How do trade costs affect international trade? This paper offers a new approach. We rely on a flexible gravity equation that predicts variable trade cost elasticities, both across and within country pairs. We apply this framework to the effect of currency unions on international trade. While we...

Using detailed firm-level transactions data for UK imports, we find that invoicing in a vehicle currency is pervasive, with more than half of transactions in our sample invoiced in neither sterling nor the exporter's currency. We then study the relationship between invoicing currency choices and...