The Probationary Period as a Screening Device: The Monopolistic Insurer

Stiglitz [1977], considering asymmetry of information in a monopolistic insurance market and the monetary deductible as a screening device, shows that an equilibrium is always of a separating type. High risks buy complete insurance whilst low risks buy partial insurance. In this paper, we show that a pooling equilibrium may exist if a probationary period, rather than the partial coverage in monetary terms, is used as a screening device.JEL Classification No.: D42, D82     

Multidimensional Screening in Insurance Markets with Adverse Selection

Bundled coverage of different losses and distinct perils, along with differential deductibles and policy limits, are common features of insurance contracts. We show that, through these practices, insurers can implement multidimensional screening of insurance applicants who possess hidden knowledge of their risks, and thereby reduce the externality cost of adverse selection. Competitive forces drive insurers to exploit multidimensional screening, enhancing the efficiency of insurance contracting. Moreover, multidimensional screening allows competitive insurance markets to attain pure strategy Nash equilibria over a wider range of applicant pools, resolving completely the Rothschild–Stiglitz nonexistence puzzle in markets where the perils space is sufficiently divisible.     

Explaining Insurance Policy Provisions via Adverse Selection

In this article, we show that common insurance policy provisions—namely, deductibles, coinsurance, and maximum limits–can arise as a result of adverse selection in a competitive insurance market. Research on adverse selection typically builds on the assumption that different risk types suffer the same size loss and differ only in their probability of loss. In this study, we allow the severity of the insurance loss to be random and, thus, generalize the results of Rothschild and Stiglitz [1976] and Wilson [1977]. We characterize the separating equilibrium contracts in a Rothschild-Stiglitz competitive market. By further assuming a Wilson competitive market, we show that an anticipatory equilibrium might be achieved by pooling, and we characterize the optimal pooling contract.     

A Theory of the Demand for Underwriting

We examine the demand for underwriting and its effect on equilibrium in an insurance market in which insureds know their risk type, but insurers do not. Our analysis indicates that a set of policies including one that requires buyers to take an underwriting test can constitute a full coverage Nash equilibrium when perfect classification is possible. We also find that underwriting equilibria, in which low risks obtain greater coverage than they would without underwriting, widely exist in a Wilsonian market with nonmyopic insurers. Our findings provide a potential explanation for why empirical evidence on adverse selection is mixed.     

On the Role of Patience in an Insurance Market With Asymmetric Information

We analyze a two-period competitive insurance market that is characterized by the simultaneous presence of moral hazard and adverse selection with regard to consumer time preferences. It is shown that there exists an equilibrium in which patient consumers use high effort and buy an insurance contract with high coverage, whereas impatient consumers use low effort and buy a contract with low coverage or even remain uninsured. This finding may help to explain why the opposite of adverse selection with regard to risk types can sometimes be observed empirically.     

Der Einfluss einer staatlichen Grundsicherung auf die Versicherungsnachfrage bei asymmetrischer Informationsverteilung

In this article, we develop a model framework in which the influence of a state assistance on insurance demand in an insurance market with imperfect information can be examined. It turned out that a state subsidy of very low level has no influence on the insurance demand at all. If the state assistance is adequately high, the individuals will prefer government assistance to market insurance. In case of adverse selection, a state assistance can have the consequence that the good risks decide not to buy any insurance while the bad risks purchase full insurance cover. The state assistance can therefore contribute to solve the problem of adverse selection. In case of moral hazard, a surprising result has been found out. The state assistance can bring the measures of loss minimizing to a standstill before the insurance can do it. The state subsidy amplifies the moral hazard behaviour and is therefore not a suitable instrument to solve problems with moral hazard.     

Unravelling vs Unravelling: A Memo on Competitive Equilibriums and Trade in Insurance Markets

Both Akerlof (1970) and Rothschild and Stiglitz (1976) show that insurance markets may “unravel”. This memo clarifies the distinction between these two notions of unravelling in the context of a binary loss model of insurance. I show that the two concepts are mutually exclusive occurrences. Moreover, I provide a regularity condition under which the two concepts are exhaustive of the set of possible occurrences in the model. Akerlof unravelling characterises when there are no gains to trade; Rothschild and Stiglitz unravelling shows that the standard notion of competition (pure strategy Nash equilibrium) is inadequate to describe the workings of insurance markets when there are gains to trade.     

