This paper develops a model of endogenous product selection by firms. The theory is motivated by new evidence we present on the importance of product switching by U.S. manufacturers. Two-thirds of continuing firms change their product mix every five years, and product switches involve more than...

Recent research in international trade emphasizes the importance of firms' extensive margins for understanding overall patterns of trade as well as how firms respond to specific events such as trade liberalization. In this paper, we use detailed US trade statistics to provide a broad overview of...

This paper examines the determinants of intra-firm trade in US imports using detailed country-product data. We create a new measure of product contractibility based on the degree of intermediation in international trade for the product. We find important roles for the interaction of country and...

This paper reviews the empirical evidence on firm heterogeneity in international trade. A first wave of empirical findings from micro data on plants and firms proposed challenges for existing models of international trade and inspired the development of new theories emphasizing firm...

We combine data on individual trade transactions from U.S. customs records with comprehensive information on firms' employment from the Census Bureau's business register to examine wholesalers and retailers in U.S. exports and imports. Exporters and importers with 100 percent employment in...

This paper presents a model of international trade that features heterogeneous firms, relative endowment differences across countries, and consumer taste for variety. The paper demonstrates that firm reactions to trade liberalization generate endogenous Ricardian productivity responses at the...

Firms' decisions about which goods to produce are often made at a more disaggregate level than the data observed by empirical researchers. When products differ according to production technique or the way in which they enter demand, this data aggregation problem introduces a bias into standard...