Infrequent Extreme Risks

The main tools and concepts of financial and actuarial theory are designed to handle standard, or even small risks. The aim of this paper is to reconsider some selected financial problems, in a setup including infrequent extreme risks. We first consider investors maximizing the expected utility function of their future wealth, and we establish the necessary and sufficient conditions on the utility function to ensure the existence of a non degenerate demand for assets with extreme risks. This new class of utility functions, called LIRA, does not contain the classical HARA and CARA utility functions, which are not adequate in this framework. Then we discuss the corresponding asset supply-demand equilibrium model.     

极端气候对商业银行风险承担的影响——来自中国地方性商业银行的经验证据

深化对气候相关金融风险的认识,对于促进绿色低碳发展,防范系统性金融风险具有重要意义。本文以2004—2018年期间281家中国地方性商业银行为样本,实证检验了极端气候对银行风险承担的影响及其机制。研究发现,极端强降水气候显著提升了银行风险承担,极端高温和极端低温气候对银行风险承担不存在明显影响。极端强降水主要通过给银行信贷主体带来经济损失,影响违约概率和银行信贷资产质量,进而影响银行风险承担水平;提高灾前的保险保障水平、强化碳减排机制以及确保银行资本的充足性均有利于弱化极端气候对银行风险承担的影响;相较于以地级和省会城市工商业和居民为主要服务对象的地方性商业银行,极端强降水对以“三农”为主要服务对象的县域地方性商业银行风险承担的影响更大。因此,提升商业银行应对极端气候风险意识,提高气候灾害保险保障水平,强化碳减排机制和银行资本充足管理,均有利于降低极端气候对银行风险的影响。     

Pricing Dynamic Insurance Risks Using the Principle of Equivalent Utility

We introduce an expected utility approach to price insurance risks in a dynamic financial market setting. The valuation method is based on comparing the maximal expected utility functions with and without incorporating the insurance product, as in the classical principle of equivalent utility. The pricing mechanism relies heavily on risk preferences and yields two reservation prices - one each for the underwriter and buyer of the contract. The framework is rather general and applies to a number of applications that we extensively analyze.     

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.     

A method for evaluating the extreme risk sources of financial markets: The case of stock markets in China

Risk contagion has attracted increasing research attention in recent years. In this paper, we combined conditional Value at Risk (CVaR), Bayesian quantile regression and Granger causality test to propose a Bayesian CVaR–Granger causality test method, which is an efficient tool in analyzing sources of extreme risks in a financial market. Using this method, we determined the sources of extreme risks in major stock markets in China.     

Optimal portfolio choice for a behavioural investor in continuous-time markets

The aim of this work consists in the study of the optimal investment strategy for a behavioural investor, whose preference towards risk is described by both a probability distortion and an S-shaped utility function. Within a continuous-time financial market framework and assuming that asset prices are modelled by semimartingales, we derive sufficient and necessary conditions for the well-posedness of the optimisation problem in the case of piecewise-power probability distortion and utility functions. Finally, under straightforwardly verifiable conditions, we further demonstrate the existence of an optimal strategy.     

Extreme Risk Measures for International REIT Markets

Extreme risks associated with extraordinary market conditions are catastrophic for all investors. The ongoing financial crisis has perfectly exemplified this point. Surprisingly, there are few studies exploring this issue for REITs. This study aims to close the knowledge gap. We conduct a comprehensive study by utilizing all three methodological categories to examine their forecasting performances of VaR and ES for nine major global REIT markets. Our findings indicate that there is no universally adequate method to model extreme risks across global markets. Also, estimating risks for the stock and REIT markets may require different methods. In addition, we compare the risk profiles between the stock and REIT markets, and find that the extreme risks for REITs are generally higher than those of stock markets. The fluctuations of risk levels are well synchronized between the two types of markets. The current crisis has significantly increased the extreme risk exposure for both REIT and stock investors. In all, our results have significant implications for REIT risk management, portfolio selection, and evaluation.     

