Optimal Dynamic Nonlinear Income Taxation under Loose Commitment

This paper examines an infinite-horizon model of dynamic nonlinear income taxation in which there exists a small probability that the government cannot commit to its future tax policy. In this "loose commitment" environment, we find that even a little uncertainty over whether the government can commit yields substantial effects on the optimal dynamic nonlinear income tax system. Under an empirically plausible parameterization, numerical simulations show that high-skill individuals must be subsidized in the short run, despite the government's redistributive objective, unless the probability of commitment is higher than 98%. Loose commitment also reverses the short-run welfare effects of changes in most model parameters. In particular, all individuals are worse-off, rather than better-off, in the short run when the proportion of high-skill individuals in the economy increases. Finally, our main findings remain qualitatively robust to a setting in which loose commitment is modelled as a Markov switching process.Dynamic Income Taxation, Loose Commitment

Expectations Traps and Monetary Policy with Limited Commitment

We study the existence and uniqueness properties of monetary policy with limited commitment in LQ RE models. We use a New Keynesian model with debt accumulation in the spirit of Leeper (1991) as a `lab', because this model generates multiple equilibria under pure discretion, and under full commitment there are two distinct determinate regimes. We study how these properties change over the continuum of intermediate cases between commitment and discretion. We find that although multiple equilibria exist for high degrees of precommitment, even a small degree of precommitment selects a unique equilibrium for a wide range of parameters. We discuss the stability properties of policy equilibria which can be used to design an equilibrium selection criterion. We also demonstrate very different welfare implications for different policy equilibria.Limited Commitment, Commitment, Discretion, Multiple Equilibria

Policy and welfare effects of within-period commitment

I study the implications of different institutional frameworks for the conduct of fiscal policy, under the assumption that the government cannot commit to future policy choices. The environments analyzed vary on whether the government is endowed with the ability to commit to beginning-of-period policy announcements or not. If it cannot, then there are two variants, depending on which actions private agents take before observing the government’s policy choice. How the three possible cases rank in terms of tax rates and welfare varies substantially with the economy’s fundamentals and whether depreciation is tax deductible or not. More generally, I find that regimes with higher tax rates do not necessarily imply lower welfare. I also find that making depreciation not tax-deductible typically involves a welfare loss. Within the context of the environments studied in this paper, I find that there are only small gains from modifying the way fiscal policy is conducted in modern developed economies. Furthermore, some reforms may lead to large welfare losses.Fiscal policy ; Welfare ; Equilibrium (Economics)

Escaping expectation traps: how much commitment is required?

We study the degree of precommitment that is required to eliminate multiplicity of policy equilibria, which arise if the policy maker acts under pure discretion. We apply a framework developed by Schaumburg and Tambalotti (2007) and Debertoli and Nunes (2010) to a standard New Keynesian model with government debt. We demonstrate the existence of expectation traps under limited commitment and identify the minimum degree of commitment which is needed to escape from these traps. We find that the degree of precommitment which is sufficient to generate uniqueness of the Pareto-preferred equilibrium requires the policy maker to stay in office for a period of two to five years. This is consistent with monetary policy arrangements in many developed countries

Fiscal sustainability in a new Keynesian model

Recent work on optimal monetary and fiscal policy in New Keynesian models suggests that it is optimal to allow steady-state debt to follow a random walk. In this paper we consider the nature of the time inconsistency involved in such a policy and its implication for discretionary policymaking. We show that governments are tempted, given inflationary expectations, to utilize their monetary and fiscal instruments in the initial period to change the ultimate debt burden they need to service. We demonstrate that this temptation is only eliminated if following shocks, the new steady-state debt is equal to the original (efficient) debt level even though there is no explicit debt target in the government's objective function. Analytically and in a series of numerical simulations we show which instrument is used to stabilize the debt depends crucially on the degree of nominal inertia and the size of the debt stock. We also show that the welfare consequences of introducing debt are negligible for precommitment policies, but can be significant for discretionary policy. Finally, we assess the credibility of commitment policy by considering a quasi-commitment policy, which allows for different probabilities of reneging on past promises

How Optimal is US Monetary Policy?

Using a small-scale microfounded DSGE model with Markov switching in shock variances and policy parameters, we show that the data-preferred description of US monetary policy is a time-consistent targeting rule with a marked increase in conservatism after the 1970s. However, the Fed lost its conservatism temporarily in the aftermath of the 1987 stock market crash, and again following the 2000 dot-com crash and has not subsequently regained it. The high inflation of the 1970s would have been avoided had the Fed been able to commit, even without the appointment of Paul Volcker or the reduction in shock volatilities

Time-consistent consumption taxation

We characterise optimal fiscal policies when the government has access to consumption taxation but cannot credibly commit to future policies, in a calibrated Real Business Cycle model of the United States economy. Contrary to the case where only labour and capital income are taxed, the optimal time-consistent policies are remarkably similar to their Ramsey counterparts, as long as the capital income tax causes some distortion within the period. The welfare gains from commitment are negligible, while they are substantial without consumption taxation. Further, the welfare gains from taxing consumption are much higher without commitment. These results suggest that the policy-maker's ability to commit is of secondary importance if consumption is taxed optimally

Public Consumption Over the Business Cycle

What fraction of the business cycle volatility of government purchases is accounted for as endogenous reactions to overall macroeconomic conditions? We answer this question in the framework of a neoclassical representative household model where the provision of a public consumption good is decided upon endogenously and in a time-consistent fashion. A simple frictionless version of such a model with aggregate productivity as the sole driving force can explain almost all the volatility of U.S. non-defense government consumption expenditures. However, such a model fails to match other important features of the business cycle dynamics of public consumption, which comes out as not persistent enough and too synchronized with the cycle. We add implementation lags and implementation costs in the budgeting process to the model, plus taste shocks for public consumption relative to private consumption, and achieve a substantially better match to the data. All these ingredients are essential to improve the fit. Depending on the precise specification of the flow utility function over private consumption, public consumption and leisure, 25-40 percent of the variance of public consumption is driven by aggregate productivity shocks.

Dealing with Time-Inconsistency: Inflation Targeting vs. Exchange Rate Targeting

Abandoning an objective function with multiple targets and adopting single mandate can be an effective way for a central bank to overcome the classic time-inconsistency problem. We show that the choice of a particular single mandate depends on an economy’s level of trade openness and the credibility of the central bank. We begin with reduced form empirical results which show that as central banks become less credible they are more likely to adopt a pegged exchange rate, and crucially, the tendency to peg depends on trade openness. Then in a model where the central bank displays “loose commitment” we show that as central bank credibility falls, they are more likely to adopt either an inflation target or a pegged exchange rate. A relatively closed economy would adopt an inflation target to overcome the time-inconsistency problem, but a highly open economy would prefer an exchange rate peg.Fujiwara gratefully acknowledges financial support from JSPS KAKENHI Grant-in-Aid for Scientific Research (A) Grant Number 15H01939. Wang is grateful for financial support from Australian Research Council Discovery Project 16010265