In this paper we analyze the implementation of socially optimal mergers when the regulator is not informed about the parameters that determine social and private gains from potential mergers. We find that most of the standard tools in dominant strategy implementation, like the revelation...

The US Merger Guidelines consider that the anticompetitive effect of a horizontal merger is increasing in the initial market concentration and decreasing in the elasticity of demand. These ideas are studied in a setting where identical firms compete a la Cournot and marginal cost is constant....