That is, many times we're not risking our own money, we're risking somebody else's money, or maybe that someone is going to back stop or downside, but we still get the upside.

We're talking about should we increase taxes? Why not put a tax on carbon emissions. It would raise a lot of money, it would reduce the environmental damages in the future, it would solve so many problems, and it would be a much more constructive thing to do than to think about raising the income tax.

I think we're fooling ourselves if we think that regulators are going to be able to outsmart the bankers. So, the task of designing regulatory reform is trying to make more or less foolproof regulation and that's one of the advantages of the systemic category.

I think that's something that investment banks have worried about for a long time and are continuing to worry about, but it's not an easy solution when you have lots of people betting the company's money, how do you really allocate those risks? How do you make sure that the people that take the risks are feeling the risks in an appropriate kind of fashion?

Credit default swap gives you something to do. You can buy some credit default swaps from them to protect yourself against the bankruptcy of people who owe you money.

If you have information that a company is not as good as its stock market valuation, you don't have a way to sell that stock unless you already own it. And so that information doesn't get incorporated in the company's stock price as fast if you don't allow short selling.

There are a lot of ways that investment banking models work, but these risks are not internalized by the people that are taking them.