When large companies take on risk, then they impose risks on the rest of the system. And these are systemic risks and these systemic risks we never used to think were really that important, but as soon as we recognize how the financial sector - the risks the financial sector takes on can impact the entire global economy, we realize that those risks needed to be controlled for the social good.

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.

I'd like to see a little more action on the energy side of things. I've been pushing for some kind of a carbon tax for years, and it seems to me we've had lots of opportunities to do it.

Risk managers and investment bankers and actually, all kinds of investors took on more risk than they expected. So there was a failure of risk management. There was a failure to recognize how much risk there was in some of these securities that people bought.

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 don't see what the alternative to risk management is. If it's just getting rid of the models and instead using the smart people who can figure it out? How do you train them? What do you teach them? Do you just put them in a cockpit and let them stumble for 10 years of their life and then after that they're good at it?

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.