Even after the fact, there can be debate on whether a bubble really existed or whether expectations had been misguided. I should add that it appears very useful to look at developments in credit and monetary variables, which often in the past signalled the build-up of dangerous financial imbalances in the economy.
As you know, the Eurosystem assigns a specific role to the monetary aggregates within the framework of its two pillars approach of its monetary strategy. Credit being one of the counterpart of M3, it is therefore carefully followed, which is important from the perspective of monitoring the preconditions for the build-up of the financial imbalances.