Thomas Seegmuller

Aggregate instability under balanced-budget consumption taxes: A re-examination

We re-examine the destabilizing role of balanced-budget fiscal policy rules based on consumption taxation. Using a one-sector model with infinitely-lived households, we consider a specification of preferences derived from Jaimovich (2008) [14] and Jaimovich and Rebelo (2009) [15] which is flexible enough to encompass varying degrees of income effect. When the income effect is not too large, we show that there exists a Laffer curve, which explains the multiplicity of steady states, and that non-linear consumption taxation may destabilize the economy, promoting expectation-driven fluctuations, if the elasticity of intertemporal substitution in consumption is sufficiently larger than one and the tax rate is counter-cyclical with respect to consumption. Numerical illustrations also show that consumption taxation may be a source of instability for most OECD countries for a wide range of structural parametersʼ configurations. We finally prove the robustness of our conclusions if we consider a discrete-time setup.

Longevity, pollution and growth

We analyze the interplay between longevity, pollution and growth. We develop an OLG model where longevity, pollution and growth are endogenous. The authorities may provide two types of public services, public health and environmental maintenance, that participate to increase agents’ life expectancy and to sustain growth in the long term. We show that global dynamics might be featured by a high growth rate equilibrium, associated with longer life expectancy and a environmental poverty trap. We examine changes in public policies: increasing public intervention on health or environmental maintenance display opposite effects on global dynamics, i.e. on the size of the trap and on the level of the stable balanced growth path. On the contrary, each type of public policy induces a negative leverage on the long run rate of growth.

*Capital–Labour Substitution and Endogenous Fluctuations: A Monopolistic Competition Approach with Variable Markup

This paper analyses an overlapping generations model with endogenous product diversity where strategic interactions between producers are introduced; it examines how they affect the stability properties of the steady state. Because of free entry, strategic interactions between producers imply a new dynamic feature, markup variability, promoting indeterminacy and endogenous cycles. Indeed, in contrast to the model without strategic interaction, endogenous fluctuations can occur when the substitution between the production factors, capital and labour, is not too weak, but in accordance with empirical estimates.

Rational Bubbles and Macroeconomic Fluctuations. The(De-)Stabilizing Role of Monetary Policy

We are interested in the existence of expectation-driven fluctuations of a rational bubble and the (de-)stabilizing role of monetary policy. This paper highlights the key role of credit market imperfections at the household level to explain bubble fluctuations and exhibits the stabilizing power of monetary rules responding to asset prices. We consider an overlapping generations exchange economy where households realize a portfolio choice between money and a bubble. Money is held because of a partial cash-in-advance constraint affected by the size of the bubble. A higher value of the bubble reduces the need of cash, and thus increases the fraction of consumption purchased on credit. Under these credit market features, multiplicity of steady-states (global indeterminacy) and expectation-driven fluctuations (local indeterminacy) can occur for arbitrarily small market distortions. Investing the stabilizing role of monetary policy, we show that when the monetary policy rule responds only to expected inflation, a more active rule can be destabilizing by promoting local indeterminacy and has no impact on the multiplicity of steady states. In contrast to the previous policy, when the rule responds also to asset prices, then the monetary policy can be stabilizing and rule out the multiplicity of steady states.

PUBLIC SPENDING AS A SOURCE OF ENDOGENOUS BUSINESS CYCLES IN A RAMSEY MODEL WITH MANY AGENTS

We introduce public spending, financed through income taxation, in the Ramsey model with heterogeneous agents. Public spending as a source of welfare generates more complex dynamics. In contrast to previous contributions focusing on similar models but with wasteful public spending, limit cycles through Hopf bifurcation and expectation-driven fluctuations appear if the degree of capital-labor substitution is large enough to be compatible with capital income monotonicity. Moreover, unlike frameworks with a representative agent, our results do not require externalities in production and are compatible with a weakly elastic labor supply with respect to wage.

On existence, efficiency and bubbles of Ramsey equilibrium with borrowing constraints

We address the fundamental issues of existence and efficiency of a Ramsey equilibrium with heterogenous discounting, elastic labor supply and borrowing constraints. In the first part, we prove the equilibrium existence in a truncated bounded economy through a fixed-point argument by Gale and Mas-Colell (1975). This equilibrium is also an equilibrium of any unbounded economy with the same fundamentals. The proof of existence is eventually given for an infinite-horizon economy as a limit of a sequence of truncated economies. Our general approach is suitable for applications to other models with different market imperfections. In the second part, we show the impossibility of bubbles in a productive economy and we give sufficient conditions for equilibrium efficiency.

Nonseparable Preferences Do Not Rule Out Aggregate Instability Under Balanced-Budget Rules: A Note

We investigate the role of nonseparable preferences in the occurrence of macroeconomic instability under a balanced-budget rule where government spending is financed by a tax on labor income. Considering a one-sector neoclassical growth model with a large class of nonseparable utility functions, we find that expectations-driven fluctuations occur easily when consumption and labor are Edgeworth substitutes or weak Edgeworth complements. Under these assumptions, an intermediate range of tax rates and a sufficiently low elasticity of intertemporal substitution in consumption lead to instability.

The Stabilizing Virtues of Monetary Policy on Endogenous Bubble Fluctuations

We explore the stabilizing role of monetary policy on the existence of endogenous fluctuations when the economy experiences a rational bubble. Considering an overlapping generations model, expectation-driven fluctuations are explained by a portfolio choice between three assets (capital, bonds and money), credit market imperfections and a collateral effect. They occur under a positive bubble on bonds. The key mechanism relies on the existence of gaps between the returns on assets due to financial distortions. Then, we study the stabilizing role of the monetary policy. Such a policy managed by a (standard) Taylor rule has no clear stabilizing virtues.