Utility maximizing portfolio insurance strategies when hedgers consider the impact of their trading on security prices

Portfolio insurance strategies can destabilize markets to such an extent that they may be counterproductive. Destabilization results when hedgers take share prices as given and follow exogenously specified price-based trading rules. We recognize that such trading rules may not be utility maximizing and that hedging affects share prices. Accordingly, we develop a portfolio insurance strategy where hedgers consider the impact of their trading on prices and endogenize their trading rule which is obtained by maximizing expected utility. Moreover, our strategy does not require the dissemination of information about the extent of portfolio-insurance based hedging activity in the economy.     

Exploring the benefits of using stock characteristics in optimal portfolio strategies

I examine the benefits of using stock characteristics to model optimal portfolio weights in stock selection strategies using the characteristic portfolio approach of Brandt, Santa-Clara, and Valkanov. [2009. “Parametric Portfolio Policies: Exploiting Characteristics in the Cross-section of Equity Returns.” Review of Financial Studies 22: 3411–3447]. I find that there are significant out-of-sample performance benefits in using characteristics in stock selection strategies even after adjusting for trading costs, when investors can invest in the largest 350 UK stocks. Imposing short selling restrictions on the characteristic portfolio strategy leads to more consistent performance. The performance benefits are concentrated in the earlier part of the sample period and have disappeared in recent years. I find that there no performance benefits in using stock characteristics when using random subsets of the largest 350 stocks.     

保险公司资产组合与最优投资比例研究

保险公司收益主要来源于承保利润和投资收益,其中承保利润受政策变动、市场条件等外部环境的影响较大,而投资收益则更多地取决于保险公司的投资能力,因此保险公司如何构建资产组合、如何确定最优投资比例就是获取投资收益最大化的重要因素。本文通过理论推导得出了保险公司的资产组合模型并运用非线性规划求解出最优投资比例,进而根据保险公司的投资数据进行了实证研究,为我国保险公司的资产组合及最优投资比例提供了一个可借鉴的思路。     

Large portfolio losses

This paper provide a large-deviations approximation of the tail distribution of total financial losses on a portfolio consisting of many positions. Applications include the total default losses on a bank portfolio, or the total claims against an insurer. The results may be useful in allocating exposure limits, and in allocating risk capital across different lines of business. Assuming that, for a given total loss, the distress caused by the loss is larger if the loss occurs within a smaller time period, we provide a large-deviations estimate of the likelihood that there will exist a sub-period of the future planning period during which a total loss of the critical severity occurs. Under conditions, this calculation is reduced to the calculation of the likelihood of the same sized loss over an initial time interval whose length is a property of the portfolio and the critical loss level.Received: March 2003Mathematics Subject Classification: 60F10, 91B28, 91B28JEL Classification: G21, G22, G33Amir Dembo is with the Department of Statistics, Stanford University. His research was partially supported by NSF grant #DMS-0072331. Jean-Dominique Deuschel is with the Department of Mathematics, Technische Universität, Berlin. His research was partially supported by DFG grant #663/2-3 and DFG FZT 86. Darrell Duffie is with the Graduate School of Business, Stanford University. We are extremely grateful for research assistance by Nicolae Gârleanu and Gustavo Manso, for conversations with Michael Gordy, and for comments from Michael Stutzer, Peter Carr, David Heath, and David Siegmund.     

Demand for insurance in a portfolio setting

This paper takes an additional step toward analyzing the demand for insurance in the context of a portfolio model. An investor is endowed with a portfolio containing a risky and riskless asset that can be augmented by purchasing insurance. Here, insurance is paid for by reducing the quantity of the risky insurable asset, holding the quantity of the riskless asset fixed. In the standard insurance demand model, insurance is paid for by reducing the amount of the riskless asset. This distinction leads to a different insurance demand function because the opportunity cost of purchasing insurance is now random.     

Constant proportion portfolio insurance strategies in contagious markets

Constant Proportion Portfolio Insurance (CPPI) strategies are popular as they allow to gear up the upside potential of a stock index while limiting its downside risk. From the issuer’s perspective it is important to adequately assess the risks associated with the CPPI, both for correct ‘gap’ fee charging and for risk management. The literature on CPPI modelling typically assumes diffusive or Lévy-driven dynamics for the risky asset underlying the strategy. In either case the self-contagious nature of asset prices is not taken into account. In order to account for contagion while preserving analytical tractability, we introduce self-exciting jumps in the underlying dynamics via Hawkes processes. Within this framework we derive the loss probability when trading is performed continuously. Moreover, we estimate measures of the risk involved in the practical implementation of discrete-time rebalancing rules governing the CPPI product. When rebalancing is performed on a frequency less than weekly, failing to take contagion into account will significantly underestimate the risks of the CPPI. Finally, in order to mimic a situation with low liquidity, we impose a daily trading cap on the risky asset and find that the Hawkes process driven models give rise to the highest risk measures even under daily rebalancing.     

