A Model of the Consumption Response to Fiscal Stimulus Payments

A wide body of empirical evidence finds that approximately 25 percent of fiscal stimulus payments (e.g., tax rebates) are spent on nondurable household consumption in the quarter that they are received. To interpret this fact, we develop a structural economic model where households can hold two assets: a low‐return liquid asset (e.g., cash, checking account) and a high‐return illiquid asset that carries a transaction cost (e.g., housing, retirement account). The optimal life‐cycle pattern of portfolio choice implies that many households in the model are “wealthy hand‐to‐mouth”: they hold little or no liquid wealth despite owning sizable quantities of illiquid assets. Therefore, they display large propensities to consume out of additional transitory income, and small propensities to consume out of news about future income. We document the existence of such households in data from the Survey of Consumer Finances. A version of the model parameterized to the 2001 tax rebate episode yields consumption responses to fiscal stimulus payments that are in line with the evidence, and an order of magnitude larger than in the standard “one‐asset” framework. The model's nonlinearities with respect to the rebate size and the prevailing aggregate economic conditions have implications for policy design.     

Liquidity in Asset Markets With Search Frictions

We develop a search‐theoretic model of financial intermediation in an over‐the‐counter market and study how trading frictions affect the distribution of asset holdings and standard measures of liquidity. A distinctive feature of our theory is that it allows for unrestricted asset holdings, so market participants can accommodate trading frictions by adjusting their asset positions. We show that these individual responses of asset demands constitute a fundamental feature of illiquid markets: they are a key determinant of trade volume, bid–ask spreads, and trading delays—the dimensions of market liquidity that search‐based theories seek to explain.     

Illiquide Assets in der Portfoliooptimierung

When optimizing a portfolio, which comprises liquid as well as illiquid assets, under the constraint of a liquidity requirement, one has to take into account the particular characteristics of illiquid assets. Illiquid assets in this context have the constituting property that they can only be sold as a whole and – if sold on a short term basis – selling leads to losses. Performing the analysis of a single period model in a mean downside risk framework with one liquid and one illiquid asset, significant differences are proven in comparison to the results of an optimization concerning solely liquid assets. For example, although the return on assets is safe in the first scenario, the portfolio value is already risky due to the uncertain liquidity requirement and situations arise where the allocation to both the liquid and the illiquid asset is optimal. Furthermore, when asset returns are uncertain, the expected portfolio value depends on the assets’ variances and can even be increased by positive correlations.     

Macroeconomic Implications of Agglomeration

Cities exist because of the productivity gains that arise from clustering production and workers, a process called agglomeration. How important is agglomeration for aggregate growth? This paper constructs a dynamic stochastic general equilibrium model of cities and uses it to estimate the effect of local agglomeration on aggregate growth. We combine aggregate time‐series and city‐level panel data to estimate the model's parameters via generalized method of moments. The estimates imply a statistically and economically significant impact of local agglomeration on the growth rate of per capita consumption, raising it by about 10%.     

Temptation and Self‐Control

We study a two‐period model where ex ante inferior choice may tempt the decision‐maker in the second period. Individuals have preferences over sets of alternatives that represent second period choices. Our axioms yield a representation that identifies the individual's commitment ranking, temptation ranking, and cost of self‐control. An agent has a preference for commitment if she strictly prefers a subset of alternatives to the set itself. An agent has self‐control if she resists temptation and chooses an option with higher ex ante utility. We introduce comparative measures of preference for commitment and self‐control and relate them to our representations.     

非流动性市场中的跨期最优消费和投资策略

本文在Merton跨期最优消费和资产组合的理论框架内引入非流动性资产,构造了一个三资产的连续时间经济模型,探讨流动性约束对投资者最优消费和投资决策的影响。本文用动态规划方法给出了跨期优化问题的解析解。数值分析表明对投资者而言,非流动性资产的真实价值低于其市值,必须引入影子价格来刻划这种流动性效应;流动性约束降低了投资者的福利,并且显著地影响到投资者的消费和投资策略。     

Temptation and Taxation

We study optimal taxation when consumers have temptation and self‐control problems. Embedding the class of preferences developed by Gul and Pesendorfer into a standard macroeconomic setting, we first prove, in a two‐period model, that the optimal policy is to subsidize savings when consumers are tempted by “excessive” impatience. The savings subsidy improves welfare because it makes succumbing to temptation less attractive. We then study an economy with a long but finite horizon which nests, as a special case, the Phelps–Pollak–Laibson multiple‐selves model (thereby providing guidance on how to evaluate welfare in this model). We prove that when period utility is logarithmic, the optimal savings subsidies increase over time for any finite horizon. Moreover, as the horizon grows large, the optimal policy prescribes a constant subsidy, in contrast to the well known Chamley–Judd result.     

