The authors thank Patrick Flannery and Michael Lehr from MayStreet for providing access to data used in this study; Jeff Bacidore, Robert Bartlett, Agostino Capponi (the department editor), Ben Connault, Kevin Crotty, Jefferson Duarte, Amy Edwards, Sean Foley, Merritt Fox, Larry Glosten, Vincent Gregoire (discussant), Björn Hagströmer, Joel Hasbrouck (discussant), Hans Heidle, Terry Hendershott, Robert Jackson, Ravi Jagannathan, Bob Korajczyk, Sophie Moinas (discussant), Esen Onur, Brett Redfearn, Gideon Saar (discussant), Kumar Venkataraman, Mao Ye, Bart Yueshen, three anonymous referees, and seminar participants at the European Finance Association Conference, Investors Exchange Academic Research Conference, the Microstructure Exchange, the Microstructure Online Seminars Asia Pacific, the NBER Big Data Conference, the Northern Finance Association Conference, the Western Finance Association Conference, Rice University, the Securities and Exchange Commission, and the University of Illinois at Chicago for helpful comments; and the Institute for Corporate Governance and Finance at the New York University School of Law for generous support. All errors are our own.