There are more than 200 currency pairs on the Exchange Traded Funds (ETF) market, with some of the most popular ones trading at an average of $5.95 a share.
The top-performing currencies in the benchmark index are: US dollars, British pounds, Canadian dollars, Japanese yen, Swiss francs, euro, Swiss Franc, Japanese renminbi, Russian ruble and Chinese yuan.
Canadian dollar, US dollar and Swiss franc stocks are also a big part of the market.
Here are some of their most important stats.
The chart below shows the top-five highest-earning currencies in each of the four major indices, and how much they are trading for each day.