The Forex market is one of the biggest and most liquid in the world, with a total daily average trading volume of USD 5.1 trillion in April 2016, according to the Bank For International Settlements (BIS).
Most of this trading activity is concentrated within 5 countries:
United Kingdom
United States
Singapore
Hong Kong SAR
Japan
These sale desks intermediates 77% of all currency trading in April 2016, according to BIS statistics.
Since 1986, the BIS monitors all Forex market activity every three years to spot any changes in global financial markets, in order to know how currencies in the world are traded.
Some of these factors include:
International trades, trading volumes
Exchange rates
Widely traded currency pairs, etc.
When traders invest in the Foreign Exchange market, it’s mainly because they want to take advantage of frequently traded Forex pairs with a large average daily price, allowing them to make big profits.