Why is the Shiller CAPE So High?

"Why is the Shiller CAPE so high?  In the last several weeks, a number of prominent academics and financial market commentators have attempted to answer this question, to include the inventor of the valuation measure himself, Nobel Laureate Robert Shiller.  In this piece, I’m going to attempt to give a clear answer.

The piece has five parts:
·         In the first part, I’m going to explain why valuations in general are higher than they have been historically.  It’s not just the CAPE that’s historically elevated; the simple TTM P/E ratio is also historically elevated, by a reasonably large amount.
·         In the second part, I’m going to highlight the main reason that the Shiller CAPE has risen relative to the simple TTM P/E over the last two decades: high real EPS growth. I’m going to introduce a schematic that intuitively illustrates why high real EPS growth produces a high Shiller CAPE.
·         In the third part, I’m going to explain how reductions in the dividend payout ratio have contributed to high real EPS growth.  In discussing the dividend payout ratio, I’m going to present a different, potentially more accurate formulation of the Shiller CAPE, a formulation that conducts the calculation based on total return instead of price.  On this formulation, the Shiller CAPE falls by around 10%, from 26.0 to 23.5.
·         In the fourth part, I’m going to explain how a secular uptrend in profit margins has contributed to high real EPS growth over the last two decades.  This effect is the most powerful of all, and is the main reason why the Shiller CAPE and the TTM P/E have diverged in their valuation signals.
·         In the fifth part, I’m going to outline a set of possible future return scenarios that investors at current valuations can reasonably expect.  I’m then going to identify the future return scenario that I find most credible."