By Joseph Kopecky and Alan Taylor
Population aging has been linked to global declines in interest rates. A similar trend shows that equity risk premia are on the rise. An existing literature can explain part of the decline in the trend in safe rates using demographics, but has no mechanism to speak to trends in relative asset prices. We calibrate a heterogeneous agent life-cycle model with equity markets, showing that this demographic channel can simultaneously account for both the majority of a downward trend in the risk free rate, while also increasing premium attached to risky assets. This is because the life cycle savings dynamics that have been well documented exert less pressure on risky assets as older households shift away from risk. Under reasonable calibrations we find declines in the safe rate that are considerably larger than most existing estimates between the years 1990 and 2017. We are also able to account for most of the rise in the equity risk premium. Projecting forward to 2050 we show that persistent demographic forces will continue push the risk free rate further into negative territory, while the equity risk premium remains elevated.
To continue on the theme mentioned here two weeks ago, population aging is crucial for some many economic outcomes. This paper adds to it. However, I am starting to wonder whether the current pandemic is going to make those changes less drastic as it will lead to less pronounced aging of the population.