Central banks play a key role in the currency markets because of their power over monetary policy. They have a direct influence over money supply, which in turn affects demand and price of the currency. Through the use of different policies, central banks can try to manipulate the markets so that they can keep their currency at specific levels. Some countries and their central banks try to peg their currency to that of another currency or basket of currencies (for example, China to the U.S.).
The central bank can participate in the forex market by buying and selling their currency at the spot market in order to keep it from changing too much. Another motivation for central banks is to keep the local currency at a specific price in order to make their local economy more attractive for international trade. If a country