How Did It Happen?

Between January 1980 and August 2000 American stock prices as measured by the S&P500 index rose by 1239%; over the same period the dividends on the shares underlying the index rose by only 188%, while the earnings rose by 254%. Between August 2000 and February 2003 the price index fell by 44% and, at the time of writing, some three and a half years later, the index is still some 25% below its August 2000 level, despite the fact that long term interest rates have fallen by around 100 basis points, and the fall is much greater if measured in terms of foreign currency such as the Euro. As Figure 1 shows, American stock price behavior at the turn of the millennium had all the characteristics of a classic bubble;2 prices climbed much faster than dividends or earnings, particularly starting from the beginning of 1995. What caused this?