According to the Bank for International Settlements in its Triennial Central Bank Survey, the average daily volume of trading in the global foreign exchange market in 2014 exceeded $5 trillion. The currency of choice is the U.S. dollar, which in 2014 accounted for more than 85 percent of all foreign exchange transactions. These exchange transactions are made to finance trade in goods and services as well as cross-border trading of financial assets. Why are dollars involved in such a large percentage of payments for goods and services and financial assets?