Enlargement of the eurozone

The enlargement of the eurozone is an ongoing process within the European Union (EU). All member states of the European Union, except Denmark which negotiated an opt-out from the provisions, are obliged to adopt the euro as their sole currency once they meet the criteria, which include: complying with the debt and deficit criteria outlined by the Stability and Growth Pact, keeping inflation and long-term governmental interest rates below certain reference values, stabilising their currency's exchange rate versus the euro by participating in the European Exchange Rate Mechanism (ERM II), and ensuring that their national laws comply with the ECB statute, ESCB statute and articles 130+131 of the Treaty on the Functioning of the European Union. The obligation for EU member states to adopt the euro was first outlined by article 109.1j of the Maastricht Treaty of 1992, which became binding on all new member states by the terms of their treaties of accession. there are 20 EU member states in the eurozone, of which the first 11 (Austria, Belgium, Finland, France, Germany, Ireland, Italy, Luxembourg, the Netherlands, Portugal and Spain) introduced the euro on 1 January 1999 when it was electronic only. Greece joined 1 January 2001, one year before the physical euro coins and notes replaced the old national currencies in the eurozone. Subsequently, the following eight countries also joined the eurozone on 1 January in the mentioned year: Slovenia (2007), Cyprus (2008), Malta (2008), Slovakia (2009), Estonia (2011), Latvia (2014), Lithuania (2015) and Croatia (2023). Six remaining states are on the enlargement agenda: Bulgaria, Czechia, Hungary, Poland, Romania and Sweden. Bulgaria and Denmark participate in ERM II, though Denmark has opted out of joining the eurozone and is therefore not obliged to do so. The United Kingdom also had an opt-out until it left the EU on 31 January 2020, though it never joined the ERM II either.