Forward Discount Bias: Is it Near-Rationality in the Foreign Exchange Market?*

A risk-averse US investor adjusts the shares of a portfolio of short-term nominal domestic and foreign assets to maximize expected utility. The optimal strategy is to respond immediately to all new information which arrives weekly. We develop a model to estimate the cost of optimizing less frequently and find that it is generally very small. For example, if the investor adjusts portfolio shares every three months, an average expected utility loss of 0.16 per cent p.a. is incurred. Hence, slight opportunity costs of frequent optimization may outweigh the benefits. This result may help explain forward discount bias.     

Holdout behaviour: a question of diversification,risk aversion and expectation

We argue a holdout is not a destructive investor behaviour but an investment decision. The decision is characterized by the mean-variance approach. We investigate intercreditor conflict by diverse portfolio structure. We demonstrate that at some point during the Greek (2012) and Argentine (2005) debt restructuring programmes, it was reasonable for the investor to hold out. This model shows that the investment decision is based on the portfolio structure, risk aversion and expected possible payment of the debtor, so there is no free-rider behaviour. This is based on the fact that the investor harms herself due to destructive and uncooperative behaviour.     

Shouldn't all eggs be putted in one basket? A portfolio model based on investor sentiment and inertial thinking

In the portfolio choice literatures and the financial market, diversification and concentration are the focus of debate of philosophers. In this paper, we develop a model of portfolio choice to integrate the diversification strategy and the concentration strategy. Our model relies on the concepts of investor sentiment and inertial thinking. The results show that: Generally, when the level of sentiment is relatively low, an investor who is affected by sentiment and inertial thinking may do a well-diversified investment the same as the rational investor. When the level of sentiment is high enough, the investment strategies including diversification and concentration are complex and volatile. Quantitative results for either diversification or concentration investment are given for all cases in the paper.     

Investor Attention Strategy

This article documents the motivation, the construction, and the profitability of an investment strategy based on investor attention in the options market. Using the option volume after a 1-week dormant period as a proxy for investor attention, the author shows that heightened investor attention after the dormant period has rich investment implications. A portfolio constructed on the basis of volume spike events immediately after the dormant period generates an abnormal return of 68 basis points on a monthly basis (8.16% on an annualized basis). This abnormal return is robust to risk adjustment using standard asset pricing models. The author's findings constitute strong evidence that it is profitable for outside investors to mimic attentive investors in the options market and reap economically and statistically significant profits.     

The evolution of portfolio rules and the capital asset pricing model

The aim of this paper is to test the performance of capital asset pricing model (CAPM) in an evolutionary framework. We model an economy where a heterogeneous population of long-lived agents invest their wealth according to different portfolio rules, and prove that traders who either “believe” in CAPM and use it as a rule of thumb, or are endowed with genuine mean-variance preferences, under some very weak conditions, vanish in the long run.We show that a sufficient condition to drive CAPM or mean-variance traders’ wealth shares to zero is that an investor endowed with a logarithmic utility function enters the market.     

Multi-period portfolio optimization under possibility measures

A single-period portfolio selection theory provides optimal tradeoff between the mean and the variance of the portfolio return for a future period. However, in a real investment process, the investment horizon is usually multi-period and the investor needs to rebalance his position from time to time. Hence it is natural to extend the single-period fuzzy portfolio selection to the multi-period case based on the possibility theory. In this paper, we propose the possibilistic expected value and variance for the terminal wealth with fuzzy forms after T periods by using the central value operator. Classes of multi-period possibilistic mean-variance models are formulated originally under the assumption that the proceeds of risky assets are fuzzy variables. Besides, we apply a particle swarm optimization algorithm to solve the proposed multi-period fuzzy portfolio selection models. A numerical example is given to illustrate the performance of the proposed models and algorithm.     

Optimal Investment Strategy in Safe-region on Consumption and Portfolio Problem

This paper investigates an optimal investment strategy on consumption and portfolio problem, in which the investor must withdraw funds continuously at a given rate. By analyzing the evolving process of wealth, we give the definition of safe-region for investment. Moreover, in order to obtain the target wealth as quickly as possible, using Bellman dynamic programming principle, we get the optimal investment strategy and corresponding necessary expected time. At last we give some numerical computations for a set of different parameters.     

