The Working Paper series of the Oesterreichische Nationalbank is designed to disseminate and to provide a platform for Working Paper series of the Oesterreichische Nationalbank is designed to disseminate and to provide a platform for Working Paper series of the Oesterreichische Nationalbank discussion of either work of the staff of the OeNB economists or outside contributors on topics which are of special interest to the OeNB. To ensure the high quality of their content, the contributions are subjected to an international refereeing process. The opinions are strictly those of the authors and do in no way commit the OeNB.