Multinational firms (MNEs) accounted for 42 percent of US manufacturing employment, 87 percent of US imports, and 84 of US exports in 2007. Despite their disproportionate share of global trade, MNEs' input sourcing and final-good production decisions are often studied separately. Using newly...

Import tariffs tend to be higher for final goods than for inputs, a phenomenon commonly referred to as tariff escalation. Yet neoclassical trade theory - and modern Ricardian trade models, in particular - predict that welfare-maximizing tariffs are uniform across sectors. We show that tariff...