1. Department of Finance, HEC Paris, 1 avenue de la Libération, 78351 Jouy-en-Josas, France, and NBER.
2. Department of Economics, Harvard University, Littauer Center, Cambridge, MA 02138, and NBER.
3. Department of Finance, Stockholm School of Economics, Sveavägen 65, Box 6501, SE-113 83 Stockholm, Sweden.