John Y Campbell1, Howell E Jackson1, Brigitte C Madrian1, Peter Tufano1. 1. John Y. Campbell is the Morton L. and Carole S. Olshan Professor of Economics, Howell E. Jackson is the James S. Reid, Jr., Professor of Law, Harvard Law School, Brigitte C. Madrian is the Aetna Professor of Public Policy and Corporate Management, Harvard Kennedy School, Peter Tufano is the Sylvan C. Coleman Professor of Financial Management, Harvard Business School, all at Harvard University, Cambridge, Massachusetts.