A risk index to model uncertain portfolio investment with options

This paper models the portfolio investment performance with options by using a risk index, which is defined as the average loss below the risk-free interest rate. Using a risk-free interest rate as the uniform reference rate for all portfolios, the risk index offers an easier-to-compare loss value than the value-at-risk return, where portfolio specific references are used to calculate the average losses. Besides, uncertainty theory is used in the paper to derive the portfolio decision when stock prices are subject to experts' estimations. By analytical computation and empirical analysis, we find that portfolios considering options generate better return than the ones without options. The empirical analysis reveals that the options can effectively hedge the risk, and the call option with a higher exercise price offers higher return per unit of option premium. Furthermore, our proposed model produces higher expected return in most cases than the model where the risk is measured by the chance of the total return failing to reach the threshold level of return.     

Optimal investment strategies in an international economy with stochastic interest rates

We investigate how investors should optimally choose to invest in a dynamically complete international market. We find closed-form solutions for the optimal investment strategy and for the wealth loss an investor suffers from not investing internationally. Theoretically, we show that the gain from international investment is due to the speculative investment only, and why it is important for an investor from a large economy to invest in a small economy. In a numerical example we compare the wealth losses investors from Denmark and the U.S. suffer due to home bias.     

Individual Decision Making and Investor Welfare

This article analyses and quantifies the costs of suboptimal decision making for an investor with a multi-period horizon. In light of the empirical evidence that investors are too conservative and hold portfolios that are insufficiently diversified, we evaluate the costs of suboptimal equity participation both analytically and using simulation, and also estimate the costs of suboptimal diversification using simulation. We find that suboptimal leverage imposes only modest costs on the investor for reasonable parameter values. While the costs of inadequate diversification can be very high, we find that, because of the higher returns on small firms, an equally weighted portfolio of as few as five randomly chosen firms can provide the same level of expected utility as the value weighted market portfolio.
(J.E.L.: G11, G18, G23).     

效用函数意义下证券组合投资问题的改进决策树方法

基于Markowitz证券组合投资决策模型,运用效用理论中的均值-方差效用函数与决策理论中的决策树方法,提出了一种证券组合投资问题的改进决策树方法;探讨与分析了改进决策树方法的构造与求解过程。改进决策树方法不但可以对证券组合投资问题的决策方案集进行最优投资策略的选择,而且可以对该决策方案集按照一定的标准进行排序。     

Delegated portfolio management and optimal allocation of portfolio managers

In this article, we investigate whether the application of the mean-variance framework on portfolio manager allocation offers any out-of-sample benefits compared to a naïve strategy of equal weighting. Based on an exclusive data-set of high-net-worth (HNW) investors, we utilize a wide variety of methodologies to estimate the input parameters including exponentially weighted moving average (EWMA), generalized autoregressive conditional heteroscedasticity (GARCH) and Bayes–Stein shrinkage estimation. We apply nine different mean-variance models, but find that none of these present any consistent benefit over a naïve strategy of equal weighting.     

Investment choices: Indivisible non-marketable assets and suboptimal solutions

Several investment decisions deal with non-marketable assets. Non-marketable assets are available only to one investor and are often indivisible. This has relevant consequences on investor investment opportunities. Adhering to a mean–variance representation of the investment space and considering a non-marketable asset (divisible or not), we derive some possible investment scenarios an investor may face. Furthermore, we show how a limited ability to gather and process information affects investor portfolio choices. Our results define a set of conditions under which the non-marketable asset represents a good investment and show that, under certain assumptions, the efficient frontier exhibits non-linearities and intervals of discontinuity.     

Further evidence on international Islamic and conventional portfolios diversification under regime switching

This article investigates the comparative performance of International Islamic and conventional portfolio diversification across different financial market regimes and provides an optimal choice from an American investor’s viewpoint during the period 2002–2014. Using a bootstrap-based stochastic dominance (SD) test and monthly MSCI prices of Islamic stock market indices and their conventional counterparts in 38 countries from North and Latin America, Europe and Asia-Pacific regions, we find that SD relationships between Islamic and conventional optimal-diversified portfolios change systematically according to investment region and market regime. Essentially, for all regimes, US investors are indifferent between Islamic diversification and its conventional counterpart, which implies that arbitrage diversification opportunities are rare and short lived in all regions. However, across all regions, especially in a crisis regime, Islamic portfolio diversification can be a good substitute for conventional diversification. Islamic portfolio diversification in North and Latin America, Europe and Global regions is an optimal choice for the risk-averse American investors. Finally, results imply that portfolio diversification among Islamic market indices can be a good hedge, offering investors superior investment alternatives during any financial meltdown or economic slowdown due to the conservative nature of Sharia-compliant investments.     

