基于投资者异质性信念的证券定价模型——对我国股票市场价格的实证检验

投资者异质性信念的相互作用影响着证券价格,证券市场上的各种证券需求与供给关系,往往表现为投资者各种不同信念的对抗和交融。本文以悲观信念（看多）和乐观信念（看空）之间的相互作用为例,研究了异质性信念对资产均衡定价的影响,并以我国股票市场的机构投资者信念为对象进行了实证检验,得出我国股票市场投资者信念与证券价格相互作用的结论。本文的建议是在投资过程中,准确分析市场中投资者的异质性信念结构,尤其是资金雄厚的机构投资者的信念结构至关重要。     

Consensus Consumer and Intertemporal Asset Pricing with Heterogeneous Beliefs

The aim of this paper is to analyse the impact of heterogeneous beliefs in an otherwise standard competitive complete market economy. The construction of a consensus probability belief, as well as a consensus consumer, is shown to be valid modulo an aggregation bias, which takes the form of a discount factor. In classical cases, the consensus probability belief is a risk tolerance weighted average of the individual beliefs, and the discount factor is proportional to beliefs dispersion. This discount factor makes the heterogeneous beliefs setting fundamentally different from the homogeneous beliefs setting, and it is consistent with the interpretation of beliefs heterogeneity as a source of risk.
We then use our construction to rewrite in a simple way the equilibrium characteristics (market price of risk, risk premium, risk-free rate) in a heterogeneous beliefs framework and to analyse the impact of beliefs heterogeneity. Finally, we show that it is possible to construct specific parametrizations of the heterogeneous beliefs model that lead to globally higher risk premia and lower risk-free rates.     

Portfolio choice, attention allocation, and price comovement

This paper models the attention allocation of portfolio investors. Investors choose the composition of their information subject to an information flow constraint. Given their expected investment strategy in the next period, which is to hold a diversified portfolio, in equilibrium investors choose to observe one linear combination of asset payoffs as a private signal. When investors use this private signal to update information about two assets, changes in one asset affect both asset prices and may lead to asset price comovement. The model also has implications for the transmission of volatility shocks between two assets.     

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.     

An Equilibrium Approach to the Aggregation of Beliefs

This paper presents a new answer to the old question of how to aggregate individual beliefs. We construct a model which allows agents to take arbitrage opportunities against the aggregated belief by making contingent claims against the states, and the aggregator (market maker) regulates the probability of states. When all claims from the agents are mutually covered for every realization of the state, an aggregation of individual beliefs is thus obtained. We prove the existence and uniqueness of the equilibrium aggregation, and also show that the aggregate belief lies in the convex hull of individual beliefs. This model allows us to address some important problems such as how individual agent’s attitude toward risk and wealth endowment affect the outcome of the aggregation process, and whether the aggregate belief satisfies the well-known properties like equal treatment.     

The capital asset pricing model in economic perspective

The capital asset pricing model (CAPM) is theoretically incomplete in its demand-side focus, risk-averse investors and internally inconsistent homogeneous beliefs; is not conclusively supported empirically; and yet it legitimizes a notion that investors can earn higher returns by bearing undiversifiable risk. Our article does not merely extend the CAPM with more realistic assumptions, it completes its original framework by including (1) risk-taking investors in the investor population, (2) investors who can have heterogeneous expectations or beliefs – an overlooked but required condition for the CAPM to be an internally consistent and meaningful model of competitive financial asset pricing under uncertainty and (3) a positive-sloped short-run supply curve based on a reasonable interpretation of the nature of financial asset trade. Upon a complete economic interpretation, it is shown that the equilibrium (systematic) risk-rate of return relationship depends on whose aggregate trading activity dominates, risk-averse or risk-taking investors’. There is no universal, or even general, positive relationship between systematic risk and rate of return. This has far-reaching implications for investors and investment advisors who serve them.     

