Weak-form Efficiency Research Articles

Testing the Weak Form State of Market Efficiency: An Empirical Evidence of Shar¯ı‘ah Compliant Index

The Efficient Market Hypothesis (EMH) proposed by Fama is considered a central premise to explain market functioning. Current research tests the stock returns behaviour of Shar¯ı‘ah-compliant Karachi Stock Exchange Meezan Index (KMI 30) under weak form efficiency. Based on the nature of data, i.e. time series, both linear and non-linear techniques are employed to assess market efficiency. The study results portray that KMI-30 is an inefficient market, and there is dependence in the series.

Lack of Reform Effect on Exchange Efficiency- Empirical Evidence from Saudi Market Index –

As development of financial markets has been a growing issue after the financial crisis 2008, this paper has tested efficiency on one of the largest emerging securities markets in the world. It examines lack of reform impact on efficiency of Saudi stock exchange (TASI index) employing random walk hypothesis (RWH) through a battery of parametric and nonparametric tests including autocorrelations, unit root, variance ratio (VR) and Brock, Dechert, and Scheinkman (BDS) test.The study specifically aims to test weak form efficiency before and after massive efforts implemented to reform Saudi exchange. Findings have concluded in a consensus verdict that there is no change observed in TASI index behaviour, and hence it rejected to be a weak-form efficient market. Thus, policy makers and regulators should initiate further reforms; deep regulations and reorganization development to address inefficiency.

THE WEAK FORM MARKET EFFICIENCY IN THE MSCI ETF INDICES: CONVENTIONAL AND THE FOURIER UNIT ROOT TEST ON THE DEVELOPED AND DEVELOPING COUNTRIES

In this study, weak form efficiency of the Exchange Traded Funds (ETF) in the Morgan Stanley Capital International (MSCI) Index of developed and developing countries is tested. The Fourier Unit Root test, which does not lose its predictive power in terms of structural break date, number and form, is used on daily data. Also, conventional unit root tests are used for comparison between two different tests. Analysis results indicate common findings in some countries for both unit root testing. However, the Fourier unit root test results relatively more support the assumption of efficient market hypothesis that developed countries may be more efficient than developing countries.

Weak form market efficiency: A case study of Asia-Pacific markets

This study aims to test the weak form market efficiency for five developed markets, nine emerging markets and three frontier markets in the Asia-Pacific region. The tools applied in the test of this form of market efficiency are serial correlation test, runs test and unit root test. The analysis is performed by using logarithm return for the period of 2008 to 2018. For all markets in our research, the results strongly reject the weak form efficiency when the unit root tests are carried out, while the results from the Durbin-Watson test are in complete contrast. However, in the runs test and variance ratio test, the results provide mixed evidences of weak form efficiency of the markets

The Existence of Random Walk in the Philippine Stock Market: Evidence from Unit Root and Variance-Ratio Tests

The efficient market hypothesis explains the random walk hypothesis suggesting that stock prices are independent of each other, hence, it is impossible to earn abnormal profits. The positive effect of a well-functioning and highly efficient stock market on the performance of an economy motivated the Philippine Stock Exchange to pursue massive modernization initiatives. This research provides evidence of the existence of random walk in the Philippine stock market employing the Augmented Dickey-Fuller (1981) and Phillips-Perron (1988) unit root tests, the Lo-MacKinlay's (1988) conventional variance ratio test, and Chow-Denning's (1993) simple multiple variance ratio test. Results of the ADF and PP unit root tests confirm the necessary condition for a random walk. The Chow-Denning (1993) maximum /z/ statistic and the Wald test statistic as in Richardson and Smith (1991) for the joint hypotheses and the Lo and MacKinlay (1988) individual statistics variance ratio test generally accepted the null hypothesis of a random walk. That is, the unit root and variance ratio tests consistently indicate that the null hypothesis of random walk cannot be rejected. The existence of a random walk in weak-form efficiency can be attributed to market liquidity as a result of continuous development and modernization of the Philippine equity market.

