The foreign exchange market (Forex, FX or currency trading) is a global, decentralized global financial market for trading currencies. Financial centers around the world act as an anchor of the exchange between a variety of different types of buyers and sellers around the clock except on weekends. The foreign exchange market determines the relative value of various currencies. 
The main purpose is to support the foreign exchange market to international trade and investment by companies to convert one currency into another currency. For example, it allows U.S. companies to import British goods and to pay in sterling, although the business income in U.S. dollars. It also supports direct speculation on the value of currencies and the carry trade, speculation on changes in interest rates in both currencies. 
In a typical exchange transaction, one party buys a quantity of one currency by paying an amount of another currency. The modern foreign exchange market began to form in the 1970s after three decades of government restrictions on foreign exchange transactions (the Bretton Woods system of monetary management, the rules for commercial and financial relations with key countries the industrialized world, after the Second World War), when the country gradually shifted to a floating exchange rate regime previously set exchange rates, which remained after the Bretton Woods system of fixed.
The Forex.dk market is unique because of:
First its enormous volume of sales representatives of the largest asset class in the world that led to high liquidity;
Second geographical distribution;
Continuous operation: 24 hours a day except on weekends, ie trade on Sundays from 20:15 GMT to 22:00 GMT Friday Clock;
Third variety of factors that affect exchange rates;
4th low profit margins compared to other markets compared to fixed income, and
5th to improve the use of leverage on the profit and loss account in respect of margins and size matters.
As such, it has been since the Forex.dk market is called the closest to the ideal of perfect competition, despite the intervention of the currency by central banks. According to the Bank for International Settlements,  Since April 2010, the average daily volume of currency in world markets is estimated at 3.98 trillion, an increase of about 20% compared to 3.21 trillion volume dollars daily trading in April 2007. Some companies that specialize in the Forex.dk exchange market was the average daily turnover of over U.S. $ 4000000000000