Thomas Seegmuller

Chercheur ,  CNRS

Macroéconomie, économie du travail et économie internationale
Seegmuller
Statut
Directeur de recherche
Domaine(s) de recherche
Économie de l'environnement, Macroéconomie
Thèse
2001, Université Louis Pasteur
Téléchargement
CV
Contact
thomas.seegmuller[at]univ-amu.fr
+33(0)4 13 55 25 73 / +33(0)4 13 94 20 28
Adresse

AMU - AMSE
5-9 Boulevard Maurice Bourdet, CS 50498
​13205 Marseille Cedex 1

Résumé In this paper, we provide a framework in which a stationary bubble can exist on a portfolio of dividend-yielding assets. Consistent with standard asset pricing theory, this portfolio bubble is defined as the difference between the portfolio market price and the present value of its future dividend stream. This bubble can coexist with a positive stationary fundamental value, without requiring the collapse of the latter over time. This result is obtained in an exchange overlapping generations economy featuring both newly issued and pre-existing financial assets that depreciate over time, and jointly constitute the asset portfolio. The introduction of new assets in each period decouples the return on bubbles from the effective discount rate applied to dividends. As a result, stationary equilibria can exist with both a positive bubble and a positive fundamental component in the portfolio value. Finally, our framework also allows us to discuss the role of the substitutability between financial assets on the level of bubbles and fundamental values.
Mots clés Fundamental value, Financial assets, Rational bubbles
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Résumé We use an overlapping generations model with physical and human capital, and two reproductive periods to explore how fertility decisions may differ in response to economic incentives in early and late adulthood. In particular, we analyze the interplay between fertility choices—related to career opportunities—and wages, and investigate the role played by work experience and investment in both types of capital. We show that young adults postpone parenthood above a certain wage threshold and that late fertility increases with work experience. The long run trend is either to converge to a low productivity equilibrium, involving high early fertility, investment in physical capital and relatively low income, or to a high productivity equilibrium, where households postpone parenthood to invest in their human capital and work experience, with higher late fertility and higher levels of income. A convergence to the latter state would explain the postponement of parenthood and the mitigation or slight reversal of fertility decrease in some European countries in recent decades.
Mots clés Fertility, Overlapping generations, Work experience, Postponement
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Résumé This paper studies the dynamic relationship between economic growth, pollution, and government intervention. To do so, we develop a model that links pollution to the economy’s productive capacity, thereby capturing the feedback loops between economic activity, environmental degradation, and fiscal policy intervention. The model incorporates a pollution-sensitive damage function, taxes, and government spending while analyzing economic growth under different levels of government intervention. Therefore, the main paper’s contributions reveal that economies can achieve favorable outcomes with low or moderate government intervention, and that our results underscore the vital role of pollution mitigation policy in dynamically balancing economic growth with environmental sustainability.
Mots clés Public debt, Fiscal policy, Pollution, Economic Growth
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Résumé Recent data from US States reveal a negative correlation between environmental degradation and environmental concerns, which in turn seem inversely linked to fertility rates. We introduce a dynamic model to examine explicitly this interplay and explain the observed positive correlation between the carbon intensity of the economy and fertility in data from US States. The key ingredient of our model is that preferences for the number of children and environmental concerns may be complementary or substitutable. Interesting results occur when environmental concerns and the number of children are substitutable. At a stable steady state, a stronger effect of environmental concerns on household preferences reduces the number of children, as stressed by recent literature. The dynamics show that lower fertility rates are associated with lower environmental impacts from economic production, such as reduced carbon intensity.
Mots clés Carbon intensity Fertility Environmental concerns Environmental degradation Transitional dynamics
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Résumé Recent data from US states reveal a negative correlation between environmental degradation and environmental concerns, which in turn seem inversely linked to fertility rates. We introduce a dynamic model to examine explicitly this interplay and explain the observed positive correlation between the carbon intensity of the economy and fertility in data from US states. The key ingredient of our model is that preferences for the number of children and environmental concerns may be complementary or substitutable. Interesting results occur when environmental concerns and the number of children are substitutable. At a stable steady state, a stronger effect of environmental concerns on household preferences reduces the number of children, as stressed by recent literature. The dynamics show that lower fertility rates are associated with lower environmental impacts from economic production, such as reduced carbon intensity.
Mots clés Environmental concerns, Environmental degradation, Transitional dynamics, Fertility, Carbon intensity
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Résumé This paper examines an endogenous growth model that allows us to consider the dynamics and sustainability of debt, pollution, and growth. Debt evolves according to the financing adaptation and mitigation efforts and to the damages caused by pollution. Three types of features are important for our analysis: the technology through the negative effect of pollution on TFP; the fiscal policy; the initial level of pollution and debt with respect to capital. Indeed, if the initial level of pollution is too high, the economy is relegated to an endogenous tipping zone where pollution perpetually increases relatively to capital. If the effect of pollution on TFP is too strong, the economy cannot converge to a stable and sustainable long-run balanced growth path. If the income tax rates are high enough, we can converge to a stable balanced growth path with low pollution and high debt relative to capital. This sustainable equilibrium can even be characterized by higher growth and welfare. This last result underlines the role that tax policy can play in reconciling debt and environmental sustainability.
Mots clés Environmental damage, Pollution, Fiscal policy, Public debt, Sustainability
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Résumé C’est la version économique de la quadrature du cercle : comment à la fois investir massivement pour la transition écologique et maîtriser la dette pour retrouver des marges de manœuvre financières ? Sous certaines conditions, les deux sont possibles simultanément. Découvrez comment.
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Résumé This paper examines an endogenous growth model that allows us to consider the dynamics and sustainability of debt, pollution, and growth. Debt evolves according to the financing adaptation and mitigation efforts and to the damages caused by pollution. Three types of features are important for our analysis: The technology through the negative effect of pollution on TFP; The fiscal policy; The initial level of pollution and debt with respect to capital. Indeed, if the initial level of pollution is too high, the economy is relegated to an endogenous tipping zone where pollution perpetually increases relatively to capital. If the effect of pollution on TFP is too strong, the economy cannot converge to a stable and sustainable long-run balanced growth path. If the income tax rates are high enough, we can converge to a stable balanced growth path with low pollution and high debt relative to capital. This sustainable equilibrium can even be characterized by higher growth and welfare. This last result underlines the role that tax policy can play in reconciling debt and environmental sustainability.
Mots clés Environmental damage, Sustainability, Public debt, Fiscal policy, Pollution
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Résumé Entrepreneurship, growth and total factor productivity are larger when asset prices are high and decline during financial crises. We explain these facts using a growth model with financial bubbles in which individuals have heterogeneous wages and returns on productive investment. Heterogeneity separates individuals between savers and entrepreneurs. Savers buy financial assets, which are deposits or a financial bubble. Entrepreneurs incur in a start-up cost and borrow to invest in productive capital. The bubble provides liquidities to credit-constrained entrepreneurs. These liquidities increase investment, growth and entrepreneurship. Finally, the bubble may increase productivity when the return of each entrepreneur's investment is positively correlated with her previous income.