Further evidence on efficiency of Bahrain Bourse: A high challenge for other industries

The purpose of the present study is to provide further evidence of the weak form efficiency of the Bahrain Bourse. The research methodology is based on daily closing index values of the Bahrain Bourse from 2011 to 2015 in order to test the efficiency of the stock market while runs test, Autocorrelation Function, and advance tools such as ARCH and GARCH models and Hurst Index to provide further evidence of the weak form efficiency of the Bahrain stock market. For instance, a volatile and inefficient stock market has a negative impact on textile and apparel industry in the Kingdom of Bahrain, which is one of the most prosperous and attractive industries in the country. The empirical results revealed that Bahrain stock market does not follow normal distribution and the successive price changes are not independent. Further, ARCH effect is significant and indicative of a time-varying conditional volatility. There is an arbitrage opportunity and extreme mispricing in the Bahrain stock market as indicated by the GARCH (1,1) model. The results of the Hurst exponent also confirm the inefficiency of the market. The results of these tests are consistent indicating that the Bahrain stock market is inefficient

Testing for efficiency in the Saudi stock market: does corporate governance change matter?

We study the informational efficiency of the Saudi stock market (SSM), while accounting for corporate governance change, based on single, multiple, and variance ratio-based WALD tests and runs test. The main findings indicate that when the whole period is considered, the random walk hypothesis is rejected, but when divided into two sub-periods separated by the pre-corporate governance and the period marked by corporate governance change, the analysis demonstrates sub-period improvement in weak-form efficiency for the examined series. Robustness of results is verified by analysis using sector indices, which point to market efficiency. Interestingly, Hurst Exponent estimates evidence long-range dependence which suggests the predictability of stock prices and the prospect of speculative opportunities.

Testing the random walk hypothesis for leading cryptocurrencies

Despite the rise in markets for cryptocurrencies at an outstanding pace, with consistently high trading volume and market capitalization, the increasing volatility of the virtual currencies raise various concerns. One of the major concerns is regarding (in)efficiency, viz. whether there exist opportunities of making excess returns based on out-performing the market or merely a game of chance. In this study, the authors investigate the weak-form efficiency of the top-ten cryptocurrencies using non-parametric and parametric random walk testing methods that are robust to unknown structural breaks and asymmetric effects. The findings do not support the random walk hypothesis, hence validating the weak-form inefficiency for daily cryptocurrencies returns. This can be attributed to the presence of asymmetric volatility clusters. This study has significant implications for portfolio managers, market participants and regulators of leading cryptocurrency markets.

How to compare market efficiency? The Sharpe ratio based on the ARMA-GARCH forecast

This paper derives a new method for comparing the weak-form efficiency of markets. The author derives the formula of the Sharpe ratio from the ARMA-GARCH model and finds that the Sharpe ratio just depends on the coefficients of the AR and MA terms and is not affected by the GARCH process. For empirical purposes, the Sharpe ratio can be formulated with a monotonic increasing function of R-squared if the sample size is large enough. One can utilize the Sharpe ratio to compare weak-form efficiency among different markets. The results of stochastic simulation demonstrate the validity of the proposed method. The author also constructs empirical AR-GARCH models and computes the Sharpe ratio for S&P 500 Index and the SSE Composite Index.

