In this paper we examine whether a generalized version of Flam and Helpman's (1987) model of vertical differentiation can reconcile three facts. One, countries import only a subset of available varieties. Two, import prices vary across exporters within narrow product categories. Three, US growth...

We examine a generalized version of Flam and Helpman’s (1987) model of vertical differentiation that maps cross-country differences in income distributions to variations in import variety and price distributions. The theoretical predictions are examined and confirmed using micro data on...

A large and growing share of international trade is carried on airplanes. Air cargo is many times more expensive than maritime transport but arrives in destination markets much faster. We model firms' choice between exporting goods using fast but expensive air cargo and slow but cheap ocean...