Search costs and the severity of adverse selection

In view of some recent empirical evidence, I suggest a relationship between the magnitude of search costs and the severity of adverse selection in the context of a dynamic model with asymmetric information. In markets with small search costs sellers with low quality products misrepresent their quality and demand a high price. If search costs are not negligible, sellers׳ price offers are truthful and all product qualities are traded over time. In markets with small search costs, a budget balanced mechanism can mitigate adverse selection: sellers should pay a per period market participation tax and receive a rebate after trading.     

General equilibrium in economies with adverse selection

We model economies of adverse selection as Arrow–Debreu economies. In the spirit of Prescott and Townsend (Econometrica 52(1), 21–45, 1984a), we identify the consumption set of the individuals with the set of lotteries over net transfers. Thus, prices are linear in lotteries, but they may be non linear in commodity bundles. First, we study a weak equilibrium notion by viewing the economy of adverse selection as a pure exchange economy. The weak equilibrium set is non empty, but some of the allocations may be inefficient, and the equilibria indeterminate. Second, following Prescott and Townsend (Econometrica 52(1), 21–45, 1984a), we introduce an intermediary (firm) supplying feasible and incentive compatible measures. Equilibria are constrained efficient, but the equilibrium set is empty for an open set of economies containing the Rothschild and Stiglitz insurance economies. The research of A. Rustichini was supported by the NSF grant NSF/SES-0136556.     

A general method of computing the cut-off point in adverse selection models

Based on the model set-up in Laffont and Tirole (1986)’s seminal paper ‘Using Cost Observation to Regulate Firms’, we provide a general method of computing the cut-off point above which inefficient firms should be shut down under asymmetric information. With the help of the transversality conditions in optimal control, this method of computing the cut-off point is directly applicable to other adverse selection models under asymmetric information provided the optimization problem in these models could be written as an optimal control problem.     

Analysis of vertical separation of regulators under adverse selection

We analyze the vertical separation of a regulator when a government delegates the task to monitor a regulated firm to an intermediate institution called a “middleman”. We deal with the double adverse selection problem between the government and the middleman, and between the middleman and the firm. We reach three main conclusions. First, we clarify the condition under which vertical separation is socially superior to vertically integrated regulation. Second, we show that when the middleman and the firm are able to collude by using a side contract, collusion can lead to information-sharing effects that enhance social welfare. Third, it is socially desirable for the government to offer a collusion-proof contract to the middleman if the collusion inefficiency is much larger than the expected socially desirable information-sharing effects.      

Liquidity supply and adverse selection in a pure limit order book market

This paper analyzes adverse selection costs and liquidity supply in a pure open limit order book market. We relax assumptions of the Glosten/Såndas modeling framework regarding marginal zero profit order book equilibrium and the parametric market order size distribution. We show that using average zero profit conditions considerably increases the empirical performance while a nonparametric specification for market order size combined with marginal zero profit conditions does not. A cross sectional analysis corroborates the finding that adverse selection costs are more severe for smaller capitalized stocks. We also find additional support for one of the central hypothesis put forth by the theory of limit order book markets, which states that liquidity supply and adverse selection costs are inversely related. Furthermore, adverse selection cost estimates based on our structural model and those obtained using popular model-free methods are strongly correlated. This indicates the robustness of the theory-based approach.     

Adverse selection and bilateral asymmetric information

A simple principal-agent model with bilateral asymmetric information and common values is developed. The agent(s) has private information about his characteristics but does not knowhow these affect outcomes. The principal knows how the characteristics translate into outcomes, but does not observe the characteristics. It is shown that equilibrium contracts aresimple in being designednot to reveal the agent's characteristics. When the agent knows howsome of his characteristics affect the outcome, contracts will be differentiated with respect to precisely those characteristics. An application to the use of genetic information is considered.     

Reputation for quality and adverse selection

We analyze a dynamic market with a seller who can make a one-time investment that affects the returns of tradable assets. The potential buyers of the assets cannot observe the seller׳s investment prior to the trade or verify it in any way after the trade. The market faces two types of inefficiency: the ex-ante inefficiency, i.e., the seller׳s moral hazard problem, and the ex-post inefficiency, i.e., inefficient ex-post allocations due to the adverse selection problem. We analyze how the observability of information by future buyers, through which the seller builds a reputation, affects the two types of inefficiency as well as the interplay between them.     