Interjurisdictional Sorting and Majority Rule: An Empirical Analysis

The goal of this paper is to provide a comprehensive empirical analysis of majority rule and Tiebout sorting within a system of local jurisdictions. The idea behind the estimation procedure is to investigate whether observed levels of public expenditures satisfy necessary conditions implied by majority rule in a general equilibrium model of residential choice. The estimator controls for observed and unobserved heterogeneity among households, observed and unobserved characteristics of communities, and the potential endogeneity of prices and expenditures, as well as the self‐selection of households into communities of their choice. We estimate the structural parameters of the model using data from the Boston Metropolitan Area. The empirical findings reject myopic voting models. More sophisticated voting models based on utility‐taking provide a potential explanation of the main empirical regularities.     

Costly Self‐Control and Random Self‐Indulgence

We study the random Strotz model, a version of the Strotz (1955) model with uncertainty about the nature of the temptation that will strike. We show that the random Strotz representation is unique and characterize a comparative notion of “more temptation averse.” Also, we demonstrate an unexpected connection between the random Strotz model and a generalization of the Gul–Pesendorfer (GP) (2001) model of temptation which allows for the temptation to be uncertain and which we call random GP. In particular, a preference over menus has a random GP representation if and only if it also has a representation via a random Strotz model with sufficiently smooth uncertainty about the intensity of temptation. We also show that choices of menus combined with choices from menus can distinguish the random GP and random Strotz models.     

Entropic Latent Variable Integration via Simulation

This paper introduces a general method to convert a model defined by moment conditions that involve both observed and unobserved variables into equivalent moment conditions that involve only observable variables. This task can be accomplished without introducing infinite‐dimensional nuisance parameters using a least favorable entropy‐maximizing distribution. We demonstrate, through examples and simulations, that this approach covers a wide class of latent variables models, including some game‐theoretic models and models with limited dependent variables, interval‐valued data, errors‐in‐variables, or combinations thereof. Both point‐ and set‐identified models are transparently covered. In the latter case, the method also complements the recent literature on generic set‐inference methods by providing the moment conditions needed to construct a generalized method of moments‐type objective function for a wide class of models. Extensions of the method that cover conditional moments, independence restrictions, and some state‐space models are also given.     

基于流动性偏好的上市公司现金持有行为研究

以流动性偏好理论为基础,通过理论模型推导出不同融资约束的公司会依据其现金流波动性进行有差异的现金持有行为决策;以2001～2006年间4 285个公司年数据为样本,实证检验并分析了中国上市公司融资约束、现金流波动性和现金持有量之间的相互关系.结果表明:在中国资本市场,融资约束公司的现金流波动性高于非融资约束公司,而现金持有量却低于非融资约束公司;前者现金持有量与现金流波动性显著正相关,而后者无显著相关性.     

Consumption Commitments and Habit Formation

We analyze the implications of household‐level adjustment costs for the dynamics of aggregate consumption. We show that an economy in which agents have “consumption commitments” is approximately equivalent to a habit formation model in which the habit stock is a weighted average of past consumption if idiosyncratic risk is large relative to aggregate risk. Consumption commitments can thus explain the empirical regularity that consumption is excessively sensitive and excessively smooth, findings that are typically attributed to habit formation. Unlike habit formation and other theories, but consistent with empirical evidence, the consumption commitments model also predicts that excess sensitivity and smoothness vanish for large shocks. These results suggest that behavior previously attributed to habit formation may be better explained by adjustment costs. We develop additional testable predictions to further distinguish the commitment and habit models and show that the two models have different welfare implications.     

An Economic Model of Friendship: Homophily,Minorities, and Segregation

We develop a model of friendship formation that sheds light on segregation patterns observed in social and economic networks. Individuals have types and see type‐dependent benefits from friendships. We examine the properties of a steady‐state equilibrium of a matching process of friendship formation. We use the model to understand three empirical patterns of friendship formation: (i) larger groups tend to form more same‐type ties and fewer other‐type ties than small groups, (ii) larger groups form more ties per capita, and (iii) all groups are biased towards same‐type relative to demographics, with the most extreme bias coming from middle‐sized groups. We show how these empirical observations can be generated by biases in preferences and biases in meetings. We also illustrate some welfare implications of the model.     

FOOD SCARES IN AN UNCERTAIN WORLD

We develop a model that explains the stylized facts of food scares: an immediate and sharp decline in consumption of the product followed by a slow and frequently partial recovery of demand after the scare passes. The model is used in conjunction with the natural experiment afforded by the ‘mad‐cow’ crisis to elicit empirical information on decision makers' perception of uncertainty. Our theoretical and quantitative results suggest that observed behavior is consistent with sharp changes in beliefs and the presence of Knightian uncertainty, as measured by the degree of imprecision in our model.     

