LIQUIDITY AND THE INFORMATIONAL EFFICIENCY OF AFRICAN STOCK MARKETS

The hypothesis that a stock market price index follows a random walk is tested for 11 African stock markets, Botswana, Côte d'Ivoire, Egypt, Ghana, Kenya, Mauritius, Morocco, Nigeria, South Africa, Tunisia and Zimbabwe using joint variance ratio tests with finite-sample critical values, over the period beginning in January 2000 and ending in September 2006. The iid random walk hypothesis is rejected in all 11 markets. In four stock markets, Egypt, Nigeria, Tunisia and South Africa, weekly returns are a martingale difference sequence. Liquidity is an important factor which contributes to whether a stock market follows a random walk.     

REVISITING THE EFFICIENT MARKET HYPOTHESIS FOR AFRICAN COUNTRIES: PANEL SURKSS TEST WITH A FOURIER FUNCTION

This study applies the panel seeming unrelated regression of the Kapetanios‐Shin‐Snell (SURKSS) test with a Fourier function to investigate the time‐series properties of stock prices in five African countries (i.e. Egypt, Kenya, Morocco, South Africa and Tunisia) over the period of January 2000–April 2011. The empirical results from the univariate unit root and panel‐based unit root tests indicate that unit root hypothesis can not be rejected for these five countries under study. However, results from the panel SURKSS test with a Fourier function indicate that unit root hypothesis can be rejected for Egypt and Morocco, two countries under study. Our results indicate that the weak‐form efficient market hypothesis holds in the other three countries, namely, Kenya, South Africa and Tunisia.     

African Stock Markets: Efficiency and Relative Predictability

The weak form of the efficient markets hypothesis is tested for eight African stock markets using three finite‐sample variance ratio tests. A rolling window captures short‐horizon predictability, tracks changes in predictability and is used to rank markets by relative predictability. These stock markets experience successive periods when they are predictable and then not predictable; this is consistent with the adaptive markets hypothesis. The degree of predictability varies widely: the least predictable African stock markets are those located in Egypt, South Africa and Tunisia, while the most predictable are in Kenya, Zambia and Nigeria.     

Efficiency,Cointegration and Contagion in Equity Markets: Evidence from China,Japan and South Korea*

This paper empirically examines whether three East Asian stock markets, namely, those of China, Japan and South Korea, are individually and/or jointly efficient, and whether contagion exists between the cointegrated markets. While individual market efficiency is examined through testing for the random walk hypothesis, joint market efficiency is examined through testing for cointegration and contagion. The present study finds that the hypothesis of individual market efficiency is strongly rejected for the Chinese stock market, but not for the Japanese and the South Korean stock markets. However, when testing for cointegration, market efficiency is strongly rejected for all these markets. We take a simple case of contagion and find that although there is a long‐term relationship among the three markets, the contagion hypothesis cannot be rejected only between Japanese and South Korean stock markets, indicating short‐run portfolio diversification benefits from these two markets.     

Weak Form Efficiency of the Nigerian Stock Market: Further Evidence

This study provides further evidence on the weak form efficiency of the Nigerian stock market, that is, whether security prices on the Nigerian stock market adjust to historical price information. Using correlation analysis, monthly stock returns data over the period January 1981–December 1992 were employed in the analysis. The results provided support for the work of Samuels and Yacout (1981) and Ayadi (1983), that is, the Nigerian stock market appears to be efficient in the weak form. — Cet article traite de la faible efficacité de la Bourse des valeurs du Nigeria, à savoir que, à partir de nouveaux éléments, il cherche àétablir si les cours des titres cotés à la Bourse du Nigeria sont réajustés pour tenir compte des données chronologiques. A l’aide d’une analyse de corrélation, un examen des données mensuelles sur le rendement des titres, pour la période allant de janvier 1981 à décembre 1992, a été réalisé. Les résultats corroborent les travaux de Samuels et Yacout (1981) et ceux de Ayadi (1983), à savoir que la Bourse des valeurs du Nigeria semble être faiblement efficace.     

LONG MEMORY IN SOUTHERN AFRICAN STOCK MARKETS

The paper examines long memory in equity returns and volatility for stock markets in Botswana, South Africa and Zimbabwe using the ARFIMA‐FIGARCH model in order to assess the efficiency of these markets in processing information. The findings are diverse. Significant long memory is demonstrated in the equity returns of Botswana; while, in South Africa this result is not statistically different from zero. For Zimbabwe returns are characterised by an anti‐persistent process. Furthermore, all the markets investigated provide evidence of long memory in volatility with the exception of Botswana where there is no evidence of volatility persistence and hence the return from taking risk in this market cannot be predicted on the basis of previous values.     

