Research

Recent publications and working papers

Low Homeownership in Germany - A Quantitative Exploration  (pdf)
(with Georgi Kocharkov, Nawid Siassi and Edgar Preugschat), Revise and Resubmit at the Journal of the European Economic Association
Abstract: The homeownership rate in Germany is one of the lowest among advanced economies. To better understand this fact, we analyze the role of three specific policies which discourage homeownership in Germany: an extensive social housing sector with broad eligibility criteria, high transfer taxes when buying real estate, and no tax deductions for mortgage interest payments by owner-occupiers. We build a lifecycle model with uninsurable income risk and endogenous homeownership in order to quantify the policy effects on homeownership and welfare. We find that all three policies have sizable effects on the homeownership rate. At the same time, household welfare would be reduced by moving to a policy regime with low transfer taxes and mortgage interest tax deductions, but it would improve in the absence of social housing, in particular when coupled with housing subsidies for low-income households.

Default Cycles  (pdf)
(with Wei Cui)
Abstract: Recessions are often accompanied by spikes of corporate default and prolonged declines of business credit. This paper shows that credit and default cycles can result from variations of self-fulfilling beliefs about credit market conditions. We develop a tractable macroeconomic model in which credit contracts reflect the expected default risk of borrowing firms. We calibrate the model to evaluate the macroeconomic impact of sunspots and fundamental shocks. Self-fulfilling changes in credit market expectations generate sizable reactions in default rates together with endogenously persistent credit and output cycles, accounting for most of the volatility of corporate default and over 20% of output volatility.

Firm Dynamics with Frictional Product and Labor Markets (pdf)
(with Bihemo Kimasa)
Abstract: This paper analyzes the joint dynamics of prices, output and employment across firms. We develop a dynamic equilibrium model of heterogeneous firms who compete for workers and customers in frictional labor and product markets. Idiosyncratic productivity and demand shocks have distinct implications for the firms' output and price adjustments. Using panel data on prices and output for German manufacturing firms, we calibrate the model to evaluate the quantitative contributions of productivity and demand for the labor market and the dispersions of prices and labor productivity. We further analyze the impact of shocks to the first and second moments of idiosyncratic risk on macroeconomic outcomes. An increase in demand uncertainty induces sizable declines in output and employment together with rising cross-sectional dispersion of price and output growth which are typical features of recessions in our data.

Sovereign and Private Default Risks over the Business Cycle (pdf)
(with Almuth Scholl and Jan Mellert), Revise & Resubmit at the Journal of International Economics
Abstract: Sovereign debt crises are often accompanied by deep recessions with sharp declines in external credit to the private sector. In a sample of emerging economies we find that both, sovereign and private risk premia are countercyclical. This paper presents a model of a small open economy that accounts for these empirical regularities. It includes private firms which finance a fraction of imports by external debt and are subject to idiosyncratic and aggregate productivity risk, and a government which borrows internationally and taxes firms to finance public expenditures. The model gives rise to endogenous private and sovereign credit spreads and a dynamic feedback mechanism between sovereign and private default risks through the endogenous response of fiscal policy to adverse productivity shocks.

Self-Fulfilling Credit Cycles  (pdf)
(with Costas Azariadis and Yi Wen), Review of Economic Studies, Vol. 83, 1364-1405, 2016.
Abstract: In U.S. data 1981-2012, unsecured firm credit moves procyclically and tends to lead GDP, while secured firm credit is acyclical; similarly, shocks to unsecured firm credit explain a far larger fraction of output fluctuations than shocks to secured credit. In this paper we develop a tractable dynamic general equilibrium model in which unsecured firm credit arises from self-enforcing borrowing constraints, preventing an efficient capital allocation among heterogeneous firms. Unsecured credit rests on the value that borrowers attach to a good credit reputation which is a forward-looking variable. We argue that self-fulfilling beliefs over future credit conditions naturally generate endogenously persistent business cycle dynamics. A dynamic complementarity between current and future borrowing limits permits uncorrelated sunspot shocks to unsecured debt to trigger persistent aggregate fluctuations in both secured and unsecured debt, factor productivity and output. We show that these sunspot shocks are quantitatively important, accounting for around half of output volatility.

Efficient Firm Dynamics in a Frictional Labor Market   (pdf)
(with Philipp Kircher), American Economic Review, Vol. 105, 3030-3060, 2015.
Abstract: We develop and analyze a labor market model in which heterogeneous firms operate under decreasing returns and compete for labor by posting long-term contracts. Firms achieve faster growth by offering higher lifetime wages, which allows them to fill vacancies with higher probability, consistent with recent empirical findings. The model also captures several other regularities about firm size, job flows and pay, and generates sluggish aggregate dynamics of labor market variables. In contrast to existing bargaining models, efficiency obtains and the model allows a tractable characterization over the business cycle.

