This paper investigates the size and scope of global production sharing in the telecom sector by analysing the international pattern of trade in telecom parts and components using bilateral trade statistics over the period 1978-2000. The results show that since 1995 the US have taken over the...

We use transaction-level data to study changes in the concentration of US imports. Concentration has fallen in the typical industry, while it is stable by industry and origin country. The fall in concentration is driven by the extensive margin: the number of exporting firms has grown, and the...

We study how financial frictions affect firm-level heterogeneity and trade. We build a model where productivity differences across monopolistically competitive firms are endogenous and depend on investment decisions at the entry stage. By increasing entry costs, financial frictions lower the...