General equilibrium pricing of nonredundant forward contracts

We derive the general equilibrium of a dynamic financial market in which the investors' opportunity set includes nonredundant forward contracts. We show that Breeden's (1979) consumption‐based CAPM equation for forward contracts contains an extra term relative to that for cash assets. We name this term a strategy risk premium. It compensates investors for the (systematic) risk that stems from their very portfolio strategies when the latter involve nonredundant forward contracts. We also show that Merton's (1973) multibeta intertemporal CAPM must be amended for forward contracts to exhibit adjusted risk premia for the market portfolio and all relevant state variables, as opposed to the usual risk premia for cash assets. Our results are shown not to depend on the usual cash‐and‐carry relationship, which, in general, does not hold. We, nevertheless, provide a well‐known special case where it does hold, albeit not grounded on the usual no‐arbitrage argument. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:817–840, 2003     

资本资产定价模型有关假设的逻辑分析

资本资产定价模型 (CAPM)假设投资者具有一致预期 ,关于资本资产各项特征的判断完全相同 ,投资者会选择同一个更优的组合。这样 ,所有投资者最终会同时买入 (或卖出 )某一项资产 ,而不存在相应的卖出 (或买入 )者 ,这说明模型假设存在逻辑上的悖论。市场有效性决定了投资者不可能运用历史数据对当前和将来趋势作出准确判断 ,CAPM模型所提供的最优组合只是对过去不同时期优化值的平均 ,有关假设忽视了投资者对资本资产预期价值判断的多样性。投资者不会统一按照CAPM给出的唯一组合来选择风险资产 ,CAPM的最优投资组合可行集实际上是投资组合可能集合的前沿曲线的渐近线 ,而不是前沿曲线的切线。     

Trading Portfolios Electronically – An Experimental Approach

This paper focuses on a simple axiom – investors prefer to hold diversified combinations of assets. Arguing that pooling vehicles like mutual funds offer approximate solutions, we propose a portfolio trading mechanism that allows individuals to trade diverse combinations of assets through a single order. Given the complexity of the market mechanism, we construct a prototype of this trading system and test it through a series of laboratory experiments with student subjects. We address the quality of the price discovery process, quality of allocations, and efficiency of the market mechanism. Results from a set of laboratory experiments indicate that the performance of such systems is sensitive to design aspects as well as relative experience of participants.     

Institutions,Corporate Governance and Capital Flows

Countries with weaker domestic investor protection hold less diversified international portfolios. An equilibrium business cycle model of North-South capital flow with corporate governance frictions between outside investors and corporate insiders explains this phenomenon through two channels. First, weak governance leads to concentrated ownership in the South because international diversification by insiders is penalized by lower stock market valuation. This reduces the float portfolio, or the supply of South assets. Second, weak governance tilts the demand of South outside investors towards domestic assets to hedge labor income risk. This is due to a higher share of labor in income, which increases labor income risk. In addition, the dynamics of investment under insider control leads relative dividend and labor income to be more negatively correlated in the South, making domestic assets a better hedge against local labor income risk. I find that the insider ownership and hedging channels are responsible for at least 29% and 11%, respectively, of the cross-country variation in international diversification. Thus, weak institutions lower international diversification primarily through concentrated ownership of firms, with outsider hedging also playing a quantitatively significant role.     

Mean‐variance efficiency of the market portfolio and futures trading

We derived an intertemporal capital asset pricing model in which the mean‐variance efficiency of the market portfolio is neither a necessary nor a sufficient condition. We obtained this result by modeling a frictionless, continuously open financial market in which nonredundant futures contracts are available for trade, in addition to cash assets. Introducing such contracts modifies the way investors optimally allocate their wealth. Their portfolios then comprise the riskless asset, a perturbed mean‐variance‐efficient portfolio of cash assets, and a perturbed mean‐variance‐efficient portfolio of futures contracts. Furthermore, a (3 + K) mutual fund separation is obtained, with K being the number of economic state variables, in lieu of the usual (2 + K) fund separation. Mean‐variance efficiency of the market portfolio is a necessary condition only when cash assets are the sole traded assets. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21:329–346, 2001     

Trading co‐integrated assets with price impact

Executing a basket of co‐integrated assets is an important task facing investors. Here, we show how to do this accounting for the informational advantage gained from assets within and outside the basket, as well as for the permanent price impact of market orders (MOs) from all market participants, and the temporary impact that the agent's MOs have on prices. The execution problem is posed as an optimal stochastic control problem and we demonstrate that, under some mild conditions, the value function admits a closed‐form solution, and prove a verification theorem. Furthermore, we use data of five stocks traded in the Nasdaq exchange to estimate the model parameters and use simulations to illustrate the performance of the strategy. As an example, the agent liquidates a portfolio consisting of shares in Intel Corporation and Market Vectors Semiconductor ETF. We show that including the information provided by three additional assets (FARO Technologies, NetApp, Oracle Corporation) considerably improves the strategy's performance; for the portfolio we execute, it outperforms the multiasset version of Almgren–Chriss by approximately 4–4.5 basis points.     