A jackknife-type estimator for portfolio revision

This article proposes a novel approach to portfolio revision. The current literature on portfolio optimization uses a somewhat naïve approach, where portfolio weights are always completely revised after a predefined fixed period. However, one shortcoming of this procedure is that it ignores parameter uncertainty in the estimated portfolio weights, as well as the biasedness of the in-sample portfolio mean and variance as estimates of the expected portfolio return and out-of-sample variance. To rectify this problem, we propose a jackknife procedure to determine the optimal revision intensity, i.e. the percent of wealth that should be shifted to the new, in-sample optimal portfolio. We find that our approach leads to highly stable portfolio allocations over time, and can significantly reduce the turnover of several well established portfolio strategies. Moreover, the observed turnover reductions lead to statistically and economically significant performance gains in the presence of transaction costs.     

The effectiveness of the VaR-based portfolio insurance strategy: An empirical analysis

This paper proposes an approach to constructing the insured portfolios under the VaR-based portfolio insurance strategy (VBPI) and provides a comprehensive analysis of its hedging effectiveness in comparison with the buy-and-hold (B&H) as well as the constant proportion portfolio insurance (CPPI) strategies in the context of the Chinese market. The results show that both of the insurance strategies are able to limit the downward returns while retaining certain upside returns, and their capabilities of reshaping the return distributions increase as the guarantee or the confidence level rises. In general, the VBPI strategy tends to outperform the CPPI strategy in terms of both the degree of downside protection and the return performance.     

Relative performance of dynamic portfolio insurance strategies: Australian evidence

This paper simulates the performance of synthetic put portfolio insurance and Constant Proportion Portfolio Insurance (CPPI) using Australian data for the period from 1992 to 2000. These strategies are implemented by trading in the index and bills and simulation is conducted across 18 scenarios. We find that while the CPPI dominates in scenarios using daily rebalancing, the synthetic put strategy delivers better outcomes when value based triggers are used. More importantly, although the two per cent market move trigger emerges as the optimal rebalancing choice, overall, neither strategy appears justifiable in terms of achieving downside protection or allowing upside gain.     

An analysis of risk-based asset allocation and portfolio insurance strategies

This paper compares traditional portfolio insurance strategies with modern risk-based dynamic asset allocation strategies within a currency portfolio context for reserve management. Given the objective of preserving reserve value, the evaluation of the hedging performances of various strategies focuses on four perspectives regarding, in particular, the return distribution of the hedged portfolio. In terms of the Sharpe Ratio, the constant proportional portfolio insurance is the best performer due to having the lowest volatility, while the Value at Risk strategy based upon the normal distribution is the worst due to its having the smallest return. From the perspective that the return distribution of the hedged portfolio is shifted to the right, the synthetic put performs the best, with the expected shortfall strategy the second best. In terms of the cumulative portfolio return across years, the expected shortfall strategy using the historical distribution ranks first, as a result of its participation in upward markets. Furthermore, the expected shortfall-based strategy results in a lower turnover within the investment horizon, thereby saving transaction costs.     

Performance evaluation of portfolio insurance strategies using stochastic dominance criteria

This paper evaluates the performance of the stop-loss, synthetic put and constant proportion portfolio insurance techniques based on a block-bootstrap simulation. We consider not only traditional performance measures, but also some recently developed measures that capture the non-normality of the return distribution (value-at-risk, expected shortfall, and the Omega measure). We compare them to the more comprehensive stochastic dominance criteria. The impact of changing the rebalancing frequency and level of capital protection is examined. We find that, even though a buy-and-hold strategy generates higher average excess returns, it does not stochastically dominate the portfolio insurance strategies, nor vice versa. Our results indicate that a 100% floor value should be preferred to lower floor values and that daily-rebalanced synthetic put and CPPI strategies dominate their counterparts with less frequent rebalancing.     

A multivariate analysis of REIT performance by financial and real asset portfolio characteristics

This paper examines the risk-adjusted performance of real estate investment trusts (REITs) from 1986 through 1990 in relation to financial and property characteristics of their portfolios. The Sharpe measure of risk-adjusted rate of return was regressed against financial ratios and property investment ratios for a sample of equity and mortgage REITs. The results show that, in general, financial ratios (gross cash flow, leverage, asset size), regional location of properties, and types of real estate investments determine the risk-adjusted performance. More specifically, location of properties in the western United States, ownership of health care properties, and investment in securitized mortgages positively affect the risk-adjusted return. The individual financial variables were not found to be statistically significant in influencing REIT returns.     

