Agglomeration Matters for Trade

We use a unique administrative dataset of Spanish exporters to document the existence of exporters' geographical agglomeration by export destination. We reveal that firms selling to countries with worse business regulations, a dissimilar language and a different currency tend to cluster significantly more. We then assess the implications of exporters' geographical agglomeration for firms' behavior and for the estimated welfare gains from trade. On the one hand, we find that exporters engage in more stable trade relationships with those countries that are the export destinations of nearby firms. On the other, we introduce agglomeration in a model of international trade à la Melitz (2003). Using our Spanish firm-level data, we find that, relative to a model without agglomeration, taking this phenomenon into account increases the elasticity of welfare with respect to fixed trade costs by 44%