Mots clés Bubble, Entrepreneurship, Growth, Productivity
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Résumé We provide a unified framework with demand for housing over the life cycle and financial frictions to analyze the existence and macroeconomic effects of rational housing bubbles. We distinguish a housing price bubble, defined as the difference between the housing market price and its fundamental value, from a housing demand bubble, which corresponds to a situation where a pure speculative housing demand exists. In an overlapping generation exchange economy, we show that no housing price bubble occurs. However, a housing demand bubble may occur, generating a boom in housing prices and a drop in the interest rate, when households face a binding borrowing constraint. The multiplicity of steady states and endogenous fluctuations can occur when credit market imperfections are moderate. These fluctuations involve transitions between equilibria with and without a housing demand bubble that generate large fluctuations in housing prices consistent with observed patterns. We finally extend the basic framework to a production economy and we show that a housing demand bubble increases housing prices, which can still be characterized by large fluctuations.
Mots clés Bubble, Housing, Self-fulfilling fluctuations
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Résumé We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending in health care and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote convergence to a stable disease-free steady state. When public policies are not able to permanently eradicate the epidemic, public debt, and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy that eliminates income and welfare inequalities between healthy and infected individuals.
Mots clés Epidemics, Pollution, Overlapping generations, Public debt
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Résumé Several papers explain why asset bubbles are observed when growth is large. These papers differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. We compare the liquidity and collateral roles of bubbles in an overlapping generations model. When the bubble is deterministic, the equilibrium is identical under these two roles, implying that the same mechanism explains the crowding-in effect of the bubble on growth. With stochastic bubbles, growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to capital investors.
Mots clés Growth, Crowding-in effect, Collateral, Liquidity, Bubble
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Résumé Several recent papers introduce different mechanisms to explain why asset bubbles are observed in periods of larger growth. These papers share common assumptions, heterogeneity among traders and credit market imperfection , but differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. In this paper, we introduce heterogeneous traders by considering an overlapping generations model with households living three periods. Young households cannot invest in capital, while adults have access to investment and face a borrowing constraint. Introducing bubbles in a quite general way, encompassing the different roles they have in the existing literature, we show that the bubble may enhance growth when the borrowing constraint is binding. More significantly, our results do not depend on the-liquidity or collateral-role attributed to the bubble. We finally extend our analysis to a stochas-tic bubble, which may burst with a positive probability. Because credit and bubble are no more perfectly substitutable assets, the liquidity and collateral roles of the bubble are not equivalent. Growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to agents who invest in capital.
Mots clés Liquidity, Bubble, Collateral, Crowding-in effect, Growth
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Résumé We analyze the effects of a debt relief, that is, a decrease in public debt of a low-income country financed by a high-income country, on environmental quality. Under perfect mobility of assets, the debt relief increases the overall capital stock, and environmental quality when public abatements are sufficiently efficient. Welfare in both countries can also improve. Under a weak mobility of assets, capital does no more increase in the richest country, but environmental quality can improve. This comes from a crowding-out effect of debt in the high-income country, which does no more take place when the mobility of assets is significant.
Mots clés Capital market integration, Global pollution, Overlappinggenerations, Public debt, Overlapping generations
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Résumé The aim of this paper is to study the role of the distribution of income by age group on the existence of speculative bubbles. A crucial question is whether this distribution may promote a bubble associated to a larger level of capital, that is a productive bubble. We address these issues in an overlapping generations model where agents live three periods and productive investment done in the first period of life is an illiquid investment whose return occurs in the following two periods. A bubble is a liquid speculative investment that facilitates intertemporal consumption smoothing. We show that the distribution of income by age group determines both the existence and the effect of bubbles on aggregate production. We also show that fiscal policy, by changing the distribution of income, may facilitate or prevent the existence of bubbles and may also modify the effect that bubbles have on aggregate production.
Mots clés Bubble, Efficiency, Income distribution, Overlapping generations
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Résumé We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote the convergence to a stable steady state with no epidemics. When public policies are not able to permanently eradicate the epidemic, public debt and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy which eliminates income and welfare inequalities between healthy and infected individuals.
Mots clés Public debt, Epidemics, Pollution, Overlapping generations
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Résumé We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote the convergence to a stable steady state with no epidemics. When public policies are not able to permanently eradicate the epidemic, public debt and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy which eliminates income and welfare inequalities between healthy and infected individuals.
Mots clés Public debt, Epidemics, Pollution, Overlapping generations
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Résumé This paper analyzes the effect of a pay-as-you-go pension system on the evolution of capital and pollution, and on the efficiency of an environmental versus health policy. In an overlapping generations model, we introduce endogenous longevity that depends on pollution and health expenditures. Global dynamics may display multiple balanced growth paths (BGPs). We show that by discouraging savings, a policy that promotes the pension system enlarges the environmental poverty trap. More surprisingly, the environmental policy has contrasting effects according to the significance of the pension system. If it has a small size, a more environmentally-friendly policy enlarges the environmental poverty trap and leads to a rise in capital over pollution at the highest stationary equilibrium. In contrast, in economies where intergenerational solidarity is well developed, capital over pollution decreases at the highest BGP. In such a case, the environmental policy does not necessarily lead to a better longevity and growth.
Mots clés Pollution, Pension system, Longevity, Health, Environment, Endogenous growth
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Résumé This paper is an introduction to the special issue of Mathematical Social Sciences on Advances in growth and macroeconomic dynamics in memory of Carine Nourry.
Mots clés Inequalities and income distribution, Migration and networks, Existence of equilibria, Macroeconomic stability and fluctuations
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Résumé The relationship between public debt, growth and volatility is investigated in a Barro-type (1990) endogenous growth model, with three main features: we consider a small open economy, international borrowing is constrained and households have taste for domestic public debt. Therefore, capital, public debt and the international asset are not perfect substitutes and the economy is characterized by an investment multiplier. Whatever the level of the debt-output ratio, the existing BGP features expectation-driven fluctuations. If the debt-output ratio is low enough, there is also a second BGP with a lower growth rate. Hence, a lower debt does not stabilize the economy with credit market imperfections. However, a high enough taste for domestic public debt may rule out the BGP with lower growth. This means that if the share of public debt held by domestic households is high enough, global indeterminacy does not occur.
Mots clés Indeterminacy, Credit constraint, Public debt, Small open economy
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Résumé This paper is a tribute for Carine Nourry for this special issue of Mathematical Social Sciences.
