We show that in oligopolistic markets the social choice correspondence which selects all socially efficient outcomes is Nash implementable if the number of firms is at least two. Thus, monopoly regulation whenever consumers are favored by the designer or the society is the only framework, among...

We examine the issue of learning in a generalized principal-agent model with incomplete information. We show that there are situations in which the agent prefers a Bayesian regulator to have more information about his private type. Moreover, the outcome of the Bayesian mechanism regulating the...