The simple point, surely, was that there was too much optimism combined with too much leverage. That is neither new, nor particularly complicated. I am prepared to assert that it will, periodically, recur. Policy makers across a range of endeavours will need to keep that very much in view in the future.
The challenge for the future Turning to the implications for the future conduct of monetary policy, we have seen that financial system complexity and the financial cycle have affected both the overall  4  BIS Review 14/2009  environment in which monetary policy operates and the transmission channels through which it affects the economy.