A third insurance company executive pleaded guilty yesterday to criminal charges in connection with New York state Attorney General Eliot L. Spitzer's investigation of payoffs and bid-rigging in the insurance industry.

Patricia Abrams, assistant vice president in the excess casualty division of ACE Ltd., pleaded guilty in state court in Manhattan to attempted combination in restraint of trade, a misdemeanor, acknowledging that she had helped Marsh & McLennan Cos. brokers rig bidding for corporate liability insurance policies.

Spitzer caught Abrams saying in a December 2000 e-mail that she increased ACE's bid for a particular policy from $990,000 to $1.1 million because Marsh brokers wanted another company, American International Group Inc., to win the business. Abrams is cooperating with Spitzer's office.

Marsh & McLennan, the nation's largest insurance broker, said yesterday it is suspending its practice of using "market services agreements" with insurance carriers, which Spitzer has alleged were used to rig bids.

The agreements -- also known as contingent commissions or placement service agreements -- are at the center of a lawsuit he announced Thursday accusing New York-based Marsh & McLennan of taking payoffs from insurance companies to steer corporate clients their way, rather than get those customers the best prices for corporate property and casualty policies.

The fees are beyond the usual commissions that brokers receive from insurance companies, mainly for steering volume business to insurers.

Marsh & McLennan said the practice would be suspended at Marsh Inc., its risk and insurance services subsidiary. "Today's decision was made in light of the serious allegations and questions that have been raised about this long-standing industry practice," the company said in a written statement.

The statement also quoted chairman and chief executive Jeffrey W. Greenberg as saying: "We are greatly disturbed by the allegations of wrongdoing."

The company also named a new chief executive at Marsh Inc., Michael G. Cherkasky, a former prosecutor who was Spitzer's boss when the two worked in the Manhattan district attorney's office. Cherkasky has been chief executive of another subsidiary, Kroll Inc. The announcement came as shares in Marsh & McLennan, which fell 25 percent on Thursday, took another beating on Friday. Moody's Investors Service put Marsh & McLennan's debt rating on "outlook negative," which often precedes a downgrade. And several brokerages, including Prudential Equities Group, lowered their ratings on the stock.

Marsh & McLennan shares closed down $5.65 at $29.20 on the New York Stock Exchange.

Shares in insurance companies named in Spitzer's civil suit fell for a second day. American International Group was down $2.15 at $57.85, ACE was off $1.49 at $34.98, and Hartford Financial Services Group Inc. was down $2.10 at $56.30.

Spitzer said other insurance companies are being investigated. MetLife Inc. disclosed yesterday that it had received four subpoenas, which could indicate the inquiry goes beyond property and casualty insurance providers.

On Friday, the chairman and chief executive of AIG, Maurice R. "Hank" Greenberg, said in a conference call with analysts that the company had launched its own investigation of the allegations, using outside investigators, and is cooperating fully with Spitzer's office.

Hank Greenberg, who is the father of the Marsh & McLennan chief executive, told analysts that AIG had sought guidance from New York state insurance regulators about contingent commissions long before Spitzer's investigation began.

He said that AIG queries in July 2002 and in October 2003 were unanswered.

Hank Greenberg also told the analysts that placement service agreements were negotiated "at the subsidiary company level."

Also Friday, National Financial Partners Corp., a life insurance and benefits broker, said it had received two additional subpoenas from Spitzer's office.