I think the people who've been the most overconfident in our business in the last decade have been the people that called themselves risk managers.

When an economist says the evidence is "mixed," he or she means that theory says one thing and data says the opposite.

Credit cards have been extremely profitable to banks. They're profitable not from the fees they collect from the retailers that use the credit cards, that pays the bills, but the real profits come from the interest payments and the charges to users that are unexpected.

A good rule of thumb is to assume that everything matters.

One simple step firms can take is make sure that people that are getting paid a lot of money, say more than a million or two, that a big chunk of that money is deferred. That's going to change the whole ballgame.

If people just put away what's left at the end of the month, that's a recipe for failure.

So the world is much more correlated than we give credit to. And so we see more of what Nassim Taleb calls "black swan events" - rare events happen more often than they should because the world is more correlated.