Globally evolutionarily stable portfolio rules

The paper examines a dynamic model of a financial market with endogenous asset prices determined by short-run equilibrium of supply and demand. Assets pay dividends that are partially consumed and partially reinvested. The traders use fixed-mix investment strategies (portfolio rules), distributing their wealth between assets in fixed proportions. Our main goal is to identify globally evolutionarily stable strategies, allowing an investor to “survive,” i.e., to accumulate in the long run a positive share of market wealth, regardless of the initial state of the market. It is shown that there is a unique portfolio rule with this property—an analogue of the famous Kelly rule of “betting your beliefs.” A game theoretic interpretation of this result is given.     

The growth of relative wealth and the Kelly criterion

We propose an evolutionary framework for optimal portfolio growth theory in which investors subject to environmental pressures allocate their wealth between two assets. By considering both absolute wealth and relative wealth between investors, we show that different investor behaviors survive in different environments. When investors maximize their relative wealth, the Kelly criterion is optimal only under certain conditions, which are identified. The initial relative wealth plays a critical role in determining the deviation of optimal behavior from the Kelly criterion regardless of whether the investor is myopic across a single time period or maximizing wealth over an infinite horizon. We relate these results to population genetics, and discuss testable consequences of these findings using experimental evolution.     

Equilibrium in securities markets with heterogeneous investors and unspanned income risk

In a finite time horizon, incomplete market, continuous-time setting with dividends and investor incomes governed by arithmetic Brownian motions, we derive closed-form solutions for the equilibrium risk-free rate and stock price for an economy with finitely many heterogeneous CARA investors and unspanned income risk. In equilibrium, the Sharpe ratio is the same as in an otherwise identical complete market economy, whereas the risk-free rate is lower and, consequently, the stock price is higher. The reduction in the risk-free rate is highest when the more risk-averse investors face the largest unspanned income risk.     

OPTIMAL INTERNATIONAL ASSET ALLOCATION WITH TIME-VARYING RISK

This paper examines the optimal allocation each period of an internationally diversified portfolio from the different points of view of a UK and a US investor. We find that investor location affects optimal asset allocation. The presence of exchange rate risk causes the markets to appear not fully integrated and creates a preference for home assets. Domestic equity is the dominant asset in the optimal portfolio for both investors, but the US investor bears less risk than the UK investor, and holds less foreign equity – 20% compared with 25%. Survey evidence indicates actual shares are 6% and 18%, respectively, making the home‐bias puzzle more acute for US than UK investors. There would seem to be more potential gains from increased international diversification for the US than the UK investor.     

异质性预期、投资者行为与房价波动：上海和广州的双城记?

房地产市场中存在大量的投资者,其市场行为会使房价出现大幅的波动,从而引起市场不稳定。文章在引入投资者异质性预期假设的基础上,构建了包含房地产消费者、投资者、供给者在内的房地产市场均衡模型,分析了房地产市场中基本面型投资者和趋势型投资者的异质性行为对房价变动的影响,并利用上海和广州两个一线城市的实际数据进行了对比分析。研究结果表明：在房地产市场中,两类投资者对于未来房价不同的预期以及投资行为会引起房价的变动;上海投资者的行为整体上会使上海的房价始终处于不断上涨的趋势中,而广州投资者的行为会随着投资策略的转变而使静态下的“整体上推动房价趋势型变化”转变为“整体上将房价‘拉回’基本面价格”;房地产市场中的投资者占比会显著影响房价的变动趋势,当基本面型投资者占比上升时,房价偏离度和房价变动率降低,而当这类投资者占比达到峰值时,房价会出现拐点;投资者之间的策略转换速度也会通过引起基本面型投资者占比的变化,引起房价的频繁波动,而且策略转换速度越快,房价波动越频繁。     

国际投资组合选择理论研究进展

国际投资组合选择理论研究的是在一定的假设条件下,当经济实现均衡时,投资者所应持有的本国与外国金融资产的比例。它的发展有5个特征:从追求金融市场的局部均衡到追求经济的一般均衡;从不考虑投资者的存在到考虑投资者个人效用的最大化;从单纯的理论模型构建到结合现实数据进行实证检验;从假设金融市场完全到考虑金融市场不完全的情况;从假设金融市场一体化到考虑金融市场存在分割的情况。     

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.     

