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 … U.S. trade statistics to provide a broad overview of how the margins of trade contribute to variation in U.S. imports …

-specific quotas following China’s entry into the World Trade Organization. Chinese import competition had two effects: first, it led …

, trade is more sensitive to trade costs if the exporting country only provides a small share of the destination country …’s imports. As a result, trade costs have a heterogeneous impact across country pairs, with some trade flows predicted to be zero …