1. European University Institute, Villa San Paolo, Via della Piazzuola 43, 50133 Florence, Italy. European University Institute, Villa San Paolo, Via della Piazzuola 43, 50133 Florence, Italy.
2. Economics Department, University of Chicago, 1126 East 59th Street, Chicago, IL 60637, USA.
3. Kellogg School of Management, Northwestern University, Evanston, IL 60208, USA.
4. Graduate School of Business, University of Chicago, 5807 South Woodlawn Avenue, Chicago, IL 60637, USA.