1. Department of Economics, University of Lugano, Via Giuseppe Buffi 13, 6900 Lugano, Ticino, Switzerland
2. Department of Economics, University of St. Gallen, Dufourstrasse 50CH‐9000 St. Gallen, Switzerland
3. Cowles Foundation and Department of Economics, Yale University, P.O. Box 208281, New Haven, CT 06520‐8281, USA