Unemployment insurance in a sticky-price model with worker moral hazard

This paper studies the role of unemployment insurance in a sticky-price model that features an efficiency-wage view of the labor market based on unobservable effort. The risk-sharing mechanism central to the model permits, but does not force, agents to be fully insured. Structural parameters are estimated using a maximum-likelihood procedure on US data. Formal hypothesis tests reveal that the data favor a model in which agents only partially insure each other against employment risk. The results also show that limited risk sharing helps the model capture many salient properties of the business cycle that a restricted version with full insurance fails to explain.     

Optimal Dividend Payment Strategy under Stochastic Interest Force

This paper attempts to study the optimal dividend barrier strategy in risk analysis of an insurance company under stochastic discount interest. Based on stochastic perturbation methodology, we first describe the random of interest by Wiener Process and Poisson process and yield some theoretical results satisfied by optimal dividend barrier. In the case of an exponential individual claim distribution, a group of barrier values are obtained. Meanwhile we also discuss the effect of stochastic interest on the barrier by data analysis and direct interpretations about interest models. It is found that the barrier is more sensitive to constant interest force than other parameters in interest model and the effect of diffusion coefficient on barrier is less sensitive than that of Poisson coefficient. These all provide insights into the effect of stochastic interest on the optimal barrier, and show the importance of introducing stochastic interest. Finally, we propose several meaningful and follow-up problems, for example, changing the criterion of finding the optimal barrier and discussing under more extended risk models.     

具有奖励机制与再保险安排的最优保险合约设计

在保险合约中引入奖励机制可以使投保人动态参与到保险合约中,赋予了投保人在面对索赔事件时是否执行索赔的可选择权,改变了传统保险合约中投保人执行索赔的单一权利,但却增加了保险人潜在的流动性风险。保险合约中再保险的安排则可以对冲由于奖励机制产生的潜在流动性风险,进一步分散保险人的风险,有助于保险人稳健经营。基于此,通过建立具有红利奖励机制与再保险安排的最优保险合约设计模型,最终求解得到最优保险合约是具有最优免赔额形式的保险合约。利用算例研究方法进行建模,研究结果显示,最优保险合约中的最优免赔额与奖励机制中的红利奖励之间具有正向关系,保费、自留额与最优免赔额之间则存在着显著的负向关系。     

Rationalizing investors’ choices

Assuming that agents’ preferences satisfy first-order stochastic dominance, we show how the Expected Utility paradigm can rationalize all optimal investment choices: the optimal investment strategy in any behavioral law-invariant (state-independent) setting corresponds to the optimum for an expected utility maximizer with an explicitly derived concave non-decreasing utility function. This result enables us to infer the utility and risk aversion of agents from their investment choice in a non-parametric way. We relate the property of decreasing absolute risk aversion (DARA) to distributional properties of the terminal wealth and of the financial market. Specifically, we show that DARA is equivalent to a demand for a terminal wealth that has more spread than the opposite of the log pricing kernel at the investment horizon.     

Optimal investment and reinsurance policies for an insurer with ambiguity aversion

In this paper, we study the optimal investment and reinsurance problem for an insurer based on the variance premium principle, in which three cases are considered. First, we assume that the financial market does not exist. The insurer only holds an insurance business, and the optimal reinsurance problem is studied. Subsequently, we assume that there exists a financial market with an accurately modeled risky asset. The optimal investment and reinsurance problem is investigated under these conditions. Finally, we consider the general case in which the insurer is concerned about the model ambiguity of both the insurance market and the financial market. In all three cases, the value function is set to maximize the expected utility of terminal wealth. By employing the dynamic programming principle, we derive the Hamilton–Jacobi–Bellman (HJB) equations, which are satisfied by the value functions and obtain closed-form solutions for optimal reinsurance and investment policies and the value functions in all three cases. Most interestingly, we elucidate how investment improves the insurer’s utility and find that the existence of ambiguity can significantly affect the optimal policies and value functions. We also compare the ambiguities in the two markets and find that ambiguity in the insurance market has much more significant impact on the value function than the ambiguity in the financial market. It implies that it is more valuable for insurer to precisely evaluate the insurance risk. We also provide some numerical examples and economic explanations to illustrate our results.     

指数风险偏好下的最优保险策略

本文讨论了当投保个体和保险公司为指数风险偏好时，在保费约束下投保个体的最优保险策略问题。本文采用求解对偶优化问题的方法求解这个问题，并给出当损失服从指数分布时最优保险策略解的解析式。本文最后讨论了投保个体和保险公司风险厌恶程度以及保费预算变化对个体最优保险策略的影响。     

Risk aversion in a model of endogenous growth

Despite the evidence on incomplete financial markets and substantial risk being borne by innovators, current models of growth through creative destruction predominantly model innovators’ as risk neutral. Risk aversion is expected to reduce the incentive to innovate and we might fear that without insurance innovation completely disappears in the long run. The present paper introduces risk averse agents into an occupational choice model of endogenous growth in which insurance against failure to innovate is not available. We derive a clear negative relationship between the level of risk aversion and long run growth. Surprisingly, we show that in an equilibrium there exists a cut-off value of risk aversion below which the growth rate of the mass of innovators tends to a strictly positive constant. In this case, innovation persists on the long run and consumption per capita grows at a strictly positive rate. On the other hand, for levels of risk aversion above the cut-off value, the economy eventually stagnates.     

