Once, at a lecture, he was asked if Wall Street professionals were better at forecasting what would happen to market, and if not, then why, and here's what he said:
"Well, we’ve been following that same question for a generation or more, and I must say frankly that our studies indicate that you have your choice between tossing coins and taking the consensus of expert opinion and the result is just about the same in each case.
Everybody in Wall St. is so smart that their brilliance offsets each other. And that whatever they know is already reflected in the level of stock prices for the much, and consequently what happens in the future represents what they don’t know." - Benjamin Graham
比较有意思的,现在股市涨了,有人觉得不能买。一年前股市比现在低30%以上,那时候他们为什么也不买呢?