RESEARCH

 

Published papers

 

“Asset Pricing in a Production Economy with Chew-Dekel Preferences” with Rui Castro and Gian Luca Clementi. 2009. Forthcoming in the Review of Economic Dynamics.

 

     In this paper we provide a thorough characterization of the asset returns implied by a simple general equilibrium production economy with Chew–Dekel risk preferences and convex capital adjustment costs. When households display levels of disappointment aversion consistent with the experimental evidence, a version of the model parameterized to match the volatility of output and consumption growth generates unconditional expected asset returns and price of risk in line with the historical data. For the model with Epstein–Zin preferences to generate similar statistics, the relative risk aversion coefficient needs to be at least 50, two orders of magnitude higher than the estimates available so far. We argue that this is not surprising, given the limited risk imposed on agents by a reasonably calibrated stochastic growth model.

 

 

“Life-cycle Portfolio Choice : The Role of Heterogeneous Under-Diversification” 2009, forthcoming in the Journal of Economic Dynamics and Control.


In life-cycle portfolio choice models it is standard to assume that all agents invest in a diversified stock market index. In contrast
recent empirical evidence, summarized in Campbell (2006) suggests that households' financial portfolios are under-diversified and that there is substantial heterogeneity in diversification. In the present paper I examine the effects of heterogeneous under-diversification in a life-cycle portfolio choice model with uninsurable uncertain earnings and fixed per period participation costs. The analysis of the model shows that realistically calibrated under-diversification gives an important contribution to the explanation of two key facts of households’ portfolio allocation: the moderate stock market participation rate and the moderate stock share for participants.

 

 

“Increasing Return to Savings and Wealth Inequality”     Review of Economic Dynamics (2007), 10,4, pp 646-675

 

In this paper I present an explanation to the fact that in the data wealth is substantially more concentrated than income. Starting from the observation that the composition of households' portfolios changes towards a larger share of high-yield assets as the level of net worth increases, I first use data on historical asset returns and portfolio composition by wealth level to construct an empirical return function. I then augment the standard neoclassical growth model with idiosyncratic labor income risk and missing insurance markets to allow for returns to savings to be increasing in the level of accumulated assets. The quantitative properties of the model are examined and show that an empirically plausible difference between the return faced by poor and wealthy agents is able to generate a substantial increase in wealth inequality compared to the basic model, enough to match the Gini index of the U.S. Distribution of wealth.

 

 

 

Working papers

 

 

     

“Private Equity Returns in a Model of Entrepreneurial Choice with Learning”  March 2009

 

Entrepreneurs invest a large share of their financial wealth in a single business that they personally manage. Despite the large risk implied by this undiversified investment they do not seem to require any extra return on a diversified public equity index. In light of the large public equity premium this fact seems puzzling. In the present paper I use a quantitative model of entrepreneurial choice with learning over unknown firm quality to explore this issue and find that the choice to be entrepreneurs can be rationalized even with a negative private equity premium when the full return on entrepreneurial investment is properly accounted for.

 

This paper is a largely revised version of a previous work that appeared under the title “Learning and the Return to Private Equity”

 

 

Learning, Ambiguity and Life-Cycle Portfolio Allocation October 2008

 

In the present paper I develop a life-cycle portfolio choice model where agents perceive stock returns to be ambiguous and are ambiguity averse. As in Epstein and Schneider (2005) part of the

ambiguity vanishes over time as a consequence of learning over observed returns. The model shows that ambiguity alone can rationalize moderate stock market participation rates and conditional shares with reasonable participation costs but has strongly counterfactual implications for conditional allocations to stocks by age and wealth. When learning is allowed, conditional shares over the life-cycle are instead aligned with the empirical evidence and patterns of stock holdings over the wealth distribution get closer to the data.