All relevant informations about the bachelor theses can be found here.
More details on the examination regulations of the university can found here: Prüfungsordnung für das Bachelorstudium. The specific information for the achelor "Wirtschaftswissenschaften" can be found here: fächerspezifischen Bestimmungen.
Information with respect to master theses can be found here.
More details can be found on the web pages of the department.