On portfolio frictions, asset returns and volatilityJournal articleAurélien Eyquem, Celine Poilly et Anna Belianska, European Economic Review, Volume 160, pp. 104623, 2023

We rationalize the observed short-run differences in corporate and long-term government bond yields in an financial-accelerator model with frictions that restrict changes in portfolio shares. We estimate the model on quarterly data for the Euro Area from 1999 to 2019, and show that the portfolio friction parameter is positive and significant. Portfolio frictions not only generate a time-varying wedge between the two returns that fits the data, but also raise the volatility of return differentials, and the precautionary motive of savers. As a result, the macroeconomic effects of uncertainty shocks are amplified by portfolio frictions.

Incertitude sur la politique commerciale et cycle économiqueJournal articleCeline Poilly et Fabien Tripier, Revue française d'économie, Volume XXXVIII, Issue 1, pp. 183-218, 2023

Cet article propose une revue de la littérature concernant les liens entre l’incertitude sur la politique commerciale et le cycle économique. Cette littérature se situe à l’intersection de deux domaines de recherche qui se sont initialement développés de manière indépendante. Le premier domaine est consacré aux fluctuations de l’incertitude comme sources des cycles économiques et le second à l’incertitude sur la politique commerciale dans le cadre des accords commerciaux. Nous montrons comment le contexte de la guerre commerciale des États-Unis initiée en 2018 a favorisé le rapprochement entre ces deux domaines, tant sur le plan des mesures empiriques de l’incertitude que de ses mécanismes de transmission à l’économie. Nous soulignons également la nécessité d’approfondir l’analyse des politiques conjoncturelles adéquates pour faire face à l’incertitude sur la politique commerciale dans le contexte actuel de tensions commerciales persistantes entre les États-Unis, la Chine et l’Europe.

Does demand noise matter? Identification and implicationsJournal articleKenza Benhima et Celine Poilly, Journal of Monetary Economics, Volume 117, pp. 278-295, 2021

We assess the role of demand noise (excessive optimism or pessimism about demand) together with supply noise (excessive optimism or pessimism about supply). To do so, we propose a methodology to decompose business cycles into supply, demand, supply noise and demand noise shocks, using a structural vector autoregression model. Key to our identification of both supply noise and demand noise is the use of sign restrictions on survey expectation errors about output growth and about inflation. We show that demand-related noise shocks have a negative effect on output and contribute substantially to its fluctuations. Monetary policy and private information seem to play a key role in the transmission of demand noise shocks.

Corporate Cash and EmploymentJournal articlePhilippe Bacchetta, Kenza Benhima et Celine Poilly, American Economic Journal: Macroeconomics, Volume 11, Issue 3, pp. 30-66, 2019

In the aftermath of the U.S. financial crisis, both a sharp drop in employment and a surge in corporate cash have been observed. In this paper, based on U.S. data, we argue that the negative relationship between the corporate cash ratio and employment is systematic, both over time and across firms. We develop a dynamic general equilibrium model where heterogenous firms need cash and external liquid funds in their production process. We analyze the dynamic impact of aggregate shocks and the cross-firm impact of idiosyncratic shocks. We show that external liquidity shocks generate a negative comovement between the cash ratio and employment, as documented in the data.

Reforms and the real exchange rate: The role of pricing-to-marketJournal articleLise Patureau et Celine Poilly, Journal of International Economics, Volume 119, pp. 150-168, 2019

The paper investigates how endogenous markups affect the extent to which policy reforms can influence international competitiveness. In a two-country model where trade costs allow for international market segmentation, we show that endogenous pricing-to-market behavior of firms acts as an important transmission channel of the policies. By strengthening the degree of competition between firms, product market deregulation at home leads to a reduction in domestic markups, which generally leads to an improvement in the international competitiveness of the Home country. Conversely, the power of competitive tax policy to depreciate the real exchange rate is dampened, as domestic firms take the opportunity of the labor tax cut to increase their markups. The variability of markups also affects the normative implications of the reforms. This indicates the importance of taking into account endogenous pricing-to-market behavior when intending to correctly evaluate the overall effects of the reforms.

