Paul Hastings Janofsky & Walker lawyer Eric Holzer has been suspended from the firm over his alleged part in suspected insider trading at Lehman Brothers.
Holzer, a tax associate in the New York office of Paul Hastings, is accused of being part of an insider trading ring with Lehman traders Jamil Bouchareb, Daniel Corbin, Frederick Bowers and Matthew Devlin.
US regulator the Securities and Exchange Commission (SEC) believes the ring earned more than $4.8m (£3.15m) from the alleged scam after benefiting from information provided by then Lehman employee Devlin.
The SEC filed a complaint in New York accusing the ring of violating US securities law.
Information regarding high profile deals such as InBev's acquisition of US drinks company Anheuser-Busch have been highlighted in the case.
In a statement, Paul Hastings said: " These allegations have no connection to any firm or client matters. We will cooperate fully with the authorities in any investigation."