Erik R. Sirri is a Professor of Finance at Babson College. His research interests include the interaction of securities law and finance, securities market structure, and investment management. From 2006-2009 he was the Director of the Division of Trading and Markets at the U.S. Securities and Exchange Commission, where he was responsible to the Commission for matters relating to the regulation of stock and option exchanges, national securities associations, brokers, dealers, clearing agencies, transfer agents, and credit rating agencies. He served as the Commission’s Chief Economist from 1996-1999, and was an Assistant Professor of Finance at the Harvard Business School from 1989 to 1995. Sirri received his B.S. in Astronomy from the California Institute of Technology in 1979, an M.B.A. from the University of California, Irvine, in 1984, and his Ph.D. in Finance from the University of California, Los Angeles, in 1990. His published writings appear in academic journals, practitioner journals, and books. He has consulted for securities firms, stock exchanges, mutual fund companies, issuers, and information vendors on a variety of regulatory and business matters.