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
World currency unit have adopted the name "World Currency Unit". The Wocu (contraction of World Currency Unit) is a standardized basket of currencies — the national currencies of the 20 largest national economies measured by GDP, established in 2008. The basket is reweighed semi-annually according to the relative growth of the economies, whereby constituent currencies are replaced by other currencies should the size of the GDP be overtaken by that of another national economy. Conceived as an apolitical and global alternative to the ECU, it is used as a reference currency for global investors and companies seeking to mitigate bilateral exchange rate volatility.