The inability to hold cash and the pressure to be fully invested at all times meant that when the plug was pulled out of the tub, all boats dropped as the water rushed down the drain.

A margin of safety is achieved when securities are purchased at prices sufficiently below underlying value to allow for human error, bad luck, or extreme volatility in a complex, unpredictable and rapidly changing world.

Benjamin Graham wrote, "Those with enterprise haven't the money, and those with money haven't the enterprise, to buy stocks when they are cheap."

The risk of an investment is described by both the probability and the potential amount of loss. The risk of an investment-the probability of an adverse outcome-is partly inherent in its very nature. A dollar spent on biotechnology research is a riskier investment than a dollar used to purchase utility equipment. The former has both a greater probability of loss and a greater percentage of the investment at stake.

In the financial markets, however, the connection between a marketable security and the underlying business is not as clear-cut. For investors in a marketable security the gain or loss associated with the various outcomes is not totally inherent in the underlying business; it also depends on the price paid, which is established by the marketplace. The view that risk is dependent on both the nature of investments and on their market price is very different from that described by beta.

When excesses such as lax lending standards become widespread and persist for some time, people are lulled into a false sense of security, creating an even more dangerous situation. In some cases, excesses migrate beyond regional or national borders, raising the ante for investors and governments. These excesses will eventually end, triggering a crisis at least in proportion to the degree of the excesses. Correlations between asset classes may be surprisingly high when leverage rapidly unwinds.

Successful investors tend to be unemotional, allowing the greed and fear of others to play into their hands. By having confidence in their own analysis and judgement, they respond to market forces not with blind emotion but with calculated reason. Successful investors, for example, demonstrate caution in frothy markets and steadfast conviction in panicky ones. Indeed, the very way an investor views the market and it’s price fluctuations is a key factor in his or her ultimate investment success or failure.