South African rand due to relatively high-quality counterfeit notes in circulation. In 2011, the South African Reserve Bank issued 100-Rand banknotes which were defective because they lacked fluorescent printing visible under UV light. In June, printing of this denomination was moved from the South African Bank Note Company to Crane Currency's Swedish division (Tumba Bruk), which reportedly produced 80 million 100-Rand notes. The South African Reserve Bank shredded 3.6 million 100-Rand banknotes printed by Crane Currency because they had the same serial numbers as a batch printed by the South African Bank Note Company. In addition, the notes printed in Sweden were not
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