中国系统重要性银行评估：来自2006-2010年中国上市银行的证据

系统重要性银行是指具有负外部性特征,并且由于规模、复杂度与系统相关度在金融市场中承担了关键功能,其无序破产可能给金融体系造成包括核心金融功能的中断、金融服务成本急剧增加等在内的系统性风险,进而可能危及金融稳定、损害实体经济的银行。通过对系统重要性银行进行评估,得出其主要影响指标包括银行规模、关联性、复杂性和可替代性,其中,交易性金融资产与负债是最重要的关联性指标,衍生金融资产与负债是最重要的复杂性指标。系统重要性银行评估结果显示,假定阀值为5%,则全部国有商业银行和股份制商业银行中的招商银行、光大银行和中信银行属于系统重要性银行,而其他股份制商业银行和全部城市商业银行则不属于系统重要性银行。     

Financial crisis and extreme market risks: Evidence from Europe

This study draws attention to the proliferation of extreme risks in financial markets prior to and during the course of the recent global financial crisis. It examines the level of such “tail” risks in selected equity, interbank lending and foreign exchange markets in selected EU Member States in relation to the United States. The extent of tail risks is assessed by applying general error distribution (GED) parameterization in GARCH volatility tests of the examined variables. The empirical tests prove that extreme market risks were pronounced across all of the examined European financial markets throughout the crisis. They were also significant prior to the crisis outbreak. The analyzed interbank lending markets exhibited more extreme volatility outbursts than the equity and foreign exchange markets did.     

Investment decisions when utility depends on wealth and other attributes

The problem of optimal investment under a multivariate utility function allows for an investor to obtain utility not only from wealth, but other (possibly correlated) attributes. In this paper we implement multivariate mixtures of exponential (mixex) utility to address this problem. These utility functions allow for stochastic risk aversions to differing states of the world. We derive some new results for certainty equivalence in this context. By specifying different distributions for stochastic risk aversions, we are able to derive many known, plus several new utility functions, including models of conditional certainty equivalence and multivariate generalisations of HARA utility, which we call dependent HARA utility. Focusing on the case of asset returns and attributes being multivariate normal, we optimise the asset portfolio, and find that the optimal portfolio consists of the Markowitz portfolio and hedging portfolios. We provide an empirical illustration for an investor with a mixex utility function of wealth and sentiment.     

Dynamic preferences for popular investment strategies in pension funds

In this paper, we characterize dynamic investment strategies that are consistent with the expected utility setting and more generally with the forward utility setting. Two popular dynamic strategies in the pension funds industry are used to illustrate our results: a constant proportion portfolio insurance (CPPI) strategy and a life-cycle strategy. For the CPPI strategy, we are able to infer preferences of the pension fund’s manager from her investment strategy, and to exhibit the specific expected utility maximization that makes this strategy optimal at any given time horizon. In the Black–Scholes market with deterministic parameters, we are able to show that traditional life-cycle funds are not optimal to any expected utility maximizers. We also prove that a CPPI strategy is optimal for a fund manager with HARA utility function, while an investor with a SAHARA utility function will choose a time-decreasing allocation to risky assets in the same spirit as the life-cycle funds strategy. Finally, we suggest how to modify these strategies if the financial market follows a more general diffusion process than in the Black–Scholes market.     

Modelling failure rates with machine-learning models: Evidence from a panel of UK firms

In this study, we investigate the ability of machine-learning techniques to predict firm failures and we compare them against alternatives. Using data on business and financial risks of UK firms over 1994–2019, we document that machine-learning models are systematically more accurate than a discrete hazard benchmark. We conclude that the random forest model outperforms other models in failure prediction. In addition, we show that the improved predictive power of the random forest model relative to its counterparts persists when we consider extreme economic events as well as firm and industry heterogeneity. Finally, we find that financial factors affect failure probabilities.     

Time series analysis for financial market meltdowns

There appears to be a consensus that the recent instability in global financial markets may be attributable in part to the failure of financial modeling. More specifically, it is alleged that current risk models have failed to properly assess the risks associated with large adverse stock price behavior. In this paper, we first discuss the limitations of classical time series models for forecasting financial market meltdowns. Then we set forth a framework capable of forecasting both extreme events and highly volatile markets. Based on the empirical evidence presented in this paper, our framework offers an improvement over prevailing models for evaluating stock market risk exposure during distressed market periods.     

DEEP sleep: The impact of sleep on financial risk taking

In this paper, we examine the relationship between sleep and financial risk taking. The results indicate that individuals who have better sleep display less distortion of probability, are less susceptible to the present bias, and have a lower discounting rate. Specifically, individuals with better self‐reported sleep quality have less distortion of probability, a more curved utility function, and are less loss averse, while those with fewer sleep disturbances display less probability distortion and have more curvature in their utility function. Overall, the results show that there are cognitive deficits in financial decision making by having poor sleep habits that can have important consequences.     

