Stock market booms and real economic activity: Is this time different?

Since World War II, the United States has experienced two large booms on the stock market. During the first boom, which lasted from the late 1940s to the mid-1960s, stock returns were clearly leading real activity. Moreover, the evidence also suggests the existence of predictable return variations in the discount rate through time as a response to changing business conditions. Therefore, the first boom does not stand out as unusual because previous studies, such as Fama (1990) or Chen (1991), confirm these results for the whole period from the 1950s to the 1980s. But during the current boom, which started in the early 1980s, these results do not hold up any more. Stock returns do not seem to lead real activity and predictable return variations as a response to business conditions cannot be detected.