Combining value averaging and Bollinger Band for an ETF trading strategy

The decision-making of investors is highly influenced by their feelings. According to behavioural finance, investor greed and fear would form irrational behaviour and affect their portfolio allocation. Although well-known mechanical investment strategy of dollar cost averaging (DCA) and value averaging (VA) could eliminate the problems of when to purchase, there are still some disadvantages to consider. For example, using a DCA strategy may be able to decrease volatility in portfolio so as to not effect investment decision, but it gives no rule for selling and may increase the opportunity cost of time if investors start deducted at peak prices. On the other hand, VA gives more aggressive sell signals to control the value of the portfolio to the level desired, but the investor may not have enough money purchase of a large number of shares in sharp decline period. Therefore, we use VA as main strategy and Bollinger Band as assist indicator for check for volatility for entry or exit. Through analysis and simulation, the new strategy we design does improve the performance during both bull and bear market periods.     

Real estate investment: Market volatility and optimal holding period under risk aversion

This paper deals with real estate portfolio optimization when investors are risk averse. In this framework, we examine an important decision making problem, namely the determination of the optimal time to sell a diversified real estate portfolio. The optimization problem corresponds to the maximization of a concave utility function defined on both the free cash flows and the terminal value of the portfolio. We determine several types of optimal times to sell and analyze their properties. We extend previous results, established for the quasi linear utility case, where investors are risk neutral. We consider four cases. In the first one, the investor knows the probability distribution of the real estate index. In the second one, the investor is perfectly informed about the real estate market dynamics. In the third case, the investor uses an intertemporal optimization approach which looks like an American option problem. Finally, the buy-and-hold strategy is considered. For these four cases, we analyze in particular how the solutions depend on the market volatility and we compare them with those of the quasi linear case. We show that the introduction of risk aversion allows to better account for the real estate market volatility. We also introduce the notion of compensating variation to better measure the impacts of both the risk aversion and the volatility.     

The impact of mean reversion model on portfolio investment strategies: Empirical evidence from emerging markets

Investors use mean reversion model to make decisions on which stocks should be taken in their portfolios according to their mean values. The first goal of the paper is to test the validity of the mean reversion model in emerging markets. Second, it aims to determine the best portfolio investment strategy on the validity of the mean reversion model. As a result of panel regression analysis, we find that the mean reversion model is valid in all of the emerging countries in the sample. This result implies that emerging markets are not efficient even in weak form. On the validity of the mean reversion model, we find that Max3–Min3 portfolio has recorded the best performance and contrarian portfolio is the best portfolio investment strategy. The paper makes contribution to the literature in terms of providing the information about which portfolio investment strategy has the best performance on the validity of the mean reversion model.     

过度自信条件下授权投资组合管理模型分析

过度自信对投资策略及资产均衡价格将产生重要影响,通过构建过度自信条件下授权投资组合管理模型,分析了过度自信对机构投资者授权投资行为的影响。研究表明,投资组合均衡主要依赖于过度自信水平,当代理人理性或者适度过度自信时,可观察到投资交易数量是过度自信水平的减函数,若过度自信水平足够强且努力成本很小时最优投资组合交易数量则是过度自信的增函数。     

Estimation and arbitrage opportunities for exchange rate baskets

This paper analyses short-term portfolio investment opportunities in a capital market where a currency is defined as a currency basket. In line with the mean-variance hedging approach, a self-financed optimal investment strategy is determined which minimizes the expected quadratic cost function. The successful implementation of the speculative strategy requires a precise estimate of the basket weights, which are possibly non-constant over time. To this end, an adaptive non-parametric procedure is suggested which provides satisfactory results both on simulated and real data. The optimal investment strategy is applied to the case of the Thai Baht basket whereby the weights are computed by means of the adaptive estimator. A recursive estimator, a rolling estimator and the Kalman filter, are implemented and serve as benchmark models. Results are compared with the literature. The different estimators are evaluated with profit-based criteria and the performance of the adaptive estimator turns out to be the best one.     

Risk aversion and allocation to long-term bonds

As risk aversion approaches infinity, the portfolio of an investor with utility over consumption at time T is shown to converge to the portfolio consisting entirely of a bond maturing at time T. Previous work on bond allocation requires a specific model for equities, the term structure, and the investor's utility function. In contrast, the only substantive assumption required for the analysis in this paper is that markets are complete. The result, which holds regardless of the underlying investment opportunities and the utility function, formalizes the “preferred habitat” intuition of Modigliani and Sutch (Amer. Econom. Rev. 56 (1966) 178).