Dynamic Merger Review
---- Acknowledgements ----
We thank Pat DeGraba, Glenn Ellison, Peter Eso, Joe Farrell, Ramon Fauli-Oller, Chiara Fumagalli, Tracy Lewis, Tore Nilsson, Patrick Rey, Carl Shapiro, Ron Siegel, Lucy White, members of the Toulouse Network for Information Technology, and audiences at numerous conferences and research seminars for their comments. Nocke gratefully acknowledges financial support from the National Science Foundation and the University of Pennsylvania Research Foundation. Whinston thanks the National Science Foundation, the Toulouse Network for Information Technology, and the Leverhulme Trust for financial support. The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research.