My conversation with Cliff Asness

Here is the full transcript, video, and podcast of the chat.  Cliff was great from beginning to end.  The first thirty minutes or so were an overview of “momentum” and “value” trading strategies, and to what extent they violate an efficient markets hypothesis.  Much of the rest covered:

…disagreeing with Eugene Fama, Marvel vs. DC, the inscrutability of risk, high frequency trading, the economics of Ayn Rand, bubble logic, and why never to share a gym with Cirque du Soleil.

Here is one excerpt:

COWEN: I think of you as doing a kind of metaphysics of human nature. On one side, there’s behavioral economics. They put people in the lab, one-off situations, untrained people. But here it’s repeated data, it’s over long periods of time, it’s out of sample. There’s real money on the line, and this still seems to work.

When you back out, what’s the actual vision of human nature? What’s the underlying human imperfection that allows it to be the case, that trading on momentum across say a 3 to 12 month time window, sorry, investing on momentum, will work? What’s with us as people? What’s the core human imperfection?

ASNESS: This is going to be embarrassing because we don’t have a problem of no explanation. We have a problem with too many explanations. Of course, we can observe the data. The explanations you have to fight over and argue over. I will give you the two most prominent explanations for the efficacy of momentum.

The first is called underreaction. Simple idea that comes from behavioral psychology, the phenomenon there called anchoring and adjustment. News comes out. Price moves but not all the way. People update their priors but not fully efficiently. Therefore, just observing the price move is not going to move the same amount again but there’s some statistical tendency to continue.

Take a wild guess what our second best, in my opinion, explanation for momentum’s efficacy is? It’s called overreaction. When your two best explanations are over- and underreaction, you have somewhat of an issue, I admit. Overreaction is much more of a positive feedback. It works over time because people in fact do chase prices. So if you do it somewhat systematically and before them you make some money.

One of the hard things you find out in many fields but I found out in empirical finance is those might be the right explanations but they’re not mutually exclusive.

And here is from the overrated/underrated part of the chat:

COWEN: …In science fiction, the author Robert Heinlein.

ASNESS: Early stuff, underrated. Later stuff, overrated.

COWEN: What’s your favorite?

ASNESS: That is a really — Methuselah’s Children.

COWEN: Ah, good pick.

ASNESS: I could have gone with the obvious. I’m a bit of a libertarian. I could have gone with, The Moon Is A Harsh Mistress. It’s his most famously libertarian book.

COWEN: But it doesn’t age so well.

ASNESS: No, no. I like Methuselah’s Children.

This was the funniest segment:

ASNESS: I live in Greenwich, Connecticut. In some parts of the world, if you said, “my daddy runs a hedge fund,” I’d say, “what’s a hedge fund?” In Greenwich, Connecticut, the kids say, “what kind of hedge fund is your daddy running? Is he event arbitrage? Trend following? What does dad do?”

Interesting throughout, as they are known to say…


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