Foreign Exchange Market

To buy foreign cargo or services, or to empower in former countries, companies and persons may need to first buy the currency of the country with which they are doing business. Generally, exporters prefer to be paid in their country’s currency or in U.S. dollars, which are accepted all over the world.
What time Canadians buy oil from Saudi Arabia they may pay in U.S. dollars and not in Canadian dollars or Saudi riyals, even though the United States is not involved in the transaction.
Communication in Singapore, Switzerland, Hong Kong, Germany, France and Australia account for most of the remaining transactions in the market. Trading goes on 24 hours a day: at 8 a.m. the exchange market is first opening in London, while the trading day is ending in Singapore and Hong Kong. At 1 p.m. in London, the New York market opens for business and later in the afternoon the traders in San Francisco can also conduct business. As the market closes in San Francisco, the Singapore and Hong Kong markets are starting their day.
The FX market is fast paced, volatile and enormous—it is the largest market in the world. In 2001 on average, an estimated $1,210 billion was traded each day—roughly equivalent to every person in the world trading $195 each day.