Until recently, foreign exchange brokers did large amounts of business, facilitating interbank trading and matching anonymous counterparts for small fees. Today much of this business has moved on to more efficient electronic systems.

Currencies can be classified as either floating currencies or fixed currencies based on their exchange rate regime.

Mauritania and Madagascar are the only remaining countries that do not use the decimal system; instead, the Mauritanian ouguiya is divided into 5 khoums, while the Malagasy ariary is divided into 5 iraimbilanja. However, due to inflation, both fractional units have in practice fallen into disuse.