Even with a margin of safety in the investor's favor, an individual security may work out badly. For the margin guarantees only that he has a better chance for profit than for loss - not that loss is impossible. But as the number of such commitments is increased the more certain does it become that the aggregate of the profits will exceed the aggregate of the losses.

Never mingle your speculative and investment operations in the same account nor in any part of your thinking.

Wall Street people learn nothing and forget everything.

For 99 issues out of 100 we could say that at some price they are cheap enough to buy and at some price they would be so dear that they would be sold.

The defensive (or passive) investor will place chief emphasis on the avoidance of serious mistakes or losses. His second aim will be freedom from effort, annoyance, and the need for making frequent decisions.

Buy not on optimism, but on arithmetic.

The only thing you should do with pro forma earnings is ignore them.