Endogenous Categorization in Insurance

This paper analyzes the welfare properties of equilibrium when insurers use observable actions to classify consumers into different risk categories, and consumers' choice is influenced by the insurance market consequences of their actions. Specifically, we analyze this problem at the example of a car insurance market, in which individual preferences over car types are correlated with risk type and used by insurance firms for ratemaking. Equilibrium premiums for each car are determined by the losses that it generates. Consumers take insurance premiums into account when deciding which car to buy. This creates an incentive to buy the car that is preferred by more low risk individuals. From a utilitarian point of view, this incentive is excessive. Depending on parameters, it may even be possible to construct a tax‐subsidy scheme with balanced budget that Pareto improves on the market equilibrium.     

不确定性与早期劳动合同 --契约理论的一个新发展

在劳动力市场上 ,劳动者和厂商未来的生产率都具有不确定性。早期劳动合同或签约由于一方面可以保证劳动者被排除在劳动力市场之外 ,同时也保证了厂商被排除在事后职位市场的风险之外 ,因而厂商和劳动者具有签订早期劳动合同的激励。尽管早期劳动合同或签约存在成本 ,但只要事前利益超过事后无效率的损失 ,那么早期劳动合同或签约就会发生。对于那些不能获得完全市场保险的人来说 ,签约是一种帕累托最优。早期劳动合同或签约是市场失灵的一种证明 ,早期劳动合同是一种不完全合同 ,也是一种非正式合同 ,它是对契约理论的一个发展。     

Welfare costs of reclassification risk in the health insurance market

We assess the quantitative importance of reclassification risk in the US health insurance market. Reclassification risk arises because the health conditions of individuals evolve over time, while a typical health insurance contract only lasts for one year. Thus, a change in the health status can lead to a significant change in the health insurance premium. We measure welfare gains from introducing explicit insurance against this risk in the form of guaranteed renewable health insurance contracts. We find that in the current institutional environment individuals are well-sheltered against reclassification risk and they only moderately gain from having access to these contracts. More specifically, we show that employer-sponsored health insurance and public means-tested transfers play an important role in providing implicit insurance against reclassification risk. If these institutions are removed, the average welfare gains from having access to guaranteed renewable contracts exceed 4% of the annual consumption.     

Measurement distortion and missing contingencies in optimal contracts

Summary Theory suggests that optimal contracts should include many contingencies to achieve optimal risk sharing. However, in practice, few contracts are as complex as theory suggests. This paper develops a model which is consistent with this observation. The lack of risk sharing results from the interplay of two factors. First, contingencies must be based on information produced by measurement systems, which may be manipulable. Second, when two parties to a contract meet, they often have incomplete information. The type of contract offered may reveal information about the party who proposes it. Different types of agents have different preferences over contingent contracts, because they have different abilities to manipulate the measurement system. These differences in preferences allow the parties to signal their types through the contracts they offer. Noncontingent contracts may be chosen in equilibrium because they are the only contracts which do not give any type an incentive to distort the measurement system and, hence, do not reveal information about the party proposing the contract.We have benefited from conversations with Oliver Hart, Rick Lambert, Michael Riordan and Jean Tirole and the comments of Michel Habib, Nick Yannelis and two anonymous referees. Financial support from the National Science Foundation under grants SES-8920048 and SES-8720589 is gratefully acknowledged.     

Corporate insurance with optimal financial contracting

Summary. This paper attemps to rationalize the use of insurance covenants in financial contracts, and shows how external financing generates a demand for insurance by risk-neutral entrepreneurs. In our model, the entrepreneur needs external financing for a risky project that can be affected by an accident during its realization. Accident losses and final returns are private information to the firm, but they can be evaluated by two costly auditing technologies. We derive the optimal financial contract: it is a bundle of a standard debt contract and an insurance contract with franchise, trading off bankruptcy costs vs auditing costs. We then analyze how this optimal contract can be achieved by decentralized trading on competitive markets when insurance and credit activities are exogenously separated. With additive risks, the insurance contract involves full coverage above a straight deductible. We interpret this result by showing how our results imply induced risk aversion for risk-neutral firms. Received: December 14, 1998; revised version: August 11, 1999     

公司债券的违约风险度量技术及应用

随着我国资本市场的进一步发展,公司债券已经成为我国资本市场重要的金融工具。因此,公司债券的违约风险已经成为投资者关注的重要因素。本文系统地论述了度量公司债券违约风险的三类主要方法：信用评级法、数理模型法和保险思想法。在此基础上,论述了我国发展债券市场提高公司债券违约风险度量技术的基本思路是重点利用信用评级方法,积极开发数理模型方法,创造条件利用保险思想模型。     

Understanding the welfare effects of unemployment insurance policy in general equilibrium

This paper analyzes the welfare effects of unemployment insurance reforms in a general equilibrium incomplete market model. In particular, it decomposes the total welfare effect for each individual into different factors. I consider a model where the consumers face an uninsurable unemployment risk, can save in an interest-bearing asset, and are subject to a borrowing constraint. The labor market is modeled using a Diamond–Mortensen–Pissarides style search and matching model. The decomposition exercises reveal how each factor contributes to the heterogeneity of welfare effects among different consumers.     

