It's nonsensical to derive a price/earnings ratio by dividing the known current price by unknown future earnings.

Knowledge is only one ingredient on arriving at a stock's proper price. The other ingredient, fully as important as information, is sound judgment.

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.

... the loss of public confidence in the financial community growing out of its own conduct in recent years. I insist that more damage has been done to stock values and to the future of equities from inside Wall Street than from outside Wall Street.

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 function of the margin of safety is, in essence, that of rendering unnecessary an accurate estimate of the future.

The margin of safety is always dependent on the price paid. It will be large at one price, small at some higher price, nonexistent at some still higher price.