Employment, hours and the welfare effects of intra-firm bargainingJournal articleMaarten Dossche, Vivien Lewis et Celine Poilly, Journal of Monetary Economics, Volume 104, pp. 67-84, 2019

Bilateral bargaining between a multiple-worker firm and individual employees leads to overhiring. With a concave production function, the firm can reduce the marginal product by hiring an additional worker, thereby reducing the bargaining wage paid to all existing employees. We show that this externality is amplified when firms can adjust hours per worker as well as employment. Firms keep down workers’ wage demands by reducing the number of hours per worker and the resulting labor disutility. Our finding is particularly relevant for European economies where hours adjustment plays an important role.

Evaluating labor market reforms: A normative analysisJournal articleCeline Poilly et Dennis Wesselbaum, Journal of Macroeconomics, Volume 39, Issue PA, pp. 156-170, 2014

This paper shows that a reform aimed at improving labor market flexibility is not necessarily welfare-enhancing. We adopt a New-Keynesian model enriched with search and matching frictions. We investigate the effects of institutional labor market reforms, described by a permanent change in firing costs and unemployment benefits. Improving labor market flexibility by cutting unemployment benefits is welfare-enhancing for households. On the contrary, cutting firing costs reduces welfare. We argue that real wage dynamics play a crucial role in the results. Furthermore, welfare effects tend to zero when the reform is pre-announced.

How do financial frictions affect the spending multiplier during a liquidity trap?Journal articleJulio Carrillo et Celine Poilly, Review of Economic Dynamics, Volume 16, Issue 2, pp. 296-311, 2013

We show that credit market imperfections substantially increase the government-spending multiplier when the economy enters a liquidity trap. This finding is explained by the tight association between capital goods and firms' collateral, a relationship that we highlight as the capital-accumulation channel. During a liquidity trap, a government spending expansion reduces the real interest rate, leading to a period of cheap credit. Entrepreneurs use this time to accumulate capital, which persistently improves their balance sheets and reduces their future costs of credit. A public spending expansion can thus encourage private investment, yielding consequently a large spending multiplier. This effect is further reinforced by Fisher's debt-deflation channel. (Copyright: Elsevier)

Welfare Implications of Heterogeneous Labor Markets in a Currency AreaJournal articleCeline Poilly et Jean-Guillaume Sahuc, Macroeconomic Dynamics, Volume 17, Issue 02, pp. 294-325, 2013

This paper investigates the role of labor markets heterogeneity in a monetary union and especially what are the welfare gains/costs of labor market reforms for each member of the area. To this end, we develop a medium-scale two-country model representing a currency union characterized by price and wage stickiness, real rigidities and labor market frictions. We make various scenarios of labor market reform and seek to determine the direction in which a country has an incentive to direct it from a welfare perspective. We find that the choice of the instrument to direct a reform (aiming at reducing the home unemployment rate) has drastic welfare implications in the union. Reforming the domestic labor market by a stronger regulation seems to give the best output. The analysis also shows that labor markets heterogeneity has sizeable effects on the amount of welfare gains, following a reform. The more flexible the foreign labor market, the higher its welfare. Finally, a sensitivity analysis shows that (i) the way the monetary authorities conduct their policy has negligible welfare effects but (ii) the size of a country in the monetary union is far to be neutral.

Firm entry, markups and the monetary transmission mechanismJournal articleVivien Lewis et Celine Poilly, Journal of Monetary Economics, Volume 59, Issue 7, pp. 670-685, 2012

Two business cycle models with endogenous firm and product entry are estimated by matching impulse responses to a monetary policy shock. The ‘competition effect’ implies that entry lowers desired markups and dampens inflation. Under translog preferences, where the substitutability between goods depends on their number, we find evidence of such an effect. That model generates more countercyclical markups than Dixit and Stiglitz (1977) monopolistic competition model, where price stickiness is the only source of markup fluctuations. In contrast, a model with strategic interactions between oligopolistic firms cannot generate an empirically relevant competition effect and is statistically equivalent to the Dixit–Stiglitz model.