The division of labor between and within countries is driven by two fundamental forces, comparative advantage and increasing returns. We set up a simple Ricardian model with a Marshallian input sharing mechanism to study their interplay. The key insight that emerges is that the interaction...

Larger cities typically give rise to two opposite effects: tougher competition among firms and higher production costs. Using an urban model with substitutability of production factors and pro-competitive effects, I study the response of the market outcome to city size, land-use regulations, and...

This paper develops and estimates a model of indivisibilities in shipping and economies of scale in consolidation. It uses highly detailed data on imports for which it is possible to observe the contents of individual containers. In the model, a firm is able to adapt to indivisibility...