Testing the weak form market efficiency of Borsa Istanbul: an empirical evidence from Turkish banking sector stocks

Purpose- The purpose of this study is to assess the weak form efficiency of Borsa Istanbul banking sector stocks using bank stocks listed in BIST 30. In addition to individual banking sector stocks, BIST 100 and BIST BANKS indexes are also investigated. Methodology- For this purpose, weekly adjusted closing prices of selected stocks and indexes are collected from finance.yahoo.com and investing.com. The study period covers from January 4, 2010, to December 20, 2019. Therefore, a total of 520 observations for each stock and index are analyzed using autocorrelation, run test and unit root tests such as Augmented Dickey-Fuller (ADF), Phillips-Perron test (PP) and Kwiatkowski-Phillips Schmidt-Shin (KPSS). Findings- The autocorrelation test results indicated that only VAKBAN and YAKBNK are efficient at the weak form of efficiency during the study period. On the other hand, the runs test result showed that only AKBANK and GARAN do not follow the random walk hypothesis and the other six samples are efficient at the weak form of efficiency. Finally, the unit root tests such as ADF, PP and KPSS results indicated that all samples do not follow the random walk hypothesis and they are not efficient at the weak form of market efficiency. BIST 100 and BIST BANKS indexes are inefficient according to all methods except in run test analysis. Conclusion- Consequently, the three types of tests employed in this study exhibited a controversial result and it is difficult to give a general conclusion regarding the efficiency of the BIST Banking sector in the weak form. This indicated the probability of making an abnormal return by examining the Borsa Istanbul banking sector stocks’ historical prices.

Are oil and gas futures markets efficient? A multifractal analysis

ABSTRACT Energy futures markets have shown high volatility, giving rise to challenges regarding their pricing and efficiency. This study investigates the weak-form efficiency hypothesis for two major energy futures markets (gas and oil) over both calm and crisis periods, using a multifractal approach and intraday data to deal with the flexible econometric framework and rich information. Our results are threefold. First, we show that multifractality in lower frequency might be more biased than in intraday data, which motivates the use of the fractal approach when testing the intraday efficiency. Second, we highlight that high frequency data are characterized by a true long memory with a higher degree of persistence during the post-crisis period for the oil market. However, for lower frequencies, the long memory becomes spurious for both markets. Finally, our forecasting results show that, for the oil market, the proposed multifractal approach outperforms conventional methodologies, especially during turmoil periods.

Evolving time-varying market efficiency of energy stock market.

Energy stocks have become an essential segment of the investment portfolios of both households and institutional investors. This study investigates the dynamic aspect of evolving weak-form efficiency in six energy stock markets: those of the United States (US), Canada, China, Australia, India, and Saudi Arabia. The generalized autoregressive conditionally heteroskedastic in the mean GARCH-M(1,1) method is applied, alongside the state-space time-varying approaches with the Kalman filter estimation, to detect the evolving efficiency for periods ending in November 2019. The empirical results reveal that the studied markets undergo various extents of time-varying efficiency, containing periods of efficiency enhancement as well as periods of deviation from efficiency. Meanwhile, the 2007-2009 global financial crisis and the 2015 changes in the energy sector-in addition to other contemporaneous crises-have a profound influence on the timeline of market efficiency evolution. Overall, all of the markets gradually became more efficient, apart from India's energy market as a result of the current energy crisis in India. Amid the energy markets explored in this study, the US energy market was found to be the most efficient.

Test of Weak Form Efficiency and Nigerian Foreign Exchange Market Volatility

Beside the stated concerns for this study, a lot of scholarly articles abound on the test of weak form efficiency and capital market. For that, the researchers deemed it fit to test if the Nigerian foreign exchange market follows a random walk or not. This and others led to this study, test of weak form efficiency and volatility of the Nigerian foreign exchange market with the following parametric tools; Augumented Dickey Fuller (ADF) unit root test, Pairwise Granger Causality test, Regression test, Normality/Random Walk test, ARCH-GARCH Model, the Autocorrelation cum partial autocorrelation method and Variance Ratio Test. After the analysis, all the results confirmed that the Nigerian foreign exchange market does not follow a random walk, hence weak form inefficient. No wonder the exchange rate business in Nigeria is very lucrative. The dealers always make abnormal profit at every slightest opportunity. Again, the result of the EGARCH framework found that volatility exacts negative impact on Nigerian foreign exchange market and that exchange rate volatility in Nigerian foreign exchange market is persistent. Again, that there is no asymmetric effect in the Nigerian foreign exchange market. Consequent upon the findings, the researchers suggest that the regulatory authorities of the Nigerian foreign exchange market tighten up their belt to enhancing the efficiency of the market. Again, the authority must do everything to stabilize the naira to ensure efficiency in the foreign market in Nigeria. Keywords: Weak form, Foreign Exchange Market, Parametric tool, Nigeria DOI: 10.7176/RJFA/11-16-14 Publication date: August 31 st 2020

