Thaler: Well, I think it’s very hard to argue that real estate prices in Phoenix, Las Vegas and south Florida were rational at the peak. Now, Gene will say, correctly, that neither I nor anyone else was able to say when that bubble would break. (I’m not allowed to use the word “bubble” when I’m with Gene.)

And that’s true. Even for my friend Bob Shiller. He correctly predicted the Nasdaq crash and the housing crash. But in both cases, he was about three years early. That makes him very wise, but not very helpful to an investor, because if you shorted the Nasdaq in 1996, when he gave his irrational exuberance talk to Greenspan, you were in trouble. Any hedge fund that shorted tech stocks in ’96 went belly up.

So when Gene and I have these arguments, he’ll say the fact that you can’t predict when they will end means you can’t say anything about them. I say, no, that’s not the case. And that’s why I separate these two aspects of the efficient markets argument: Whether you can get rich (the “no-free-lunch” part) and whether the “price is right.”

It’s hard to get rich because even though I thought Scottsdale real estate was overpriced, there was no way to short it. Even if there were a way—Shiller tried to create markets in that, so that you could have shorted it—you might have gone broke before you were right.

But I think of these two components. Gene will always say the “you can’t beat the market” part is the more important part. Now, I don’t know whether that’s self-serving or whether that’s what he believes.

Region: Self-serving in the sense that it’s the theory behind his passive-investing mutual fund, DFA?

Thaler: Well, no, that’s not really what I mean. First of all, whether DFA is purely passive or not is open to question. You know, they buy small-value stocks and they add a little momentum. Now, how is that different from what LSV does?

But, the point is, Mike Jensen’s thesis still holds, that most active managers underperform the market. So, I think Gene and I would give similar advice to people, which would be to buy index funds. Or invest in the [mutual fund] companies that each of us is associated with.

He would claim his are index funds, and I won’t quibble with him in print about that. I think it’s hard to beat the market. Nobody thinks it’s easy, and so that part of the hypothesis is truer, but if we look at what happened to Nasdaq in 2000, and then the recent crash, well, of course, we’ve never gotten back to 5,000. So it’s very hard to accept that markets always get prices right.

Can we say that the Internet has disappointed us since 2000? I mean, did we ever think we would be carrying around anything like this [smart phone] in our pockets? If anything, the Internet has wildly exceeded our expectations, but the Nasdaq has still not gotten close to where it was in 2000. So I think it’s pretty obvious that market was overheated, just like the Las Vegas and Phoenix real estate markets were, but you couldn’t say necessarily when it was going to end.







2000年以降のインターネットは失望させられるものだった、と言えるでしょうか? 例えば、これ(スマートフォン)のようなものをポケットに入れて持ち歩くことになる、などと我々は考えていたでしょうか? どちらかと言えば、インターネットは我々の期待を大きく上回りました。しかし、ナスダック指数は2000年の水準にはまだ及びません。従って、ラスベガスやフェニックスの不動産価格市場とまったく同様に、当時の市場が過熱していたことは明々白々だと私は思います。ただ、それがいつ終わると言えはしなかった、ということです。

*1:グリーンスパンの講演からシラーが「根拠なき熱狂(irrational exuberance)」という言葉を自著のタイトルに採用したというのが定説だが、Wikipedia経由のバリー・リソルツ経由のGlobal Macro Monitorブログによると、シラーの言葉をグリーンスパンが受け売りしたという異説があるらしい。セイラーのこの言葉はそちらの解釈に立っているようである。