Laffer traps and monetary policy

This article focuses on the interaction, in a stylized economy with flexible prices, of monetary and fiscal policy when both are active-active in the sense that how the policy instrument is set depends on the state of the economy. Fiscal policy finances a given stream of government expenditures through distortionary labor taxes, and it operates under a strict balanced-budget rule. If monetary policy is passive, the economy may occasionally switch, because of self-fulfilling expectations, from the neighborhood of a "Laffer trap" equilibrium to the saddle-path leading to the high-welfare steady state. In the low-welfare stationary state, output, investment, and consumption are low while the tax rate is correspondingly high. However, active monetary policy may, by following a rule such that the nominal interest rate responds positively to the state of the economy, push the economy toward the high-welfare equilibrium and rule out expectation-driven business cycles.Monetary policy ; Fiscal policy

Collateral constraints and the amplification-persistence trade-off

Kiyotaki and Moore (1997) have stressed that an amplification-persistence trade-off arises when collateral constraints on borrowing interact with lumpy investment. In this paper, I confirm by way of example that collateral constraints are not by themselves responsible for such a deceptive trade-off. More precisely, I show in a standard general-equilibrium two-agent model that the amplification and persistence of the impact of temporary shocks go hand in hand. Unlike Kiyotaki-Moore's, the economy features concave utility and production functions, an endogenous interest rate and neo-classical input accumulationcollateral constraints; amplification and persistence of aggregate shocks

Endogenous Business Cycles and Dynamic Inefficiency

This paper explores how the occurrence of local indeterminacy and endogenous business cycles relates to dynamic inefficiency, as defined by Malinvaud (1953), Phelps (1965) and Cass (1972). We follow Reichlin (1986) and Grandmont (1993) by considering a two-period OLG model of capital accumulation with labor-leisure choice into the first-period of agents’ life and consumption in both periods. We first show that local indeterminacy and Hopf bifurcation are necessarily associated with a capital-labor ratio that is, at steady state, larger than the Golden Rule level. Consequently, paths converging asymptotically towards the steady state are shown to be dynamically inefficient, as there always exists another trajectory that starts with the same initial conditions and produces more aggregate consumption at all future dates. More surprising, however, is our main result showing that stable orbits, generated around a dynamically inefficient steady state through a supercritical Hopf bifurcation, may, in contrast, be dynamically efficient.Overlapping generations, endogenous labor supply, multiple equilibria, endogenous fluctuations, dynamic inefficiency

Resuscitating the credit cycle

This paper resuscitates the credit-cycle theory of Kiyotaki and Moore (1997) in a two-agent RBC model with conventional preferences and standard neoclassical technologies. It is shown that small transitory shocks to credit demand (or supply) can generate large, highly persistent, dampened cycles in aggregate output. Key to our results is the interaction between credit constraints and habit formation. Credit constraints based on collateralized assets mainly amplify the impact of shocks while habit formation in consumption demand mainly propagates it. Hump-shaped boom-bust cycles do not arise in the model under standard parameter values if either one of the two elements is missing.Credit

Leveraged borrowing and boom-bust cycles

Investment booms and asset "bubbles" are often the consequence of heavily leveraged borrowing and speculations of persistent growth in asset demand. We show theoretically that dynamic interactions between leveraged borrowing and persistent asset demand can generate a multiplier-accelerator mechanism that transforms a one-time technological innovation into large and long-lasting boom-bust cycles. The predictions are consistent with the basic features of investment booms and the consequent asset-market crashes led by excessive credit expansion.Asset pricing ; Credit

Is History a Blessing or a Curse? International Borrowing without Commitment, Leapfrogging and Growth Reversals

We develop a simple open-economy AK model with collateral constraints that accounts for growth-reversal episodes, during which countries face abrupt changes in their growth rate that lead to either growth miracles or growth disasters. Absent commitment to investment by the borrowing country, imperfect contract enforcement leads to an informational lag such that the debt contracted upon today depends upon the past stock of capital. The no-commitment delay originates a history effect by which the richer a country has been in the past, the more it can borrow today. For (arbitrarily) small deviations from perfect contract enforcement, the history effect offsets the growth benefits from international borrowing and dampens growth, and it leads to leapfrogging in long-run levels. When large enough, the history effect originates growth reversals and we connect the latter to leapfrogging. Finally, we argue that the model accords with the reported evidence on growth disasters and growth accelerations. We also provide examples showing that leapfrogging and growth reversals may coexist, so that currently poor but fast-growing countries experiencing sharp growth reversals may end up, in the long-run, significantly richer than currently rich but declining countries.Growth Reversals; Leapfrogging; International Borrowing; Open Economies

