Observation over many years has taught us that the chief losses to investors come from the purchase of low-quality securities at times of good business conditions. The purchasers view the good current earnings as equivalent to 'earning power' and assume that prosperity is equivalent to safety.
Benjamin GrahamThe market is always making mountains out of molehills and exaggerating ordinary vicissitudes into major setbacks.
Benjamin GrahamIt's nonsensical to derive a price/earnings ratio by dividing the known current price by unknown future earnings.
Benjamin GrahamWe have been trying to point out that this concept of an indefinitely favorable future is dangerous, even if it is true; because even if it is true you can easily overvalue the security, since you make it worth anything you want it to be worth. Beyond this, it is particularly dangerous too, because sometimes your ideas of the future turn out to be wrong. Then you have paid an awful lot for a future that isn't there. Your position then is pretty bad.
Benjamin Graham