Quote:On a macro basis, quantification doesn't have to be complicated at all. Below is a chart, starting almost 80 years ago and really quite fundamental in what it says. The chart shows the market value of all publicly traded securities as a percentage of the country's business--that is, as a percentage of GNP. The ratio has certain limitations in telling you what you need to know. Still, it is probably the best single measure of where valuations stand at any given moment. And as you can see, nearly two years ago the ratio rose to an unprecedented level. That should have been a very strong warning signal.

For investors to gain wealth at a rate that exceeds the growth of U.S. business, the percentage relationship line on the chart must keep going up and up. If GNP is going to grow 5% a year and you want market values to go up 10%, then you need to have the line go straight off the top of the chart. That won't happen.

For me, the message of that chart is this: If the percentage relationship falls to the 70% or 80% area, buying stocks is likely to work very well for you. If the ratio approaches 200%--as it did in 1999 and a part of 2000--you are playing with fire. As you can see, the ratio was recently 133%.

Even so, that is a good-sized drop from when I was talking about the market in 1999. I ventured then that the American public should expect equity returns over the next decade or two (with dividends included and 2% inflation assumed) of perhaps 7%. That was a gross figure, not counting frictional costs, such as commissions and fees. Net, I thought returns might be 6%.