NEW YORK—A judge last week acquitted three former Marsh Inc. executives in a bid-rigging and price-fixing scheme, offering a boost to the remaining defendants, one of whom already has indicated he will seek to have charges against him dismissed.

Meanwhile, two former Marsh executives previously found guilty in the case are seeking to have their convictions thrown out.

New York County Supreme Court Judge James A. Yates last week found Joseph Peiser, former managing director and head of Marsh's global broking excess casualty unit; Greg J. Doherty, former Marsh senior vp and ACE USA local broking coordinator team leader; and Kathleen M. Drake, former Marsh managing director and local broking coordinator team leader, not guilty of scheme to defraud and restraint of trade charges.

The judge previously dismissed four grand larceny charges against the trio, citing insufficient evidence.

Judge Yates did not comment on his verdict, which prompted a large gathering of family members and former colleagues to erupt into cheers. If convicted in the bench trial, the three could have faced up to four years in prison for each charge.

“It's been five long years, but the judge has been very patient and he kept an open mind. I am very appreciative,” Mr. Peiser said after the acquittal.

Defense lawyers, who attacked the prosecution's case during closing arguments, said the acquittal was “well deserved.”

“I still believe Greg Doherty never should have been prosecuted,” said Maranda Fritz, a partner at Hinshaw & Culbertson L.L.P. in New York, who represented Mr. Doherty. We are “so grateful that he can begin to rebuild his life.”

A spokesman for New York Attorney General Andrew Cuomo did not respond to a request for comment on the verdict, which drew mixed reactions from industry observers and legal experts (see related story).

Last week's acquittals came after the February 2008 convictions of former Marsh Managing Directors William Gilman, who prosecutors called the “architect” of the bid-rigging scheme, and Edward J. McNenney, deemed the “enforcer.” Messrs. Gilman and McNenney were found guilty of violating New York's antitrust law, but were acquitted of all other charges including fraud and grand larceny.

The duo had begun the process of appealing their convictions. However, lawyers for Messrs. Gilman and McNenney since have filed a motion seeking to have the convictions thrown out citing “prosecutorial misconduct.” (see related story)

Prosecutors argued during the three defendants' trial that they misled the broker's excess casualty clients by steering business to selected insurers and preventing competitive bids. During closing arguments, Assistant Attorney General Evelyn Baez asked the judge to “send a message to the defendants that no matter how powerful, no one is above the law.”

The three were among a group of eight executives indicted in 2005 by then-New York Attorney General Eliot Spitzer after a probe of the broker's contingent commission practices. Prosecutors accused them of colluding with employees at various insurers—including American International Group Inc., ACE USA, Liberty International Insurance Co., Zurich American Insurance Co. and others, to rig the market for excess casualty insurance. One of the former executives, Edward J. Keane Jr., pleaded guilty to criminal charges and agreed to cooperate with the government.

About a dozen other individuals who previously pleaded guilty to criminal charges also served as cooperating witnesses during the trial.

Observers said last week's verdict is a boost for former Marsh Senior Vps Thomas T. Green Jr. and William L. McBurnie, the remaining defendants awaiting trial.

Mr. Green's attorney last week said he will seek to have his client's charges dismissed. Given the verdict, “I would be very surprised, if the prosecution wants to move forward,” said Stephen P. Scaring of Stephen P. Scaring P.C. in New York.

A status hearing for Mr. Green is scheduled for this week, Mr. Scaring said. “The charges will either be dismissed or we will go to trial,” he said.

Dane Keller Rutledge, an attorney for Mr. McBurnie, said he and his client “are delighted” by the acquittal, but declined further comment.

Others said the prosecution likely is considering its next move.

“I would not be surprised if there was an announcement from the New York (attorney general) that they were not going forward with the prosecution of the remaining two defendants,” said James W. Carbin, a partner with Duane Morris L.L.P. in New York.

Fran Semaya, chair of the insurance regulatory practice of Nelson Levine de Luca & Horst in New York, said it's possible the prosecution may try to settle to avoid another failure. “I would expect them to push more for a settlement, rather than withdraw the charges,” said Ms. Semaya, who was not involved with the case.