1. Department of Economics, Bocconi University , Milan 20136, Italy
2. Institut d’Economia de Barcelona (IEB), University of Barcelona , Barcelona 08034, Spain
3. IGIER, Bocconi University , Milan 20136, Italy
4. PERICLES, Bocconi University , Milan 20136, Italy
5. CEPR
6. Business School, Department of Economics, University of St Andrews , St Andrews KY16 9AZ, United Kingdom