Who should sell stocks?

Never selling stocks is optimal for investors with a long horizon and a realistic range of preference and market parameters, if relative risk aversion, investment opportunities, proportional transaction costs, and dividend yields are constant. Such investors should buy stocks when their portfolio weight is too low and otherwise hold them, letting dividends rebalance to cash over time rather than selling. With capital gains taxes, this policy outperforms both static buy‐and‐hold and dynamic rebalancing strategies that account for transaction costs. Selling stocks becomes optimal if either their target weight is low or intermediate consumption is substantial.     

Quantile price convergence and spillover effects among Bitcoin,Fintech, and artificial intelligence stocks

This research explores the distributional and directional predictabilities among Fintech, Bitcoin, and artificial intelligence stocks from March 2018 to January 2021 using nonparametric causality-in-quantile and crossquantilogram approaches. We also examine connectedness across the assets using a quantile VAR approach. The results indicate the existence of bidirectional causality-in-variance between the variables in a normal market. We also find that directional predictability among the assets is oscillatory over time lags. Finally, we observe a strong price connectedness for highly positive and negative changes. These results further document the diversification potential and safe-haven properties of technology-related assets for portfolio investors.     

Liability driven investment with alternative assets: Evidence from Brazil

We study the portfolio choice problem for an asset-liability investor who invests in stocks, equity mutual funds, government bonds, short term interest, hedge funds, listed real estate, and commodities futures available in Brazil. Inflation and real interest play as important risk sources. We estimate the asset classes and liabilities time-varying conditional covariance structure using an asymmetric multivariate dynamic conditional correlation GARCH model and compare the asset-liability portfolio's global minimum variance allocation with Brazilian pension funds' market portfolio. The conditional covariance structure provides insights about the complex dynamic relationships between the asset classes and liabilities. We find that some (though not all) Brazilian alternative assets render strong diversification and liabilities hedging benefits for asset-liability investors. There are significant strategic asset allocation differences between the market portfolio and the liability driven portfolio as given by our model. We, therefore, question the Brazilian pension funds' allocation.     

An alternative perspective on the relationship between downside beta and CAPM beta

In this paper we derive relationships between the CAPM beta and three measures of downside risk discussed in the literature. The relationships are derived assuming data generating processes in the mean-variance and mean-semivariance frameworks. In a sample of emerging market index returns we highlight that the association between the CAPM beta and downside beta depends on the standard deviation, skewness and kurtosis of the market portfolio return distribution. Therefore choice of risk measure may depend on the market being investigated. We argue that the derived relationships may also help explain anomalous results in empirical investigations.     

Home bias and high turnover: Dynamic portfolio choice with incomplete markets

Why do investors trade a lot in foreign assets and hold so little of them in their portfolios? This paper shows that both observations can arise naturally in the presence of nondiversifiable nontraded consumption risk when each country specializes in production, preferences exhibit consumption home bias, and asset markets are incomplete. Using a general equilibrium two-country, two-sector (tradable and nontradable) model of the world economy with production I show that low diversification occurs because variations in relative prices (i) increase the riskiness of foreign assets and (ii) facilitate risk-sharing across countries. Large and volatile capital flows are necessary to take advantage of international risk premia differentials that occur in response to productivity changes in the nontradable sector. I characterize the optimal portfolio holdings, the evolution of the investment opportunity set, the risk premium, and the dynamics of capital flows using a new methodology for solving dynamic general equilibrium models with incomplete markets and portfolio choice.     

Short sales restrictions and the security market line

A reformulation of the CAPM is derived by taking account of short-sales restrictions on both risky and safe assets. The induced security market line is shown to be consistent with the empirical security market lines of various researchers.     

Diversification potential of Asian frontier,BRIC emerging and major developed stock markets: A wavelet-based value at risk approach

This study examines the portfolio risk and the co-movements between each of the BRIC emerging and South Asian frontier stock markets and each of the major developed stock markets (U.S., UK and Japan), using the wavelet squared coherence approach as well as the wavelet-based Value at Risk (VaR) method. The results show that the co-movements and diversification benefits between these markets vary over time and across frequencies. Additionally, the co-movements are intensified in the wake of the recent global financial crisis (GFC) and the Eurozone sovereign debt crisis (ESDC). More precisely, the wavelet-based VaR ratio indicates that including a BRIC or a South Asian (particularly Pakistan and Sri Lanka at both the short- and long-term) stock market in a portfolio of the developed stock markets reduces the resulting portfolio's VaR. Specifically, adding China in the medium term to this portfolio reduces risk in the pre- and during both the GFC and ESDC periods. By assigning optimal weights to the different market assets in the portfolio formulation, the analysis thus has implications for international investors.     

An intertemporal capital asset pricing model under heterogeneous beliefs

An intertemporal CAMP under heterogeneous beliefs is derived. It is shown that an asset's risk consists of three components: the market consensus of volatility risk, the market consensus of the risk induced by changes in the investment opportunity set, and risk associated with uncertain shifts in investor's subjective expectations. The multiperiod market price of risk with heterogeneous beliefs defines a new structure of market risk that captures contemporaneous changes in investors' subjective expectations and the dynamics of the investment opportunity set. The investors' demand for risky assets also is examined under heterogeneous belief. In addition, the model derived provides a generalized version of other CAPM's, such as the classical CAPM, Merton's intertemporal CAPM, and Bredeen's consumption-based CAPM.     