Individual home bias,portfolio churning and performance

This study investigates economic consequences of individual investors’ home bias and portfolio churning in their personal pension accounts. The empirical analysis is carried out within a Heckman style two-stage framework to account for selection bias with respect to individuals’ investment activity, and to allow for an endogenously determined home bias, portfolio churning and performance. Results indicate that home bias induces a worse risk-adjusted performance. Home-biased individuals’ relatively bad performance originates in insufficient risk-reduction, due to a lack of international diversification. A higher degree of portfolio churning also deteriorates performance, despite the fact that churning is not associated with any direct transaction costs. However, home-biased individuals do not churn portfolios as often as individuals with a larger share of international asset holdings, which diminishes the negative effects of home bias on performance. Overconfidence is driven by a return-chasing behavior, where overconfident individuals favor international assets with high historical returns. Individuals with actual skill are more often men than women, are not tempted by high historical returns, and use international assets for the right reason – diversification.     

国际保险业增长水平的新比较

本文通过构建基准深度比这一新方法,对相关国家和经济集团的保险业增长水平进行重新评估和比较,并在此基础上讨论其政策启示。主要结论是:第一,我们需要对国际保险业增长格局有一个新的认识:发达市场的保险业相对增长水平较传统指标有所降低,发展中市场的保险业相对增长水平较传统指标有所提升;发达市场的保险业相对增长水平仍高于发展中市场,但新兴市场和金砖四国的增长态势十分强劲,并已达到较高水平。第二,保险公司的全球战略布局,一方面要继续巩固发达市场,另一方面要积极开拓发展中市场,同时需要特别注意新兴市场和金砖四国的保险业相对增长已经达到较高水平,未来增长潜力虽仍然很大,但将主要依靠经济增长的常规拉动,保险业增长模式将发生很大变化。第三,发展中国家保险产业政策的重点不应是强调量上的增长,而应是强调增长方式的调整和提升,以便为未来长远阶段的保险业持续增长奠定坚实的基础。第四,传统分析范式存在局限,亟需构建更加完善的保险业国际比较的新范式,以使国际保险监管合作和相关国际贸易谈判具备一个更加合理的对话基础。     

A general equilibrium model of portfolio insurance

This article examines the effects of portfolio insurance onmarket and asset price dynamics in a general equilibrium continuous-timemodel. Portfolio insurers are modeled as expected utility maximizingagents. Martingale methods are employed in solving the individualagents' dynamic consumption-portfolio problems. Comparisonsare made between the optimal consumption processes, optimallyinvested wealth and portfolio strategies of the portfolio insurersand 'normal agents'. At a general equilibrium level, comparisonsacross economies reveal that the market volatility and riskpremium are decreased, and the asset and market price levelsincreased, by the presence of portfolio insurance.     

A multicriteria model for portfolio management

The paper presents a new model to support the selection of a portfolio of stocks based on the results of the fieldwork undertaken with fund managers and using direct rating, MACBETH and optimisation techniques. The model consists of defining a benchmark portfolio (in this case, the Dow Jones Eurostoxx50) and scoring its different stocks according to several expected return criteria. Based on this multicriteria value analysis, a procedure is proposed to suggest adjustments to the proportions of the stocks in the portfolio. Finally, the risk of this modified portfolio is taken into consideration in an optimization module that includes constraints concerning the limits of variation for the proportion of each stock.     

Optimal life insurance with no-borrowing constraints: duality approach and example

We solve an optimal portfolio choice problem under a no-borrowing assumption. A duality approach is applied to study a family’s optimal consumption, optimal portfolio choice, and optimal life insurance purchase when the family receives labor income that may be terminated due to the wage earner’s premature death or retirement. We establish the existence of an optimal solution to the optimization problem theoretically by the duality approach and we provide an explicitly solved example with numerical illustration. Our results illustrate that the no-borrowing constraints do not always impact the family’s optimal decisions on consumption, portfolio choice, and life insurance. When the constraints are binding, there must exist a wealth depletion time (WDT) prior to the retirement date, and the constraints indeed reduce the optimal consumption and the life insurance purchase at the beginning of time. However, the optimal consumption under the constraints will become larger than that without the constraints at some time later than the WDT.     

我国保险保障基金风险费率模拟分析

常用的保险保障基金征收方法分为平均比率费率法和风险费率法。与国际上大多数国家一样,我国保险保障基金目前采用平均比率费率法。平均比率费率法不与保险公司自身的风险挂钩,不会因为其冒险行为而收取更高费率;而风险费率法则是保险公司风险程度与其所交的保险保障基金费率呈正比。本文对我国25家财险公司和25家寿险公司进行风险等级分类,对我国保险保障基金风险费率进行模拟分析,提出了我国保险保障基金宜采用风险费率征收方式的基本构想,体现出公平合理、防范风险的发展要求。