Chapter 18. How Efficient Is the Stock Market?
Essentially, it [Efficient Market Theory] said that analyzing stocks was useless because all public information about them was appropriately reflected in their stock prices. In other words, the market always knew everything.
Few people consistently make money betting on horse races. In finance terms, the horse racing market is efficient. But is the stock market efficient?
Some people argue that the stock market is efficient and that you should not spend any time trying to beat the market averages. On the other hand, others, including Buffett, argue that the market is not efficient. It is not productive to debate whether the market is efficient; the important point is to think about the extent to which it is efficient. We come across many questions in our lives when a simple yes-or-no answer is not very meaningful. When someone asks, "Am I going to be able to make a living if I study engineering?" or "Am I going to get a job if I have a degree in mathematics?" the correct answer is generally "Yes, of course." However, it is more important to know how good a living you can expect to make if you become an engineer or what kind of job you can land if you get a degree in mathematics. In the same manner, a simple yes or no to the market efficiency question is not worth getting agitated about. It is more important to know how, when, why, and to what extent the market is efficient and, especially, how, when, why, and to what ...