History of the euro midnight on 1 January 1999, when the national currencies of participating countries (the eurozone) ceased to exist independently in that their exchange rates were locked at fixed rates against each other, effectively making them mere non-decimal subdivisions of the euro. The euro thus became the successor to the European Currency Unit (ECU). The notes and coins for the old currencies, however, continued to be used as legal tender until new notes and coins were introduced on 1 January 2002 (having been distributed in small amounts in the previous December). Beginning on 1 January 1999, all bonds and other forms of
International status and usage of the euro is attractive for international transactions when it demonstrates stability, a well-developed financial market to trade the currency, and acceptability to others. While the euro has made substantial progress, a few challenges undermine the ascension of the euro as a major reserve currency. Persistent excessive budget deficits of some member nations, economically weak new members, conservatism of financial markets, and inertia or path dependence are important factors keeping the euro as a junior international currency to the US dollar. However, at the same time, the USD has increasingly suffered from a double deficit and has its own concerns. As the euro