It would be much more consumer friendly for them to beep you when you swipe your card that says, uh-oh you're over your limit, are you sure you want to use that?

So, what's a nudge? A nudge is some small feature of the environment that attracts our attention and alters our behavior.

The assumption that everybody will figure out how much they have to save and then will just implement that plan is obviously preposterous.

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.

Every American worker should be able to save for retirement via payroll deductions.

LTCM lost money when Russia defaulted on a certain class of bonds, and then they had other investments like on the spread between two different kinds of shares of Royal Dutch Shell Oil Company. Now that seems completely unrelated to Russian bonds. But they were related because other hedge funds saw similar discrepancies and they were all making similar bets.

Most economists, including me, agree that longevity insurance would make sense for a lot of people.