Euro number-2 global currency

The euro's share as a global reserve currency declined by 0.9 percent in 2013 to 24.4 percent, according to a report by the European Central Bank (ECB) called "The International Role of the Euro," published on Wednesday.

It means the euro remains the number-two reserve currency, but what the ECB called the "lingering effects of the euro area sovereign debt crisis" contributed to the slight decline last year.

The US dollar retains the number-one spot, with a 61-percent share. The Japanese yen managed to boost its share to 3.9 percent of reserves, almost on a par with sterling, which has a 4-percent share.

Euro as parallel currency

The ECB notes that the sovereign debt crisis has had no impact on the use of the euro as a parallel currency in central, eastern and southeastern Europe, with Romania, Bulgaria, Poland and Turkey topping that list.

International investors' interest in euro-denominated debt securities and equities "grew markedly," and reached its highest level since the onset of the financial crisis in 2007. The report said it made up 3.7 percent of eurozone GDP.

The bank emphasized that a "genuine Economic and Monetary Union" in the euro area, including the banking union, were essential for the euro's future strength and stability.