De facto currency April 2009. Both South African rand and Botswana pula circulate in Zimbabwe. The small French island of St. Pierre and Miquelon has the Canadian dollar as its de facto currency. Hong Kong Dollar is widely accepted in Macau, even though it hasn't gained any official recognition from Autoridade Monetária de Macau (AMCM) as legal tender in Macau. Currently, Macauese Pacata is pegged to Hong Kong Dollar at 1.029(buy)/1.032(sell). However, many merchants who accept Hong Kong Dollars may now offer to pay the difference between 2 currencies, such practice is often called '不补水' in Chinese. If merchandise priced in Patacas is
Optimum currency area Optimum currency area In economics, an optimum currency area (OCA), also known as an optimal currency region (OCR), is a geographical region in which it would maximize economic efficiency to have the entire region share a single currency. The underlying theory describes the optimal characteristics for the merger of currencies or the creation of a new currency. The theory is used often to argue whether or not a certain region is ready to become a currency union, one of the final stages in economic integration. An optimal currency area is often larger than a country. For instance, part of the