Forward Guidance in the Yield Curve: Short Rates versus Bond Supply
by Robin Greenwood, Samuel G. Hanson, and Dimitri Vayanos
Executive Summary — Since late 2008, central banks have been conducting monetary policy through two primary instruments: quantitative easing (QE), in which they buy long-term government bonds and other long-term securities, and “forward guidance,” in which they guide market expectations about the path of future short rates. This paper analyzes the effects of forward guidance on both short rates and QE. Results show that forward guidance on QE tends to impact longer maturities than forward guidance on short rates, even when expectations about bond purchases by the central bank concern a shorter horizon than expectations about future short rates.
We present a model of the yield curve in which the central bank can provide market participants with forward guidance on both future short rates and on future Quantitative Easing (QE) operations, which affect bond supply. Forward guidance on short rates works through the expectations hypothesis, while forward guidance on QE works through expected future bond risk premia. If a QE operation is expected to be undone in the near term, then its announcement will have a hump-shaped effect on the yield and forward-rate curves; otherwise the effect may be increasing with maturity. Humps associated to QE announcements typically occur at maturities longer than those associated to short-rate announcements, even when the effects of the former are expected to last over a shorter horizon. We use our model to re-examine the empirical evidence on QE announcements in the United States.