Worker Mobility in a Search Model with Adverse Selection (pdf)
(with Carlos Carrillo-Tudela), Journal of Economic Theory, Vol. 160, 340-386, 2015.
Abstract: We analyze the effects of adverse selection on worker turnover and wage dynamics in a frictional labor market. We consider a model of on-the-job search where firms offer promotion wage contracts to workers of different ability, which is unknown to firms at the hiring stage. With sufficiently strong information frictions, low-wage firms offer separating contracts and hire all types of workers in equilibrium, whereas high-wage firms offer pooling contracts, promoting high-ability workers only. Low-ability workers have higher turnover rates and are more often employed in low-wage firms. The model replicates the negative relationship between job-to-job transitions and wages observed in the U.S. labor market.
Previous version: Wage Dispersion and Labor Turnover with Adverse Selection (IZA Discussion Paper No. 5936)

Does Homeownership Promote Wealth Accumulation? (pdf)
(with Georgi Kocharkov and Edgar Preugschat), forthcoming in Applied Economics Letters
Abstract: It is well known that homeowners are richer than renters, even after controlling for observable household characteristics. This is often used as an argument for policies that foster homeownership. However, the causal link between homeownership and wealth is difficult to establish due to many potential sources of endogeneity. Utilizing the Household Finance and Consumption Survey for the Euro area, we correct for endogeneity by using inheriting the household’s main residence as an instrument. The exclusion restriction is that conditional on the total amount of inheritance, inheriting a home affects the wealth position of the household only through homeownership. For the sample of inheritors we find that the local average treatment effect for households that inherit a home and stay homeowners is negative. Owning a home reduces riches due to sizable reductions in the net holdings of financial and other real wealth of the treated households.

Wealth Inequality and Homeownership in Europe (pdf)
(with Georgi Kocharkov and Edgar Preugschat), forthcoming in the Annals of Economics and Statistics
Abstract: The recently published Household Finance and Consumption Survey has revealed large differences in wealth inequality between the countries of the Euro area. We document a strong negative correlation between wealth inequality and homeownership rates across countries. We show that this negative relationship is robust to controlling for other observables using a counterfactual decomposition of cross-country inequality differences based on a recentered influence function regression. Furthermore, by decomposing the Gini coefficient across owners and renters we argue that the negative relationship is mostly driven by large inequality between the two groups. We also find  that the cross-country differences in the homeownership rate and its negative correlation with wealth inequality are to a large extent driven by households in the lower half of the wealth distribution. Thus, not only the top percentiles but also the lower tail is important in accounting for overall wealth inequality.

Public Debt and Total Factor Productivity 
(pdf)
Economic Theory, Vol. 61, 309-333, 2016.
Abstract: This paper explores the role of public debt and fiscal deficits on factor productivity in an economy with credit market frictions and heterogeneous firms. When credit market conditions are sufficiently weak, low interest rates permit the government to run Ponzi schemes so that  permanent primary deficits can be sustained. For small enough deficit ratios, the model has two steady states of which one is an unstable bubble and the other one is stable. The stable equilibrium features higher levels of credit and capital, but also a lower interest rate, lower total factor productivity and output. The model is calibrated to the US economy to derive the maximum sustainable deficit ratio and to examine the dynamic responses to changes in debt policy. A reduction of the primary deficit triggers an expansion of credit and capital, but it also leads to a deterioration of total factor productivity since more low-productivity firms prefer to remain active at the lower equilibrium interest rate.

Land Collateral and Labor Market Dynamics in France  (pdf)
(with Patrick Pintus and Simon Ray), European Economic Review, Vol. 84, 202-218, 2016.
Abstract: The value of land in the balance sheet of French firms correlates positively with their hiring and investment flows. To explore the relationship between these variables, we develop a macroeconomic model with firms that are subject to both credit and labor market frictions. The value of collateral is driven by the forward-looking dynamics of the land price, which reacts endogenously to fundamental and non-fundamental (sunspot) shocks. We calibrate the model to French data and find that land price shocks give rise to significant amplification and hump-shaped responses of investment, vacancies and unemployment that are in line with the data. We show that both the endogenous movements in the firms' discount factor and the sluggish response of the land price are key elements that drive the results.

For other publications and papers, see my IDEAS page.