We embed a North-South trade model into an incomplete contracts setting where the production of heterogeneous firms can be geographically separated. When a Northern headquarter contracts with a Southern supplier instead of a Northern supplier, the presence of international incomplete contracts...

Using six years of firm-level data covering 224 regions of the enlarged European Union, we evaluate the importance to a firm of locating its activities (production, headquarters, R&D, logistics and sales) close together. We find that, after controlling for regional characteristics, being closely...

Why do cities differ so much in productivity? We document that most of the measured dispersion in productivity across US cities is spurious and reflects granularity bias: idiosyncratic heterogeneity in plant-level productivity and size, combined with finite plant counts. As a result, economies...

Larger Indian firms selling inputs to other firms tend to have more customers, tend to be used more intensively by their customers, and tend to have larger customers. Motivated by these regularities, I propose a novel empirical model of trade featuring endogenous formation of input-output...

Ever since Marshall (1890) agglomeration externalities have been viewed as the key factor explaining the existence of cities and their size. However, while the various micro foundations of agglomeration externalities stress the importance of Total Factor Productivity (TFP), the empirical...

International trade is dominated by a small number of very large firms. Models of trade with heterogeneous firms have been developed to study the causes and consequences of this observation. The canonical model of trade with heterogeneous firms shows that trade leads to between-firm...

We use transaction-level data to study changes in the concentration of US imports. Concentration has fallen in the typical industry, while it is stable by industry and origin country. The fall in concentration is driven by the extensive margin: the number of exporting firms has grown, and the...

Applying the methodology developed by Duranton and Overman (2005, 2008), we analyze localization and dispersion of firms in China. Using a unique and detailed dataset on manufacturing firms in China, we are able to follow the changes in location patterns of firms between 2002 and 2008. Our...

The comparative advantage of many cities is based on their efficiency in the production of "functions", e.g., business services such as finance, law, engineering, or similar functions that are used by firms in a wide range of sectors. Firms that use these functions may choose to source them...

We provide an overview and synthesis of recent work on models of monopolistic competition with heterogeneous firms in international trade, paying particular attention to competition effects, pass-through, selection effects, and linking distributions of firm characteristics and outcomes. A...