We study the gains from trade in a model with oligopolistic competition, heterogeneous firms and innovation, and provide a formula to decompose the mechanism. The new insight we provide is that market concentration can be a welfare-relevant feature of market power above and beyond markup...

Professions such as doctors and lawyers often enjoy some degree of self-regulation, i.e. they can set the codes of conduct in the market and even determine the rules for joining the profession. We address the problem of the optimal scope of self-regulation. Specifically, we model a profession...