Consumption insurance and entrepreneurial risk: Evidence from Italian micro-data

Using cross-sectional data from the Bank of Italy's Survey on Household Income and Wealth, we make an attempt to assess the relevance of entrepreneurial risk, i.e., idiosyncratic risk borne by firm owners while running their operations. Our new testing procedure will show that progressively more articulated forms of entrepreneurship do not enjoy a larger degree of risk sharing and will suggest some links between a larger or smaller degree of consumption insurance and variables such as net wealth, asset holding, and net indebtedness. The opinions expressed in this paper are those of the authors and do not necessarily reflect the views of the corresponding institutions.     

Does risk sharing increase with risk aversion and risk when commitment is limited?

I consider a risk-sharing game with limited commitment, and study how the discount factor above which perfect risk sharing is self-enforcing in the long run depends on agents׳ risk aversion and the riskiness of their endowment. When agents face no aggregate risk, a mean-preserving spread may destroy the sustainability of perfect risk sharing if each agent׳s endowment may take more than three values. With aggregate risk the same can happen with only two possible endowment realizations. With respect to risk aversion the intuitive comparative statics result holds without aggregate risk, but it holds only under strong assumptions in the presence of aggregate risk. In simple settings with two endowment values I also show that the threshold discount factor co-moves with popular measures of risk sharing.     

Asymmetric sequential search under incomplete information

We study a multistage sequential search model with n agents who compete for one job. The agents arrive sequentially, each one in a different stage. The agents' abilities, which are private information, are derived from heterogeneous distribution functions. In each stage, the designer chooses an ability threshold. If an agent has a higher ability than the threshold in the stage in which he arrives, he gets the job and the search is over. The agent's ability is not revealed when he wins the job and the designer has only an estimation of this ability according to the threshold placed by him. We analyze the optimal ability thresholds imposed by the designer who wishes to maximize the ability estimation of the agent who gets the job net of the search cost. We also investigate the relation between the optimal ability thresholds as well as the optimal order of agents in all stages according to the agents' distributions of abilities.     

A sharing mechanism of investment outcome for interest-sensitive life insurance products

As growing sales of insurance contracts with a saving feature, an issue of sharing investment outcome gets the attention of insurers and policyholders. This paper focuses on a systematic way of finding the sharing mechanism for an optimal contract design in such a way that a policyholder and an insurer maximize their expected utilities. We adopt the policyholder and the insurer as a principal and an agent, respectively, and regard a share of the investment performance as an incentive for the insurer to elicit efforts. As a result of this setting, the moral hazard issue generated from the insurer is unavoidable. For the purpose, the Holmström (1979)’s principal-agent model with limited observability of the insurer’s action plays a leading role in resolving a pie-cutting problem. Under our model assumption, the sharing mechanism states that a portion of the outcome belonging to the insurer is a nondecreasing function of the excess of the portfolio return over a benchmark return when the two parties are risk-averse. In particular, the sensitivity of the sharing portion has an S-shape curve which is consistent with the insurer’s risk propensity.An empirical study based on companies’ portfolio attributes and crediting rates verifies that our theoretical findings are consistent with statistically significant results. In particular, we confirm that the bargaining power of the insurer has a considerable impact on the sharing mechanism as it is theoretically important.     

Risk sharing,risk shifting and the role of convertible debt

This paper considers a financial contracting problem between a risk neutral entrepreneur and a risk averse investor. Once the venture is started, the entrepreneur chooses an action that determines the riskiness of the venture’s payoff. When action choice is contractible, the optimal risk sharing consideration under limited liability calls for a pure debt contract and the low risk action is adopted. When the action choice is not contractible, due to the risk shifting problem implementing the low risk action requires a deviation from the optimal risk sharing. I focus on situations where despite this deviation, the risk averse investor prefers to implement the low risk action and show that a convertible debt contract is superior to pure debt, pure equity and any mixture of debt and equity.     

Risk management under a prudential policy

In this paper, we study the structure of optimal contracts in banking system when there is no risk of moral hazard. We consider a risk management problem under a policy that reduces the excessive risk-taking behavior by making all banks bear part of the risk that they transfer to other parties in the market. First, we characterize the optimal solutions to the risk management problem, and, second, we find a necessary and sufficient condition under which the “risk of the tail events” will not be transferred. In particular, we will study the problem using two known risk measures, value at risk and conditional value at risk, and will show that in these cases, the optimal solutions are in the form of stop-loss policies.     

Profit sharing with a contest among agents

We consider how an internal competition in the form of a contest among agents can be combined with profit sharing in team production. The principal can choose to share between the principal and the agents as well as the sharing rule with a competitive contest among the agents. We show that under some conditions, a pure strategy equilibrium of profit sharing exists. In equilibrium, internal sharing involves a contest that is more competitive than proportional sharing, and the principal can get higher profit compared to proportional sharing.     

