1. College of Business, University of Illinois, Champaign, Illinois 61820;
2. National Bureau of Economic Research, Cambridge, Massachusetts 02138
3. Samuel Curtis Johnson Graduate School of Management, Cornell University, Ithaca, New York 14853:
4. Nova School of Business and Economics, Lisbon, Portugal 1099-032;
5. Department of Finance, Fisher College of Business, Ohio State University, Columbus, Ohio 43210;
6. Stockholm Institute for Financial Research, Stockholm, 113 60, Sweden