沪市封闭式基金流动性、买卖价差与市场深度分析——一个基于高频数据的经验研究

本文采用Brockman and Chung（1999）使用的买卖价差分解技术，将价差分解成逆向选择成本、指令处理成本和指令持续性成本三部分，并运用在上海证券交易所上市的25只封闭式基金2005年9月9日至2006年9月28日期间的高频交易数据进行回归分析。实证结果表明，价差中逆向选择成本仅占27．36％，明显低于沪市股票市场（37．05％，见杨朝军等（2002）），沪市封闭式基金市场的信息不对称程度较沪市股票市场轻。进一步实证分析表明，沪市封闭式基金的买卖价差对收益率波动率较为敏感，而以报价深度度量的市场深度则对价格的变动较为敏感。     

Adverse selection and corporate governance

This paper examines the impact of corporate governance on the adverse selection component of the bid-ask spread of stocks listed on the Singapore Exchange. These companies have been identified by Credit Lyonnais Securities Asia (CSLA) with the highest level of corporate governance among 25 emerging markets. We measure corporate governance by several criteria: discipline, transparency, independence, accountability, responsibilities, fairness, and social awareness. The results show that corporate governance has an inverse relationship with adverse selection. However, only the transparency dimension exhibits a significant inverse relationship with adverse selection. In addition, Government-Linked Companies (GLCs) are shown to have a smaller adverse selection component than non-GLCs.     

Genetic adverse selection: Evidence from long-term care insurance and Huntington disease

Individual, personalized genetic information is increasingly available, leading to the possibility of greater adverse selection over time, particularly in individual-payer insurance markets. We use data on individuals at risk for Huntington disease (HD), a degenerative neurological disorder with significant effects on morbidity, to estimate adverse selection in long-term care insurance. We find strong evidence of adverse selection: individuals who carry the HD genetic mutation are up to 5 times as likely as the general population to own long-term care insurance. This finding is supported both by comparing individuals at risk for HD to those in the general population and by comparing across tested individuals in the HD-risk population with and without the HD mutation.     

双边市场与平台理论研究综述

有关双边市场和平台理论的研究是近年来产业经济学的最新进展之一.传统的"单边"市场仅涉及商品的交易,但在双边市场中,"平台"则成为核心,它通过实现两种(或多种)顾客之间的接触获取利润.研究中一般将双边市场分为交易中介、媒体、支付工具、软件平台等四种类型,根据这一划分对这四个方面的研究成果进行综述,总结各领域所重点关注的问题、得到的主要结论及研究中的重点,并指出未来可能的研究方向.     

Adverse selection under ignorance

Summary. We examine an adverse selection relationship in which the principal may ignore the ex ante distribution of the agent's types. The principal's behavior is described by a disutility function that covers the standard minimax regret and minimax loss criteria. We show that the incentive compatible and individually rational mechanism, which minimizes the maximal (or the minimal) principal's disutility over a set of priors, requires the efficient agents to realize the corresponding first-best actions and may demand actions lower than the first-best ones from less efficient agents. We also analyze the qualitative differences between the case in which the principal considers regrets and the case in which he considers losses. Received: 19 October 1998; revised version: 9 November 1999     

Starting Small and Commitment

I study a model of a long-term partnership with two-sided incomplete information. The partners jointly determine the stakes of their relationship and individually decide whether to cooperate with or betray each other over time. I characterize the extremal—interim incentive efficient—equilibria. In these equilibria, the partners generally “start small,” and the level of interaction grows over time. The types of players separate quickly. Further, cooperation between “good” types is viable regardless of how pessimistic the players are about each other initially. The quick nature of separation in an extremal equilibrium contrasts with the outcome selected by a strong renegotiation criterion (as studied in Watson (1999, J. Econ. Theory85, 52–90). Journal of Economic Literature Classification Numbers: C72, C73, D74.     

