Just as other prices in the economy are determined by the interaction of buyers and sellers, exchange rates are determined by the interaction of the households, firms, and financial institutions that buy and sell foreign currencies to make international payments. The market in which international currency trades take place is called the foreign exchange market, often abbreviated as the forex or FX market. Foreign exchange trading takes place in many financial centers, with the largest volumes of trade occurring in such major cities as London (the largest market), New York, Tokyo, Frankfurt, and Singapore. The worldwide volume of foreign exchange trading is enormous, and it has skyrocketed during recent years. In May 1989, the average total value of global foreign exchange trading was close to $600 billion per day. Twenty-four years later, in April 2013, the daily global value of foreign exchange trading had jumped to around $5.3 trillion, making it the largest market globally.