The Revenue–Expenditure Nexus: The Experience of 13 African Countries

Abstract: The aim of this paper is to investigate the causal relationship between government revenue and government expenditure for 13 African countries within a multivariate framework using a modified version of the Granger causality test due to Toda and Yamamoto (1995) . The empirical evidence suggests that there was a bi‐directional causality running between expenditure and revenue for Mauritius, Swaziland and Zimbabwe; no causality in any direction for Botswana, Burundi and Rwanda; unidirectional causality running from revenue to expenditure for Ethiopia, Ghana, Kenya, Nigeria, Mali and Zambia; and a uni‐directional causality running from expenditure to revenue for Burkina Faso only.     

中美股市间的联动性变化分析

将中国加入WTO后至今中美股市的数据以2005年为界划分为两部分,研究了中国入市后中美股市联动性的发展变化。研究结果表明,2005年以前中美股市没有显著的联动性,但2005年以后至今中美股市之间存在比较弱的联动性,而且表现出相互影响的特征。     

亚太地区股票市场的联动程度——基于次级贷冲击的研究

本文从长期关系、短期作用和方差分解方面,分析了次级贷危机前后亚太股市的联动程度。首先,协整检验表明,亚太股市存在长期均衡关系,但这种关系在次级贷危机前后发生了明显的结构转变。其次,Granger非因果检验表明,亚太股市在次级贷危机后,市场间短期作用大大加强。再次,我们定义了单个市场联动程度判断准则,并且结合方差分解发现,亚太地区股市在次级贷危机后单个市场独立性显著降低。总体而言,亚太地区股市在次级贷危机之后联动程度进一步加强,支持弱分割市场理论;美国股市是地区股市领导者;日本股市变化最大,次级贷危机后,市场独立性变得最弱;中国大陆股市也不断融入区域市场。建议政府和投资者对于本国(本地区)之外的实体经济和股市风险都要密切关注。     

Interactions of stock markets within the greater China economic bloc

This paper investigates what types of mutual relationships exist among the stock markets of the Greater China economic bloc, which include stock markets in Hong Kong and Taiwan, as well as stock markets in Shanghai and Shenzhen. Using the unit root test, co‐integration analysis, and vector error correction model (VECM), this paper analyzes interrelationships among daily stock indices for the period from the beginning of 1992 to the end of 2001. Test results indicate the existence of one co‐integrating vector, implying that a long‐run equilibrium relationship holds among the four stock indices. Variance decomposition of forecast errors provides evidence that the Shenzhen stock market is the market most heavily influenced by the unexpected variations of other markets in the Greater China economic bloc.     

股改前后中国A股市场有效性广义谱方法检验

股改是我国资本市场发展过程中的一项重大制度变革,本文对股改前后A股市场的有效性分别进行了检验。我们采用的广义谱方法考虑了高频时间序列的特征事实,可以检测出序列存在的线性和非线性序列依赖,允许存在未知形式的条件异方差,并且可以检验所有的滞后阶数,具有较强的检验效力。检验结果表明,股改前市场是非有效的,股改之后市场达到了弱式有效。本文从股权的全流通效应、股市参与度的提升两个角度给出了实证结果的经济解释。     

有效市场假说的争论与发展

本文系统回顾了有效市场假说的发展历程,重点评述了信息经济学派对完全信息假设的质疑和争论、行为金融学派对完全理性人假设及有效套利的质疑和争论,进一步从实证工作的角度,结合金融市场异象,对弱式有效、半强有效、强式有效的争论和发展也进行了总结。     

Stock prices and the efficient market hypothesis: Evidence from a panel stationary test with structural breaks

This paper investigates whether the efficient market hypothesis holds in stock markets under different economic development levels over the period January 1999 to May 2007. We employ a state-of-the-art panel data stationarity test which incorporates multiple structural breaks. Evidence indicates that when accommodating general forms of cross-sectional dependence as well as controlling for finite-sample bias, the real stock price series appear to be stationary in 32 developed and 26 developing countries, respectively, which is in sharp contrast to the findings in the existing literature. Thus, real stock price indices are stationary processes that are inconsistent with the efficient market hypothesis. This shows the presence of profitable arbitrage opportunities among stock markets. According to these estimated structural breakpoints, we are also able to discover the reason for why there has been a huge impact from past stock prices.     

