This paper analyzes the effects of international openness on vertical integration. Vertical integration can confer a negative externality, by thinning the market for inputs and thus worsening opportunism problems; this induces strategic complementarity and multiple equilibria in the integration...

We analyze the international operations of multinational firms to measure the spatial barriers to transferring knowledge. We model firms that can transfer bits of knowledge to their foreign affiliates in either embodied (traded intermediates) or disembodied form (direct communication). The model...

We find that prior to World Trade Organization membership, countries set import tariffs 9 percentage points higher on inelastically supplied imports relative to those supplied elastically. The magnitude of this effect is similar to the size of average tariffs in these countries, and market power...

International relative prices across industrialized countries show large and systematic deviations from relative purchasing power parity. We embed a model of imperfect competition and variable markups in a quantitative model of international trade. We find that when our model is parameterized to...

We evaluate two alternative models of international trade in differentiated products. An increasing returns model where varieties are linked to firms predicts home market effects: increases in a country's share of demand cause disproportionate increases in its share of output. In contrast, a...

This paper estimates the productivity gains from reducing tariffs on final goods and from reducing tariffs on intermediate inputs. Lower output tariffs can increase productivity by inducing tougher import competition, whereas cheaper imported inputs can raise productivity via learning, variety,...

We show that relaxing the assumption of CES preferences in monopolistic competition has surprising implications when trade is restricted. Integrated and segmented markets behave differently, the latter typically exhibiting reciprocal dumping. Globalization and lower trade costs have different...

We show that endogenous firm selection provides a new welfare margin for heterogeneous firm models of trade (relative to homogeneous firm models). Under some parameter restrictions, the trade elasticity is constant and is a sufficient statistic for welfare, along with the domestic trade share....

The rise of offshoring of intermediate inputs raises important questions for commercial policy. Do the distinguishing features of offshoring introduce novel reasons for trade policy intervention? Does offshoring create new problems of global policy cooperation whose solutions require...

How large are optimal tariffs? What tariffs would prevail in a worldwide trade war? How costly would a breakdown of international trade policy cooperation be? And what is the scope for future multilateral trade negotiations? I address these and other questions using a unified framework which...