Janssen and Rasmusen (2002) show that a Bertrand model with an uncertain number of firms has only one symmetric equilibrium, and profits in that equilibrium fit the empirical data in Bresnahan and Reiss (1991). However, unless its equilibrium is unique, Janssen and Rasmusen's model cannot be...

The 1914 Clayton Act prohibited any acquisition whose effect may be to “substantially” lessen competition. International Shoe defined § 7's word “substantially” by saying that an acquisition's effect is “substantial” only if it “will injuriously affect the public.” This paper...