In a typical foreign exchange transaction, a party purchases a quantity of one currency by paying a quantity of another currency. The modern foreign exchange market began forming during the 1970s when countries gradually switched to floating exchange rates from the previous exchange rate regime, which remained fixed as per the Bretton Woods system.
The foreign exchange market is unique because of
its huge trading volume, leading to high liquidity;
its geographical dispersion;
its continuous operation: 24 hours a day except weekends, i.e. trading from 20:15 GMT on Sunday until 22:00 GMT Friday;
the variety of factors that affect exchange rates;
the low margins of relative profit compared with other markets of fixed income; and
the use of leverage to enhance profit margins with respect to account size.
As such, it has been referred to as the market closest to the ideal of perfect competition, notwithstanding market manipulation by central banks. According to the Bank for International Settlements, as of April 2010, average daily turnover in global foreign exchange markets is estimated at $3.98 trillion, a growth of approximately 20% over the $3.21 trillion daily volume as of April 2007.
The $3.98 trillion break-down is as follows:
$1.490 trillion in spot transactions
$475 billion in outright forwards
$1.765 trillion in foreign exchange swaps
$43 billion currency swaps
$207 billion in options and other products