Haphazard Linkages

An abrupt market drop causes a rally in gloom-n-doom hypotheses. More than a few that landed in my inbox recently focused on the relationship between corporate profits and GDP. The core theme was this: corporate profits as a percentage of GDP exhibit a mean-reverting characteristic. Whenever they overshoot too far from the mean, they fall back; and this isn’t good for long-term equity returns. Current levels are close to historical highs, so equity bears invoke the above to build a bear case. Historical references cite the peaks hit in 1965/66 and 2006 as strong evidence for weak subsequent equity performance. History provides some insights. The following exhibit uses after-tax corporate profits from NIPA and uses the Dow Jones Industrial Average as a barometer of equity performance. The DJIA was chosen as a longish history of prices was readily available. For comparative purposes, a similar exhibit for the S&P 500 is appended later.    Only 2 out of the previou