Optimal tariffs with inframarginal exporters

This paper shows that an importing country can have an incentive to impose a tariff to extract rents earned by foreign exporters even in a perfectly competitive setting. To demonstrate this, I develop a new model of international trade that incorporates fixed costs of exporting and firm heterogeneity within a perfectly competitive framework. In this setting, despite the fact that there are no preexisting distortions, the optimal tariff is positive even for a small country with no world market power. In the limit, as either firm heterogeneity or the fixed costs of exporting vanish, the optimal tariff approaches zero.