To examine the historical relationship between demographic trends and stock prices, we consider a statistical model in which the equity price/earnings (P/E) ratio depends on a measure of age distribution (for another example, see Geanakoplos et al. 2004). We construct the P/E ratio based on the year-end level of the Standard & Poor’s 500 Index adjusted for inflation and average inflation-adjusted earnings over the past 12 months. We measure age distribution using the ratio of the middle-age cohort, age 40–49, to the old-age cohort, age 60–69. We call this the M/O ratio.
Okay, in addition the current younger generation is saddled with record levels of student loan debt, the economy isn’t generating many good paying jobs, and we’re in a post credit crisis sucky cyclical recovery.
By these lights the bear market could go another ten years.