Optimal selling mechanisms for multiproduct monopolists: incentive compatibility in the presence of budget constraints

We analyze the nonlinear pricing problem faced by an incomplete information monopolist operating in a market populated by agents with budget constraints. We show that if other goods are available and if the monopolist's goods are nonessential relative to other goods, then there exists an optimal, individually rational, and incentive compatible selling mechanism for the monopolist (Theorem 1). Moreover, we show that a solution to all such nonlinear pricing problems exists if and only if the monopolist's goods are nonessential (Theorem 2). In the absence of nonessentiality, we show that if the monopolist's profit function is independent of quantity (e.g., if all costs are fixed), then an optimal selling mechanism exists (Theorem 3). Finally, we show that if there is reporting (of types by agents) and partial recognition of types (by the monopolist), then an optimal selling mechanism exists, even in the absence of nonessentiality, provided agents' utility functions are affine and continuous in goods (Theorem 4).     

Insurance and climate-driven extreme events

We investigate how insurance affects agents’ decisions when being faced by endogenous, climate-driven extreme events. This is not only important in order to understand how the possibility of insurance augments mitigation and saving decisions, but it also improves our understanding of how insurance should be provided. Since there are no studies as of now that rely on such an integrated approach, we extend the literature along two lines. Firstly, we develop a neoclassical growth framework with endogenous extreme events and an insurance sector. Secondly, we introduce a simulation method that allows us to explicitly take these extreme events into account and which yields additional numerical insights. In doing so we can fully characterize and quantify the impact of different insurance policies for mitigation and economic growth decisions.Our analytical results and computational experiments show that (i) transparency of the insurance sector is the decisive requisite for abatement activities, implying substantial policy opportunities; (ii) a decentralized economy will under-invest in abatement without adequate policy interventions; (iii) precautionary beliefs on the frequency of extreme events lead to more sustainability; (iv) a social security system which prices insurance fairly is preferable to an insurance industry which provides insurance with an overhead.     

Prevention incentives in long‐term insurance contracts

Long‐term insurance contracts are widespread, particularly in public health and the labor market. Such contracts typically involve monthly or annual premia which are related to the insured's risk profile. A given profile may change, based on observed outcomes which depend on the insured's prevention efforts. The aim of this paper is to analyze the latter relationship. In a two‐period optimal insurance contract in which the insured's risk profile is partly governed by her effort on prevention, we find that both the insured's risk aversion and prudence play a crucial role. If absolute prudence is greater than twice absolute risk aversion, moral hazard justifies setting a higher premium in the first period but also greater premium discrimination in the second period. This result provides insights on the trade‐offs between long‐term insurance and the incentives arising from risk classification, as well as between inter‐ and intragenerational insurance.     

Managing security risks for inter-organisational information systems: a multiagent collaborative model

Information sharing across organisations is critical to effectively managing the security risks of inter-organisational information systems. Nevertheless, few previous studies on information systems security have focused on inter-organisational information sharing, and none have studied the sharing of inferred beliefs versus factual observations. In this article, a multiagent collaborative model (MACM) is proposed as a practical solution to assess the risk level of each allied organisation’s information system and support proactive security treatment by sharing beliefs on event probabilities as well as factual observations. In MACM, for each allied organisation’s information system, we design four types of agents: inspection agent, analysis agent, control agent, and communication agent. By sharing soft findings (beliefs) in addition to hard findings (factual observations) among the organisations, each organisation’s analysis agent is capable of dynamically predicting its security risk level using a Bayesian network. A real-world implementation illustrates how our model can be used to manage security risks in distributed information systems and that sharing soft findings leads to lower expected loss from security risks.     

Automobile insurance ratemaking in the presence of asymmetrical information

Automobile insurance is an example of a market where multi-period contracts are observed. This form of contract can be justified by asymmetrical information between the insurer and the insured. Insurers use risk classification together with bonus-malus systems. In this paper we show that the actual methodology for the integration of these two approaches can lead to inconsistencies. We develop a statistical model that adequately integrates risk classification and experience rating. For this purpose we present Poisson and negative binomial models with regression component in order to use all available information in the estimation of accident distribution. A bonus-malus system which integrates a priori and a posteriori information on an individual basis is proposed, and insurance premium tables are derived as a function of time, past accidents and the significant variables in the regression. Statistical results were obtained from a sample of 19,013 drivers.     

Eliciting the socially optimal allocation from responsible agents

We consider designing a mechanism to allocate objects among agents without monetary transfers. There is a socially optimal allocation, which is commonly known by the agents but not observable by the designer. The designer possibly has information about the existence of responsible agents. A responsible agent, when indifferent between his objects at two different allocations, prefers the first allocation to the second if the first allocation is closer to the optimal allocation than the second, in the sense that all the agents who are allocated their optimal objects in the second allocation are allocated their optimal objects also in the first allocation, and there is at least one more agent in the first allocation receiving his optimal object. We show that, if the designer knows that there are at least three responsible agents, even if the identities of the responsible agents are not known, the optimal allocation can be elicited.