A necessary condition for the international use of a currency, therefore, is that a currency’s future value in terms of goods and services has to be perceived as predictable and stable. Clearly, many currencies meet this test; yet few emerge as international currencies. Therefore, there must be - and there are - additional factors that help determine the internationalisation of a currency.
One such factor has to do with size. The size factor relates to the relative economic and demographic area for which the currency serves as legal tender - in other words the “habitat” of the currency.