The **European Currency Unit (ECU)** was a basket currency used as a unit of account within the European Monetary System (EMS). It served as an artificial accounting unit and was used for the purpose of determining exchange rates among the participating currencies. The ECU was a precursor to the euro, which eventually replaced it as the official currency of the Eurozone.

Key features and characteristics of the European Currency Unit (ECU) include:

1. **Composite Currency:**
– The ECU was not a physical currency; rather, it was a composite or basket currency composed of a weighted average of the currencies of the European Community member states. The weights were determined based on the economic importance of each currency within the European Community.

2. **Unit of Account:**
– The primary purpose of the ECU was as a unit of account within the European Monetary System. It provided a common denominator for expressing the value of goods, services, and financial instruments across the participating countries.

3. **Exchange Rate Mechanism (ERM):**
– The ECU played a central role in the exchange rate mechanism (ERM) of the European Monetary System. Exchange rates among participating currencies were expressed in terms of ECUs, and countries were required to maintain their exchange rates within certain bands against the ECU.

4. **Interest Rates and Bonds:**
– The ECU was also used in the pricing and issuance of financial instruments, such as ECU-denominated bonds. Interest rates for these bonds were often quoted in terms of the ECU.

5. **Transition to the Euro:**
– The ECU existed as a virtual currency within the EMS from its inception in 1979 until the introduction of the euro. The Maastricht Treaty, signed in 1992, paved the way for the Economic and Monetary Union (EMU) and the establishment of the euro as the official currency of the Eurozone.

6. **Euro’s Introduction:**
– On January 1, 1999, the euro was introduced as an electronic currency for accounting purposes. During this phase, the exchange rates of the participating currencies were irrevocably fixed, and the euro became the unit of account for the newly established currency area.

7. **Legacy:**
– While the ECU itself is no longer in use, its legacy is evident in the formation of the European Union and the Economic and Monetary Union. The principles and experiences gained from the ECU contributed to the establishment of the euro as a tangible currency.

8. **Symbol:**
– The ECU had a symbol that resembled the letter “E” with a double crossbar, but it was not widely used or recognized in the same way as symbols for physical currencies.

The transition from the ECU to the euro marked a significant step in the process of European economic and monetary integration, leading to the establishment of a common currency for many European countries. The euro, introduced as an accounting currency in 1999 and in physical form in 2002, is now the official currency of the Eurozone.