Collusion and group lending with adverse selection

In an environment with correlated returns, this paper characterizes optimal lending contracts when the bank faces adverse selection and borrowers have limited liability. Group lending contracts are shown to be dominated by revelation mechanisms which do not use the ex post observability of the partners' performances. However, when collusion between borrowers under complete information is allowed, group lending contracts are optimal in the class of simple revelation mechanisms (which elicit only the borrower's own private information) and remain useful with extended revelation mechanisms.     

Adverse selection,commitment and exhaustible resource taxation

This paper studies the contractual relationship between a government and a firm in charge of the extraction of an exhaustible resource. Governments design taxation scheme to capture resource rent and they usually propose contracts with limited duration and possess less information on resources than the extractive firms do. This article investigates how information asymmetry on costs and an inability to commit to long-term contracts affect tax revenue and the extraction path. This study gives several unconventional results. First, when information asymmetry exists, the inability to commit does not necessarily lower tax revenues. Second, under asymmetric information without commitment, an efficient firm may produce during the first period more or less than under symmetric information. Hence, the inability to commit has an ambiguous effect on the exhaustion date. Third, the modified Hotelling's rule is such that an increase in the discount factor does not necessarily reduce the first-period extraction.     

Insurance contracts with imprecise probabilities and adverse selection

Summary. This article deals with optimal insurance contracts in the framework of imprecise probabilities and adverse selection. Agents differ not only in the objective risk they face but also in the perception of risk. In monopoly, a range of configurations that VNM preferences preclude appears: a pooling contract may be optimal, incomplete coverage may be offered to high risks, low risks may be better covered.Received: 1 November 2001, Revised: 15 April 2003, JEL Classification Numbers: D81, D82, G22.Useful suggestions by Emmanuelle Auriol, Bernard Bensaïd, Michéle Cohen, Isaac Meilijson and the anonymous referee are acknowledged. Correspondence to: M. Jeleva     

Assortative matching, adverse selection, and group lending

This note reconsiders a theoretical result asserted to explain the success of group lending programs in LDCs. It has been claimed that if groups are allowed to form themselves, risky and safe borrowers will sort themselves into relatively homogenous groups. This “positive assortative matching” can be exploited by lenders to solve an adverse selection problem that would otherwise undermine the effectiveness of such lending programs. I show that the positive assortative matching result does not necessarily hold if earlier models are extended to incorporate dynamic incentives.     

有限信息与假冒伪劣商品的识别

基本竞争模型完全信息的假设与现实相悖:由于信息的真伪难辨;信息收集需要成本;消费者能够记忆并回想的信息有限;消费者对信息的加工能力有限以及信息市场不完善等原因,致使消费者所掌握的信息非常有限.信息有限的结果是市场稀薄和假冒伪劣商品盛行.消费者可以借助担保、信誉、专家、标准以及价格制度等方法去识别假冒伪劣商品.     

Group size and the private supply of a best-shot public good

This paper examines the relationship between group size and the likelihood that a best-shot public good is voluntarily provided. Holding fixed each member's individual probability of supplying the public good, the likelihood of supply increases as the group grows. This is the size effect. However, as group size increases, the probability that each individual member supplies decreases. This is the strategic effect. The net effect of group size on the likelihood is thus ambiguous. As group size increases without bounds, the two effects are offset—the likelihood approaches a finite limit.     

Consistent firm choice and the theory of supply

Summary. This paper analyzes the problem of deriving predictions, regarding supply behavior of a competitive firm, from prior consistency postulates about input-output choices made by such a firm. It extends the literature by introducing a consistency postulate for firm choice, which is weaker than profit-maximization. This consistency postulate is nevertheless both necessary and sufficient for supply responses predicted by the standard theory of firm choice based on the postulate of profit-maximization. Furthermore, our rationality postulate, in conjunction with another condition, is shown to be equivalent to firm choice behavior that can be rationalized in terms of profit maximization.Received: 11 April 2003, Revised: 26 April 2004, JEL Classification Numbers: D21.Indraneel Dasgupta: I thank Bhaskar Dutta and two anonymous referees for helpful comments on earlier versions.     

