Quantifying the risk-sharing welfare gains of social security

The welfare effects of intergenerational risk sharing through a pay-as-you-go social security system that is efficiently indexed to wages or interest rates are quantified. Comparing steady states, there are large welfare gains of being born into an economy with efficient risk sharing as compared to the current U.S. system. Efficient policy involves an increasingly risky net of tax income over the life cycle. When adjustment to steady state is taken into account, the welfare gains largely turn negative. The results are also compared and contrasted to the first best allocation.     

Do lack of transparency and enforcement undermine international risk-sharing?

This paper studies the extent to which poor institutions compromise risk-sharing. We model a multilateral organization as a social contract that provides insurance to members. Countries privately observe the realization of a performance variable with a verification cost that differs across countries, reflecting the “transparency” of institutions. When the level of transparency is exogenous, the optimal contract provides complete expected risk sharing across countries and states. Poor transparency and enforcement reduce consumption and result in insurance rationing. When a country can increase transparency endogenously, this generates an externality and moral hazard. We first characterize the outcome when the multilateral agency can influence members’ institutions by choosing the countries’ level of effort. Next we derive a tax/subsidy scheme that can induce countries to choose the socially optimal level. JEL Classification Numbers D8, F3 We are grateful to Biung-Ghi Ju, Ted Juhl, Donald Lien, Joseph Sicilian and Jianbo Zhang for helpful comments. We are especially grateful to an anonymous referee for comments that improved the paper substantially.     

Asset market games of survival: a synthesis of evolutionary and dynamic games

The paper examines a game-theoretic model of a financial market in which asset prices are determined endogenously in terms of a short-run equilibrium. Investors use general, adaptive strategies (portfolio rules) depending on the exogenous states of the world and the observed history of the game. The main goal is to identify portfolio rules, allowing an investor to “survive,” i.e., to possess a positive, bounded away from zero, share of market wealth over an infinite time horizon. The model under consideration combines a strategic framework characteristic for stochastic dynamic games with an evolutionary solution concept (survival strategies), thereby linking two fundamental paradigms of game theory.     

Equilibrium Subprime Lending

This paper develops an equilibrium model of a subprime mortgage market. Our goal is to offer a benchmark with which the recent subprime boom and bust can be compared. The model is tractable and delivers plausible orders of magnitude for borrowing capacities, as well as default and trading intensities. We offer simple explanations for several phenomena in the subprime market, such as the prevalence of teaser rates and the clustering of defaults. In our model, both nondiversifiable and diversifiable income risks reduce debt capacities. Thus, debt capacities need not be higher when a larger fraction of income risk is diversifiable.     

Equilibrium dominance in experimental financial markets

We examine the predictive power of equilibrium dominance inexperimental markets where firms with investment opportunitieshave an informational advantage over potential investors andare permitted to purchase a money-burning signal. Equilibriumdominance often fails to predict well when a Pareto-superiorsequential equilibrium is also available. Instead, equilibriumselection appears to be related to the potential earnings ofa more valuable firm that can signal its type successfully bydefecting from the sequential equilibrium.     

Signaling-Screening Equilibrium in the Mortgage Market

The signaling model of Spence (1973a) and the screening model of Rothchild and Stiglitz (1976) have been separately used to explain economic phenomena when there is asymmetric information. In the real world, however, situations of asymmetric information often simultaneously involve signaling and screening. In this paper, we combine signaling and screening mechanisms and demonstrate a signaling-screening separating equilibrium. We present the analysis within the framework of mortgage markets. Borrowers signal their default risk types to lenders by acquiring different credit records. This partially separates borrowers into subsets. Lenders screen each subset by offering menus of mortgage loan contracts. Borrowers, then, self-select by choosing particular contracts from the menu. We show the conditions under which the signaling-screening equilibrium is Pareto superior to a screening-only equilibrium.     

Strategic market games with cyclic endowments

We consider an infinite horizon cash-in-advance market economy with symmetric agents. In each stage, a representative agent receives an independent, random endowment from one of k known distributions. The endowment distribution changes cyclically across stages. We suppose that a central bank sets a fixed, nominal interest rate for both borrowing and investing. In equilibrium, the expected rate of inflation across each cycle of length k is strictly greater with random endowments from cyclic distributions than with deterministic endowments.      

Equilibrium Exchange Rate Hedging

We assume a world like the one that gives the capital asset pricing model, but with many goods and many countries. We assume that investors in a given country have homothetic utility functions with the same weights, and a currency that has a sure end-of-period value using a price index with those weights. Siegel's paradox (derived from Jensen's inequality) makes investors want a positive amount of exchange risk. When average risk tolerance is the same across countries, every investor will hold the same mix of market risk (through the world market portfolio of all assets) and exchange risk (in a diversified basket of foreign currencies). In fact, the ratio of exchange risk to market risk is equal to the average investor's risk tolerance. We can write the ratio of exchange risk to market risk (and the fraction of the market's exchange risk that investors hedge) as depending on an average of world market risk premia, an average of world market volatilities, and an average of exchange rate volatilities. The weights in these averages are the same as the weights of the different countries in the currency basket. Given these averages, the ratio (and the fraction hedged) will not depend directly on exchange rate means or covariances. In equilibrium, we can use the ratio of exchange risk to market risk to measure average risk tolerance: in this model, risk tolerance is observable.     

