Person:

Viceira, Luis

The exposure of US Treasury bonds to the stock market has moved considerably over time. While it was slightly positive on average in the period 1960-2011, it was unusually high in the 1980s and negative in the 2000s, a period during which Treasury bonds enabled investors to hedge macroeconomic risks. This paper explores the effects of monetary policy parameters and macroeconomic shocks on nominal bond risks, using a New Keynesian model with habit formation and discrete regime shifts in 1979 and 1997. The increase in bond risks after 1979 is attributed primarily to a shift in monetary policy towards a more anti-inflationary stance, while the more recent decrease in bond risks after 1997 is attributed primarily to an increase in the persistence of monetary policy interacting with continued shocks to the central bank’s inflation target. Endogenous responses of bond risk premia amplify these effects of monetary policy on bond risks.

Our new model of consumption-based habit generates time-varying risk premia on bonds and stocks from loglinear, homoskedastic macroeconomic dynamics. Consumers' first-order condition for the real risk-free bond generates an exactly loglinear consumption Euler equation, commonly assumed in New Keynesian models. We estimate that the correlation between inflation and the output gap switched from negative to positive in 2001. Higher inflation lowers real bond returns, and higher output raises stock returns, explaining why the bond-stock return correlation changed from positive to negative. In the model, risk premia amplify this change in bond-stock return comovement and are crucial for a quantitative explanation.