Exporters are few---less than one fifth among U.S. manufacturing firms---and are larger than non-exporting firms---about 4-5 times more total sales per firm. These facts are often cited as support for models with economies of scale and firm heterogeneity as in Melitz (2003). We find that the...

A number of stylized facts have been documented about the extensive margin of trade---which firms export, and how many products they send to how many destinations. We argue that the sparse nature of trade data is crucial to understanding these stylized facts. Typically the number of...