Extreme co-movements and extreme impacts in high frequency data in finance

Extreme co-movement and extreme impact problems are inherently stochastic control problems, since they will influence the decision taken today and ultimately influence a decision taken in the future. Extreme co-movements among financial assets have been reported in the literature. However, extreme impacts have not been carefully studied yet. In this paper, we use the newly developed methodology to further explore extreme co-movements and extreme impacts in financial market. Particularly, two FX spot rates are studied. Based on the results of our analysis with FX returns, we conclude that there exist extreme co-movements and extreme impacts in FX returns and care has to be taken when we employ portfolio optimization models, especially models without the ability of handling extreme dependencies.     

First steps towards an equilibrium theory for Lévy financial markets

For a continuous-time financial market with a single agent, we establish equilibrium pricing formulae under the assumption that the dividends follow an exponential Lévy process. The agent is allowed to consume a lump at the terminal date; before that, only flow consumption is allowed. The agent’s utility function is assumed to be additive, defined via strictly increasing, strictly concave smooth felicity functions which are bounded below (thus, many CRRA and CARA utility functions are included). For technical reasons we require for our equilibrium existence result that only pathwise continuous trading strategies are permitted in the demand set. The resulting equilibrium asset price processes depend on the agent’s risk aversion (through the felicity functions). Even in our simple, straightforward economy, the equilibrium asset price processes will essentially only be (stochastic) exponential Lévy processes when they are already geometric Brownian motions. Our equilibrium asset pricing formulae can also be modified to obtain explicit equilibrium derivative pricing formulae.     

我国短期跨境资本极端流动测度与影响因素研究——基于CDF模型的实证分析

众所周知,跨境资本无序流动容易诱发金融危机,相对于平常流动,极端流动与金融危机发生的关系更加密切。通过测算,短期资本是影响我国跨境资本流动形势的重要因素,因此我们需要对短期资本极端流动进行有效管理。本文进一步测算了我国短期跨境资本净流入的极端波动情况,运用累积分布函数模型分别分析影响激增和急停发生概率的宏观因素,同时通过回测验证了模型具有一定的预测能力,最后根据实证结果提出针对短期跨境资本极端流动实施管理的政策建议。     

Equity-Indexed Life Insurance: Pricing and Reserving Using the Principle of Equivalent Utility

Abstract

The author applies the principle of equivalent utility to price and reserve equity-indexed life insurance. Young and Zariphopoulou (2002a, b) extended this principle to price insurance products in a dynamic framework. However, in those papers, the insurance risks were independent of the risky asset in the financial market. By contrast, the death benefit for equity-indexed life insurance is a function of a risky asset; therefore, this paper further extends the principle of equivalent utility. In a second extension, the author applies the principle of equivalent utility to calculate reserves, as introduced by Gerber (1976). In a related paper, Moore and Young (2002) price equity-indexed pure endowments, the building blocks of equity-indexed life annuities.     

功能金融理论与我国金融体系的稳定性和效率性

功能金融理论认为,金融体系具有便利清算和支付、聚集和分配资源以及分散风险的功能.一个稳定和富有效率的金融体系通过有效发挥这三大核心功能,能够极大地促进一国国民经济的增长.根据该理论,本文通过研究我国金融体系上述三大功能的发挥程度来判断其稳定性和效率性.大量实证资料表明,我国金融体系虽然能够最大限度地动员社会储蓄,便利各种交易的清算和支付,但是其储蓄-投资转化率低下,资源配置功能弱化,风险分散和转移能力不高.因此,应在提高投资转化率、创新金融工具和技术、建立高效融资平台、改善公司治理机制和信息披露机制等方面完善我国的金融体系.     

Optimal proportional reinsurance from the point of view of cedent and reinsurer

In the reinsurance market, the cedent and the reinsurer make their subjective evaluations of the utility and riskiness of the financial operations covered by a treaty by deriving preference rankings of the different kinds of agreements. If both the cedent and the reinsurer evaluate the operation underlying the treaty by means of their utility functions and adopt the criterion based on the comparison between the expected utilities in order to take into account the subjective attitude toward risk, then the indifference prices play a crucial role because they define the preference thresholds of the exchange, thus restricting the range of variability of the reinsurance price. By using an analytical approach, this paper examines the above problem identifying the margins for achieving Pareto-optimal solutions in trading insurance risks.