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.     

THE CHANGING EFFICIENCY OF AFRICAN STOCK MARKETS

This paper classifies formal African stock markets into four categories and discuses the principal characteristics of the seven markets covered in this study: South Africa, Egypt, Morocco, Nigeria, Zimbabwe, Mauritius and Kenya. Using a GARCH approach with time‐varying parameters, a test of evolving efficiency (TEE) is implemented for periods starting in the early 1990s and ending in June 2001. This test detects changes in weak form efficiency through time. The TEE finds that the Johannesburg stock market is weak form efficient throughout the period, and three stock markets become weak form efficient towards the end of the period: Egypt and Morocco from 1999 and Nigeria from early 2001. These contrast with the Kenya and Zimbabwe stock markets which show no tendency towards weak form efficiency and the Mauritius market which displays a slow tendency to eliminate inefficiency. The paper relates weak form efficiency to stock market turnover, capitalisation and institutional characteristics of markets.     

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.     

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.     

VARIANCE RATIO TESTS OF THE RANDOM WALK HYPOTHESIS FOR SOUTH AFRICAN STOCK FUTURES

The hypothesis that stock futures follow a random walk is tested for four stock index futures and a sample of 36 single stock futures traded on the JSE Securities Exchange, South Africa, using joint variance ratio tests based on (i) ranks and signs and (ii) wild bootstrapping. Overall, there is a high degree of weak‐form efficiency: all four stock index futures and twenty‐five of the sample of 36 single stock futures follow a random walk.     

Equity,Bonds, Institutional Debt and Economic Growth: Evidence from South Africa

We examine the finance‐growth nexus in South Africa accounting for the role of bond markets, stock markets, and bank and non‐bank financial intermediaries using a vector autoregressive technique. Extant empirical literature has largely accounted for only banks and stock markets, ignoring bond market and non‐bank financial intermediaries. We find that bond market development affects economic growth in South Africa, and no similar effect is observed for the bank and non‐bank financial intermediaries and the stock market. Our finding shows that examination of individual elements of the financial system is important in understanding the unique effect of each on growth. The observation that the bond market rather than stock market, bank and non‐bank institutions promote economic growth in South Africa induces an intriguing question as to what unique roles bond markets play that the intermediaries and equity market are unable to play.     

Is Violation of the Random Walk Assumption an Exception or a Rule in Capital Markets?

Both the efficient market hypothesis and modern portfolio theory rest on the assumptions of the Gaussian probability distribution and independence of consecutive returns. This paper provides a brief excursion into the history of capital market research. A measure of long-range dependence (Hurst exponent) was applied to daily returns of selected stock indices and individual firms. The Hurst exponent was estimated using rescaled range analysis. The estimates are based on an unusually large sample of empirical-time series from capital markets. This method distinguishes whether the data-generating process follows random walk or exhibits antipersistent or persistent behavior. Both the efficient market hypothesis and modern portfolio theory assume that the data-generating process has no memory, i.e. follows Brownian motion. The random walk process is characterized by a Hurst exponent value of 0.5. Values greater than 0.5 and less than 1 indicate a persistence of local trends. Values between 0 and 0.5 indicate a process that reverts to the mean more often than a random process (mean-reverting process). The results indicated that the series of daily returns exhibit predominantly persistent or antipersistent behavior. Therefore, Brownian motion cannot be perceived as the norm for describing stock market behavior. These findings challenge the assumption of a random walk in stock prices, valuation models and assessment of risk.

     

RISK–RETURN TRADE‐OFF AND BEHAVIOUR OF VOLATILITY ON THE SOUTH AFRICAN STOCK MARKET: EVIDENCE FROM BOTH AGGREGATE AND DISAGGREGATE DATA

The study analyses the nature and behaviour of volatility, the risk–return relationship and the long‐term trend of volatility on the South African equity markets using aggregate level, industrial level and sectoral level daily data for the period 1995‐2009. By employing dummy variables for the Asian and the sub‐prime financial crises and the 11 September political shock, the study further examines whether the long‐term trend of volatility structurally breaks during financial crises and major political shocks. Three time‐varying generalised autoregressive conditional heteroskedasticity models were employed: one of them symmetric, and the other two asymmetric. Each of these models was estimated based on three error distributional assumptions. The findings of the study are as follows: First, volatility is largely persistent and asymmetric. Second, risk at both aggregate and disaggregate level is generally not a priced factor on the South Africa (SA) stock market. Third, the threshold autoregressive conditional heteroscedasticity (TARCH) model under the generalised error distribution is the most appropriate model for conditional volatility of the SA stock market. Fourth, volatility generally increases over time, and its trend structurally breaks during financial crises and major global shocks. The policy and investment implications of the findings are outlined.     

