1. The T.N. Thiele Centre for Mathematics in Natural Science, Department of Mathematical Sciences, and CREATES, University of Aarhus, Ny Munkegade, DK‐8000 Aarhus C, Denmark
2. Department of Economics, Stanford University, Landau Economics Building, 579 Serra Mall, Stanford, CA 94305‐6072, USA
3. Department of Marketing and Statistics, Aarhus School of Business, and CREATES, University of Aarhus, Bartholins Allé 10, DK‐8000 Aarhus C, Denmark
4. Oxford‐Man Institute, and Department of Economics, University of Oxford, Eagle House, Walton Well Road, Oxford OX2 6ED, UK