The problem with a single model.............

"People don't behave - for both good and bad reasons - in line with the economic model of rationality.  In consequence others do devise strategies that make money at their expense.  That consequence is critical to an understanding of how financial markets operate today."

-John Kay, as excerpted from Other People's Money:  The Real Business of Finance

I'm only on page 70 (224 more to go) of Kay's book.  Started reading it last week, then got interrupted by an engrossing Michael Connelly tale, but I suspect that Kay believes that all is not well with the world of Wall Street and those who "regulate" them.  Will report back.