Forex, also known as foreign exchange, FX, or currency trading, is a decentralized global market where all the world's currencies trade. The forex market is the largest, most liquid market in the world with an average daily trading volume exceeding $5 trillion. All the world's combined stock markets don't even come close to this. But what does that mean to you? Take a closer look at forex trading and you may find some exciting trading opportunities unavailable with other investments.