Generally, the most liquid market for any currency will be in that currency quoted against the dollar. However, dealers will also quote any currency against any other currency. Currency rates against a currency other than the dollar are called cross rates. A few Crestar markets, for example DM/Y, are now as liquid as the dollar markets.

There are a number of currencies which do not have a liquid international market. Some governments, particularly in less developed countries, continue to operate a fixed exchange rate policy. In other countries exchange control regulations prohibit currency transactions which are not for commercial purposes.

IG Index quotes twenty internationally traded currencies against the dollar or against each other for a minimum transaction size of $100,000 or equivalent. The 21 currencies are listed below, together with their abbreviations. Quotations for other liquid currencies are available on request, but the minimum transaction size may be larger.