Before you invest, you must ensure that you have realistically assessed your probability of being right and how you will react to the consequences of being wrong.

In an ideal world, the intelligent investor would hold stocks only when they are cheap and sell them when they become overpriced, then duck into the bunker of bonds and cash until stocks again become cheap enough to buy.

Most businesses change in character and quality over the years, sometimes for the better, perhaps more often for the worse. The investor need not watch his companies' performance like a hawk; but he should give it a good, hard look from time to time.

We have not known a single person who has consistently or lastingly make money by thus "following the market". We do not hesitate to declare this approach is as fallacious as it is popular.

It is no difficult trick to bring a great deal of energy, study, and native ability into Wall Street and to end up with losses instead of profits. These virtues, if channeled in the wrong directions, become indistinguishable from handicaps.

We are convinced that the intelligent investor can derive satisfactory results from pricing of either type (market timing or fundamental analysis via price). We are equally sure that if he places his emphasis on timing, in the sense of forecasting, he will end up as a speculator and with a speculator's financial results." And "The speculator's primary interest lies in anticipating and profiting from market fluctuations. The investor's primary interest lies in acquiring and holding suitable securities at suitable prices.

Mathematics is ordinarily considered as producing precise and dependable results; but in the stock market the more elaborate and abstruse the mathematics the more uncertain and speculative are the conclusions we draw there from. Whenever calculus is brought in, or higher algebra, you could take it as a warning that the operator was trying to substitute theory for experience, and usually also to give to speculation the deceptive guise of investment.