Mots clés Deep and endearing person, Director of the school AMSE, Internationally recognized
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Résumé This paper analyzes the link between asset bubbles, endogenous labor and capital. First, we explicitly and theoretically derive the conditions to have a crowding-in effect of the bubble, i.e. higher levels of capital and labor. Second, the utility function we consider shows that this result does not require an arbitrarily high elasticity of intertemporal substitution in consumption.
Mots clés Overlapping generations, Endogenous labor, Crowding-in effect, Asset bubbles
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Résumé We consider an overlapping generations economy in which agents differ through their ability to procreate. Ex‐ante infertile households may incur health expenditure to increase their chances of parenthood. This health heterogeneity generates welfare inequalities that deserve to be ruled out. We explore three different criteria of social evaluation in the long‐run: the utilitarian approach, the ex‐ante egalitarian criterion and the ex‐post egalitarian one. We propose a set of economic instruments to decentralize each solution. To correct for the externalities and health inequalities, both a preventive (a taxation of capital) and a redistributive policy are required. We show that a more egalitarian allocation is associated with higher productive investment but reduced health expenditure and thus, lower population growth.
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Résumé This article analyzes the impacts of debt relief on production and pollution. We develop a two-country overlapping generations model with environmental externalities, public debts and perfect mobility of assets. Pollutant emissions arise from production, but agents may invest in pollution mitigation. Could debt relief be an efficient tool to encourage less developed countries to engage in the fight against climate change? We consider a decrease of the debt of the poor country balanced by an increase of the richer country's debt. We show that debt relief makes it possible to engage poor countries in the process of pollution abatement. Capital, environmental quality and welfare can increase in both countries. This result relies on the environmental sensitivity and the discount factor in the poor country relative to the rich one: the greater they are the more beneficial the debt relief is.
Mots clés Capital market integration, Pollution, Abatement, Overlapping generations, Public debt, Capital market integra- tion
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Résumé In this paper, we are interested in the interplay between real estate bubble, aggregate capital accumulation and taxation in an overlapping generations economy with altruistic households. We consider a three-period overlapping generations model with three key elements: altruism, portfolio choice, and financial market imperfections. Households realise different investment decisions in terms of asset at different periods of life, face a binding borrowing constraint and leave bequests to their children. We show that altruism plays a key role on the existence of a productive real estate bubble, i.e. a bubble in real estate raising physical capital stock and aggregate output. The key mechanism relies on the fact that a real estate bubble raises income of retired households. Because of higher bequests, there children are able to invest more in productive capital. Introducing fiscal policy, we show that raising real estate taxation dampens capital accumulation.
Mots clés Real estate, Overlapping generations, Credit, Bubble, Altruism
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Résumé As illustrated by some French departments, how can we explain the existence of equilibria with different fertility and growth rates in economies with the same fundamentals , preferences, technologies and initial conditions? To answer this question we develop an endogenous growth model with altruism and love for children. We show that independently from the type of altruism, a multiplicity of equilibria might emerge if the degree of love for children is high enough. We refer to this condition as the love for children hypothesis. Then, the fertility rate is determined by expectations on the future growth rate and the dynamics are not path-dependent. Our model is able to reproduce different fertility behaviours in a context of completed demographic transition independently from fundamentals, preferences, technologies and initial conditions.
Mots clés Bal- anced Growth Path, Endogenous growth, Expectations, Love for Children, Fertility
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Résumé This article analyzes the impacts of debt relief on production and pollution. We develop a two-country overlapping generations model with environmental externalities, public debts and perfect mobility of assets. Pollutant emissions arise from production, but agents may invest in pollution mitigation. Could debt relief be an efficient tool to encourage less developed countries to engage in the fight against climate change? We consider a decrease of the debt of the poor country balanced by an increase of the richer country's debt. We show that debt relief makes it possible to engage poor countries in the process of pollution abatement. Capital, environmental quality and welfare can increase in both countries. This result relies on the environmental sensitivity and the discount factor in the poor country relative to the rich one: the greater they are the more beneficial the debt relief is.
Mots clés Capital market integration, Pollution, Abatement, Overlapping generations, Public debt, Capital market integra- tion
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Résumé As it is documented, households’ investment in their own education (human capital) is negatively related to the number of children individuals will have and requires some loans to be financed. We show that this contributes to explain episodes of bubbles associated to higher growth rates. This conclusion is obtained in an overlapping generations model where agents choose to invest in their own education and decide their number of children. A bubble is a liquid asset that can be used to finance either education or the cost of rearing children. The time cost of rearing children plays a key role in the analysis. If the time cost per child is sufficiently high, households have only a small number of children. Then, the bubble has a crowding-in effect because it is used to provide loans to finance investments in education. On the contrary, if the time cost per child is low enough, households have a large number of children. Then, the bubble is mainly used to finance the total cost of rearing children and has a crowding-out effect on investment. Therefore, the new mechanism we highlight shows that a bubble enhances growth if the economy is characterized by a high rearing time cost per child.
Mots clés Human capital, Fertility, Sustained growth, Bubble
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Résumé The interplay between growth and public debt is addressed considering a Barro-type (1990) endogenous growth model where public spendings are financed through taxes on income and public debt. The government has a target level of public debt relative to GDP, and the long-run debt-to-GDP ratio is used as a policy parameter. We show that when debt is a large enough proportion of GDP, two distinct balanced-growth paths (BGPs) may coexist, one being indeterminate. We exhibit two types of important trade-offs associated with self-fulfilling expectations. First, we show that the lowest BGP is always decreasing with respect to the debt-to-GDP ratio while the highest one is increasing. Second, we show that the highest BGP, which provides the highest welfare, is always locally indeterminate while the lowest is always locally determinate. Therefore, local and global indeterminacy may arise and self-fulfilling expectations appear as a crucial ingredient to understand the impact of debt on growth, welfare, and macroeconomic fluctuations. Finally, a simple calibration exercise allows to provide an understanding of the recent experiences of many OECD countries.
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Résumé The aim of this paper is to study the interplay between long term productive investments and more short term and liquid speculative ones. A three-period lived overlapping generations model allows us to make this distinction. Agents have a portfolio decision. When young, they can invest in human capital that is a productive long term investment that provides a return during the following two periods. When young or in the middle age, they can invest in a bubble. Young individuals can also borrow on a credit market to finance the productive investment. However, the amount borrowed is limited by a credit constraint. We show that the existence of a stationary bubble raises productive investment and production when the bubleless economy is credit constrained and dynamically efficient. Indeed, young agents sell short the bubble to increase productive investments, whereas traders at middle age transfer wealth to old age. The bubble allows to relax the credit constraint. We outline that a permanent technological shock inducing either a larger return of capital in the short term or a similar increase in the return of capital in both periods raises productive capital, production and the bubble size. We use our framework to discuss the effect on the occurrence of bubbles of financial regulation and fiscal policy.
