After the 2008 financial crash, bank CEOs had a message: We've learned. We won't do it again.

This seemed like a reasonable offer, too. Capital increased. Leverage came down. Lending standards improved.

But then last year, JPMorgan Chase (NYSE:JPM) suffered a multibillion-dollar loss in the London Whale fiasco. Suddenly, the idea that risk management had improved since 2008 was called into question.

I recently sat down with Nobel Prize-winning economist Joseph Stiglitz in his office at Columbia Business School. In this clip, Stiglitz discusses what Wall Street has (and hasn't) learned since 2008 (transcript follows): 

Joseph Stiglitz: I think some have learned their lesson as I look over the landscape, I'm not sure. We all saw what happened with what we call "The Whale Trader" at JPMorgan; clearly they didn't learn the lesson. I think one of the problems is that the too-big-to-fail problem has gotten worse. So these banks know that they're so big that they will almost surely be bailed out. The problem of incentive structures being perverse and encouraging excess risk taking is only being slightly muted. So as I look at the basic structural problems, they are still there, and in some ways worse. I think that obviously the government's looking over their shoulders more, and that has made them perhaps a little bit more cautious.