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.

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.

If a lot of people feel like this company is undervalued and go out and buy the stock, the stock price will go up reflecting the higher value of this company. You might have information because you trade with them or because you've done some research on them.

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?

Well if you've got information about a company, or you believe that a company is undervalued, you can go out and buy their stock and you can make some profit on it.

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 what we need is better understanding of how to do risk analysis of a CDO, but that they still can perform a very valuable function because they can aggregate these risks and pass them around so that mortgages or other kinds of loans can be packaged and sold to investors all over the world, who in most times, would justify a small amount of each one.