Allen & Overy (A&O) has hired the former chief of the securities fraud unit for the Southern District US Attorney’s Office in a boost for its New York office.

David Esseks will join the City giant’s Manhattan arm as a partner, where he will specialise in white-collar and securities litigation. From 2003 until June 2007, Esseks served as head of the US’ premier white-collar prosecution unit, supervising a staff of 20 Assistant US Attorneys.