German prosecutors are investigating whether Swiss bank Vontobel might have helped German residents set up secret accounts via a -subsidiary in Liechtenstein, bringing a second bank into the focus of the scandal involving alleged tax -evasion.

The Zurich-based bank said that "client data were neither stolen nor misappropriated from" Liechtenstein unit Vontobel Treuhand, the bulk of a statement in which one of Switzerland's best-known banks did not comment further on "rumours" of prosecutors' interest.