The role of domestic and cross-border venture capital investors in the growth of portfolio companies

This paper studies how the presence of cross-border as opposed to domestic venture capital investors is associated with the growth of portfolio companies. For this purpose, we use a longitudinal research design and track sales, total assets and payroll expenses in 761 European technology companies from the year of initial venture capital investment up to seven years thereafter. Findings demonstrate how companies initially backed by domestic venture capital investors exhibit higher growth in the short term compared to companies backed by cross-border investors. In the medium term, companies initially backed by cross-border venture capital investors exhibit higher growth compared to companies backed by domestic investors. Finally, companies that are initially funded by a syndicate comprising both domestic and cross-border venture capital investors exhibit the highest growth. Overall, this study provides a more fine-grained understanding of the role that domestic and cross-border venture capital investors can play as their portfolio companies grow and thereby require different resources or capabilities over time.     

A BENCHMARK APPROACH TO FINANCE

This paper derives a unified framework for portfolio optimization, derivative pricing, financial modeling, and risk measurement. It is based on the natural assumption that investors prefer more rather than less, in the sense that given two portfolios with the same diffusion coefficient value, the one with the higher drift is preferred. Each such investor is shown to hold an efficient portfolio in the sense of Markowitz with units in the market portfolio and the savings account. The market portfolio of investable wealth is shown to equal a combination of the growth optimal portfolio (GOP) and the savings account. In this setup the capital asset pricing model follows without the use of expected utility functions, Markovianity, or equilibrium assumptions. The expected increase of the discounted value of the GOP is shown to coincide with the expected increase of its discounted underlying value. The discounted GOP has the dynamics of a time transformed squared Bessel process of dimension four. The time transformation is given by the discounted underlying value of the GOP. The squared volatility of the GOP equals the discounted GOP drift, when expressed in units of the discounted GOP. Risk-neutral derivative pricing and actuarial pricing are generalized by the fair pricing concept, which uses the GOP as numeraire and the real-world probability measure as pricing measure. An equivalent risk-neutral martingale measure does not exist under the derived minimal market model.     

基于确定性偏好的投资组合选择

文章在对马科维茨证券投资组合模型简要评述的基础上，针对投资者可选标的证券信息集非对称的现实，依据确定性偏好原理，将投资者对可选标的证券信息的确定性程度转换成偏好次序关系，同时结合行为金融学中的前景理论，依确定性偏好次序规则来确定权重函数，并在价值函数-风险的框架下探讨了证券投资组合模型的构建及其最优解，从而在行为金融理论下扩展了马氏证券投资组合模型。实证分析表明，我国证券市场投资者基本是采用线性赋权方式来处理非对称信息集下的投资组合选择的。     

INVESTING WITH LIQUID AND ILLIQUID ASSETS

We find optimal trading policies for long‐term investors with constant relative risk aversion and constant investment opportunities, which include one safe asset, liquid risky assets, and an illiquid risky asset trading with proportional costs. Access to liquid assets creates a diversification motive, which reduces illiquid trading, and a hedging motive, which both reduces illiquid trading and increases liquid trading. A further tempering effect depresses the liquid asset's weight when the illiquid asset's weight is close to ideal, to keep it near that level by reducing its volatility. Multiple liquid assets lead to portfolio separation in four funds: the safe asset, the myopic portfolio, the illiquid asset, and its hedging portfolio.     

Market integration in developed and emerging markets: Evidence from the CAPM

Beta, as measured by the Capital Asset Pricing Model (CAPM), is widely used for pricing stocks, determining the cost of capital, and gauging the extent to which markets are integrated. The CAPM model assumes that equilibrium conditions prevail. The choice of which market portfolio to use in the regression – the home country or global index – depends on the level of global market integration. We present several new empirical observations on the pricing of stocks and market integration. We provide guidance on how practitioners should calculate beta on securities in various developed and emerging markets.     

Does corporate governance risk at home affect investment choices abroad?

Disparity between control and ownership rights gives rise to the risk of tunneling by the controlling shareholder, and is prevalent in many emerging market economies and present in some developed countries. At the same time, international investors come from different countries whose home markets are characterized by varying degrees of control–ownership disparity. This paper studies whether this difference in investors' home countries affects their portfolio choice in an emerging market. It combines two unique data sets on ownership and control in business groups, and investor-stock level foreign investment in Korea. A key finding is that investors from low-disparity countries disfavor high-disparity stocks in Korea, but investors from high-disparity countries are indifferent. Moreover, investors from low-disparity countries became averse to disparity only after the Asian financial crisis. These results suggest that the nature of corporate governance in international investors' home countries affects their portfolio choice abroad, and therefore these investors should not be lumped together in the analyses of their portfolio choice.