International status and usage of the euro

The international status and usage of the euro has grown since its launch in 1999. When the euro formally replaced 12 currencies on 1 January 2002, it inherited their use in territories such as Montenegro and replaced minor currencies tied to pre-euro currencies, such as in Monaco. Four small states have been given a formal right to use the euro, and to mint their own coins, but all other usage outside the eurozone (the EU states who have adopted the euro) has been unofficial. With or without an agreement, these countries, unlike those in the eurozone, do not participate in the European Central Bank or the Eurogroup.

Its growing use in this regard has led to its becoming the only significant challenger to the U.S. dollar as the world's main reserve currency.