The Superinvestors of Grahamand-Doddsville (Excerpt)

格雷厄姆—多德都市的超级投资者们（节选）　

——沃伦·巴菲特1984年在哥伦比亚大学的演讲

这是股神沃伦·巴菲特1984年在哥伦比亚大学的一次演讲。在演讲中，他首先提及了格雷厄姆和多德的证券分析法，分析了价值投资为导向的投资赢利群所秉行的一些共同原则，之后，他又提出了价格和价值差所产生的赢利，并举出了真人实例用以证明自己的分析结果和理论。

经典再现

Is the Graham and Dodd “look for values with a significant margin of safety relative toprices” approach to security analysis out of date? Many of the professors who writetextbooks today say yes. They argue that the stock market is efficient; that is, that stock prices reflecteverything that is known about a company’s prospects and about the state of the economy.

There are no undervalued stocks, these theorists argue, because there are smart securityanalysts who utilize all available information to ensure unfailingly appropriate prices. Investors whoseem to beat the market year after year are just lucky. “If prices fully reflect available information,this sort of investment adeptness is ruled out,” writes one of today’s textbook authors.

Well, maybe. But I want to present to you a group of investors who have, year in andyear out, beaten the Standard & Poor’s 500 stock index. The hypothesis that they do this bypure chance is at least worth examining. Crucial to this examination is the fact that thesewinners were all well known to me and pre-identified as superior investors, the most recentidentification occurring over fifteen years ago.

I think you will find that a disproportionate number of successful coin-flippers in theinvestment world came from a very small intellectual village that could be called Graham-and-Doddsville. A concentration of winners that simply cannot be explained by chance can betraced to this particular intellectual village. In this group of successful investors that I want toconsider, there has been a common intellectual patriarch, Ben Graham.

The common intellectual theme of the investors from Graham-and-Doddsville is this: theysearch for discrepancies between the value of a business and the price of small pieces of thatbusiness in the market. The investors simply focus on two variables: price and value.

I always find it extraordinary that so many studies are made of price and volume behavior,the stuff of chartists. Can you imagine buying an entire business simply because the price ofthe business had been marked up substantially last week and the week before? Of course, thereason a lot of studies are made of these price and volume variables is that now, in the age ofcomputers, there are almost endless data available about them. It isn’t necessarily because suchstudies have any utility; it’s simply that the data are there and academicians have worked hardto learn the mathematical skills needed to manipulate them. Once these skills are acquired,it seems sinful not to use them, even if the usage has no utility or negative utility. As a friendsaid, to a man with a hammer, everything looks like a nail.

I think the group that we have identified by a common intellectual home is worthy ofstudy. Incidentally, despite all the academic studies of the influence of such variables as price,volume, seasonality, capitalization size, etc., upon stock performance, no interest has beenevidenced in studying the methods of this unusual concentration of value-oriented winners.