Mots clés Overlapping generations, Short sellers, Credit, Vintage capital, Efficiency, Bubble
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Résumé This article analyzes the impacts of Environmental Tax Reform (ETR) when the government is constrained not to increase the public debt-to-output ratio. We consider an overlapping generations model with pollution. Public spending for pollution abatement are financed by tax revenues and public debt. We show that keeping constant the public debt-output ratio is not an obstacle to attain a double dividend, i.e. an increase of both (i) environmental quality and (ii) aggregate consumption. First, if the capital stock is low and the pollution abatement is large enough, a successful ETR consists in a rise of the environmental tax, compensated by a decrease of the income tax. Secondly, we show that the environmental tax revenues may help reduce the public debt-output ratio. We give conditions (on the initial level of the environmental tax and the debt-output ratio) such that an increase of the environmental tax, budget-balanced by a decrease of the debt-output ratio may also achieve a double dividend. We conclude that public debt crisis should not compromise ETR, instead, environmental tax revenues could be part of the solution. JEL: Q5, H23, H63 / KEY WORDS: Environmental Tax Reform, Debt, Public Emission Abatement, Double Dividend, Overlapping Generations Model
Mots clés Environmental Tax Reform, Debt, Public Emission Abatement, Double Dividend, Overlapping Generations Model
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Résumé 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.
Mots clés Indeterminacy, Expectations-driven business cycles, Labor income taxes, Balanced-budget rule, Non-separable preferences, Economie quantitative
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Résumé 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.
Mots clés Economie quantitative
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Résumé Imposing some constraints on public debt is often justified regarding sustainability and stability issues. This is especially the case when the ratio of public debt over GDP is restricted to be constant. Using a Ramsey model, we show that such a constraint can however be a fundamental source of indeterminacy, and therefore, of expectations-driven fluctuations. Indeed, through the intertemporal budget constraint of the government, income taxation negatively depends on future debt, i.e. on the expected level of production. This mechanism ensures that expectations on the future tax rate may be self-fulfilling. We show that this is promoted by a larger ratio of debt over GDP.
Mots clés Public debt, Indeterminacy, Income taxation, Endogenous cycles, Endogenous cycles
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Résumé 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.
Mots clés Economie quantitative
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Résumé We introduce public debt in a Ramsey model with heterogenous agents and a public spending externality affecting utility which is financed by income tax and public debt. We show that public debt considered as a fixed portion of GDP can have a stabilizing or destabilizing effect depending on some fundamental elasticities. When the public spending externality is weak and the elasticity of capital labor substitution is low enough, public debt can only be destabilizing, generating damped or persistent macroeconomic fluctuations. Whereas when the public spending externality and the elasticity of capital labor substitution are strong enough, public debt can be stabilizing, driving to monotone convergence an economy experiencing damped or persistent fluctuations without debt.
Mots clés Economie quantitative
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Résumé 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 extend 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 an 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.
Mots clés Growth, Health, Pollution, Life expectancy
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Résumé We study the existence of equilibrium and rational bubbles in a Ramsey model with heterogeneous agents, borrowing constraints and endogenous labor. Applying a Kakutani's fixed-point theorem, we prove the existence of equilibrium in a time-truncated bounded economy. A common argument shows this solution to be an equilibrium for any unbounded economy with the same fundamentals. Taking the limit of a sequence of truncated economies, we eventually obtain the existence of equilibrium in the Ramsey model. In the second part of the paper, we address the issue of rational bubbles and we prove that they never occur in a productive economy à la Ramsey.
Mots clés Bubbles, Ramsey model, Heterogeneous agents, Endogenous labor, Borrowing constraint, Existence of equilibrium, Agents hétérogènes, Contraintes d&#039, emprunt, Travail endogène, Equilibre, Bulles, Modèle de Ramsey
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Résumé This article analyzes the consequences on capital accumulation and environmental quality of environmental policies financed by public debt. A public sector of pollution abatement is financed by a tax and/or public debt. We show that if the initial capital stock is high enough, the economy monotonically converges to a long-run steady state. On the contrary, when the initial capital stock is low, the economy is relegated to an environmental-poverty trap. We also explore the implications of public policies on the trap and on the long-run stable steady state. In particular, we find that government should decrease debt and increase pollution abatement to promote capital accumulation and environmental quality at the stable long-run steady state.
Mots clés Public debt, Poverty trap, Economic development, Environmental policies, Pollution abatement
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Résumé We provide a methodology to study the role of market distortions on the emergence of indeterminacy and bifurcations. It consists in introducing general specifications for the elasticities of the crucial functions defining the aggregate equilibrium dynamics of the model. This allows us to study how market distortions influence the range of values for the elasticity of input substitution under which local indeterminacy and bifurcations occur, highlighting the main channels and classes of distortions responsible for indeterminacy. Most of the specific market imperfections considered in the related literature are particular cases of our framework. Comparing them we obtain several equivalence results in terms of local dynamic properties. Applying this methodology to the Woodford [30] framework we find that distortions in the capital market, per se, do not play a major role. We further show that, for empirically plausible values of elasticity of substitution between inputs, indeterminacy requires a minimal degree of distortions. This degree seems to be high under output market distortions, while with labor market distortions the required degree is empirically plausible.
Mots clés Taxation
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Résumé Recently, many contributions have focused on the relationship between capital level, growth and population dynamics, introducing fertility choice in macro-dynamic models. In this paper, we go one step further highlighting also the link with pollution. We develop a simple overlapping generations model with paternalistic altruism according to wealth and environmental concerns. One can therefore explain a simultaneous increase in capital intensity, population growth and pollution, namely a polluting industrialization. We show in addition that a permanent productivity shock, possibly associated to technological innovations, promotes such a polluting development process, escaping a trap where the economy is relegated to low levels of capital intensity, population growth and pollution.
Mots clés Population dynamics, Pollution, Growth, Development, Altruism
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Résumé 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.
Mots clés Indeterminacy, Income effect, I, Endogenous business cycles, Consumption taxes, Balanced-budget rule
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Résumé No abstract is available for this item.
Mots clés Economie quantitative
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Résumé This article analyzes the consequences of environmental tax policy under public debt stabilization constraint. A public sector of pollution abatement is financed by a tax on pollutant emissions and/or by public debt. At the same time, households can also invest in private pollution abatement activities. We show that the economy may be characterized by an environmental-poverty trap if debt is too large or public abatement is not sufficiently efficient with respect to the private one. However, there exists a level of public abatement and debt at which a stable steady state is optimal.
Mots clés Optimality, Trap, Public debt, Public and Private Abatements, Environmental Taxation
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Résumé Un des objectifs principaux de la plupart des politiques économiques est de favoriser le développement économique. Si le travail et le capital constituent une source de croissance, ils ne peuvent l’expliquer à eux seuls. En effet, il semble que l’innovation soit un facteur prépondérant dans la dynamique économique.
