Among these are the rapid financial market liberalization in the years prior to the crisis in combination with an insufficient regulatory framework, a build-up of asset price bubbles and the widening of global imbalances. An exceptionally long period of high growth and low inflation made financial market participants less aware of risks.
All these factors promoted an unsustainable explosion of asset prices and private indebtedness.   At the same time, the global financial crisis was in several respects unique and required policy reactions in uncharted waters. Central bankers had to learn to expand their portfolio of policy instruments.