What is Monetary Union

Which countries should be in Economic and Monetary Union (EMU)? This question has been debated frequently in the aftermath of the Sovereign Debt Crisis. But this has been asked in every stages of European integration. This discussion has rooted in the Optimum Currency Area (OCA) theory. The theory simply reveals that; if the countries have similar business cycles, one size fits all monetary policy would able to address the problems of member countries. Otherwise, no single monetary policy could be able to satisfy all members. In this respect, we test the business cycle convergence in EMU12 countries over time and we have also analyzed the effects of crisis on this convergence. We have found that business cycles converged over time in these countries. This convergence rises in the times of crisis as they slump together after the shock, but falls sharply in the aftermath of the crisis. This reflects the divergent recovery paths of the countries and put a pressure on single monetary policy especially after crisis.