1 We thank seminar participants at the 15 th SMYE in Luxembourg, the 17 th CEF conference in London, the 2010 EEA meeting in Glasgow, for helpful discussions and comments. We also thank Luca Dedola, Oreste Tristani, Fiorella De Fiore and an anonymous referee for their useful comments. The views presented in this paper are those of the authors and not necessarily of the NBP. Abstract 4 Non-technical summary 5