"We have sort of a three-to-five-year view, and we know we can't pick bottoms. You buy when it's good enough, you don't time the bottom and don't worry about the market."
-- Marty Whitman, Third Avenue Value Fund

By the end of last week, the worst single week in the market in more than 60 years, investors were looking left and right to figure out just who it was that was doing all that selling. All told more than 14% of the Dow Jones Industrial Average -- comprised of 30 large U.S. companies -- evaporated in the last five days.

Don't blame MetLife (NYSE: MET). The second-largest U.S. insurer in terms of the value of its outstanding policies used last week's rapid drop in stock prices to purchase some $1 billion in equities on the open market. Company spokesmen would not comment upon which stocks MetLife bought except to say that they represented a wide range of American businesses.

MetLife had an existing strategy of increasing its exposure to stocks prior to last week's drop. Its equity portfolio now comprises 3.2% of its $165 billion general account, up from 2.6% last week. This means that more than 20% of all of MetLife's stock holdings were initiated in the past five days.

MetLife is one of the oldest insurance companies in the U.S., having been around for more than 130 years. Prior to April 2000, MetLife was a mutual insurance company, meaning its policyholders owned the equity in the company. However, in one of last year's few successful initial public offerings, MetLife converted into a stock company, which gives it much greater flexibility in terms of the vehicles it can use to increase shareholder value. This includes the ability to take on a much larger position in common stock, and MetLife's stock portfolio has been increasing ever since.

While it is an active stock investor, as an insurance company MetLife is not your everyday mutual fund. The company must be able to pay out claims at any time, and as such it and other insurers tend to be more conservative in their deployment of capital in non-guaranteed instruments. That MetLife was out buying in such an enthusiastic manner signals that its investment managers are finding what they consider to be significant bargains in the stock market. Unfortunately, they are not dumb enough to clue the rest of us in on what these companies are.

Investors need to recognize that the economy, the mood, the psyche of America and much of the world have been damaged, not only by the terrorist attacks, but also by the economic distress that was apparent for some months before. That price-to-earnings ratios are still high now is little surprise -- earnings are dropping nearly as fast as share prices, as is the case in a declining economic environment. But the massive buying by MetLife and others in the last week provides a valuable lesson: During the worst of times, the best companies end up in conservative hands.

Bill Mann believes that the biggest sign that things are far from normal is the fact that the University of Toledo has the highest-ranked football team in the state of Ohio. Bill owns none of the companies mentioned in this article. The Motley Fool is investors writing for investors. Go Rockets.