Equilibrium matching and termination

In an equilibrium model of the labor market with moral hazard, jobs are dynamic contracts, job separations are terminations of optimal dynamic contracts. Transitions from unemployment to new jobs are modeled as a process of random matching and Nash bargaining. Non-employed workers make consumption and saving decisions as in a standard growth model, as well as whether or not to participate in the labor market. The stationary equilibrium is characterized. The model is then calibrated to the U.S. labor market to study quantitatively the worker flows and distributions, the compensation dynamics, and the effects of UI system.     

Equilibrium "Anomalies"

Many empirical “anomalies” are actually consistent with the single beta capital asset pricing model if the empiricist utilizes an equity‐only proxy for the true market portfolio. Equity betas estimated against this particular inefficient proxy will be understated, with the error increasing with the firm's leverage. Thus, firm‐specific variables that correlate with leverage (such as book‐to‐market and size) will appear to explain returns after controlling for proxy beta simply because they capture the missing beta risk. Loadings on portfolios formed on relative leverage and relative distress completely subsume the powers of the Fama and French (1993) returns to small minus big market capitalization (SMB) portfolios and returns to high minus low book‐to‐market (HML) portfolios factors in explaining cross‐sectional returns.     

Equilibrium in a Dynamic Limit Order Market

We model a dynamic limit order market as a stochastic sequential game with rational traders. Since the model is analytically intractable, we provide an algorithm based on Pakes and McGuire (2001) to find a stationary Markov‐perfect equilibrium. We then generate artificial time series and perform comparative dynamics. Conditional on a transaction, the midpoint of the quoted prices is not a good proxy for the true value. Further, transaction costs paid by market order submitters are negative on average, and negatively correlated with the effective spread. Reducing the tick size is not Pareto improving but increases total investor surplus.     

关系型融资模式的均衡分析和均衡的突破

距离型融资模式是未来融资方式的一个合理选择,但在我国该模式并无法如预期简单实现,因为关系型融资模式是一个均衡,而模式的转换是一个均衡的突破.我国的企业偏好债务融资而非股本融资,银行有维持和发展银企关系的激励,国家则通过金融支持来保护和控制银行,三方都没有积极性偏离均衡.均衡的突破关键在于政银关系.政府退出"金融支持"具有必要性、合理性和可行性.另外,缩小"破产罚金",WTO的冲击,也有助于该均衡的瓦解.     

True Spreads and Equilibrium Prices

Stocks and other financial assets are traded at prices that lie on a fixed grid determined by the minimum tick size. Observed prices and quoted spreads do not correspond to the equilibrium prices and true spreads that would exist in a market with no minimum tick size. Using Monte Carlo Markov Chain methods, this paper estimates the equilibrium prices and true spreads. For large stocks, most of the quoted spread is attributable to the rounding of prices and the adverse selection component is small. The true spread and the adverse selection component are greater for mid-sized stocks.     

Equilibrium Exhaustible Resource Price Dynamics

We develop equilibrium models of exhaustible resource markets with endogenous extraction choices and prices. Our analysis demonstrates how adjustment costs can generate oil and gas forward price dynamics with two factors, consistent with the behavior these commodities exhibit in the Schwartz and Smith (2000) calibration. Our two‐factor model predicts that stochastic volatility will arise in these markets as a natural consequence of production adjustments, however, and we provide supporting empirical evidence. Differences between endogenous price processes from our general equilibrium model and exogenous processes in earlier papers can generate significant differences in both financial and real option values.     

Consumption Externality and Equilibrium Underinsurance

Relative consumption has been found to be crucial in many areas, such as asset pricing, the design of taxation, and economic growth. This article extends this line of research to the individual's insurance decision. We first define “keeping up with the Joneses” in the purchase of insurance and find that jealousy does not necessarily give rise to “keeping up with the Joneses.” We also identify several sufficient conditions that cause the optimal coverage in the private market to be less than the social optimum (equilibrium underinsurance). Jealousy is found to be neither a sufficient nor a necessary condition for equilibrium underinsurance. We further show that a social welfare maximizing government could adopt a tax system to correct for the consumption externality and make individuals better off.     

权益均衡论:关于财务会计目标的思考

作为规范会计理论的两大学派:受托责任学派和决策有用学派只是片面地以委托方对会计信息的要求作为会计目标,忽略了会计信息系统中各利益相关者之间在会计信息质和量的规定性的界定上的利益冲突和会计信息系统这种制度安排的激励机制效应以及会计信息披露成本的制约。本文通过对会计信息系统中各利益相关者之间在涉及会计事项的各类交易中的利益冲突与“纳什均衡”转换机理的分析,逻辑推导出“纳什均衡”状态下的会计信息质和量的规定性和财务会计目标。     

Equilibrium Forward Curves for Commodities

We develop an equilibrium model of the term structure of forward prices for storable commodities. As a consequence of a nonnegativity constraint on inventory, the spot commodity has an embedded timing option that is absent in forward contracts. This option's value changes over time due to both endogenous inventory and exogenous transitory shocks to supply and demand. Our model makes predictions about volatilities of forward prices at different horizons and shows how conditional violations of the 'Samuelson effect' occur. We extend the model to incorporate a permanent second factor and calibrate the model to crude oil futures data.