服务供应链动态能力、组织学习与合作绩效关系研究

在服务业竞争日趋激烈、市场环境多变的背景下,如何通过组织学习来构建动态能力,从而提升合作绩效是服务企业不可回避的焦点问题。在梳理动态能力理论研究的基础上,提出服务供应链动态能力由环境感知能力、资源整合能力和组织变革能力3个维度构成,探讨了组织学习对服务供应链动态能力形成的作用机理及其对合作绩效的影响,从树立共同目标、强化合作联盟、培养组织学习氛围等方面提出了服务供应链协同发展建议。     

Minimum standards, insurance regulation and adverse selection: evidence from the Medigap market

This paper examines the implications of minimum standards for insurance markets. I study the imposition of binding minimum standards on the market for voluntary private health insurance for the elderly. The central estimates suggest that the introduction of the standards was associated with an 8 percentage point (25%) decrease in the proportion of the population with coverage in the affected market, with no evidence of substitution toward other, unregulated sources of insurance coverage. To explore possible factors contributing to the impact of the minimum standards, I develop comparative static predictions of the impact of imposing minimum standards in an insurance market with adverse selection. The observed changes in market equilibrium associated with the minimum standards are broadly consistent with these predictions, providing evidence of the existence of adverse selection in this insurance market. More importantly, they suggest that the presence of adverse selection—which in principle may provide an economic rationale for minimum standards—in practice may have exacerbated the declines in insurance coverage associated with the minimum standards.     

Cycles and multiple equilibria in the market for durable lemons

Summary. The paper investigates the nature of market failure in a dynamic version of Akerlof (1970) where identical cohorts of a durable good enter the market over time. In the dynamic model, equilibria with qualitatively different properties emerge. Typically, in equilibria of the dynamic model, sellers with higher quality wait in order to sell and wait more than sellers of lower quality. The main result is that for any distribution of quality there exist an infinite number of cyclical equilibria where all goods are traded within a certain number of periods after entering the market. Received: December 21, 2000; revised version: September 5, 2001     

Entry,growth, and survival: The new learning on firm selection and industry evolution

This paper tries to shed some light on the seeming paradox posed by the findings in the industrial organization literature that (1) the bulk of firms in an industry are not only very small, but also sufficiently small so that they are operating at a sub-optimal scale of output, and (2) entrepreneurs are apparently not deterred from starting new firms even in industries where scale economies play an important role. A dynamic view of the process of firm selection and industry evolution is that new firms typically start at a very smal scale of output. Because this level of output may be sub-optimal, the firm must grow in order to survive. The empirical evidence supports such a dynamic view of the evolutionary nature of industries. Viewed through a dynamic lens, the often-observed asymmetric size distribution of firms becomes more understandable. The persistence of an asymmetric firm-size distribution skewed towards small enterprises presumably reflects a continuing process of entry into industries and not necessarily the survival of such small and suboptimal enterprises over a long period of time.     

Trade prices and supply in the UK economy

Current account imbalances are a major source of instability in the world monetary and trading system. Measures to correct these imbalances have largely involved adjustments to exchange rates. In the international trade literature, when the current account is in deficit, the Marshall-Lerner condition is sufficient for a successful devaluation. However, this partial equilibrium condition — apart from being based on the assumption that supply elasticities are infinite — abstracts from how the domestic economy responds to the change in relative prices. In this paper we develop a model of price and output determination in an open economy with imperpectly competitive markets, and draw a distinction between goods which are exported and those which are supplied to the domestic market. This means that we have to determine jointly both export prices and the domestic price of house sales. We show that as long as there is no money illusion in the labour market a fall in the nominal exchange rate raises domestic and export prices proportionally and leaves trade volumes unaffected. However, shifts in domestic absorption relative to overseas demand — by changing relative prices — cause shifts in the relative supply of exports and domestically sold goods and affect the trade balance. Thus fiscal and monetary measures directed towards reducing domestic absorption are more likely to be successful in correcting current account imbalances than exchange rate depreciation.