Nonlinear incentive provision in Walrasian markets: a Cournot convergence approach

The paper studies insurance with moral hazard in a system of contingent-claims markets. Insurance buyers are modelled as Cournot monopolists or oligopolists. The other agents condition their expectations on market prices, as in models of rational-expectations equilibrium with asymmetric information. Thereby they correctly anticipate accident probabilities corresponding to effort incentives induced by insurance buyers’ net trades. When there are many agents to share the insurance buyers’ risks, Cournot equilibrium outcomes are close to being second-best. In contrast, if insurance buyers are price takers, equilibria fail to exist or are bounded away from being second-best.     

出力不确定下基于保险机制的风电供应链 最优交易决策

随着新一轮电力体制改革的日益推进,参与电力市场竞争是消纳风电等可再生能源的必经之路。由于风电出力受风速等自然条件影响,出力具有较强不确定性,导致其实际出力难以预测,使得风电商参与电力市场面临巨大的收益风险。合理地转移风电商的市场风险,引入有效的风险规避机制,对提高风电商收益稳定性具有重要意义。因此本文基于电量损失保险机制,建立了风电商、售电公司以及保险公司的Stackelberg博弈模型,通过逆向递归法求解纳什均衡,分析保险费率与市场三方利润之间的关系,得出市场主体风电商、售电公司以及保险公司的最优交易决策。最后通过具体算例分析验证得出,引入电量保险机制,制定适当的保险费率,能够使风电商、售电公司以及保险公司三方利益实现共赢。     

Strategic incentive in mixed oligopoly

This paper develops a two stage game model with two competing firms in a mixed oligopolistic market, a public firm and a private firm, and only the public firm giving its manager an incentive contract. The paper presents three types of public firm owner’s objective function and each objective function corresponds to three types of delegation, either of a profit-revenue type, or of a relative performance, or, finally, of a market share one. In an equilibrium, the public firm owner has a dominant strategy to reward his manager with an incentive contract combining own profits and competitor’s profits. Different from Manasakis et al. (2007), this paper suggests that the dominant strategy of the public firm owner is to reward his manager with a profit-revenue type of contract or a market-share type of contract, that is to say profit-revenue is identical with market-share. Using relative-performance type of contract will move the manager away from the owner’s true objective function when the public firm owner only pursues maximizing the social welfare. The private firm will be crowded out and the public firm is the only producer of the market. Under profits-revenues type of contract, the owner’s objective of maximizing the summation of the profit and consumer surplus leads the manager more aggressive. Different combinations give us different results. By comparing the results, each type of incentive contract is an owner’s best response to his decision.     

保险资金持股与股价崩盘风险——市场“稳定器”还是崩盘“加速器”?

现阶段,有关保险资金持股与资本市场稳定相互关系的讨论多止于推测,少有学者以大样本数据进行实证考察。在理论上,保险资金持股上市公司,一方面可以抑制经理人负面信息隐藏,作为市场“稳定器”降低股价暴跌风险;另一方面,也能引发投资者跟风炒作,导致市场情绪高涨和股价高估,成为股价崩盘风险的“加速器”。本文基于2007—2016年中国沪深两市A股上市公司的数据,实证分析保险资金持股上市公司是否加剧市场暴跌及其作用机制。结果显示:保险资金持股加剧了股价崩盘风险,是公司股价崩盘的“加速器”。这一结论在经过DID模型、工具变量回归、PSM+OLS等内生性分析,以及稳健性检验之后依然成立。进一步研究表明,相比于民营、小型和财产保险公司,在股市投资规模更大的国有、大型和人寿保险公司更能引发市场跟风炒作,加剧股价崩盘风险;不过,当保险资金作为前十大股东参与公司治理时则能够降低股价崩盘风险。本文不仅为保险资金持股与资本市场稳定相互关系的讨论提供了经验证据,也为规范保险资金股权投资,维护资本市场稳定提供有益借鉴。     

A coalition proof equilibrium for a private information credit economy

Summary This paper examines an economy in which agents with private information about their own productive capabilities seek to raise capital to fund their investment projects. We employ an equilibrium concept which is closely related to Coalition Proof Nash Equilibrium. In equilibrium, all agents who succeed in raising capital (entrepreneurs) are pooled; they all receive the same contract or consumption schedule. Entrepreneurs, however, are separated from those who fail to raise capital. This separation results in productive efficiency for the economy. If the economy has no viable alternative investment opportunity (other than agents' projects) then equilibrium allocations can be supported by a (non-intermediated) securities market. If there is a viable alternative, the equilibrium allocations cannot be supported by a securities market equilibrium. We interpret this case as suggesting the emergence of financial intermedary coalitions.     

