An Anatomy of International Trade: Evidence from French Firms

Data on the individual export destinations of French firms shed light on the nature of entry barriers to national markets. The data reveal some striking regularities: (1) Looking across des tinations, the relationship between market size, French market share, and the number of French firms selling there is very tight, with the number of participants rising almost in proportion with respect to market share and with an elasticity of about two-thirds with respect to market size. (2) Looking across firms, most exporters sell to very few markets while a small number sell almost everywhere. Firms that export more widely sell much more within France and have higher value-added per worker. We show that a simple Ricardian model of export behavior with Cournot competition and a fixed cost of entry, calibrated to data on trade shares around the world, can explain these features. A relatively low fixed cost implies a di¤erence in the number of goods supplied to the largest and smallest markets of a factor of nearly 500. But with our assumption about the elasticity of substitution across commodities and our model's implication that lowest cost suppliers are verrepresented in the smallest markets, the implied welfare advantage is only 1.5