Equilibrium in Competitive Insurance Markets Under Adverse Selection and Yaari's Dual Theory of Risk

Under Yaari's dual theory of risk, we determine the equilibrium separating contracts for high and low risks in a competitive insurance market, in which risks are defined only by their expected losses, that is, a high risk is a risk that has a greater expected loss than a low risk. Also, we determine the pooling equilibrium contract when insurers are assumed non-myopic. Expected utility theory generally predicts that optimal insurance indemnity payments are nonlinear functions of the underlying loss due to the nonlinearity of agents' utility functions. Under Yaari's dual theory, we show that under mild technical conditions the indemnity payment is a piecewise linear function of the loss, a common property of insurance coverages.     

Financial Markets for Unknown Risks if Beliefs Differ

We consider a general equilibrium model with individual and collective risks. The article builds on a contribution by Chichilnisky and Heal, who show that contingent Arrow–Debreu equilibria can also be supported in economies with Arrow securities and mutual insurance contracts. However, they show this to be true in general only if beliefs are identical, a very restrictive assumption in the context of unknown risks. Moreover, they claim complete insurance in equilibrium to be impossible if beliefs are different. We show that even with different beliefs, firstly, complete insurance is possible in each statistical state, and secondly, contingent equilibrium can still be supported in economies with insurance and securities.     

On the Demand for Portfolio Insurance

While insurers manage underwriting risk with various methods including reinsurance, insurers increasingly manage asset risk with options, futures, and other derivatives. Previous research shows that buyers of portfolio insurance pay considerably for downside protection. We add to this literature by providing the first evidence on the cost of portfolio insurance, the payoff to portfolio insurance, and the relative demand for portfolio insurance across VIX levels. We find that the demand for portfolio insurance is relatively high at low levels of VIX, suggesting purchasers demand more downside protection when this protection is cheap on an absolute basis (but expensive on a relative basis). We also provide the first evidence on the hedging behavior of specific investor classes and show that the demand for portfolio insurance is driven by retail investors (individuals) who buy costly insurance from institutional investors. Results are consistent with other types of paradoxical insurance‐buying behavior.     

Hidden Overconfidence and Advantageous Selection

Theories of adverse selection and moral hazard predict the occurrence of the risk and the coverage of the insurance should be positively correlated, whereas empirical researches find little support of it. This paper provides a theoretical model of hidden overconfidence and demonstrates that a competitive insurance market may settle on separating equilibrium with advantageous selection predicting a negative relationship between risk and coverage. By assuming heterogeneity in risk perception and hidden action on self-protection, we find that, in equilibrium, the rational type of individual takes precautions to reduce the loss probability, whereas the overconfident type of individual will not make any effort. In the separating equilibrium, the insurer provides a product with high coverage to attract rational type of individual (low risk), and a product with low coverage for overconfident type of individual (high risk). In addition, other types of equilibrium such as adverse selection or linear premium rate are also found.     

Captives zur Absicherung von Extremrisiken? Eine Untersuchung am Beispiel der OIL Insurance Limited

The use of captive insurance companies (captives) is quite common among big and international companies. Generally, captives are used to insure against high frequency/low severity risks. However, we can find captives which have been founded to deal with extreme risks as well. An example is the OIL Insurance Limited (OIL Insurance). In this context, we examine from a theoretical perspective whether captives are suitable for insurance against catastrophe risks. We show that regarding actuarial aspects captives have advantages in comparison to internal self-insurance and disadvantages in comparison to external insurance. The foundation of industry captives through the association of several companies can solve some of the problems, but further criteria especially costs have to be considered. Based on the developed arguments, we analyse whether our case example OIL Insurance is an appropriate instrument to transfer extreme risks.     

Chancen und Herausforderungen der Rückversicherung in der gesetzlichen Krankenversicherung

In 2009 a so-called morbidity orientated risk structure equalization scheme was installed for the German statutory health insurance in order to minimize structural differences between different providers with respect to revenue and expenditures. Even with this mechanism some risks to the individual health insurance providers remain. Reinsurance could be a way to mitigate these risks, but so far only very few contracts have been signed. Moreover the existing reinsurance contracts only focus on the periphery of the statutory health insurance system such as travel health insurance. In this article we therefore analyse existing risks for individual health insurance providers and evaluate their (re-)insurability. Hereafter the potential for reinsurance solutions in the German statutory health insurance itself as well as in newer forms of healthcare provision (e.g. integrated health care and managed care) is discussed. We find that reinsurance may be a reasonable solution for many of the risks in the statutory health insurance scheme. But as research in this area is very young further analysis of the nature of risks is necessary.     

