Publications

Abstract [Fr] Les normes comptables IFRS ont intégré dans le bilan des banques l'essentiel des instruments financiers dérivés que nous considérons ici sous le terme de « hors-bilan », au prix d'une certaine invisibilité de leur « effet de levier ». Nous décrivons l'activité des banques de financement et d'investissement et montrons que ces instruments dérivés correspondent à une fonction d'intermédiation du risque dans l'économie où les banques ne « portent » pas ce risque au bilan, contrairement au métier bancaire traditionnel de « transformation ». Nous décrivons la banque comme une source d'« accroissement des possibles de la taille du marché » que nous définissons au préalable d'une manière générale. Une telle source, comme toute innovation, est synonyme de risque. Le « hors-bilan » bancaire apparaît dans ce cadre comme un effet de levier sans limite naturelle. Nous étudions alors ce que pourraient être des fiscalités adaptées à trois objectifs différents : corriger et capter les rentes, limiter le risque systémique, maîtriser l'« accroissement des possibles ». Une assiette considérant une mesure des engagements en valeur absolue associés aux positions sur les produits dérivés, dans le bilan des banques, paraît pertinente pour limiter l'accroissement des possibles et, partant de là, le risque. [Eng] The accounting standard IRFS have integrated the bulk of derivatives (the off-balance sheet in this paper) in the balance sheet of the banks at the cost of masking their leverage effect. We describe the bank activity and we show that these derivatives correspond to a financial intermediation function of the banking system, which supplements the standard lending role of banks. We show that the banking activity naturally increases the possibility set of the capital market that we define in general terms. As all innovations, this increase bears additional risk. The off-balance sheet appears in this framework as bringing a leverage effect without natural limit. We study what could be the role of different types of taxes: first, correcting and capturing the rents, second, limiting the systemic risk, third, mastering the “growth of the feasible set”. A tax base consisting in financial liabilities (in absolute value) associated to positions on financial derivatives may be viewed as well-focused to limit the growth of the possibility set and therefore of the risk.
Publication HAL Google Scholar
Abstract We study count processes in insurance, in which the underlying risk factor is time varying and unobservable. The factor follows an autoregressive gamma process, and the resulting model generalizes the static Poisson-Gamma model and allows for closed form expression for the posterior Bayes (linear or nonlinear) premium. Moreover, the estimation and forecasting can be conducted within the same framework in a rather efficient way. An example of automobile insurance pricing illustrates the ability of the model to capture the duration dependent, nonlinear impact of past claims on future ones and the improvement of the Bayes pricing method compared to the linear credibility approach. Introduction We propose a time series model for count variables encountered in insurance, when the underlying risk factor is time varying and unobservable. We introduce the au-toregressive gamma process for the latent factor dynamics and show how it provides an integrated framework for the efficient estimation, pricing, and forecasting of the risk. One typical application of the model is automobile insurance, for which the insurer holds the history of individual yearly claim counts over several periods. This information should then be taken into account in order to update the future premium regularly, on an individual basis.
Publication HAL Google Scholar
Abstract This article presents a dynamic pricing model of a retailer selling an inventory, accounting for consumer behavior. The authors propose an optimal control model, maximizing the intertemporal profit with consumers sensitive to the selling price and to a reference price. The optimal dynamic pricing policy is solved with Pontryagin's maximum principle with a structural (general) demand function. The authors obtain an original pricing rule, which explicitly accounts for the impact of price and inventory on future profits. The dynamics of price do not have to imitate the dynamics of the reference price. Instead, the dynamics of price are tied to opposing effects linked to this reference price. The authors also discuss managerial implications with regards to behavioral pricing policies.