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Résumé This paper considers the dynamics of pollution and sustainable growth in a context where the detrimental effects of pollution on total factor productivity can push the economy to a point of collapse. With environmental policy constrained by tax revenues, we investigate how the proximity to collapse -distance to the end -influences the balance between mitigation and adaptation spending. We show that adaptation policies are recommended when pollution intensity is high, whereas mitigation policies may be more effective when pollution intensity is low. Financing these policies by a carbon tax is more effective than an income tax. Examining the welfare of present and future generations, we reveal that the trade-off between mitigation and adaptation does not align across generations: while current generations may prefer adaptation, future generations tend to benefit more from mitigation.
Mots clés Environmental policy, Fiscal policy, Sustainability, Environmental damage
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Résumé We use an overlapping generations model with physical and human capital, and two reproductive periods to explore how fertility decisions may differ in response to economic incentives in early and late adulthood. In particular, we analyze the interplay between fertility choices—related to career opportunities—and wages, and investigate the role played by work experience and investment in both types of capital. We show that young adults postpone parenthood above a certain wage threshold and that late fertility increases with work experience. The long run trend is either to converge to a low productivity equilibrium, involving high early fertility, investment in physical capital and relatively low income, or to a high productivity equilibrium, where households postpone parenthood to invest in their human capital and work experience, with higher late fertility and higher levels of income. A convergence to the latter state would explain the postponement of parenthood and the mitigation or slight reversal of fertility decrease in some European countries in recent decades.
Mots clés Fertility, Overlapping generations, Work experience, Postponement
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Résumé This paper examines an endogenous growth model that allows us to consider the dynamics and sustainability of debt, pollution, and growth. Debt evolves according to the financing adaptation and mitigation efforts and to the damages caused by pollution. Three types of features are important for our analysis: The technology through the negative effect of pollution on TFP; The fiscal policy; The initial level of pollution and debt with respect to capital. Indeed, if the initial level of pollution is too high, the economy is relegated to an endogenous tipping zone where pollution perpetually increases relatively to capital. If the effect of pollution on TFP is too strong, the economy cannot converge to a stable and sustainable long-run balanced growth path. If the income tax rates are high enough, we can converge to a stable balanced growth path with low pollution and high debt relative to capital. This sustainable equilibrium can even be characterized by higher growth and welfare. This last result underlines the role that tax policy can play in reconciling debt and environmental sustainability.
Mots clés Environmental damage, Sustainability, Public debt, Fiscal policy, Pollution
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Résumé In this paper, we provide a simple framework to show the existence of stationary bubbles on dividend-yielding financial assets. These bubbles are compatible with a positive stationary fundamental value, rather than requiring its collapse in the long run. This result is obtained in an exchange overlapping generations economy with vintage financial assets that depreciate over time. New assets are introduced in each period, ensuring a constant aggregate supply of financial assets. Depreciation introduces a gap between the return of bubbles and the rate at which the dividends are discounted. Because the return of bubble can be lower or equal to the growth rate, we can have stationary equilibria with both a positive bubble and a positive fundamental value. Finally, our framework also allows us to discuss the role of the substitutability between financial assets on the level of bubbles and fundamental values.
Mots clés Rational bubbles, Financial assets, Fundamental value
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Résumé This paper contributes to the literature interested in the new factors that may determine fertility behaviors. Many studies underlay that environmental concerns have a direct effect on households' fertility decisions. We present a dynamic model that explicitly examines this interplay, considering whether the number of children and environmental concerns may be complementary or substitutable. Interesting results occur when environmental concerns and the number of children are substitutable. At a stable steady state, a stronger effect of environmental concerns on household's preferences reduces the number of children, as also stressed by a recent literature. The dynamics can be described by an inversely Ushaped relationship between fertility and environmental indicators reflecting the impact of economic production, such as the carbon intensity, as we illustrate using data on US States. The dynamics also explain that regions with lower carbon intensity are those with lower fertility.
Mots clés Fertility, Environmental concerns, Quantity-quality trade-off, Transitional dynamics
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Résumé Several recent papers introduce different mechanisms to explain why asset bubbles are observed in periods of larger growth. These papers share common assumptions, heterogeneity among traders and credit market imperfection , but differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. In this paper, we introduce heterogeneous traders by considering an overlapping generations model with households living three periods. Young households cannot invest in capital, while adults have access to investment and face a borrowing constraint. Introducing bubbles in a quite general way, encompassing the different roles they have in the existing literature, we show that the bubble may enhance growth when the borrowing constraint is binding. More significantly, our results do not depend on the-liquidity or collateral-role attributed to the bubble. We finally extend our analysis to a stochas-tic bubble, which may burst with a positive probability. Because credit and bubble are no more perfectly substitutable assets, the liquidity and collateral roles of the bubble are not equivalent. Growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to agents who invest in capital.
Mots clés Liquidity, Bubble, Collateral, Crowding-in effect, Growth
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Résumé We use an overlapping generations setup with two reproductive periods to explore how fertility decisions may differ in response to economic incentives in early and late adulthood. In particular, we analyze the interplay between fertility choices-related to career opportunities-and wages, and investigate the role played by late fertility. We show that young adults only postpone parenthood above a certain wage threshold and that late fertility increases with investment in human capital. The long run trend is either to a low productivity equilibrium, involving high early fertility, no investment in human capital and relatively low income, or to a high productivity equilibrium, where households postpone parenthood to invest in their human capital, with higher late fertility and higher levels of income. A convergence to the latter state would explain the postponement of parenthood and the fertility rebound observed in Europe in recent decades.
Mots clés Fertility, Postponement, Reproductive health, Overlapping generations
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Résumé In this paper, we investigate the impact of redistribution and polluting commodity taxation on inequality and pollution in a dynamic setting. We build a two-sector Ramsey model with a green and a polluting good. Households are heterogeneous, which allows for income inequality, and have a level of subsistence consumption for the polluting commodity, modeled by non-homothetic preferences. Increasing the tax rate has a mixed effect depend on the level of subsistence consumption. A low level allows to tackle both the pollution and inequality issues. Under a high level of it, pollution increases: if inequality can be reduced through redistribution, taxation does not allow to solve for environmental degradation. Looking at the stability properties of the economy, we find that the level of subsistence consumption and the externality matter. A high subsistence level of polluting consumption leads to instability or indeterminacy of the steady-state, while the environmental externality plays a stabilizing role in the economy. This leaves room for taxation and redistribution: increasing the tax rate and redistributing more towards workers play a key role in the occurrence of indeterminacy and instability.