Competition and Insurance Twenty Years Later

We are honored to address the European Group of Risk and Insurance Economists and will take the opportunity to make some reflections on the rather uneasy relationship between insurance and competition. Economists generally prescribe competition as a solution for markets that do not work well. Competition allocates resources efficiently and encourages innovation and attention to what customers want. Insurance markets differ from most other markets because in insurance markets competition can destroy the market rather than make it work better. One of the dimensions along which insurance companies compete is underwriting—trying to ensure that the risks covered are “good” risks or that if a high risk is insured, the premium charged is at least commensurate with the potential cost. The resulting partitioning of risk limits the amount of insurance that potential insurance customers can buy. In the extreme case, such competitive behavior will destroy the insurance market altogether. A simple model illustrates.     

博弈论视角下公估人的理性选择及外部约束

保险公估人是保险业发展不可缺少的重要组成部分,但“公估不公”始终是公估行业发展中的一个难题。作为一种典型的承揽关系,保险人与公估人之间存在着信息不对称,以及由此带来的道德风险。本文从博弈论的角度,构建公估人和保险人之间的策略型博弈,通过求解纳什均衡发现,公估人的理性选择并不总是诚实公正。因此,只有加强外部约束,才能实现...     

Self‐Insurance and Self‐Protection as Public Goods

Many public goods provide utility by insuring against hazardous events. Those public goods can have self‐insurance and self‐protection character. For both situations we analyze the efficient public provision level and the provision level resulting from Nash behavior in a private provision game. We consider the interaction of public goods as insurance devices with market insurance. The availability of market insurance reduces the provision level of the public good for both public and private provision, regardless of whether we consider self‐insurance or self‐protection. Moreover, we show that Nash behavior has always a larger impact than the availability of market insurance.     

Complete Versus Incomplete Insurance Contracts under Adverse Selection with Multiple Risks

This article extends the standard adverse-selection model for competitive insurance markets, which assumes a single source of risk, to the case where individuals are subject to multiple risks. We compare the following market situations—the case where insurers can offer comprehensive policies against all sources or risks (complete contracts) and the case where different risks are covered by separate policies (incomplete contracts). In the latter case, we consider whether the insurer of a particular risk has perfect information regarding an individual's coverage against other sources of risks. The analysis emphasizes the informational role of bundling in multidimensional screening. When the market situation allows bundling, it is shown that in equilibrium the low-risk type with respect to a particular source of risk does not necessarily obtain partial coverage against that particular risk.     

Competitive Insurance Markets and Adverse Selection in the Lab

We provide an experimental analysis of competitive insurance markets with adverse selection. Our parameterised version of the lemons’ model of Akerlof in the insurance context predicts total crowding-out of low risks when insurers offer a single full insurance contract. The therapy proposed by Rothschild and Stiglitz consists of adding a partial insurance contract so as to obtain self-selection of risks. We test the theoretical predictions of these two models in two experiments. A clean test is obtained by matching the parameters of these experiments and by controlling for the risk neutrality of insurers and the common risk aversion of their clients by means of the binary lottery procedure. The results reveal a partial crowding-out of low risks in the first experiment. Crowding-out is not eliminated in the second experiment and it is not even significantly reduced. Finally, instead of the predicted separating equilibrium, we find pooling equilibria. The latter can be sustained because insureds who objectively differ in their risk level do not perceive themselves as being so much different.     

Corporate Insurance Strategy: The Case of British Petroleum

The authors provide a fundamental rethinking of how corporations should evaluate various kinds of risks and risk management solutions—a rethinking that leads to a major shift in British Petroleum's approach to insuring property and casualty losses, product liability suits, and other insurable events. Conventional corporate practice—and until the early 1990s (when this article was written) the longstanding policy of BP and most large oil companies—was to insure against large losses while self‐insuring against smaller ones. In this article, the authors explain why BP has chosen to go against the conventional wisdom and instead buy insurance for mainly smaller losses while self‐insuring larger ones. The BP decision came down to factors affecting the market supply of insurance as well as the corporate demand for it. On the demand side, the authors demonstrate that the primary source of demand for insurance by large public companies is not, as standard insurance textbooks assume, to transfer risk away from the corporation's owners. Because corporate stockholders and bondholders effectively manage the effects of such risks by diversifying their own portfolios, the corporate demand for insurance in BP's case stems from the insurers' comparative advantage in evaluating and monitoring BP's smaller risks and in processing claims. On the supply side, the authors explain why the capacity of insurance companies and markets to underwrite very large or highly specialized exposures—when compared to the industry expertise and financial resources of companies like BP—is quite limited, and likely to remain so. Since premiums would be experience‐rated and prior years' losses simply rolled into the following years' premiums, there would be no effective transfer of risk, and so no gain to BP from buying insurance.