Publication HAL Google Scholar
Abstract This is a reprint of articles from the Special Issue published online in the open access journal Econometrics (ISSN 2225-1146) from 2017 to 2018 (available at: https://www.mdpi.com/journal/ econometrics/special issues/inequality)
HAL Google Scholar
Abstract On the face of it, econometrics and machine learning share a common goal: to build a predictive model, for a variable of interest, using explanatory variables (or features). However, the two fields have developed in parallel, thus creating two different cultures. Econometrics set out to build probabilistic models designed to describe economic phenomena, while machine learning uses algorithms capable of learning from their mistakes, generally for classification purposes (sounds, images, etc.). Yet in recent years, learning models have been found to be more effective than traditional econometric methods (the price to pay being lower explanatory power) and are, above all, capable of handling much larger datasets. Given this, econometricians need to understand what the two cultures are, what differentiates them and, above all, what they have in common in order to draw on tools developed by the statistical learning community with a view to incorporating them into econometric models.
Keywords Least squares, Modelling, Econometrics, Big data, Learning
Publication HAL Google Scholar
Abstract The article investigates the effects of Employment Protection Legislation (EPL) on capital and skills according to the intensity of international competition. Grounded on a panel data sample for 14 OECD countries and 18 industries from 1988 to 2007, and a difference-in-difference approach, we find that strengthening EPL: (i) leads to a capital-labour substitution in favour of non ICT non R&D capital to the detriment of employment, this effect being mitigated in industries highly exposed to international competition; (ii) lowers ICT capital and, even more severely, R&D capital relatively to other capital components; and (iii) works at the relative disadvantage of low-skilled workers. Strengthening EPL can therefore be an impediment to organizational and so technological change and risk taking on globalized markets. An illustrative simulation suggests that structural reforms weakening EPL could have a significant favorable impact on firms’ ICT and R&D investment and on hiring low-skilled workers.
Publication HAL Google Scholar
Abstract We evaluate the introduction of various forms of antihypertensive treatments in France with a distribution-sensitive cost-benefit analysis. Compared to traditional cost-benefit analysis, we implement distributional weighting based on equivalent incomes, a new concept of individual well-being that does respect individual preferences but is not subjectively welfarist. Individual preferences are estimated on the basis of a contingent valuation question, introduced into a representative survey of the French population. Compared to traditional cost-effectiveness analysis in health technology assessment, we show that it is feasible to go beyond a narrow evaluation of health outcomes while still fully exploiting the sophistication of medical information. Sensitivity analysis illustrates the relevancy of this richer welfare framework, the importance of the distinction between an ex ante and an ex post approach, and the need to consider distributional effects in a broader institutional setting.
Keywords Equivalent income, Distributional weights, Cost-benefit analysis, Antihypertensive treatment
Publication HAL Google Scholar
Abstract Constraints that prevent women from working longer hours are argued to be important drivers of the gender wage gap in the United States. We provide evidence that in couples where the wife's working hours exceed the husband's, the wife reports lower life satisfaction. By contrast, there is no effect on the husband's satisfaction. The results still hold when controlling for relative income. We argue that these patterns are best explained by perceived fairness of the division of household labor, which induces an aversion to a situation where the wife works more at home and on the labor market.
Publication HAL Google Scholar
Abstract This paper shows that a large dimensional vector autoregressive model (VAR) of finite order can generate fractional integration in the marginalized univariate series. We derive high-level assumptions under which the final equation representation of a VAR(1) leads to univariate fractional white noises and verify the validity of these assumptions for two specific models.
Keywords Marginalization, Long memory, Final equation representation, Vector autoregressive model
Publication HAL Google Scholar
Abstract This paper deals with the effects of economic integration in a 2x 2x 2 model of overlapping generations. We distinguish between a non-tradable and a tradable sector which use human and physical capital. We show that the preference for non-tradable consumption in total consumption expenditure and sectoral productivities are crucial factors to determine which country does benefit from integration in terms of economic growth. Short-run and long-run effects of integration may differ, especially when countries are heterogeneous and when there exist high cross border externalities in education. Moreover, an impatient country may lose to integration when it has a comparative advantage in the tradable sector and/or when the preference for non-tradable goods is high.