Mots clés Externalities, Heterogeneous agents, Inequality, Pollution, Redistribution, Taxation
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Résumé We provide a unified framework with demand for housing over the life cycle and financial frictions to analyze the existence and macroeconomic effects of rational housing bubbles. We distinguish a housing price bubble, defined as the difference between the housing market price and its fundamental value, from a housing demand bubble, which corresponds to a situation where a pure speculative housing demand exists. In an overlapping generation exchange economy, we show that no housing price bubble occurs. However, a housing demand bubble may occur, generating a boom in housing prices and a drop in the interest rate, when households face a binding borrowing constraint. Multiplicity of steady states and endogenous fluctuations can occur when credit market imperfections are moderate. These fluctuations involve transitions between equilibria with and without a housing demand bubble that generate large fluctuations in housing prices consistent with observed patterns. We finally extend the basic framework to a production economy and we show that a housing demand bubble increases the housing price, housing price to income ratio and economic growth.
Mots clés Bubble, Housing, Self-fulfilling fluctuations
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Résumé We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote the convergence to a stable steady state with no epidemics. When public policies are not able to permanently eradicate the epidemic, public debt and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy which eliminates income and welfare inequalities between healthy and infected individuals.
Mots clés Public debt, Epidemics, Pollution, Overlapping generations
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Résumé We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote the convergence to a stable steady state with no epidemics. When public policies are not able to permanently eradicate the epidemic, public debt and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy which eliminates income and welfare inequalities between healthy and infected individuals.
Mots clés Public debt, Epidemics, Pollution, Overlapping generations
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Résumé We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote the convergence to a stable steady state with no epidemics. When public policies are not able to permanently eradicate the epidemic, public debt and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy which eliminates income and welfare inequalities between healthy and infected individuals.
Mots clés Overlapping generations, Pollution, Epidemics, Public debt
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Résumé Entrepreneurship, growth and total factor productivity are larger when there is a financial bubble. We explain these facts using a growth model with financial bubbles in which individuals face heterogeneous wages and returns on productive investment. The heterogeneity in the return of in- vestment separates individuals between savers and entrepreneurs. Savers buy financial assets, which are deposits or a financial bubble. Entrepreneurs incur in a start-up cost and borrow to invest in productive capital. The bubble provides liquidities to credit-constrained entrepreneurs. These liquidities increase investment and entrepreneurship when the start- up cost is large enough, which explains that growth and entrepreneurship can be larger with bubbles. Finally, productivity can be larger when the bubble further increases the investment of more productive entrepreneurs. This can occur when the return of investment is correlated with wages.
Mots clés Productivity, Growth, Entrepreneurship, Bubble
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Résumé This paper analyzes the link between asset bubbles, endogenous labor and capital. The question is whether endogenous labor, per se, can explain a crowding-in effect of the bubble, i.e. higher levels of capital and labor. With respect to the existing literature, our contribution is twofold. First, we explicitly and theoretically derive the conditions to have a crowding-in effect of the bubble. Second, the utility function we consider allows us to show that this result does not require an arbitrarily high elasticity of intertemporal substitution in consumption. Our result still holds for a unit value of this elascticity (Cobb-Douglas utility).
Mots clés Overlapping generations, Endogenous labor, Crowding-in effect, Asset bubbles
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Résumé Several recent papers introduce different mechanisms to explain why asset bubbles are observed in periods of larger growth. These papers share common assumptions, heterogeneity among traders and credit market imperfection , but differ in the role of the bubble, used to provide liquidities or as collateral in a borrowing constraint. In this paper, we introduce heterogeneous traders by considering an overlapping generations model with households living three periods. Young households cannot invest in capital, while adults have access to investment and face a borrowing constraint. Introducing bubbles in a quite general way, encompassing the different roles they have in the existing literature, we show that the bubble may enhance growth when the borrowing constraint is binding. More significantly, our results do not depend on the-liquidity or collateral-role attributed to the bubble. We finally extend our analysis to a stochas-tic bubble, which may burst with a positive probability. Because credit and bubble are no more perfectly substitutable assets, the liquidity and collateral roles of the bubble are not equivalent. Growth is larger when bubbles play the liquidity role, because the burst of a bubble used for liquidity is less damaging to agents who invest in capital.
Mots clés Growth, Crowding-in effect, Collateral, Bubble, Liquidity
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Résumé The relationship between public debt, growth and volatility is investigated in a Barro-type (1990) endogenous growth model, with three main features: we consider a small open economy, international borrowing is constrained and households have taste for domestic public debt. Therefore, capital, public debt and the international asset are not perfect substitutes and the economy is characterized by an investment multiplier. Whatever the level of the debt-output ratio, the existing BGP features expectation-driven fluctuations. If the debt-output ratio is low enough, there is also a second BGP with a lower growth rate. Hence, lower debt does not stabilize the economy with credit market imperfections. However, a high enough taste for domestic public debt may rule out the BGP with lower growth. This means that if the share of public debt hold by domestic households is high enough, global indeterminacy does not occur.
Mots clés Small open economy, Public debt, Credit constraint, Indeterminacy
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Résumé In this paper, we are interested in the interplay between real estate bubble, aggregate capital accumulation and taxation in an overlapping generations economy with altruistic households. We consider a three-period overlapping generations model with three key elements: altruism, portfolio choice, and financial market imperfections. Households realise different investment decisions in terms of asset at different periods of life, face a binding borrowing constraint and leave bequests to their children. We show that altruism plays a key role on the existence of a productive real estate bubble, i.e. a bubble in real estate raising physical capital stock and aggregate output. The key mechanism relies on the fact that a real estate bubble raises income of retired households. Because of higher bequests, there children are able to invest more in productive capital. Introducing fiscal policy, we show that raising real estate taxation dampens capital accumulation.
Mots clés Bubble, Altruism, Real estate, Credit, Overlapping generations
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Résumé Based on epidemiological evidence, we consider an economy where agents differ through their ability to procreate. Households with impaired fertility may incur health expenditures to increase their chances of parenthood. This health heterogeneity generates welfare inequalities that deserve to be ruled out. We explore three different criteria of social evaluation in the long-run: the utilitarian approach, which considers the well- being of all households, the ex-ante egalitarian criterion, which considers the expected well-being of the worst-off social group, and the ex-post egalitarian one, which only considers the realized well-being of the worst- off. In an overlapping generations model, we propose a set of economic instruments to decentralize each solution. To correct for the externality and inequalities, both a preventive (a taxation of capital) and a redistributive policy are required.