基于金融周期视角下股票市场的联动效应研究

世界经济全球化已成为趋势,发达经济体的股市之间以及发达经济体与新兴经济体股市之间的联动性也在经济全球化的趋势中更加紧密。各国金融领域以及金融市场间的快速融合,不断形成统一规范的金融行为准则,也使得全球金融周期性特征越来越明显。文章选取世界五个主要股票市场指数为研究对象,按照已有研究对全球金融周期的划分,将该样本区间分成了繁荣期、衰退期和正常期三个阶段,然后基于这三个阶段分析了在不同金融周期五国股票市场指数收益率联动效应。基于实证研究结论,认为美国和欧洲股市联动性较强,与亚洲股市联动性相对较弱,且美国和中国股市之间联动性最弱,基本捕捉不到下尾相关。相关实证结论有利于国际投资者的投资组合管理,也有助于各国股票市场的风险规避。     

Herding behaviour in the Chinese and Indian stock markets

The existence of herding behaviour challenges the validity of the “efficient market hypothesis”. This study examines herding behaviour in the Chinese and Indian stock markets; our findings suggest that herding behaviour exists in both. The level of herding depends on market conditions. In the Chinese market, herding behaviour is greater when the market is falling and the trading volume is high. On the other hand, in India the study finds that it occurs during up-swings in market conditions. Herding behaviour is more prevalent during large market movements in both markets. In relative terms, a lower prevalence of herding behaviour was detected in the Indian stock market.     

International equality of stock market returns

Real returns, excess returns, and nominal returns from stock markets in 11 developed countries are compared for the difference in their means and variances by using a new procedure to test their equality and to determine if one stock market dominates another. The sample period from January 1973 to September 1989 is divided into three subperiods. Results show that stock markets in the United States and Germany dominate those in the other countries in early sub-periods, but not in a recent sub-period, to indicate an increasing capital market integration. Integration with Germany has increased more than with the United States, due possibly to the European Monetary System.     

China＇s Stock Market： Inefficiencies and Institutional Implications

The dramatic movements of China＇s stock market in the past two and a half years have renewed debate among academics over the efficiency of China＇s stock market. The present paper tests the efficiency of China＇ s stock market. The realization of efficient markets requires the effective operation of a complete set of macro and micro mechanisms. However, such mechanisms are not only incomplete in China＇ s stock market, but are also ineffective because of the prevalence of institutional deficiencies.     

中国商品期货市场有效性的方差比率检验

随机游动模型的方差比率检验方法可以被用于检验中国商品期货市场的有效性程度。对1999-2004年间六个商品期货品种的收盘价和结算价的分阶段（1999-2001和2002-2004）检验结果表明：铜期货市场在整个样本期间都基本上达到了弱式有效,而铝、天胶、大豆／豆一、豆粕等品种在2002-2004年间的有效性却表现出一定程度的下降。但是,在2002-2004年间,小麦期货市场的有效性得到了一定程度的提高。这些实证结果表明监管当局应该汲取以往期货市场大幅震荡的教训,有针对性地继续努力改进并提高期货市场的有效性水平。     

TESTING PROFIT AND STRUCTURE RELATIONSHIP IN THE EUROPEAN BANKING MARKETS USING EFFICIENCY MEASURES

This paper provides a comparison between the developed and developing European countries through investigating the profit–structure relationship in the banking industries. The reduced‐form profit equations are estimated for each group of countries for the period 1995–2006. The results suggest that the inclusion of X‐efficiency and scale efficiency directly in the reduced‐form profit equation is crucial in explaining the bank profit–structure relationship in the European banking markets. When we control for direct measures of efficiency, the market share and concentration coefficient become insignificant in all regressions. The results support the efficiency versions of the efficient‐structure hypothesis over the relative market power and structure–conduct–performance hypothesis. For the developing economies of Europe, the findings of the paper indicate that efficiency is a crucial factor for establishing a sound banking system and the banks in these countries should increase their scale of operations to attain an optimal profit level.     

Libéralisation du commerce et intégration spatiale des marchés: Le cas du maïs au Togo

Abstract: The cereal market of Togo was liberalized in 1987. This policy aims to improve markets' spatial integration through the development of arbitrage. The paper assesses the extent of maize market spatial integration in order to understand how it has been affected by price liberalization. The monthly retail maize prices collected on 13 markets for the period from 1980 to 2001 are considered. The results show that the impact of price liberalization on markets integration is moderate. The liberalization has not significantly improved the extent of long‐run and short‐run integration of maize markets. The speed of price adjustment is relatively weak for most of the markets. In order to improve market efficiency, it is suggested that the government should create a market information service (SIM) which will be entrusted in collecting and disseminating weekly cereal prices all over the country.