Banks trading in currencies

Q 5: Banks trade in currencies; for example, they buy the British Sterling for six riyals and sell them again for six and a half riyals. Is this trade permissible?

A: There is no wrong in that if the exchange takes place (Part No. 13; Page No. 453) on the spot and the two currencies are of different types.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his Family, and Companions.