Market size and liquidity

The foreign exchange market is the largest and most liquid financial market in the world. Traders include large banks, central banks, currency speculators, corporations, governments, and other financial institutions. The average daily volume in the global foreign exchange and related markets is continuously growing. Daily turnover was reported to be over US$3.2 trillion in April 2007 by the Bank for International Settlements. [2] Since then, the market has continued to grow. According to Euromoney's annual FX Poll, volumes grew a further 41% between 2007 and 2008.[3]
Of the $3.98 trillion daily global turnover, trading in London accounted for around $1.36 trillion, or 34.1% of the total, making London by far the global center for foreign exchange. In second and third places respectively, trading in New York accounted for 16.6%, and Tokyo accounted for 6.0%.[4] In addition to "traditional" turnover, $2.1 trillion was traded in derivatives.
Exchange-traded FX futures contracts were introduced in 1972 at the Chicago Mercantile Exchange and are actively traded relative to most other futures contracts.