When the chief financial officer of Germany's largest insurance company repeats for the 37th time that one of its divisions is not for sale, the matter would normally be closed.

But Paul Achleitner knows that when the company concerned is Dresdner Bank, and its subsidiary Dresdner Kleinwort, the investment banking arm of Allianz, even the clearest statement will not halt speculation that seems to have hung over it almost since 2001, when Allianz paid €21bn for the business.