The importance of foreign exchange banks. Designated foreign exchange banks are also called authorized foreign exchange banks. Banks designated by the central bank to handle foreign exchange business. It is an intermediary in the foreign exchange market. In addition to buying and selling foreign exchange on behalf of customers and providing services, you can also buy and sell foreign exchange according to your own interests to obtain foreign exchange profits. In countries that implement foreign exchange control, foreign exchange banks must be approved by the competent foreign exchange authorities before they can handle foreign exchange business.