INTERTEMPORAL CHOICE AND CONSUMPTION MOBILITY

The theory of intertemporal consumption choice makes sharp predictions about the evolution of the entire distribution of household consumption, not just about its conditional mean. In the paper, we study the empirical transition matrix of consumption using a panel drawn from the Bank of Italy Survey of Household Income and Wealth. We estimate the parameters that minimize the distance between the empirical and the theoretical transition matrix of the consumption distribution. The transition matrix generated by our estimates matches remarkably well the empirical matrix, both in the aggregate and in samples stratified by education. Our estimates strongly reject the consumption insurance model and suggest that households smooth income shocks to a lesser extent than implied by the permanent income hypothesis. (JEL: D52, D91, I30)     

Endogenous Liquidity and Defaultable Bonds

This paper studies the interaction between default and liquidity for corporate bonds that are traded in an over‐the‐counter secondary market with search frictions. Bargaining with dealers determines a bond's endogenous liquidity, which depends on both the firm fundamental and the time‐to‐maturity of the bond. Corporate default decisions interact with the endogenous secondary market liquidity via the rollover channel. A default‐liquidity loop arises: Assuming a relative illiquid secondary bond market in default, earlier endogenous default worsens a bond's secondary market liquidity, which amplifies equity holders' rollover losses, which in turn leads to earlier endogenous default. Besides characterizing in closed form the full interdependence between liquidity and default for credit spreads, our calibrated model can jointly match empirically observed credit spreads and liquidity measures of bonds across different rating classes.     

A Dynamic Equilibrium Model of International Portfolio Holdings

This paper develops a continuous‐time equilibrium model of a two‐country exchange economy with heterogeneous agents and nontraded goods. Nontraded goods play the role of state variables that shift the marginal utility of traded goods. This affects prices and generates dynamic hedging demands that explain the well documented home bias puzzle in international equity portfolios. When calibrated to both consumption and production data, the model is able to generate significative home bias in equity portfolios. A new methodology, based on Malliavin calculus, is presented to solve for the portfolio policies along the equilibrium path. This methodology allows one to reduce the determination of equilibrium portfolio holdings to the solution of a linear algebraic system, rather than a partial differential equation.     

Exposure Assessment for Pesticide Intake from Multiple Food Products: A Bayesian Latent‐Variable Approach

Pesticide risk assessment for food products involves combining information from consumption and concentration data sets to estimate a distribution for the pesticide intake in a human population. Using this distribution one can obtain probabilities of individuals exceeding specified levels of pesticide intake. In this article, we present a probabilistic, Bayesian approach to modeling the daily consumptions of the pesticide Iprodione though multiple food products. Modeling data on food consumption and pesticide concentration poses a variety of problems, such as the large proportions of consumptions and concentrations that are recorded as zero, and correlation between the consumptions of different foods. We consider daily food consumption data from the Netherlands National Food Consumption Survey and concentration data collected by the Netherlands Ministry of Agriculture. We develop a multivariate latent‐Gaussian model for the consumption data that allows for correlated intakes between products. For the concentration data, we propose a univariate latent‐t model. We then combine predicted consumptions and concentrations from these models to obtain a distribution for individual daily Iprodione exposure. The latent‐variable models allow for both skewness and large numbers of zeros in the consumption and concentration data. The use of a probabilistic approach is intended to yield more robust estimates of high percentiles of the exposure distribution than an empirical approach. Bayesian inference is used to facilitate the treatment of data with a complex structure.     

Estimation of Continuous‐Time Markov Processes Sampled at Random Time Intervals

We introduce a family of generalized‐method‐of‐moments estimators of the parameters of a continuous‐time Markov process observed at random time intervals. The results include strong consistency, asymptotic normality, and a characterization of standard errors. Sampling is at an arrival intensity that is allowed to depend on the underlying Markov process and on the parameter vector to be estimated. We focus on financial applications, including tick‐based sampling, allowing for jump diffusions, regime‐switching diffusions, and reflected diffusions.     

Self‐Control and the Theory of Consumption

To study the behavior of agents who are susceptible to temptation in infinite horizon consumption problems under uncertainty, we define and characterize dynamic self‐control (DSC) preferences. DSC preferences are recursive and separable. In economies with DSC agents, equilibria exist but may be inefficient; in such equilibria, steady state consumption is independent of initial endowments and increases in self‐control. Increasing the preference for commitment while keeping self‐control constant increases the equity premium. Removing nonbinding constraints changes equilibrium allocations and prices. Debt contracts can be sustained even if the only feasible punishment for default is the termination of the contract.