No abstract

We evaluate the hypothesis that the zero lower bound (ZLB) constraint was, in practice, irrelevant during the recent ZLB episode experienced by the U.S. economy (2009Q1-2015Q4). We focus on two dimensions of economic performance that were ex-ante likely to have been affected by a binding ZLB: (i) the volatility of macro variables and (ii) the economy's response to shocks. Using a variety of empirical methods, we find little evidence against the irrelevance hypothesis, with our estimates suggesting that the responses of output, inflation and the long-term interest rate were hardly affected by the binding ZLB constraint. We show how a shadow interest rate rule (which we take as a proxy for forward guidance) can reconcile our empirical findings with the predictions of a simple New Keynesian model with a ZLB constraint.

We evaluate the hypothesis that the zero lower bound (ZLB) constraint was, in practice, irrelevant during the recent ZLB episode experienced by the U.S. economy (2009Q1-2015Q4). We focus on two dimensions of economic performance that were ex-ante likely to have been affected by a binding ZLB: (i) the volatility of macro variables and (ii) the economy's response to shocks. Using a variety of empirical methods, we find little evidence against the irrelevance hypothesis, with our estimates suggesting that the responses of output, inflation and the long-term interest rate were hardly affected by the binding ZLB constraint. We show how a shadow interest rate rule (which we take as a proxy for forward guidance) can reconcile our empirical findings with the predictions of a simple New Keynesian model with a ZLB constraint.

This paper develops a model of optimal government debt maturity in which the government cannot issue state-contingent bonds and cannot commit to fiscal policy. If the government can perfectly commit, it fully insulates the economy against government spending shocks by purchasing short-term assets and issuing long-term debt. These positions are quantitatively very large relative to GDP and do not need to be actively managed by the government. Our main result is that these conclusions are not robust to the introduction of lack of commitment. Under lack of commitment, large and tilted positions are very expensive to finance ex-ante since they exacerbate the problem of lack of commitment ex-post. In contrast, a flat maturity structure minimizes the cost of lack of commitment, though it also limits insurance and increases the volatility of fiscal policy distortions. We show that the optimal time-consistent maturity structure is nearly flat because reducing average borrowing costs is quantitatively more important for welfare than reducing fiscal policy volatility. Thus, under lack of commitment, the government actively manages its debt positions and can approximate optimal policy by confining its debt instruments to consols.