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,
De facto currency De facto currency A de facto currency is a unit of money that is not legal tender in a country but is treated as such by most of the populace. The United States dollar and the European Union euro are the most common de facto currencies. Andorra used the euro unofficially prior to June 2013, at which point the euro became its official currency. The euro remains the de facto currency in Kosovo and Montenegro. Countries using the United States dollar as their de facto currency include Aruba and Cambodia, where most hotels, restaurants, and transportation are priced in dollars;