Louise Story, in the New York Times, describes how economists find that disparities between rich and poor widened as financial regulations eased and bank failures rose: http://www.nytimes.com/2010/08/22/weekinreview/22story.html?_r=1
 
She asks..." do huge gaps in income create perverse incentives that put the financial system at risk. If so, their  findings could become an argument for tax and social policies aimed at  closing the income gap and for greater regulation of Wall Street".

And the academic scholar behind this research, David A Moss of the Harvard Business School, says that 'inequality, by putting too much power in the hands of Wall Street titans, enables  them to promote policies that benefit them — like deregulation — that could put the system in jeopardy'. 

Scholars who study inequality often focus on people at the bottom.  But, as Mr. Moss says, 'the incentives of people at the top also deserve  more scrutiny'.