Dufourt

Publications

On sunspot fluctuations in variable capacity utilization modelsJournal articleFrédéric Dufourt, Alain Venditti and Rémi Vivès, Journal of Mathematical Economics, Volume 76, Issue C, pp. 80-94, 2018

We investigate the extent to which standard one sector RBC models with positive externalities and variable capacity utilization can account for the large hump-shaped response of output when the model is submitted to a pure sunspot shock. We refine the Benhabib and Wen (2004) model considering a general type of additive separable preferences and a general production function. We provide a detailed theoretical analysis of local stabilities and local bifurcations as a function of various structural parameters. We show that, when labor is infinitely elastic, local indeterminacy occurs through Flip and Hopf bifurcations for a large set of values for the elasticity of intertemporal substitution in consumption, the degree of increasing returns to scale and the elasticity of capital–labor substitution. Finally, we provide a detailed quantitative assessment of the model and conclude with mixed results. We show that although the model is able theoretically to generate a hump-shaped dynamics of output following an i.i.d. sunspot shock under realistic parameter values, the hump is too persistent for the model to be considered fully satisfactory from an empirical point of view.

Sunspot Fluctuations in Two-Sector Models with Variable Income EffectsBook chapterFrédéric Dufourt, Kazuo Nishimura, Carine Nourry and Alain Venditti, In: Sunspots and Non-Linear Dynamics - Essays in Honor of Jean-Michel Grandmont, K. Nishimura, A. Venditti and N. C. Yannelis (Eds.), 2017, Volume 31, pp. 71-96, Springer-Verlag, 2017

We analyze a version of the Benhabib and Farmer (1996) two-sector model with sector-specific externalities in which we consider a class of utility functions inspired from the one considered in Jaimovich and Rebelo (2009) which is flexible enough to encompass varying degrees of income effect. First, we show that local indeterminacy and sunspot fluctuations occur in 2-sector models under plausible configurations regarding all structural parameters—in particular regarding the intensity of income effects. Second, we prove that there even exist some configurations for which local indeterminacy arises under any degree of income effect. More precisely, for any given size of income effect, we show that there is a non-empty range of values for the Frisch elasticity of labor and the elasticity of intertemporal substitution in consumption such that indeterminacy occurs. This contrasts with the results obtained in one-sector models in both Nishimura et al. (2009), in which it is shown that indeterminacy cannot occur under either GHH and KPR preferences, and in Jaimovich (2008) in which local indeterminacy only arises for intermediary income effects.

Banking and sovereign debt crises in a monetary union without central bank interventionJournal articleJin Cheng, Meixing Dai and Frédéric Dufourt, Journal of Mathematical Economics, Volume 68, Issue C, pp. 142-151, 2017

We analyze the conditions of emergence of a twin banking and sovereign debt crisis within a monetary union in which: (i) the central bank is not allowed to provide direct financial support to stressed member states or to play the role of lender of last resort in sovereign bond markets, and (ii) the responsibility of fighting against large scale bank runs, ascribed to domestic governments, is ensured through the implementation of a financial safety net (banking regulation and government deposit guarantee). We show that this broad institutional architecture, typical of the Eurozone at the onset of the financial crisis, is not always able to prevent the occurrence of a twin banking and sovereign debt crisis triggered by pessimistic investors’ expectations. Without significant backstop by the central bank, the financial safety net may actually aggravate, instead of improve, the financial situation of banks and of the government.

Optimal fiscal policy in sunspot-driven oligopolistic economiesJournal articleRodolphe Dos Santos Ferreira and Frédéric Dufourt, Journal of Public Economic Theory, Volume 19, Issue 3, pp. 620-638, 2017

Economies with oligopolistic markets are prone to inefficient sunspot fluctuations triggered by autonomous changes in firms equilibrium conjectures. A well-designed taxation-subsidization scheme can eliminate these fluctuations by coordinating firms in each sector on a single equilibrium, left unaffected. The optimal taxation scheme must select the number of active firms that makes the best trade-off (in terms of consumer welfare) between the markup and the scale inefficiency distortions. Implementing such stabilization policy leads to significant welfare gains, attributable to an “efficient stabilization effect,” typically ignored in usual computations of the welfare costs of fluctuations.

Sunspot fluctuations in two-sector models: New results with additively separable preferencesJournal articleFrédéric Dufourt, Kazuo Nishimura and Alain Venditti, International Journal of Economic Theory, Volume 12, Issue 1, pp. 67-83, 2016

We analyze local indeterminacy and sunspot-driven fluctuations in the standard two-sector model with additively separable preferences. We provide a detailed theoretical analysis enabling us to derive relevant bifurcation loci and to characterize the steady-state local stability properties as a function of various structural parameters influencing the degree of increasing returns to scale, the amount of intertemporal substitution in consumption, and the elasticity of the aggregate labor supply curve. On the theoretical side, we prove the existence of both a flip and a Hopf bifurcation locus in the corresponding parameter space. We also show that local indeterminacy can be obtained under any labor supply elasticity or under an arbitrarily low elasticity of intertemporal substitution in consumption. On the empirical side, we find that indeterminacy and sunspot fluctuations are robust features of two-sector models, prevailing for most empirically plausible calibrations for these parameters. (This abstract was borrowed from another version of this item.)