反垄断法总则与双边市场理论的铆合适用--以互联网医药行业为例

互联网医药行业中,私人经济与公共利益交叉程度高,同时涉及经济垄断和行政垄断领域,部分适用通过市场机制配置资源的原则。其涉及市场机制的部分,可能会触动反垄断调查。医药实体行为或业务的性质,是界定该行为或业务是否适用市场机制的标准,同时也是判断《反垄断法》适用性的标准。互联网平台经济具有双边市场的特性,会在相关市场的界定和竞争分析的路径方面与传统医药行业案件不同。另一方面,并非所有医药行业与互联网平台的结合都适用双边市场理论,决定双边市场理论适用性的标准是医药实体与互联网平台之间的相互关系。在处理互联网医药行业垄断案件时,需正确区分两个关系:市场机制与非市场机制的关系、医药实体与互联网平台的关系。     

Adverse Selection in the Annuities Market and the Impact of Privatizing Social Security

The observation that few Americans purchase life annuities has often been attributed to adverse selection. A still unanswered question is whether observable price increases caused by adverse selection can be generated endogenously in a life cycle model. This paper calibrates a pure life cycle model for a characteristic US cohort and reproduces three stylized facts. Adverse selection increases annuity prices by 7–10 percent; the cost of adverse selection rises with the age of the annuitant; and the cost is smaller for females than for males. Social security privatization could reduce annuity prices by between 2 and 3 percent.     

成交风险、交易成本、逆向选择风险与投资者订单选择

本文利用多元对教条件自田归计数模型讨论了交易概率、交易成本以及选择成本等市场微观结构因素对中国证券市场投资者订单选择的影响.实证研究发现:(1)交易成本的增加会削弱投贵者递交指令的积极性,当成交风险较大时,投资者更偏好市价订单;(2)由于中国证券市场订单类型较为单一,逆向选择风险对投资者订单选择行为并无显著性的影响;(3)在同质信息的驱动下不同类型订单之间具有显著的持续和交叉相关性.     

Taxation,insurance, and precautionary labor

We examine optimal taxation and social insurance with adverse selection in competitive insurance markets. In a previous literature, it has been shown that, with perfect insurance markets, social insurance improves welfare since it is able to redistribute without creating distortions. This result has been taken as robust to the introduction of adverse selection as this would only provide additional justifications for social insurance. We show, however, that adverse selection can weaken the case for social insurance compared to a situation with perfect markets. Whenever social insurance mitigates private underinsurance, it also causes welfare-reducing effects by decreasing precautionary labor supply and hence tax revenue. In addition, adverse selection may reduce the redistributive potential of social insurance. We illustrate our general results using different equilibrium concepts for the insurance market. Notably, we derive conditions under which a complete renunciation of social insurance is optimal and the government only relies on income taxation to achieve its redistributive objectives.     

The scope of auctions in the presence of downstream interactions and information externalities

We scrutinize the scope of auctions for firm acquisitions in the presence of downstream interactions and information externalities. We show that no mechanism exists that allows an investor to acquire a low-cost firm under incomplete information: a separating auction implies adverse selection and relies substantially on commitment to allocation and transfer rules. A pooling auction serves as a commitment device against ex-post opportunistic behavior and alleviates adverse selection. It can earn the investor a higher expected payoff than a separating auction, even when consistency is required as to qualify for a sequential equilibrium.     

Adverse Selection in Health Insurance Markets: A Classroom Experiment

Adverse selection as it relates to health care policy will be a key economic issue in many upcoming elections. In this article, the author lays out a 30-minute classroom experiment designed for students to experience the kind of elevated prices and market collapse that can result from adverse selection in health insurance markets. The students should come away from the experiment understanding why adverse selection leads to high prices on good quality insurance and why it forces healthy individuals into low quality plans. Additionally, the experiment helps students think about the market characteristics that make health insurance particularly vulnerable to problems of asymmetric information. Finally, the experiment connects the adverse selection problem with key features of the 2010 Patient Protection and Affordable Care Act.     

Adverse selection and statistical discrimination: An analysis of Canadian automobile insurance

Statistical discrimination occurs when a characteristic, such as sex, is used as an indicator of the risk group of an individual. The theory of adverse selection is used to explain the occurrence of statistical discrimination. A model of the market for collision insurance, which is based on the theory of adverse selection, is estimated on Canadian data. The results suggest that adverse selection occurs in this market. Simulations of the effect of prohibiting sexual discrimination in the 21–24 age group indicate that the premiums for single females would increase substantially and that a significant proportion would no longer purchase collision insurance.     

