If you pay attention to where your exposures are, you might tend up buying credit default swaps against a variety of people that you - companies that you deal with.

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.

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.

So what is the role that credit default swaps can play in an economy? Well my feeling is that if these things actually will now be traded on either exchanges or some kind of central clearing, they are going to be a very good measure of the credit worthiness of different companies.

The collateralized debt obligation, the CDO, is a structure which allows you to more or less continuously choose how much risk you want to take in a whole batch of securities. And the reason why they got us into so much trouble is that it's hard to figure out how much risk you really are taking.

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

I think global coordination is tremendously important. I hope we can see this happening through the G20 and through coordination of regulatory regimes around the world. I guess those are the main features of this bill that are important.