I am a lecturer (assistant professor) at the Department of Economics at UCL.
My research is in macroeconomics with a focus on incomplete markets, business cycles, and monetary policy.
Next office hour: 3pm, 06/03/, room 312
Solving heterogeneous agent models in discrete time with many idiosyncratic states by perturbation methods (with Christian Bayer)
This paper describes a method for solving heterogeneous agent models with aggregate risk and many idiosyncratic states formulated in discrete time. It extends the method proposed by Reiter (2009) and complements recent work by Ahn et al. (2017) on how to solve such models in continuous time. We suggest first solving for the stationary equilibrium of the model without aggregate risk. We then write the functionals that describe the recursive equilibrium as sparse expansions around their stationary equilibrium counterparts. Finally we use the perturbation method of Schmitt-Grohé and Uribe (2004) to approximate the aggregate dynamics of the model.
Transmission of Monetary Policy with Heterogeneity in Household Portfolios
Monetary policy affects both intertemporal consumption choices and portfolio choices between liquid and illiquid assets. The monetary transmission, in turn, depends on the distribution of marginal propensities to consume and invest. This paper assesses the importance of heterogeneity in these propensities for the transmission of monetary policy in a New Keynesian business cycle model with uninsurable income risk and assets with different degrees of liquidity. Liquidity-constrained households have high propensities to consume but low propensities to invest, which makes consumption more and investment less responsive to monetary shocks compared to complete markets. Redistribution through earnings heterogeneity and the Fisher channel from unexpected inflation further amplifies the consumption response but dampens the investment response.
Precautionary Savings, Illiquid Assets, and the Aggregate Consequences of Shocks to Household Income Risk
(Econometrica 87 (1), 255-290 )
(with Christian Bayer, Lien Pham-Dao, and Volker Tjaden)
U.S. households face large income uncertainty that varies substantially over the business cycle. We examine the macroeconomic consequences of these variations in a model with incomplete markets, liquid and illiquid assets, and a nominal rigidity. Heightened uncertainty depresses aggregate demand as households respond by hoarding liquid paper assets for precautionary motives, thereby reducing both illiquid physical investment and consumption demand. This translates into output losses. We document the empirical response of portfolio liquidity and aggregate activity to surprise changes in idiosyncratic income uncertainty and find both to be quantitatively in line with our model. The welfare consequences of uncertainty shocks and of the policy response thereto depend crucially on a household's asset position.
Housing Freezes, Deleveraging, and Aggregate Demand
(with Christian Bayer)
This paper develops a general equilibrium model of incomplete markets, liquid paper assets, and illiquid housing. In this model the liquidity of housing fluctuates stochastically over time. A decrease in the liquidity of housing leads to an increased demand for liquid paper assets and a decrease in demand for houses (as assets). We show that the model generates substantial business cycle effects of fluctuations in housing liquidity on housing prices, employment and output, while being in line with relatively small fluctuations in rental rates of housing.
Fiscal Uncertainty and Precautionary Savings
(with Othman Bouabdallah, Giovanni Callegari, and Thomas Warmedinger)
Uncertainty about the timing and type of fiscal consolidations raises the uncertainty of future household income. We examine this channel in a model with incomplete markets and a nominal rigidity. In this setup, uncertainty about tax- or spending-based consolidation and its timing depresses aggregate demand as households respond by increasing their savings.
Fiscal Consolidations Under Incomplete Markets - A Capital Taxation Paradox
(with Christian Bayer)
Fiscal Stimulus Payments and Economic Activity in a Model of Liquidity-Constrained Households (with Lien Pham-Dao)
We examine the effects of lump-sum transfers from the government on individual consumption and aggregates under different financing schemes in a New Keynesian model with liquid and illiquid assets. We find that size and sign of aggregate effects change with the financing considered. Raising taxes today lowers aggregate effects considerably in comparison to deficit financing.
What can we learn from HANK?
Overview presentation with focus on monetary policy
Monetary Policy with Heterogeneous Agents: Insights from TANK models
by Davide Debortoli and Jordi Galí
Inequality and Aggregate Demand
by Adrien Auclert and Matthew Rognlie
Consumption and House Prices in the Great Recession
by Greg Kaplan, Kurt Mitman, and Gianluca Violante
The Automatic Stabilizer Property of Social Insurance Programs
by Alisdair McKay and Ricardo Reis