Inflation Illusion and the Decomposition of Stock Valuations

Summary

The document reviews a study that decomposes the S&P 500 dividend yield into expected long-run real dividend growth, a subjective risk premium, and a residual attributed to differences between investors’ subjective growth expectations and rational expectations. It contrasts this framework with the Fed model, which relates stock yields to nominal bond yields, and explains why inflation should not mechanically affect equity valuations if nominal growth and discount rates adjust together.

Using a log-linear valuation framework and a vector autoregression, the study estimates the components over historical data. It reports that inflation is strongly associated with the mispricing residual, while its association with the subjective risk premium is small. The authors interpret this as evidence consistent with inflation illusion: equity investors may fail to adjust expected nominal dividend growth for inflation. The results depend on the model’s assumptions, including how expected growth and risk premia are estimated; the analysis does not establish that inflation illusion is the only cause of mispricing or provide a trading rule.

Key ideas

• The study separates dividend yields into expected growth, subjective risk premia, and a mispricing residual.
• The Fed model describes a historical link between stock yields and nominal interest rates but may not provide a sound valuation explanation.
• The authors estimate valuation components with a log-linear framework and a vector autoregression.
• Their results associate inflation more strongly with the mispricing residual than with the subjective risk premium.
• The interpretation supports inflation illusion, while depending on the model’s assumptions and estimated components.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.