Aon also accused the three of poaching 50 clients and robbing Aon of key employees "so that Aon no longer had brokers with existing relationships with the targeted clients."

In response, Marsh said by e-mail, "We do not believe there is any merit to the litigation and are aggressively defending the lawsuit."

The Aon complaint, filed Monday, said the three employees downloaded proprietary trade secrets and unlawfully disclosed those trade secrets to Marsh.

Aon says the three had access to information concerning its trade credit practices and the information exposed to Marsh included proprietary information on its trade credit practice, identity of clients and their purchasing decisions and contact information.

The complaint identifies Mr. Kornblau as a managing director in the trade credit insurance broker area, who purportedly entered into a written agreement to protect the firm's trade secrets. Both Mr. Wendleken and Ms. Angoff are identified as brokers, who though they did not sign a similar agreement, Aon claims, were well aware of the proprietary nature of Aon's business.

Aon does not identify the lost accounts, noting them as "DOES" but reserved the right to amend the complaint once it has fully identified what it says is the loss of up to 50 clients. Financial information regarding the firm's loss was redacted from the document.

Aon is seeking the return of a bonus to the employees, plus costs and punitive damage.

In an e-mail message, a representative from Aon said the complaint stands on its own and there would be no further comment.