AN EQUILIBRIUM SEARCH MODEL OF SYNCHRONIZED SALES*

We demonstrate the existence of periodic nonstationary equilibria with self‐generating cycles in a simple model of random search. Our results provide a theory of synchronized sales based on product market search by heterogeneous consumers. That is, our model explains how it can be optimal for all sellers to follow a repeated pattern of posting a high price for several periods and then posting a low price for one period.     

BUSINESS CYCLES IN THE EQUILIBRIUM MODEL OF LABOR MARKET SEARCH AND SELF‐INSURANCE*

I introduce risk‐aversion, labor‐leisure choice, capital, individual productivity shocks, and market incompleteness to the standard model of labor search and matching and investigate the model’s cyclical properties. I find that the model can generate the observed large volatility of unemployment and vacancies with a reasonable replacement rate of unemployment insurance benefits of 64%. Labor‐leisure choice plays a crucial role through additional utility from leisure when unemployed and further amplification from adjustments of hours worked. On the other hand, the borrowing constraint or individual productivity shocks do not significantly affect the cyclical properties of unemployment and vacancies.     

AN EQUILIBRIUM SEARCH MODEL WHEN FIRMS OBSERVE WORKERS' EMPLOYMENT STATUS*

This article considers an equilibrium search model, where firms post wages using information on workers' employment status. Earnings differentials between workers of different employment statuses are driven by firms' ability to discriminate workers' reservation wages. I study how these wage policies depend on firms' and workers' characteristics, and how these policies affect the wage distribution. The model delivers new predictions for the amount of wage dispersion that can be generated with search models and provides a better representation of the left tail of the wage distribution in the presence of a legal minimum wage than standard equilibrium search models.     

INCENTIVES AND THE COST OF FIRING IN AN EQUILIBRIUM LABOR MARKET MODEL WITH ENDOGENOUS LAYOFFS*

I study the effects of firing costs in an equilibrium model of the labor market with moral hazard. Layoff is an incentive device, modeled as termination of the optimal long‐term contract. When the economy’s stock of firms is fixed, firing costs could reduce layoffs and increase worker welfare. In the long run when firms are free to enter and exit the market, firing costs generate not only lower employment, longer unemployment durations, and lower aggregate output, but also lower welfare for both employed workers and new labor market entrants.     

IT'S ABOUT TIME: IMPLICATIONS OF THE PERIOD LENGTH IN AN EQUILIBRIUM SEARCH MODEL

Empirical evidence suggests that transitions between employment states are highly clustered around the first day of each workweek or month. I analyze the effect of this phenomenon by presenting an equilibrium search model in which the period length is a parameter determining the degree of clustering. Infinitesimally short periods result in a continuous‐time model with bilateral meetings, whereas longer time periods introduce the possibility of recall or simultaneity of job offers. In this environment, I show that the period length has a profound effect on equilibrium outcomes, including the unemployment rate, unemployment duration, and the cross‐sectional wage distribution.     

EXISTENCE OF STATIONARY EQUILIBRIUM IN AN INCOMPLETE-MARKET MODEL WITH ENDOGENOUS LABOR SUPPLY

In this article, I first study an income fluctuation problem with endogenous labor supply. Let β be the agent's time discount factor and be the constant gross rate of return on assets. For , I show that the agent's wealth either approaches infinity almost surely or converges to a finite level almost surely. For , I prove the existence, uniqueness, and stability of the stationary distribution of state variables. I then show the existence of the stationary general equilibrium in an incomplete-market model with endogenous labor supply.     

THE DISTRIBUTION OF MONEY AND PRICES IN SEARCH EQUILIBRIUM*

This article considers a search‐theoretic model of monetary exchange. Agents bargain over both the amount of money and the quantity of goods to be exchanged in bilateral meetings, determining endogenously the distributions of money and of prices. I show that money is neutral if changes in the money supply are accomplished via proportional transfers. However, within the class of lump‐sum transfers, an increase of the rate of monetary expansion tends to decrease the dispersion of wealth and prices and to improve welfare when inflation is low; but when inflation is high enough, the opposite effects occur.     