Publication HAL Google Scholar
Abstract This articles focuses on the recent research efforts to incorporate income, wage and wealth inequality in macroeconomic models. I start by reviewing recent models on the impact of inequality on, on the one hand, long-run growth and, on the other, and macroeconomic fluctuations. The articles then reviews the literature concerned with the macroeconomic determinants of wage and wealth inequality. It concludes by discussing a number of possible avenues of research that seem to me particularly important, such as the impact of macroeconomic policy on distribution or the effect that firm size can have on both growth and wage inequality.
Publication HAL Google Scholar
Abstract Why, in some urban communities, do rich and poor households cohabit while, in others, we observe sorting by income? Does income inequality impact residential choices and community segregation? To answer these questions, I develop a two‐community general equilibrium framework of school quality, residential choice, and tax decision with probabilistic voting. The model predicts that an equilibrium with income mixing in which households segregate across public schools and low‐ and high‐income households choose to live in the same community might emerge in highly unequal societies. In this particular equilibrium, income‐mixing communities perform lower public school quality than communities populated by middle‐income households. The effect of inequality on the quality of public schooling in the income‐mixing community is ambiguous and depends on the relative endowments of private goods, such as housing, in the two communities.
Keywords No keyword available
Publication HAL Google Scholar
Keywords Tax competition, Top income earners, Migration
Publication HAL Google Scholar
Abstract In this study, we model realized volatility constructed from intra-day highfrequency data. We explore the possibility of confusing long memory and structural breaks in the realized volatility of the following spot exchange rates: EUR/USD, EUR/JPY, EUR/CHF, EUR/GBP, and EUR/AUD. The results show evidence for the presence of long memory in the exchange rates' realized volatility. FromtheBai-Perrontest,wefoundstructuralbreakpointsthatmatch significant events in financial markets. Furthermore, the findings provide strong evidence in favour of the presence of long memory.
HAL Google Scholar
Keywords Customer discrimination Matching frictions Neighborhood externalities Housing market
Publication HAL Google Scholar
Abstract This paper investigates the predictive power of several risk attitude measures on a series of medical practices. We elicit risk preferences on a sample of 1500 French general practitioners (GPs) using two different classes of tools: scales, which measure GPs' own perception of their willingness to take risks between 0 and 10; and lotteries, which require GPs to choose between a safe and a risky option in a series of hypothetical situations. In addition to a daily life risk scale that measures a general risk attitude, risk taking is measured in different domains for each tool: financial matters, GPs' own health, and patients' health. We take advantage of the rare opportunity to combine these multiple risk attitude measures with a series of self-reported or administratively recorded medical practices. We successively test the predictive power of our seven risk attitude measures on eleven medical practices affecting the GPs' own health or their patients' health. We find that domain-specific measures are far better predictors than the general risk attitude measure. Neither of the two classes of tools (scales or lotteries) seems to perform indisputably better than the other, except when we concentrate on the only non-declarative practice (prescription of biological tests), for which the classic money-lottery test works well. From a public health perspective, appropriate measures of willingness to take risks may be used to make a quick, but efficient, profiling of GPs and target them with personalized communications, or interventions, aimed at improving practices.
Keywords Lottery choice, Medical practices, Risk attitude, Scale, Domain specificity JEL Classification C93, D81, I10
Publication HAL Google Scholar
Abstract Economists ceased at some point to discuss the “self” of the “economic agent.” Moralists criticized them for this. Yet attention had been paid to the “self” from the start of modern economics with Adam Smith “self-love.” Granted, the contemporary mathematized mainstream in economics ignores the “self,” its representations, and its realization through economic life. Economic philosophers, however, bring it to the fore and debate identity issues, the flesh and “reality” of agents beyond an axiomatic skeleton. Inspired by Ancient thought and heterodox individualistic currents (like the Austrian school), the inquiry as to what “self-realization” may, or may not mean in the economists’ realm and in economic life is essential to ethical and methodological issues so as to make sense of how to realize the self from an economic viewpoint (and far from popular folk psychology).
Publication HAL Google Scholar