How do import tariffs and R&D subsidies help domestic firms compete globally? How do these policies affect aggregate growth and economic welfare? To answer these questions, we build a dynamic general equilibrium growth model where firm innovation endogenously determines the dynamics of...

We study the gains from trade in an economy with oligopolistic competition, firm heterogeneity, and innovation. Oligopolistic competition together with free entry make markups responsive to firm productivity and trade costs. Lowering trade costs reduces markups on domestic sales but increases...

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...