Indeterminacy and sunspots in two-sector RBC models with generalized no-income-effect preferencesJournal articleFrédéric Dufourt, Kazuo Nishimura and Alain Venditti, Journal of Economic Theory, Volume 157, Issue C, pp. 1056-1080, 2015

We analyze sunspot-driven fluctuations in the standard two-sector {RBC} model with moderate increasing returns to scale and generalized no-income-effect preferences à la Greenwood, Hercovitz and Huffman [13]. We provide a detailed theoretical analysis enabling us to derive relevant bifurcation loci and to characterize the steady-state local stability properties as a function of various structural parameters. We show that local indeterminacy occurs through flip and Hopf bifurcations for a large set of values for the elasticity of intertemporal substitution in consumption, provided that the labor supply is sufficiently inelastic. Finally, we provide a detailed quantitative analysis of the model. Computing, on a quarterly basis, a new set of empirical moments related to two broadly defined consumption and investment sectors, we are able to identify, among the set of admissible calibrations consistent with sunspot equilibria, the ones that provide the best fit of the data. The model properly calibrated solves several empirical puzzles traditionally associated with two-sector {RBC} models.

Empirical evaluation of nominal convergence in Czech Republic, Poland and Hungary (CPH)Journal articleMamoudou Toure, Jamel Trabelsi and Frédéric Dufourt, Economic Modelling, Volume 26, Issue 5, pp. 993-999, 2009

We estimate a four variable structural vector auto regression (SVAR) model of the Czech Republic, Poland and Hungary economies in order to evaluate the links between the instruments of monetary policy and inflation outcomes. We find that the linkages between the interest rates and price levels are weak. However, the exchange rate constitutes the most important channel of monetary policy transmission for Poland and Hungary. For the Czech Republic, the link between interest rate rise and price level is rather indirect.

Indeterminacy with constant money growth rules and income-based liquidity constraintsJournal articleStefano Bosi and Frédéric Dufourt, Research in Economics, Volume 62, Issue 2, pp. 57-63, 2008

We study the implications of constant money growth rules on the stability properties of the equilibrium, in economies where the agents are subject to a partial cash-in-advance constraint applying simultaneously to consumption and investment purchases. By reference to similar models in which the liquidity constraint applies only to consumption, we show that the inclusion of investment has dramatic, but contrasting, effects on the range of values giving rise to indeterminacy. First, it increases strongly a lower bound on the share of purchases requiring cash, below which the steady state is always indeterminate. Second, it creates a higher bound on this share, above which the steady state is always determinate. In this context, the steady-state value of the velocity of money becomes a crucial parameter for gauging whether constant money growth rules may be stabilizing or destabilizing for the economy.

Indeterminacy, Bifurcations, and Unemployment FluctuationsJournal articleFrédéric Dufourt, Teresa Lloyd-Braga and Leonor Modesto, Macroeconomic Dynamics, Volume 12, Issue S1, pp. 75-89, 2008

We incorporate imperfectly insured unemployment in the finance constrained economy proposed by Woodford (1986), by introducing unions and unemployment benefits financed by labor taxation. We show that this simple extension of the Woodford model changes drastically its stability conditions and local dynamics around the steady state. In fact, in contrast to related models in the literature, we find that, under constant returns to scale in production: (i) indeterminacy always prevails in the case of a unitary elasticity of substitution between capital and labor and (ii) flip and Hopf bifurcations occur for empirically credible elasticities of substitution between capital and labor, so that a rich set of dynamics may emerge at “realistic” parameters' values.

Free entry equilibria with positive profits: A unified approach to quantity and price competition gamesJournal articleRodolphe Dos Santos Ferreira and Frédéric Dufourt, International Journal of Economic Theory, Volume 3, Issue 2, pp. 75-94, 2007

Free entry equilibria are usually characterized by the zero profit condition. We plead instead for a strict application of theNash equilibriumconcept to a symmetric simultaneous game played by actual and potential entrants, producing under decreasing average cost. Equilibrium is then typically indeterminate, with a number of active firms varying between an upper bound imposed by profitability and a lower bound required by sustainability. We use a canonical model with strategies represented by prices, although covering standard regimes of quantity and price competition, to show that in equilibrium the critical (profit maximizing) price must lie between the break-even and the limit prices.