Mots clés Egalitarianism, Fairness, Reproductive health, OLG model, Optimal policy
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Résumé This paper analyses the effect of a pay-as-you-go pension system on the evolution of capital and pollution, and on the efficiency of an environmental versus health policy. In an overlapping generations model (OLG), we introduce endogenous longevity that depends on pollution and health expenditures. Global dynamics may display multiple balanced growth paths (BGP). We show that by discouraging savings, a policy that promotes the pension system enlarges the environmental poverty trap. More surprisingly, the environmental policy has contrasted effects according to the significance of the pension system. If it has a low size, a raise of the environmental policy enlarges the environmental poverty trap and leads to a rise in capital over pollution at the highest stationary equilibrium. In contrast, in economies where intergenerational solidarity is well developed, capital over pollution decreases at the highest BGP. In such a case, the environmental policy does not necessarily lead to a better longevity and growth.
Mots clés Pension system, Health, Pollution, Longevity, Environment, Growth
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Résumé The aim of this paper is to study the role of the distribution of income by age group on the existence of speculative bubbles. A crucial question is whether this distribution may promote a bubble associated to a larger level of capital, i.e. a productive bubble. We address these issues in a three period overlapping generations (OC) model, where productive investment done in the first period of life is a long term investment whose return occurs in the following two periods. A bubble is a short term speculative investment that facilitates intertemporal consumption smoothing. We show that the distribution of income by age group determines both the existence and the effect of bubbles on aggregate production. We also show that fiscal policy, by changing the distribution of income, may facilitate or prevent the existence of bubbles and may also modify the effect that bubbles have on aggregate production.
Mots clés Bubble, Efficiency, Income distribution, Overlapping generations
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Résumé As it is documented, investment of households in human capital is negatively related to the number of children individuals will have and requires some loans to be financed. We show that this negative relationship contributes to explain episodes of bubbles that are associated to higher growth rates. This conclusion is obtained in an overlapping generations model where agents choose to invest in a productive asset, that can be interpreted as human capital, and decide their number of children. A bubble allows to smooth consumption and expenses over the life-cycle, and can therefore be used to finance either productive investment or the cost of rearing children. The time cost of rearing children plays a key role in the analysis. If the time cost per child is sufficiently large, households have only a small number of children. The bubble then has a crowding-in effect because it is used to finance productive investment. On the contrary, if the time cost per child is low enough, households have a large number of children. Then, the bubble is mainly used to finance the total cost of rearing children and has a crowding-out effect on investment. Therefore, the new mechanism we highlight shows that a bubble enhances growth only if the economy is characterized by a high rearing time cost per child.
Mots clés Fertility, Bubble, Sustained growth
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Résumé As illustrated by some French departments, how can we explain the existence of equilibria with different fertility and growth rates in economies with the same fundamentals, preferences, technologies and initial conditions? To answer this question we develop an endogenous growth model with altruism and love for children. We show that independently from the type of altruism, a multiplicity of equilibria might emerge if the degree of love for children is high enough. We refer to this condition as the love for children hypothesis. Then, the fertility rate is determined by expectations on the future growth rate and the dynamics are not path-dependent. Our model is able to reproduce different fertility behaviours in a context of completed demographic transition independently from fundamentals, preferences, technologies and initial conditions.
Mots clés Love for Children, Expectations, Fertility, Endogenous growth, Balanced growth path
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Résumé We develop an overlapping generations model of growth, in which agents differ through their ability to procreate. Based on epidemiological evidence, we assume that pollution is a cause of this health heterogeneity, affecting sperm quality. Nevertheless, agents with impaired fertility may incur health treatments in order to increase their chances of parenthood. In this set-up, we analyse the dynamic behaviour of the economy and characterise the situation reached in the long run. Then, we determine the optimal solution that prevails when a social planner maximises a Millian utilitarian criterion and propose a set of available economic instruments to decentralise the optimal solution. We underscore that to correct for both the externalities of pollution and the induced-health inefficiency, it is necessary to tax physical capital while it requires to overall subsidy mostly harmed agents within the economy. Hence, we argue that fighting against the sources of an altered reproductive health is more relevant than directly inciting agents to incur health treatments.
Mots clés Pollution, Growth, Fertility, Health
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Résumé The interplay between growth and public debt is addressed considering a Barro-type [1] endogenous growth model where public spending is financed through taxes on income and public debt. Debt is assumed to be a fixed proportion of GDP which is used as a policy parameter by the government. We first show that when debt is a large enough proportion of GDP, two distinct BGPs may co-exist, one being indeterminate. Therefore, local and global indeterminacy may arise and self-fulfilling expectations appear as a crucial ingredient to understand the impact of debt on growth and on macroeconomic fluctuations. We then exhibit two types of important trade-off associated with self-fulfilling expectations. First, we show that the lowest BGP is always decreasing with respect to the ratio of debt/GDP while the highest one is increasing. As a result, depending on the BGP selected by agents’ expectations, the relationship between debt and growth is not always negative. Second, we show that the highest BGP, which provides the highest welfare, is always locally indeterminate while the lowest is always locally determinate. Therefore, depending on the expectations of agents, when debt is increasing, large fluctuations associated to self-fulfilling believes may occur and be associated at the same time with welfare losses if there is a coordination on the low steady-state. Finally, a simple calibration exercise allows to provide an understanding of the recent experiences of many OECD countries.
Mots clés Endogenous growth, Public spending, Public debt, Sunspot fluctuations
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Résumé The aim of this paper is to study the interplay between long term productive investments and more short term and liquid speculative ones. A three-period lived overlapping generations model allows us to make this distinction. Agents have two investment decisions. When young, they can invest in productive capital that provides a return during the following two periods. When young or in the middle age, they can also invest in a bubble. Assuming, in accordance with the empirical evidence, that the bubbleless economy is dynamically efficient, the existence of a stationary bubble raises productive investment and production. Indeed, young agents sell short the bubble to increase productive investments, whereas traders at middle age transfer wealth to the old age. We outline that a technological change inducing either a larger return of capital in the short term or a similar increase in the return of capital in both periods raises productive capital, production and the bubble size. This framework also allows us to discuss several economic applications: the effects of both regulation on limited borrowing and fiscal policy on the occurrence of bubbles, the introduction of a probability of market crash and the effect of bubbles on income inequality.
Mots clés Bubble, Vintage capital, Efficiency, Short sellers, Overlapping generations
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Résumé We investigate the role of non-separable preferences on 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 non-separable utility functions, we find that expectations-driven fluctuations easily occur when consumption and labor are Edgeworth substitutes or weak Edgeworth complements. Under these properties, an intermediate range of tax rates and a sufficiently low elasticity of intertemporal substitution in consumption lead to instability.
Mots clés Indeterminacy, Expectations-driven business cycles, Labor income taxes, Balanced-budget rule, Non-separable preferences
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Résumé This paper presents an overlapping generations model where pollution, private and public healths are all determinants of longevity. Public expenditure, financed through labour taxation, provide both public health and abatement. We study the complementarity between the three components of longevity on welfare and economic stability. At the steady state, we show that an appropriate fiscal policy may enhance welfare. However, when pollution is heavily harmful for longevity, the economy might experience aggregate instability or endogenous cycles. Nonetheless, a fiscal policy, which raises the share of public spending devoted to health, may display stabilizing virtues and rule out cycles. This allows us to recommend the design of the public policy that may comply with the dynamic and welfare objectives.
