Mr Devlin has been married to Nina Devlin, a partner at public relations firm Brunswick. As well as allegedly trading on non-public information on deals involving Brunswick clients, he is also accused of tipping off friends and clients. The high-profile deals allegedly include InBev's offer for Anheuser-Busch in June and Take-Two's defence of a pending bid from Electronic Arts in February.

Mr Devlin is understood to have allegedly obtained the information by listening in on his wife's "phone calls and interpreting her travel schedules".

Mr Devlin, who worked in Lehman Brothers' private investment management business while the alleged offences took place, was able to curry favour with those to whom he allegedly provided the information. It is claimed he received a Cartier watch, a TV set and cash from one friend and business contacts and cash from others.

The SEC believes the ring profited by more than $4.8 million. The details are disclosed in a 46-page complaint lodged in a New York court by the Securities and Exchange Commission, accusing Mr Devlin and those who allegedly traded on the information of violating US securities laws.

Barclays Wealth yesterday suspended Mr Devlin, and said both it and Lehman had "co-operated fully with law enforcement authorities to assist them in their investigation into this alleged insider trading ring".

Brunswick said: "He has pleaded guilty to the charges and the Brunswick employee has not been charged or implicated in any way. We believe she was unaware of her husband's activities and is devastated." It said the firm has "always been totally committed to protecting the confidentiality of our clients".

Four of the men involved in the insider ring – day traders Jamil Bouchareb and Daniel Corbin, tax lawyer Eric Holzer and another Lehman broker, Frederick Bowers – were yesterday arrested by the FBI and charged with conspiracy and securities fraud.