AN EMPIRICAL MODEL OF LEARNING UNDER AMBIGUITY: THE CASE OF CLINICAL TRIALS*

This article presents a two‐dimensional structural model of learning under ambiguity in the context of clinical trials. Clinical trials offer an ideal environment to study learning under ambiguity. The randomization process found in these studies leaves patients uncertain to their actual group assignment. Therefore, patients cannot immediately attribute changes in health to the experimental drug. The article proposes the use of “learning instrumental variables” to simultaneously update patients’ beliefs of the treatment effect and group assignment. Patient learning is found to be faster when observable side effects are incorporated to account for the uncertainty in group assignment.     

OPPORTUNISTIC MATCHING IN THE HOUSING MARKET*

We construct a model of the housing market in which agents differ in their flow values while searching. Agents enter the market relaxed (with high flow values) but move to a desperate state (low flow values) at a Poisson rate if they have not already transacted. We characterize the equilibrium steady‐state matching pattern and the joint distribution of price and time to sale (for sellers). The expected price conditional on time to sale falls with time spent on the market, whereas the conditional variance of price first rises and then falls with time on the market.     

MARKET POWER AND EFFICIENCY IN A SEARCH MODEL*

We build a theoretical model to study the welfare effects and policy implications of firms’ market power in a frictional labor market. The main characteristics of our environment are that wages play a role in allocating labor across firms and the number of agents is finite. The decentralized equilibrium is inefficient and the firms’ market power results in the misallocation of workers from the high to the low productivity firms. A minimum wage exacerbates the inefficiencies by forcing the low‐productivity firms to increase their wage. Moderate unemployment benefits can increase welfare by improving the workers’ outside option.     

UNEMPLOYMENT IN AN EQUILIBRIUM MODEL WITH BARGAINING*

This paper develops a model which embeds the Nash-equilibrium version of McDonald and Solow's (1981) wage-bargaining model into an otherwise standard static equilibrium macro model. Equilibrium unemployment is possible. Real shocks to demand result in pro-cyclical employment and anti-cyclical real wage movements while money shocks are neutral. This is in some contrast to the results obtained by McDonald and Solow.     

MIDDLEMEN IN SEARCH EQUILIBRIUM*

This article shows how allowing for goods to be divisible at the point of consumption and incorporating productive heterogeneity lead to the emergence of middlemen in an equilibrium search environment. In the baseline model, middlemen are welfare reducing and their number increases as market frictions are reduced. When the model is extended to allow for time taken in production and increasing returns to scale in the market meeting technology, middlemen can be beneficial to society by speeding up the meeting process.     

ON THE GAME‐THEORETIC FOUNDATIONS OF COMPETITIVE SEARCH EQUILIBRIUM*

We provide a unified directed search framework with general production and matching specifications that encompass most of the existing literature. We prove the existence of subgame perfect Nash equilibria in pure firm strategies in a finite version of the model. We use this result to derive a more complete characterization of the equilibrium set for the finite economy and to extend convergence results as the economy becomes large to general production and matching specifications. The latter extends the microfoundations for the standard market utility assumption used in competitive search models with a continuum of agents to new environments.     

中国证券市场系统性风险结构的实证分析

实证研究表明:我国证券市场的系统性风险整体呈现降低趋势;系统性风险与市场指数存在负相关性,牛市期间系统性风险显著降低,熊市期间系统性风险持续走高;行业间变异系数增大,风险比重方差随时间变化而呈显著性差异;政策因子对系统性风险具有显著性影响,这说明我国股市很大程度上仍为政策市。     

房价对城市全要素生产率的影响机制研究——基于Tobit模型实证分析

基于2008—2016年全国35个大中型城市的面板数据,利用Tobit模型和投入导向型的数据包络分析(DEA)方法探究城市房屋销售价格对城市全要素生产率的影响。研究发现：在整体维度城市房价与城市生产率呈现先增加后减少的倒U型曲线,且城市的房价水平超过了“房住不炒”的最高临界值,房价上升的抑制效应显著。房价对于不同人口规模城市的生产率影响具有异质性,在人口规模达到特大城市时,房价与城市生产率呈现倒U型特征,人口规模达到超大城市后,房价与城市生产率倒U型特征消失。不同类型城市房价与城市生产率之间的倒U型关系和城市的异质性特征表明,我国大中型城市应进行房价的“一城一策”精细化调节,“房住不炒”的政策定位具有坚实理论依据和现实必然。