股权分置下我国上市公司并购的逆向选择问题实证研究

基于对我国上市公司掏空行为和支持行为的分析,本文提出中国上市公司在股权分置下并购行为的逆向选择问题和长期均衡问题。文章通过对股票市场近10年的走势分析以及通过对2002～2003两年间180起并购事件的并购行为的实证研究,得到股权分置下掏空行为逆向选择问题和长期均衡特征:股市长期低迷,在低迷的股市中绝大部分上市公司更倾向于掏空行为。文章同时指出,我国的一股独大和股权分置的制度安排是这种逆向选择问题和社会福利低水平上长期均衡的重要影响因素。     

Bank structure, capital accumulation and growth: a simple macroeconomic model

Summary. This paper analyzes the equilibrium growth paths of two economies that are identical in all respects, except for the organization of their financial systems: in particular, one has a competitive banking system and the other has a monopolistic banking system. In addition, the sources of inefficiencies, as a result of monopoly banking, and their relationship to the existence of credit rationing are explored. Monopoly in banking tends to depress the equilibrium law of motion for the capital stock for either of two reasons. When credit rationing exists, monopoly banks ration credit more heavily than competitive banks. When credit is not rationed, the existence of monopoly banking leads to excessive monitoring of credit financed investment. Both of these have adverse consequences for capital accumulation. In addition, monopoly banking is more likely to lead to credit rationing than is competitive banking. Finally, the scope for development trap phenomena to arise is considered under both a competitive and a monopolistic banking system. Received: September 20, 1999; revised version: December 3, 1999     

Asymmetric Information and Adverse Selection in Mauritian Slave Auctions

Information asymmetry is a necessary prerequisite for testing adverse selection. This paper applies this sequence of tests to Mauritian slave auctions. The theory of dynamic auctions with private and common values suggests that when an informed participant is known to be active, uninformed bidders will be more aggressive and the selling price will be higher. We conjecture that observable family links between buyer and seller entailed superior information and find a strong price premium when a related buyer purchased a slave, indicative of information asymmetry. We then test for adverse selection using sale motivation. Our results indicate large discounts on voluntary as compared to involuntary sales. Consistent with adverse selection, the market anticipated that predominantly low-productivity slaves would be brought to the market in voluntary sales.     

Does asymmetric information matter in the early insurance market? Evidence from the auto insurance market

In the late 1960s, the performance of automobile insurance declined dramatically in Japan in spite of rapid growth in the diffusion rate, and the premiums were sharply raised several times in order to improve the situation. This observation indicates the possible presence of adverse selection (death spiral), and provides an ideal situation for assessing informational asymmetry. Using bodily injury liability (BIL) insurance data from 46 Japanese prefectures over the period 1966 to 1975, this article tests two hypotheses of adverse selection: (i) high-risk drivers were more likely to join the BIL insurance market and (ii) sharp premium increases drove low-risk policyholders away. Various empirical analyses show that there is little evidence for either type of adverse selection. We also test whether a risk-misperception hypothesis can explain our results, and find some evidence that the population density have a significantly positive impact on the demand for BIL insurance.     

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.     

展览产品定价模型及价格影响因素研究——基于双边市场理论视角

本文借鉴近年来兴起的双边市场理论对展览产品的定价模型及影响因素进行了理论研究。本文指出，展览市场是典型的双边市场，具有明显的网络外部性。本文通过建立垄断和竞争两种模型研究了展览产品的定价，并指出参展商和观众的需求价格弹性、一方消费者给另一方消费者带来的网络外部性、展览市场的竞争以及产品差异化都是影响展览产品定价的主要因素。     

Equilibrium in a decentralized market with adverse selection

Summary. This paper deals with trade volume and distribution of surplus in markets subject to adverse selection. In a model where two qualities of a good exist, I show that if trade is decentralized (i.e. conducted via random pairwise meetings of agents), then all units of the good are traded, and all agents have positive ex-ante expected payoffs. This feature is present regardless of the quality distribution, and persists in the limit as discounting is made negligible. This offers a sharp contrast to models of centralized trade with adverse selection (Akerlof, Wilson). Received: April 2, 2001; revised version: March 29, 2002 RID="*" ID="*" This research was funded by a grant from UQAM. I wish to thank Roberto Serrano and seminar participants at UQAM, Queen's University at Kingston, the 2001 CEME General Equilibrium Conference (Brown University), and the 2001 North American Summer Meeting of the Econometric Society (University of Maryland) for comments.