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 Impact of Firm Size and Liquidity on the Cost of External Finance in Africa

Established illiquidity measures are constructed for emerging markets in Africa and used to determine which best explains trading costs. Costs of equity are derived from an augmented Capital Asset Pricing Model for a sample of emerging financial markets generally ignored in the literature. These include: South Africa and Namibia, three countries in North Africa and four in Sub‐Saharan Africa (SSA), plus London and Paris as examples of integrated markets. Minimum variance portfolios are constructed and asset weights derived, with the sample divided into countries dependent on their legal regime. Portfolio weights are shown to be directly related to well‐regulated markets with high standards of corporate governance and disclosure, and firms seeking cost‐effective finance from SSA stock markets are at a distinct disadvantage compared with those in Northern Africa, South Africa and, in particular, London and Paris.     

The impact of economic fundamentals on stock markets in southern Africa

The issue of whether stock markets reflect economic fundamentals or speculative bubbles is an important one for their potential role in allocating capital, and relates to a policy issue of whether stock markets should be encouraged in developing countries. This article examines the impact of both domestic and foreign economic factors on real stock market returns in three southern African stock markets – South Africa, Zimbabwe and Botswana, from 1985-95 – using cointegration and error correction techniques. It finds that, while in all cases stock markets are influenced by domestic economic growth, there are no common patterns beyond this. The influence of other domestic and economic variables depends on the size, openness and market-orientation of the individual economies, as well as the size and liquidity of the various stock exchanges. Where foreign economic variables are important, they appear to be those related to trade, rather than international capital flows, indicating that there is little integration of these capital markets, whether regionally or internationally.     

Major International Information Flows Across the Safex Wheat Market

We study information flows across four wheat futures markets on four continents: Zhengzhou Commodity Exchange (ZCE), South African Futures Exchange (SAFEX), Euronext/Liffe and Kansas City Board of Trade (KCBT). Three approaches for studying information flows among non‐synchronous markets are applied: cointegration techniques, vector autoregressive analysis and multiple regression proposed. Although comparable underlying assets are traded in the four markets, our results indicate that no long‐run links exist among them. ZCE is by far the most endogenous market, and Euronext/Liffe is the most exogenous one. Finally, the model points to KCBT as the most influential and sensitive wheat market. Our findings indicate that the relative openness of the SAFEX wheat market supports information flows and linkages from KCBT and Euronext/Liffe. Therefore, our results suggest that more supportive policies to incentivise higher wheat production in South Africa are required to mitigate the impact of price shocks emanating from the global wheat markets.     

分形市场假说与股票市场的有效性分析

主流的金融计量理论是以价格的随机游走和收益的正态分布假设为基础的。而分形市场研究认为价格是分形,价格遵循有偏随机游走,并用分形分布描述收益的分布规律。在分形研究的框架下,作为主流有效市场假说的替代理论,分形市场假说用不同投资期水平下的投资者对信息的不同评估来解释价格行为的分形机制,也启发我们从动态的和相对的角度去思考股票市场的有效性问题。     

Testing the Validity of the Simultaneous Openness Hypothesis in Nigeria (1990–2015)

Since the seminal paper by Rajan and Zingales in 2003, a plethora of studies have been motivated to establish whether the simultaneous opening of trade and capital borders leads to financial sector development. We test whether the simultaneous openness hypothesis is valid for Nigeria, with a focus on the banking sector and stock market. Using annual data from 1990 to 2015 and an instrumental variable regression estimation technique, we show that the simultaneous increase of trade and financial openness limits banking sector and stock market development. Thus, there is no empirical evidence to validate the simultaneous openness hypothesis in Nigeria. It also shows that trade openness is more beneficial for banking sector and stock market development in Nigeria than financial openness.     

LIQUIDITY AND VALUATION IN EAST AFRICAN SECURITIES MARKETS

This study estimates liquidity premiums using the recently developed Liu measure within a multifactor capital asset pricing model including size premiums and a time‐varying parameter model for the East African emerging markets of Uganda, Tanzania and Kenya together with London and South Africa. The evidence suggests that while size and liquidity effects are significant in the smaller emerging markets of Uganda and Kenya, they are less important in explaining returns in South Africa and London. Costs of equity are highest in Uganda followed by Kenya, with industrial and consumer non‐cyclical sectors being lowest, and then South Africa and London.     

