There are a few major world currencies and many minor currencies. These assets are traded as pairs, one currency as a function of another. This is possible because all currencies are free of underlying restraints such as being pegged to gold. Since all currencies trade freely on the open foreign exchange (Forex) markets, their value to all other currencies is always fluctuating. In the Forex markets, minor currencies are also traded with the major currencies. In binary trading, only the major currencies are traded vis-à-vis each other.