The Iranian central bank has allowed trading in its currency at market levels after fixing the exchange rate in January, as the threat of sanctions over the country's nuclear programme and economic risks spurred Iranians to buy-up dollars, Bloomberg has reported. On January 26, the bank fixed the rate at 12,260 after the US dollar surged to almost double that level in unofficial currency markets as Iranians concerned over the economy rushed to buy. "Licensed exchange houses are given permission to buy and sell foreign currencies and answer customers' needs based on the mechanism of the market's supply and demand," the central bank said.