Reproductive health, fairness, and optimal policiesJournal articleJohanna Etner, Natacha Raffin et Thomas Seegmuller, Journal of Public Economic Theory, Volume 22, Issue 5, pp. 1213-1244, 2020

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.

Asset bubble and endogenous labor supply: A clarificationJournal articleKathia Bahloul Zekkari et Thomas Seegmuller, Economics Letters, Volume 196, pp. 109537, 2020

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.

On the interplay between speculative bubbles and productive investmentJournal articleXavier Raurich et Thomas Seegmuller, European Economic Review, Volume 111, pp. 400-420, 2019

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.

Growth and Public Debt: What Are the Relevant Trade‐Offs?Journal articleArnaud Cheron, Kazuo Nishimura, Carine Nourry, Thomas Seegmuller et Alain Venditti, Journal of Money, Credit and Banking, Volume 51, Issue 2-3, pp. 655-682, 2019

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.

Growth and bubbles: Investing in human capital versus having childrenJournal articleXavier Raurich et Thomas Seegmuller, Journal of Mathematical Economics, Volume 82, pp. 150-159, 2019

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.

The love for children hypothesis and the multiplicity of fertility ratesJournal articlePaolo Melindi-Ghidi et Thomas Seegmuller, Journal of Mathematical Economics, Volume 83, Issue C, pp. 89-100, 2019

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.

Bubble on real estate: the role of altruism and fiscal policyJournal articleLise Clain-Chamosset-Yvrard et Thomas Seegmuller, Studies in Nonlinear Dynamics & Econometrics, Volume 23, Issue 4, pp. 20190020, 2019

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.

Environmental Tax Reform under Debt ConstraintJournal articleMouez Fodha, Thomas Seegmuller et Hiroaki Yamagami, Annals of Economics and Statistics, Issue 129, pp. 33-52, 2018

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

The Stabilizing Virtues of Monetary Policy on Endogenous Bubble FluctuationsBook chapterLise Clain-Chamosset-Yvrard et Thomas Seegmuller, In: Studies in Economic Theory, K. Nishimura, A. Venditti et N. C. Yannelis (Eds.), 2017, Volume 31, pp. 231-257, Springer-Verlag, 2017

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.

Nonseparable preferences do not rule out aggregate instability under balanced-budget rules: a noteJournal articleNicolas Abad, Thomas Seegmuller et Alain Venditti, Macroeconomic Dynamics, Volume 21, Issue 1, pp. 259-277, 2017

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.

Pollution and growth: The role of pension in the efficiency of health and environmental policiesJournal articleArmel Ngami et Thomas Seegmuller, International Journal of Economic Theory, Forthcoming

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.