The overarching concern I have to have, however, is enforcing the law."