European Currency Unit opportunity for foreign diversification without reliance on the currency of a single country. The ECU was conceived on 13 March 1979 as an internal accounting unit. It had the ISO 4217 currency code XEU. On 1 January 1999, the euro (with the code EUR and symbol €) replaced the ECU, at the value €1 = 1 ECU. Unlike the ECU, the euro is a real currency, although not all member states participate (for details on euro membership see Eurozone). Two of the countries in the ECU basket of currencies, UK and Denmark, did not join the eurozone, and a third,
Euro 3.3%. The euro inherited and built on the status of the Deutsche Mark as the second most important reserve currency. The euro remains underweight as a reserve currency in advanced economies while overweight in emerging and developing economies: according to the International Monetary Fund the total of euro held as a reserve in the world at the end of 2008 was equal to $1.1 trillion or €850 billion, with a share of 22% of all currency reserves in advanced economies, but a total of 31% of all currency reserves in emerging and developing economies. The possibility of the euro becoming