Letting money ‘work’ is a fine thing. For banks, this has been part of their core business at least since the invention of the current account in Italy in the late Middle Ages; they lend it out on a short, medium or long-term basis and earn interest themselves with their customers' deposits. However, this does not apply to German payment and e-money institutions according to a leaflet issued by the German Federal Financial Supervisory Authority (BaFin). The following article examines whether such a ‘prohibition on drawing interest’ is legally valid for these institutions.