On the optimal control of a linear neutral differential equation arising in economics

In this paper, we apply two optimization methods to solve an optimal control problem of a linear neutral differential equation (NDE) arising in economics. The first one is a variational method, the second follows a dynamic programming approach. Due to the infinite dimensionality of the NDE, the second method requires the reformulation of the latter as an ordinary differential equation in an appropriate abstract space. It is shown that the resulting HJB equation admits a closed-form solution, allowing for a much finer characterization of the optimal dynamics compared to the alternative variational method. The latter is clearly limited by the nontrivial nature of asymptotic analysis of NDEs.Neutral differential equations; economic dynamics; optimal control; calculus of variations; dynamic programming; infinite dimension

Leapfrogging, Growth Reversals and Welfare

We show that leapfrogging and growth reversals entail sizeable welfare gains and losses, respectively, in an AK economy that cannot credibly commit to investment when borrowing from international financial markets. Small no-commitment delays originate a trade-off that has an ambiguous effect on welfare: they reduce the long-run consumption growth rate but increase the initial level of consumption that is optimally chosen. Essentially, the larger the delay, the tighter the borrowing constraint and the weaker the incentives to accumulate capital, so that smaller growth and larger initial consumption follow. We show under logarithmic utility and small delays that the short-run effect dominates the long-run effect and that welfare improves, provided that the economy has historically been growing fast enough, and numerical examples suggest that this benchmark result extends to CRRA utility. When relative risk aversion is larger than one, it follows that there exists a positive welfare-maximizing delay associated with slower growth relative to the no-delay case. We then apply our results to show that leapfrogging in consumption level typically imply large welfare gains. In contrast, growth reversals occur for large delays and lead to significant welfare losses. Finally, financial integration, as measured by the credit multiplier given the no-commitment delay, is welfare-improving only for economies that have historically been growing fast enough.Growth Reversals; Leapfrogging; International Borrowing; Open Economies; Welfare

Leveraged financing, over investment, and boom-bust cycles

It has long been argued in the history of economic thought that over investment through highly leveraged borrowing under elastic credit supply may generate large boom-bust business cycles. This paper rationalizes this idea in a dynamic general equilibrium model with infinitely lived rational agents. It shows that dynamic interactions between strong asset-accumulation motives (based on habit formation on the borrower side) and elastic credit supply (based on collateralized lending on the lender side) generate a multiplier-accelerator mechanism that can transform a one-time technological innovation into large and long-lasting boom-bust cycles. Such cycles share many features in common to investment bubbles observed in the history (such as the IT bubble in the 1990s and the 2000s housing bubble)

Are Progressive Fiscal Rules Stabilizing?

This paper studies how income-based, progressive taxes and transfers may reduce aggregate volatility by protecting the economy against expectation-driven business cycles. Eliminating “local” sunspots that are arbitrarily close to an indeterminate steady state requires, for sensible parameter values, strong levels of progressivity so as to make labor supply close to inelastic. However, progressive taxes and transfers are shown to be ineffective to rule out stable deterministic cycles (and the associated “global” sunspots) that are located close to a determinate steady state. Our results are formalized within two benchmark models and show how the efficiency of progressive fiscal schemes as local automatic stabilizers depends on the fiscal base. In the first setting with heterogeneous agents and segmented asset markets in which wage income mostly finances consumption, we show that progressive taxes and transfers should be made dependent on labor income, so as to rule out local indeterminacy. On the contrary, progressive fiscal rules should be applied to capital income in an overlapping generations economy where consumption comes from savings income. Incidentally, the latter results suggest that capital income taxes may be desirable, when progressive, to make local expectation-driven fluctuations less likely. In both frameworks, key to the results is the property that progressive fiscal rules provide insurance in the presence of imperfect capital markets