Aggregative Oligopoly Games with Entry1 Simon P. Anderson2, Nisvan Erkal3 and Daniel Piccinin4 First version: November 2009 This version: January 2014 1We thank Maxim Engers, Daniel Halbheer, Joe Harrington, Simon Loertscher, Clau- dio Mezzetti, Volker Nocke, Frank Stähler, Jidong Zhou, and especially Richard Cornes for comments and discussion. We also thank seminar participants at the Federal Trade Commis- sion, Johns Hopkins University, University of Mannheim, National University of Singapore, and conference participants at Université Catholique de Louvain (Conference in Honor of Jacques Thisse), EARIE (2010), Australasian Economic Theory Workshop (2011), North American Winter Meeting of the Econometric Society (2013) for their comments. Imogen Halstead, Charles Murry, and Yiyi Zhou have provided excellent research assistance. The …rst author thanks National Science Foundation (0752923) for …nancial support and the Department of Economics at the University of Melbourne for its hospitality. The second author gratefully acknowledges funding from the Australian Research Council (DP0987070). 2Department of Economics, University of Virginia P.O. Box 400182, Charlottesville, VA 22904-4182, USA.
[email protected]. 3Department of Economics, University of Melbourne, VIC 3010, Australia.
[email protected]. 4Brick Court Chambers, 7-8 Essex Street, London, WC2R 3LD, United Kingdom.
[email protected]. Abstract We compile an IO toolkit for aggregative games and use inclusive reaction functions to compare long-run market structures in aggregative oligopoly games. We show strong neutrality properties across market structures. The IIA property of demands (CES and logit) implies that consumer surplus depends on the aggregate alone, and that the Bertrand pricing game is aggregative. We link together the following results: merging parties’pro…ts fall but consumer surplus is unchanged, Stackelberg leadership raises welfare, monopolistic competition is the market structure with the highest surplus.