The demand of energy from an optimal portfolio choice perspective

This paper analyses the demand for energy sector by employing a model form strategic asset allocation literature and quantifying the welfare losses incurred by an investor due to sub-optimal asset allocation. Our sample group includes fifteen major oil producing and consuming countries. We analyze the short-run and long-run desirability of energy sector in the optimal portfolio of an investor with varying level of risk aversion; that is, risk averse and risk tolerant investors. Our results show that the portfolio demand for energy sector is myopic or short-run. For long-run investors, investing in a portfolio of equity market and government bonds is a better proposition. In addition, energy sector is more desirable for risk tolerant investors.     

Strategic Privatization in Developing Countries

Privatization of state‐owned enterprises may have important welfare implications, in particular in less developed economies where markets are small and domestic firms are typically relatively weak, both technologically and financially. In these environments, a high‐tech foreign investor acquiring the state‐owned assets may end up dominating the local market, thereby harming local consumer and producer interests. A foreign investor, however, is likely to be both willing and able to offer a higher bid for the assets than local investors. This paper addresses the trade‐off for local governments between privatization revenues and foreign market power. The authors find that there may be an incentive to privatize “strategically” by selling the state‐owned firm to a local (less advanced) investor at a lower price in order to achieve a more competitive post‐privatization market structure.     

Beauty contest,bounded rationality,and sentiment pricing dynamics

We present a dynamic asset pricing model that incorporates investor sentiment, bounded rationality and higher-order expectations to study how these factors affect asset pricing equilibrium. In the model, we utilize a two-period trading market and investors make decisions based on the heterogeneous expectations principle and the “sparsity-based bounded rational” sentiment. We find that bounded rationality results in mispricing and reduces it in next period. Investor sentiment produces more significant effects than private signals, optimistic investor sentiment increases hedging demand, thus causing prices to soar. Higher-order investors are more rational and attentive to the strategies of other participants rather than private signals. This model also derives the dampening effect of higher-order expectations to price volatility and the heterogeneity expectation depicts inconsistent investor behavior in financial markets. In the model, investors' expectations about future price is distorted by their sentiment and bounded rationality, so they obtain a biased mean from the signal extraction.     

Market states and disposition effect: evidence from Taiwan mutual fund investors

We study the disposition effect across market states in the context of mutual fund investors in Taiwan. Using mutual fund data at the fund and individual levels during July 2001 to October 2008, we find that the disposition effect varies across market states. Our results suggest that investors redeem their mutual fund units more under a bear market than a bull market when they have extreme capital losses. When investors have moderate capital gains, they are less active in redeeming their mutual fund units under a bull market relative to a bear market. Under a neutral market, investors actively redeem mutual fund units in both winner and loser mutual funds except when they have extreme capital losses. Thus, disposition effect is not uniform; it varies by market condition. In addition, the disposition effect phenomenon also exists for Taiwan mutual fund investors as well. Our findings are robust to aggregate and individual investor levels.     

Over-the-counter loans,adverse selection,and stigma in the interbank market

We study a model of interbank credit where physical and informational frictions limit the opportunities for intertemporal trade among banks and outside investors. Banks obtain loans in an over-the-counter market (involving search, bilateral matching, and negotiations over the terms of the loan) and hold assets of heterogeneous quality that in turn determine their ability to repay those loans. When asset quality is not observable by outside investors, information about the actions taken by a bank in the loan market may influence prices in the asset market. In particular, under some conditions, borrowing from the central bank can be regarded as a negative signal about the quality of the borrower?s assets and banks may be willing to borrow in the market at rates higher than the one offered by the central bank.     

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.     

Skewness preferences,asset prices and investor sentiment

Prior research has found that investors have strong preferences for stocks with positive skewness. These preferences have been shown to lead to price premiums and subsequent underperformance. This study extends this growing body of literature by testing whether the underperformance of stocks with positive skewness is driven by periods of high investor sentiment. The motivation for these tests is based on a broad literature in Psychology that an individual’s mood can directly affect the individual’s subjective probability assessments. In the framework of our tests, more optimism among investors may strengthen investors’ skewness preferences. The empirical results in this study support this idea as the underperformance of positively skewed stocks is shown to be primarily driven by periods of high investor sentiment.