"It wasn't a surprise," CEO Thomas Gottstein said at a conference hosted by financial media group Finanz und Wirtschaft in Zurich, adding it was to be expected after the bank had been visited by an auditor in recent months.

FINMA's decision to take enforcement proceedings comes after it hired an auditor to review the bank's corporate governance and its use of electronic communications in connection with the surveillance.

Gottstein became CEO in February, after his predecessor Tidjane Thiam was forced out over the scandal.

(Reporting by Brenna Hughes Neghaiwi; editing by David Evans)