Inequality and the risk of financial crisis

Are there causal links between the scale of income and wealth inequality and the risks of financial crisis and distress? This article from the New York Times reports on research from David A Moss at the Harvard Business School who continues to mine cross country data on inequalities to see if there are close correlations with banking crises in particular countries.

Might it be the case that persistent relative poverty among lower income groups was a factor driving the expansion of sub-prime lending and excessive borrowing on very expensive credit cards?

Or was the sub-prime debacle largely the result of inappropriate financial deregulation and policy interest rates being held close to zero for too long rather than a trend rise in inequality?

What of the incentives of people at the top of the income scale? Has the rising economic power and influence of the super rich played some role in creating the conditions for financial and macroeconomic instability.

Correlation does not necessarily imply causation as the article makes clear in an interview with Glenn Hubbard from the Columbia Business School.