It's only when the tide goes out that you learn who's been swimming naked. - Warren Buffett

The line separating investment and speculation, which is never bright and clear, becomes blurred still further when most market participants have recently enjoyed triumphs. Nothing sedates rationality like large doses of effortless money. After a heady experience of that kind, normally sensible people drift into behavior akin to that of Cinderella at the ball. They know that overstaying the festivities — that is, continuing to speculate in companies that have gigantic valuations relative to the cash they are likely to generate in the future — will eventually bring on pumpkins and mice. But they nevertheless hate to miss a single minute of what is one helluva party. Therefore, the giddy participants all plan to leave just seconds before midnight. There’s a problem, though: They are dancing in a room in which the clocks have no hands.

The stock market is a device for transferring money from the impatient to the patient.

"The Economics of Property-Casualty Insurance With the acquisition of General Re — and with GEICO’s business mushrooming — it becomes more important than ever that you understand how to evaluate an insurance company. The key determinants are: (1) the amount of float that the business generates; (2) its cost; and (3) most important of all, the long-term outlook for both of these factors. To begin with, float is money we hold but don't own. In an insurance operation, float arises because premiums are received before losses are paid, an interval that sometimes extends over many years. During that time, the insurer invests the money. Typically, this pleasant activity carries with it a downside: The premiums that an insurer takes in usually do not cover the losses and expenses it eventually must pay. That leaves it running an "underwriting loss," which is the cost of float. An insurance business has value if its cost of float over time is less than the cost the company would otherwise incur to obtain funds. But the business is a lemon if its cost of float is higher than market rates for money. A caution is appropriate here: Because loss costs must be estimated, insurers have enormous latitude in figuring their underwriting results, and that makes it very difficult for investors to calculate a company's true cost of float. Errors of estimation, usually innocent but sometimes not, can be huge. The consequences of these miscalculations flow directly into earnings. An experienced observer can usually detect large-scale errors in reserving, but the general public can typically do no more than accept what's presented, and at times I have been amazed by the numbers that big-name auditors have implicitly blessed. As for Berkshire, Charlie and I attempt to be conservative in presenting its underwriting results to you, because we have found that virtually all surprises in insurance are unpleasant ones. The table that follows shows the float generated by Berkshire’s insurance opera