Mots clés Longevity, Pollution, Welfare, Complex dynamics
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Résumé This article analyzes the consequences of environmental tax policies when the government imposes a constraint on stabilizing public debt. A public sector of pollution abatement is financed by taxation and by issuing public debt. Considering a simple overlapping-generations model, the tax reform stimulates steady-state investment. Then, the environmental quality and the aggregate consumption increase if and only if (i) pollution abatement is large enough and (ii) there is under-accumulation of the per capita capital stock. This arises if environmental taxation allows a decrease of either income taxation or debt-output ratio.
Mots clés Environmental Tax Reform, Debt, Public Emission Abatement, Double Dividend
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Résumé Imposing some constraints on public debt is often justified regarding sustainability and stability issues. This is especially the case when the ratio of public debt over GDP is restricted to be constant. Using a Ramsey model, we show that such a constraint can however be a fundamental source of indeterminacy, and therefore, of expectation-driven fluctuations. Indeed, through the intertemporal budget constraint of the government, income taxation negatively depends on future debt, i.e. on the expected level of production. This mechanism ensures that expectations on the future tax rate may be self-fulfilling. We show that this is promoted by a larger ratio of debt over GDP.
Mots clés Indeterminacy, Endogenous cycles, Public debt, Income taxation
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Résumé We introduce public debt in a Ramsey model with heterogenous agents and a public spending externality affecting utility which is financed by income tax and public debt. We show that public debt considered as a fixed portion of GDP can have a stabilizing or destabilizing effect depending on some fundamental elasticities. When the public spending externality is weak and the elasticity of capital labor substitution is low enough, public debt can only be destabilizing, generating damped or persistent macroeconomic fluctuations. Whereas when the public spending externality and the elasticity of capital labor substitution are strong enough, public debt can be stabilizing, driving to monotone convergence an economy experiencing damped or persistent fluctuations without debt.
Mots clés Endogenous cycles, Heterogeneous agents, Public spending, Public debt, Borrowing constraint
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Résumé We investigate the role of preferences in the existence of expectation-driven instability under a balanced budget rule where government spendings are financed by a tax on labor income. Considering a one-sector neoclassical growth model with a large class of preferences, we find that expectation-driven fluctuations are more likely when consumption and labor are Edgeworth substitutes. Under this property, an intermediate range of tax rates and a sufficiently low elasticity of intertemporal substitution in consumption lead to instability. Numerical simulations of the model support the conclusion that labor income taxation is a plausible source of instability in most OECD countries.
Mots clés Indeterminacy, Expectation-driven business cycles, Labor income taxes, Balanced-budget rule, Infinite-horizon model
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Résumé We study the existence of equilibrium and rational bubbles in a Ramsey model with heterogeneous agents, borrowing constraints and endogenous labor. Applying a nonstandard fixed-point theorem by Gale and Mas-Colell's (1975), we prove the existence of equilibrium in a time-truncated bounded economy. A common argument shows this solution to be an equilibrium for any unbounded economy with the same fundamentals. Taking the limit of a sequence of truncated economies, we eventually obtain the existence of equilibrium in the Ramsey model. In the second part of the paper, we address the issue of rational bubbles and we prove that they never occur in a productive economy à la Ramsey.
Mots clés Heterogeneous agents, Borrowing constraint, Endogenous labor, Existence of equilibrium, Bubbles, Ramsey model
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Résumé We explore the existence of endogenous fluctuations with a rational bubble and the stabilizing role of fiscal and monetary policies. Consumers' credit constraints, the role of collateral and a portfolio choice are the key ingredients of our analysis. We consider an overlapping generations model where households realize a portfolio choice between three assets with different returns (capital, money and bonds). Expectation-driven fluctuations and the multiplicity of steady states occur under a positive bubble on bonds, gross substitutability and large input substitution because of credit market imperfections. Focusing on the stabilizing role of policies, we show that a progressive taxation on capital income may rule out expectation-driven fluctuations and the multiplicity of steady states. In contrast, a monetary policy under a Taylor rule has a mitigated stabilizing role, depending on the reactiveness of the policy rule and the concavity of the utility function. When the monetary authority decides instead to fix the nominal interest rate regardless the inflation, decreasing the level of the nominal interest rate can rule out expectation-driven fluctuations, restore the uniqueness of steady states, but can damage the welfare at the steady state.
Mots clés Indeterminacy, Cash-in-advance constraint, Rational bubble, Collateral, Progressive taxation, Monetary policy
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Résumé We are interested in the occurrence of expectation-driven fluctuations of a rational bubble and the (de-)stabilizing role of monetary policy. Our explanation of fluctuations is based on credit market imperfections. For this purpose, we consider an overlapping generations exchange economy where households realize a portfolio choice between money and bubble. Money is held because of a partial cash-in-advance constraint affected by the bubble. Bubble acts as a store of value, but also as a collateral. Indeed, a higher value of the bubble implies a higher amount of collateral, which, in turn, reduces the need of cash, and thus increases consumption purchased on credit. Under these credit market features, expectation-driven fluctuations and the multiplicity of steady-states occur, in particular for arbitrarily small market distortions. Investing the stabilizing role of monetary policy, we show that when the monetary policy rule depends on expected inflation only, a more active rule stabilizes only if collateral has a large effect on consumption financed on credit. Finally, we enrich this rule by including asset prices. A policy which depends on asset prices can stabilize whatever the effect of collateral and can also rule out the multiplicity of steady states. More generally, this paper emphasizes the key role of consumers' credit market imperfections to explain bubble fluctuations and exhibits the stabilizing power of monetary rules including asset prices.
Mots clés Rational bubble, Cash-in-advance constraint, Collaterals, Endogenous fluctuations, Monetary policy
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Résumé 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.
Mots clés Heterogeneous agents, Indeterminacy, Endogenous cycles, Public spending, Endogenous labor supply, Borrowing constraint
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Résumé 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.
Mots clés Life expectancy, Pollution, Health, Growth
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Résumé We examine the impact of balanced-budget consumption taxes on the existence of expectations-driven business cycles in two-sector economies with infinitely-lived households. We prove that, whatever the relative capital intensity difference across sectors, aggregate instability can occur if the consumption tax rate is not too low. Moreover, we show through a numerical exercise based on empirically plausible tax rates that endogenous business-cycle fluctuations may be a source of instability for all OECD countries, including the US.
Mots clés Aggregate instability, Indeterminacy, Expectations-driven fluctuations, Consumption taxes, Balanced-budget rule, Infinite-horizon two-sector model
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