Understanding the Growth of African Financial Markets*

Abstract: This paper examines empirically the determinants of financial market development in Africa with an emphasis on banking systems and stock markets. The results show that income level, creditor rights protection, financial repression, and political risk are the main determinants of banking sector development in Africa, and that stock market liquidity, domestic savings, banking sector development, and political risk are the main determinants of stock market development. We also find that liberalizing the capital account promotes financial market development only in countries with high incomes, well‐developed institutions, or both. The powerful impacts of political risk on both banking sector and stock market development suggest that resolution of political risk may be important to the development of African financial markets.     

Who Plays the Key Role among Shanghai, Shenzhen and Hong Kong Stock Markets？

In this paper we examine the daily frequency stock market indices of Shanghai, Shenzhen and Hong Kong from January 2000 to June 2012, and use the Morlet wavelet coherence model to determine who is playing the most important role in the financial markets of China. We find that there are significant comovements between these stock markets in the medium and long run. This provides investors with opportunities to increase their capital gains. The Hong Kong stock market plays a leading role in the long run, but its leader position is threatened by fast‐growing Chinese mainland stock markets, especially the Shanghai Stock Exchange. Based on our analysis, the following suggestions apply to the Chinese stock markets: establish and improve international and regional finance centers in Chinese mainland; encourage more qualified institutional investors; reposition the market relations among Hong Kong, Shanghai and Shenzhen; and increase deregulation and internationalization to speed up the integration of financial resources.     

MACROECONOMIC UNCERTAINTY AND CONDITIONAL STOCK MARKET VOLATILITY IN SOUTH AFRICA*

This paper analyses how systematic risk emanating from the macroeconomy is transmitted into stock market volatility using augmented autoregressive Generalised Autoregressive Conditional Heteroscedastic (AR‐GARCH) and vector autoregression (VAR) models. Also examined is whether the relationship between the two is bidirectional. By imposing dummies for the 1997‐1998 Asian and the 2007‐2009 sub‐prime financial crises, the study further analyses whether financial crises affect the relationship between macroeconomic uncertainty and stock market volatility. The findings show that macroeconomic uncertainty significantly influences stock market volatility. Although volatilities in inflation, the gold price and the oil price seem to play a role, it is found that volatility in short‐term interest rates and exchange rates are the most important, suggesting that South African domestic financial markets are increasingly becoming interdependent. Finally, the results show that financial crises increase volatility in the stock market and in most macroeconomic variables, and, by so doing, strengthen the effects of changes in macroeconomic variables on the stock market.     

Systemic Risks Spillovers and Interdependence among Stock Markets: International Evidence with Covar‐Copulas

Empirical studies have provided ample evidence on the potential benefits of international diversification with portfolios that consist of both domestic and foreign assets. This coupled with sudden and periodic crashes in global and developed equity markets have stimulated the interest of investors to diversify across markets that have the potential to provide decorrelation with global markets during turbulent periods. At the same time, international diversification may intensify cross‐border listing of stocks with its antecedent implication of shocks transmission. The above have engendered renewed interest among researchers to explore the dependence levels and spillover effects of shocks among emerging and developed equity markets. This paper examines tail dependence structure and (extreme) systemic risks spillover effects among international equity markets using advanced econometric techniques that underpin the modelling of asset returns. We find evidence of low positive significant dependencies between all African markets and their developed counterparts, except for Egypt. Although no evidence of spillover effects to the markets in Africa was found, both unidirectional and bi‐directional causality between some African and developed equity markets is found, albeit with differences. We are unable to ascribe the dynamics in the causality structure to level of market integration. It is inferred that the degree of individual local markets interdependence with developed counterparts may reflect the relative size, liquidity and degree of foreign investors' participation.     

收益波动与随机冲击的非对称性影响：中国与美国股票市场的对比

通过讨论股票收益与随机;中击之间的关系,对中国股票市场和美国股票市场进行了对比研究。研究中使用了中国上海和深圳股票市场1990年12月31日至2005年12月30日的两市A股算术平均周指,以及美国股票市场1973年1月2日至2004年月12月30日的标准普尔500周指。在进行经验研究的过程中,分别使用了线性GARCH模型和GJR—GARCH模型计量股票收益的条件波动——即模型中的条件方差。研究发现,中国股票市场自1990年——1995年波动剧烈,之后波动趋于平缓,而美国股票市场在研究期间内收益波动一直处于一定范围内。同时还发现,美国股票市场的随机冲击对股票收益产生非对称性影响,即负冲击使股票收益产生的波动大于正冲击。而在中国股票市场却找不到相似的证据。鉴于对中国股票市场收益波动的研究结果,在剔除1996年以前的数据之后又进行了扩展研究,但是似然比率检验结果表明,正冲击对股票收益的影响还要略强于负冲击。