A Swiss bank said Friday one of its top executives has resigned amid a German tax-fraud investigation that is recently expanded across national borders.

Bank J. Safra Sarasin AG said deputy chief executive Eric Sarasin has resigned, in a bid to ensure that accusations raised as part of the investigation "do not tarnish the image and reputation of the bank." Officials are looking into Sarasin's and the bank's role in providing investments that allegedly enabled clients to fraudulently earn tax rebates.