All this was reflected in growing worldwide external imbalances; while the role of other areas of the world economy should not be ignored, their direct contribution to the imbalances is more difficult to assess. These macroeconomic factors created enormous stress for a US and global financial system in which financial innovation and regulatory failures had progressively introduced serious structural flaws.
Moreover, the complacency on the part of risk managers and financial supervisors that allowed the resulting vulnerabilities to grow unchecked owed much to the climate of general optimism that those macro conditions supported.