Random Walks and Market Efficiency Tests of Latin American Emerging Equity Markets: A Revisit

The few existing studies on equity price dynamics and market efficiency for Latin American emerging equity markets show conflicting results. This study uses multiple varianceratio and auto-regressive fractionally integrated moving-average tests and new data (U.S. dollar-based national equity indices for the 1987–1997 period) to clarify these results. Documented evidence shows that equity prices in major Latin American emerging equity markets — Argentina, Brazil, Chile and Mexico—follow a random walk, and that they are, generally, weak-form efficient. In sum, therefore, the evidence suggests that international investors in these markets cannot use historical information to design systematically profitable trading schemes because future long-term returns are not dependent on past returns.     

资本市场投资回报率与我国养老金体系改革

理论上，投资回报率的高低是我国养老金体系转轨能否成功的关键。本文指出，我国建立基金制养老金体系面临极为特殊的背景——高工资增长率和低投资回报率。基于这个背景，本文认为现阶段进行体制转轨的时机还不成熟，当前需要大力提高我国养老基金的投资回报率或者为提高投资回报率创造条件。本文最后提出了关于提高我国养老基金投资回报率的几点建议。     

对全部投资现金流量表计算指标的一些思考

根据实际筹资情况对全部投资现金流量表计算指标进行思考和修正，并对ＦＩＲＲ、ＦＮＰＶ和投资回收期等指标的理解给予通俗的解释。     

沪市主要板块指数市场波动实证分析

GARCH—M模型通常应用于预期收益与预期风险密切相关的领域，根据金融理论股票的风险越大，其收益也就越高，故可认为股票收益的指数变动依赖于一个常数。利用GARCH—M模型和E—GARCH—M模型对沪市主要板块指数进行实证分析。结果显示沪市重要板块指数日收益率存在信息非对称效应、高风险对应高回报。     

Learning, hubris and corporate serial acquisitions

Recent empirical research has shown that, from deal to deal, serial acquirers' cumulative abnormal returns (CAR) are declining. This has been most often attributed to CEOs hubris. We question this interpretation. Our theoretical analysis shows that (i) a declining CAR from deal to deal is not sufficient to reveal the presence of hubris, (ii) if CEOs are learning, economically motivated and rational, a declining CAR from deal to deal should be observed, (iii) predictions can be derived about the impact of learning and hubris on the time between successive deals and, finally, (iv) predictions about the CAR and about the time between successive deal trends lead to testable empirical hypotheses.     

Asset Revaluations in the Accounts of UK National Health Service Trusts

This paper reports the results of an investigation into the impact of the revaluation of fixed assets on the reported results of NHS ambulance services. It recalculates the accounting rate of return of individual trusts after removing revaluation adjustments and examines the published responses of trusts. The numerical analysis demonstrates that, in general, revaluation has depressed the stated rate of return in an inconsistent manner. Failure to meet the required rate of return may cause a trust to be subjected to additional monitoring and management reorganisation while the trusts respond by explaining deviations in the accounting return measure by referring to revaluations and other technical adjustments. Management decisions made in response to these accounting measures may be sub-optimal in delivering health care but appropriate in achieving the desired accounting outcome.     

The Gilt-Equity Yield Ratio and the Predictability of UK and US Equity Returns

A number of financial variables have been shown to be effective in explaining the time-series of aggregate equity returns in both the UK and the US. These include, inter alia , the equity dividend yield, the spread between the yields on long and short government bonds, and the lagged equity return. Recently, however, the ratio between the long government bond yield and the equity dividend yield – the gilt-equity yield ratio – has emerged as a variable that has considerable explanatory power for UK equity returns. This paper compares the predictive ability of the gilt-equity yield ratio with these other variables for UK and US equity returns, providing evidence on both in-sample and out-of-sample performance. For UK monthly returns, it is shown that while the dividend yield has substantial in-sample explanatory power, this is not matched by out-of sample forecast accuracy. The gilt-equity yield ratio, in contrast, performs well both in-sample and out-of-sample. Although the predictability of US monthly equity returns is much lower than for the UK, a similar result emerges, with the gilt-equity yield ratio dominating the other variables in terms of both in-sample explanatory power and out-of-sample forecast performance. The gilt-equity yield ratio is also shown to have substantial predictive ability for long horizon returns.     

Robust min–max portfolio strategies for rival forecast and risk scenarios

We consider an extension of the Markowitz mean–variance optimization framework to multiple return and risk scenarios. It is well known that asset return forecasts and risk estimates are inherently inaccurate. The method proposed provides a means for considering rival representations of the future. The optimal portfolio is computed, simultaneously with the worst case, to take account of all rival scenarios. This is a min-max strategy which is essentially equivalent to a robust pooling of the scenarios. Robustness is ensured by the noninferiority of min–max. For example, a basic worst-case optimal return is guaranteed in view of multiple return scenarios. If robustness happens to have too high a cost, guided by the min–max pooling, it is also possible to explore other pooling alternatives. A min–max algorithm is used to solve the problem and illustrate the robust character of min–max with return and risk scenarios. We study the properties of the min–max risk–return frontier and compare with the potentially suboptimal worst-case where the investment strategy and the worst case are computed separately.     

供应链体系中不容忽视的一环——逆向物流

随着企业竞争的加剧以及政府和社会公众环保意识的加强,逆向物流的研究得到高度重视。本文通过供应链体系中正向物流和逆向物流的比较,分析阐述了逆向物流的起因及运作策略和未来发展方向。