The implementation of decisions - that is operations, which in practice account for most of a national central bank’s work - is effected by the national central banks on a decentralized basis, coordinated by the ECB Executive Board. Like a red thread, these two principles – centralized decisions and guidelines, decentralized implementation – govern all the ESCB’s operations.
At this point, three concepts must be explained. The first relates to the ESCB’s tasks and functions. The Maastricht Treaty provides a very clear definition of those areas which from Stage Three of EMU will fall within the Community’s field of competence.