Are Cryptocurrency Markets, Efficient Markets?

This paper examines the market efficiency of three key cryptocurrency markets namely: Bitcoin, Ethereum and Monero, before and during the COVID-19 pandemic. This research makes use of a Durbin-Watson test and a non-parametric runs test to test for weak-form efficiency, and two comprehensive event studies to test for semi-strong form and strong form efficiency. We conclude neither market can be considered efficient due to the presence of strong positive correlation, and inefficient reactions to our event studies. Despite this, each market became more efficient during the COVID-19 pandemic than before, due to the presence of weaker positive correlation during this timeframe, but inefficient, nonetheless. Thus, the study finds that of the tested cryptocurrency markets, none can be consider wholly efficient. This conclusion is consistent with the vast majority of existing literature.

Hangi Sektörlerde Getiri Öngörülebilirliği İçin Tarihsel Fiyatlar Kullanılabilir Otomatik Portmanteau Testi ile Borsa İstanbul Üzerine Ampirik Bir Çalışma

The aim of this study, to compare return predictability in other words, the weak form of market efficiency of different sectors in Turkey. For this purpose, analyses were carried out by automatic portmanteau test with a 2-year sub-sample size using the daily data between 19.04.2000-07.02.2020 of 19 primary sector indexes within Borsa Istanbul. As a result of the analyses, it was understood that Transportation, Insurance, Electricity, and Metal Products Machinery sectors have higher return predictability periods and therefore their weak form market efficiency is lower than other sectors. In addition, it was determined that the sectors that have the least predictable periods of return, in other words, that have more weak form efficiency than other sectors, are Food Beverage, Banks, Wholesale and Retail Trade, and Wood Paper Printing.

Hisse Senedi Piyasalarının Zayıf Form Piyasa Etkinliğinin Küresel Ölçekte Karşılaştırılması: G-20 Üyeleri Üzerine Ampirik Bir Çalışma

This paper analyzes stock markets of G-20 members in terms of comparing return predictability, in other words, weak-form market efficiency using stock indexes weekly data of the G-20 members between 07.06.2009 and 09.02.2020. As a result of the wild bootstrap automatic variance ratio test analysis developed by Kim (2009), it is found that the stock markets of Brazil, South Africa, and Germany were weak-form efficient in the date range within the scope of the study, so the returns are unpredictable, while the weak-form efficiency (return predictability) of other markets are time-varying. In addition to Brazil, South Africa, and Germany, there is a very low chance to estimate returns with historical price movements or returns in Russia, France, Italy, United States, United Kingdom, and Canada stock markets. It is also found that the return predictability periods of Japan, Australia, China, Saudi Arabia, and especially Mexico’s stock markets are higher than other markets and the chance of success in estimating returns by using historical price information in these markets is quite high.

