Suppose that some Britons expect to receive payments in euros, while others face future obligations in euros. In each case this presents a risk, since nobody knows the future exchange rate between euros and pounds. But those expecting euro receipts can sell "forward" euros, locking in their price, while those expecting to make euro payments can buy forward euros. You might think that there is still no guarantee that there will be as many forward sellers as buyers. But if you work through the logic, it turns out that for the world as a whole it is in principle possible to hedge away all foreign exchange risk.