I also want to suggest that the cumulative effect over the past few decades of changes in financial technology, financial regulation, monetary policy itself, and perhaps the real economy have significantly altered the ways in which monetary instruments transmit through to the real economy. These changes may argue for refinement of monetary policy tools.
The third vulnerability I will quickly mention is related to cyber security. There has been a worldwide increase in the frequency, severity and sophistication of cyber attacks. Because our financial system is so interconnected, a successful attack on one institution can potentially lead to widespread disruptions.