Efficient Market Hypotheses of Nepalese Stock Market

The purpose of this paper is to examine the random walk hypothesis (RWH) by testing the weak-form efficiency in the Nepalese capital market. Descriptive, correlation and causal comparative research design has been used for analyzing the variables and different phenomenon. This research has been prepared only with the help of secondary data. Closing price of company has been collected and analyzed for the period 2015/16-2019/20. Thus researcher tried to analyze the market efficiency with the help of five years data (daily closing price).There are altogether around 233 companies listed in NEPSE. So to make this research feasible and simple researcher has selected only 10 companies from the NEPSE by using purposive sampling technique. In course of selecting company researcher has tried to incorporate only financial sectors as commercial banks, finance companies, insurance, and microfinance companies but development bank has not been taken as sample due to same nature of commercial bank. Researcher examined the weak form efficiency of the Nepal stock exchange (NEPSE) using auto correlation test (parametric test) and run test (non-parametric test) for the period of 2015/16-2019/20. Mainly this research work tested the efficient market hypothesis of Nepalese stock market with the help of daily closing price of 10 Sample Company of different sectors. The market is inefficient in the weak form implies that the NEPSE does not follow a random walk. This means that the NEPSE provides an opportunity for out- performance by skillful managers and investment specialists. Auto correlation exists in price of stock evident that there is high level of dependency of price of stock with the previous ones. It will be easy for speculator and trader to exploit the market and gain handsome profit from the market. All investor are not assumed to be rational in inefficient market, most of the people say investor are investing on the basis of market rumor. Market may be inefficient due the asymmetric of information and insider trading.

The Changing Efficiency of the European Stock Markets

<p>The purpose of this article is to examine how the weak-form efficiency of the European stock markets has changed over the years. The study focuses its attention not on answering the question if the markets were efficient but on explaining how efficiency evolved. With a process based on the random walk model proposed by Louis Bachelier in 1900 still commonly applied in this research, market efficiency was examined using three different tests of the normality of the distribution for the returns of 20 selected European stock market indexes. The tests were performed for each year and for additional two-year sub-periods during the 20-year research period (1999–2018). Moreover, the tests were run for one-, two-, three- and four-day returns’ intervals. The study allowed for a partial rejection of the research hypothesis, finding that on a long-term basis the efficiency of European stock markets tends to improve. Indeed, the results indicate that overall efficiency tended to improve but only since the end of the 2008 global financial crisis. From the very beginning of the research period until 2008, overall efficiency was shown to decrease.</p>

Nigerian Stock Exchange and Weak Form Efficiency

This study, Nigerian Stock Exchange and Weak Form Efficiency with two intervals of All Share Index collected from the Nigeria Stock Market fact books. This study employed various parametric tools found for daily and annual all share index as follows: a significant relationship between the price series and their lagged values; coefficient of variance equations are statistically significant; price series do not follow a random walk or are abnormally distributed; level series not significant and causality is found in daily price series with no causality found in the annual price series. The finding in this study in balance affirmed that the Nigeria Stock Exchange is not efficient in weak form, by extension is inefficient in any form. As result the researchers suggest to the supervisory and regulatory authorities to promulgate laws that will strengthen the Nigerian Stock Market. Keyword s: NSE, Weak Form, Parametric Tools DOI: 10.7176/RJFA/11-8-09 Publication date: April 30 th 2020

The Analysis of Multifractal System, Long-Term Memory, and Weak Form Efficiency of the Returns in Tehran Stock Exchange

Studying and recognizing the behaviour of securities returns has always been the focus of investors and researchers since the dawn of capital markets. Based on the statistics of the last decade, the stock market has been one of the major centres for making investment and getting high returns. Analysis and forecasting the price of financial assets has always been an intriguing topic in both scientific and practical disciplines which created various challenges for financial analysis. Chaos theory and fractal analysis are the latest theories in this regard. The present study has reviewed the information on Tehran Stock Exchange (TSE) companies’ returns between 2014 and 2018 in monthly intervals to measure the multifractal system, long-term memory (LTM), and weak-form efficiency of the stock return variable. The aim of the study has been addressed by using Hurst’s rescaled range (R/S) statistic model. Any R/S larger than 0.5 indicated a correlation between future stock returns and previous returns and that previous data influence the market. Consequently, it is not a random market but has an LTM, a fractal dimension, and is relevant to the Efficient Market Hypothesis (EMH) that confirms these variables.