"龙头"企业与农户的合约选择--基于风险和风险态度的解释

和现有文献基于交易成本理论解释"龙头"企业和农户之间的合约选择不同,本文把农业项目的风险分解为生产风险和市场风险,运用委托--代理理论分析了风险和风险态度对"龙头"企业和农户之间合约选择的影响.分析表明,在不存在机会主义行为或市场风险为零的情况下,"龙头"企业和不同农户之间合约的选择取决于双方对风险的态度和农业项目生产风险的大小.     

Labour contracts in a stock market economy

In this paper, labour contracts are examined in the context of a general stock market economy where all shareholders are risk averse, and firms act in shareholders interest. The problem considered is whether some firm can offer a wage contract that will make all its shareholders better off. We show by example that, contrary to the arguments in the partial equilibrium framework, it is possible that no such contract will exist, even when there are potential gains to risk sharing. A sufficient condition for the existence of a feasible pareto improving contract is given. It is shown that contract trading will arise provided some firm has no large shareholders.     

Learning rational expectations in an asset market

Will traders in a risky asset market learn Muthian expectations when they initially lack the necessary information? If some traders learn from their observations, will market dynamics depend only on “fundamentals,” as implied by the Efficient Market Hypothesis? This paper shows that at any finite point in time the answer to these questions is “no”. The context is a constant absolute risk aversion model with two kinds of traders and asymmetric information. The market converges asymptotically to a rational expectations equilibrium where prices depend only on fundamentals and the market is efficient.     

Electricity market mergers with endogenous forward contracting

We analyze the effects of electricity market mergers in an environment where firms endogenously choose their level of forward contracts prior to competing in the wholesale market. We apply our model to Alberta’s wholesale electricity market. Firms have an incentive to reduce their forward contract coverage in the more concentrated post-merger equilibrium. We demonstrate that endogenous forward contracting magnifies the price increasing impacts of mergers, resulting in larger reductions in consumer surplus. Current market screening procedures used to analyze electricity mergers consider firms’ pre-existing forward commitments. We illustrate that ignoring the endogenous nature of firms’ forward commitments can yield biased conclusions regarding the impacts of market structure changes such as mergers. In particular, we show that the price effects of mergers can be largely underestimated when forward contract quantities are held at pre-merger levels. Whether the profits of the merged firm are greater with fixed or endogenous forward quantities is ambiguous.     

The linkage between life insurer spread behaviour and credit swap transaction: policyholder protection analysis

ABSTRACT

The paper develops a contingent claim model to evaluate the equity of a life insurer when the insurer could act as a protection buyer or a protection seller in a credit swap transaction market. The investment market and the life insurance market faced by the insurer are assumed to be imperfectly competitive in order to capture the insurer’s asset-leading or liability-reducing spread behaviour. This paper complements the insurance literature by analysing how the effects of credit swap transactions on insurer spread behaviour and policyholder protection, and how they might differ across various degrees of capital regulation, premature default risk, and profit-sharing participation. Our findings offer some useful insights for achieving the stability of the insurance system.     

Efficient risk sharing,non-marketable labor income and fixed-wage contracts

This paper seeks to explain fixed-wage labor contracts. The traditional rationale that fixed wages represent an implicit sale of ‘wage insurance’ by risk-neutral firms to risk-averse workers is rejected as being incompatible with the fact that firms are owned by risk-averse investors. Instead, it is shown that fixed-wage contracts might arise from the non-marketability of labor income. When human capital is not marketable, it becomes optimal to shift all the risk in production onto the firm, since trading in equity markets enables efficient allocation of the uncertainty. The fixed-wage contract shifts the risk to equity owners and in fact replicates the first-best equilibrium that would emerge if individuals were paid their realized marginal product and allowed to trade shares in human capital.     

Long-run industry equilibrium with uncertainty

In this paper we consider the effects of uncertainty on industry equilibrium when firms must commit themselves to production before prices are revealed. We show that (a) an increase in demand uncertainty will (i) not affect the equilibrium number and size of firms if they are risk neutral, (ii) reduce the equilibrium number of firms if they are risk averse, but will have an ambiguous effect on their size. (b) In equilibrium, firms operate at capacity if they are risk neutral, but at excess capacity if they are risk averse.