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

2020 ◽  
Author(s):  
Mamdouh Abdulaziz Saleh Al-Faryan ◽  
Everton Dockery
Keyword(s):  
Corporate Governance ◽  
Stock Market ◽  
Stock Prices ◽  
Hurst Exponent ◽  
Weak Form ◽  
Long Range Dependence ◽  
Informational Efficiency ◽  
Variance Ratio ◽  
Wald Tests ◽  
Random Walk Hypothesis

Abstract 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.

scholarly journals Random Walk Hypothesis for Stock Prices in Fiji

2021 ◽  
Vol 13 (2) ◽  
pp. 79-88
Author(s):  
Janesh Sami
Keyword(s):  
Random Walk ◽  
Stock Market ◽  
Unit Root ◽  
Stock Prices ◽  
Structural Break ◽  
Weak Form ◽  
Efficient Market Hypothesis ◽  
Random Walk Hypothesis ◽  
Augmented Dickey Fuller ◽  
Historical Movement

The main goal of this paper is to investigate the random walk hypothesis in Fiji using monthly data from January 2000 to October 2017. Applying augmented Dickey Fuller (ADF 1979, 1981) and Phillips-Perron (1988), Zivot-Andrews (1992), and Narayan and Popp (2010) unit root tests, this study finds that stock prices is best characterized as non-stationary. The estimated multiple structural break dates in the stock prices corresponds with devaluation of Fijian dollar by 20 percent in 2009 and General Elections in September 2014, which Fiji First Party won by majority votes. The empirical results indicate that stock prices are best characterized as a unit root (random walk) process, indicating that the weak-form efficient market hypothesis holds in Fiji’s stock market. Hence, it will be difficult to predict future returns based on historical movement of stock prices in Fiji’s stock market.

scholarly journals On the Efficiency of Stock Markets: A Case of Selected OPEC Member Countries

2019 ◽  
pp. 75-101
Author(s):  
Ebenezer A. Olubiyi ◽  
Peter O. Olopade
Keyword(s):  
Stock Market ◽  
Stock Returns ◽  
Weak Form ◽  
Nonparametric Tests ◽  
Variance Ratio ◽  
Monthly Data ◽  
Random Walk Hypothesis ◽  
Risk Return ◽  
Stock Market Efficiency ◽  
Opec Member

The study investigates the stock market efficiency of selected OPEC member countries within the context of random walk hypothesis and volatility approaches using monthly data on stock market indices from January, 2005 to April, 2016. Parametric (variance ratio: homoskedastic and heteroskedastic martingale), nonparametric (the Wright ranks and scores) tests and ARCH type estimation are performed. Results of both parametric and nonparametric tests indicate that only Qatar's stock market is weak-form efficient. The volatility results suggest that monthly stock returns of OPEC countries are volatile, with Qatar being most volatile and shocks to volatility of stock returns are asymmetric. The implications of this are that: first, investors should be conscious of these shocks when making risk-return decision of their portfolios; second, the results provide useful information to regulators to enable them develop safeguard mechanisms to shield the market from possible asymmetric information emanating from the participants.

scholarly journals An Empirical Investigation of the Random Walk Hypothesis in the Nigerian Stock Market

2021 ◽  
Vol 4 (1) ◽  
pp. 62-77
Author(s):  
DA Kuhe ◽  
J Akor
Keyword(s):  
Random Walk ◽  
Stock Market ◽  
Stock Returns ◽  
Unit Root ◽  
Stock Prices ◽  
Null Hypothesis ◽  
Serial Correlation ◽  
Ratio Test ◽  
Variance Ratio ◽  
Random Walk Hypothesis

The Random Walk Hypothesis (RWH) states that stock prices move randomly in the stock market without following any regular or particular pattern and as such historical information contained in the past prices of stocks cannot be used to predict current or future stock prices. Hence, stock prices are unpredictable and that investors cannot usurp any available information in the market to manipulate the market and make abnormal profits. This study empirically examines the random walk hypothesis in the Nigerian stock market using the daily quotations of the Nigerian stock exchange from 2nd January, 1998 to 31st December, 2019. The study employs Augmented Dickey-Fuller unit root test, the random walk model, Ljung-Box Q-statistic test for serial dependence, runs test of randomness, and the robust variance ratio test as methods of analyses. The result of the study rejected the null hypotheses of a unit root and random walk in the stock returns. The null hypothesis of no serial correlation in the residuals of stock returns was also rejected indicating the presence of serial correlation/autocorrelation in the residual series. The result of the runs test rejected the null hypothesis of randomness in the Nigerian stock returns. The results of the variance ratio test under homoskedasticity and heteroskedasticity assumptions both strongly rejected the null hypothesis of a random walk for both joint tests and test of individual periods. Based on the results of the four tests applied in this study, it is concluded that the Nigerian daily stock returns under the period of investigation do not follow a random walk and hence the null hypothesis of a random walk is rejected. The results of the study further revealed that the Nigerian stock market is weak-form inefficient indicating that prices in the Nigerian stock market are predictable, dependable, consistently mispriced, inflated, liable to arbitraging and left unprotected to speculations and market manipulations. The study provided some policy recommendations

Political connection and firm value: an Indian perspective

2014 ◽  
Vol 3 (2) ◽  
pp. 170-189 ◽  
Author(s):  
Debabrata Datta ◽  
Santanu K. Ganguli
Keyword(s):  
Corporate Governance ◽  
Theoretical Model ◽  
Stock Market ◽  
Stock Prices ◽  
Empirical Test ◽  
Political Connection ◽  
Content Type ◽  
Election Results ◽  
Political Governance ◽  
Practical Implications

Purpose – The purpose of this paper is to verify existence of political connection of firms in India. For this purpose the paper first presents a theoretical model and then tests empirically the movement of stock prices during two state elections in India. Design/methodology/approach – The methodology is theoretical modelling where the paper applies the standard Cournot model of oligopoly. The paper then applies correlation and Wilcoxon Paired Rank Sum test to verify the results of the theoretical model by using data from the Indian stock market during the election results. Findings – The theoretical result states that some firms opt for political connection and some remain independent in an oligopoly. It also shows that political connection affects stock price. The empirical results find out that divergent responses of stock prices to the election results can be linked to politically connection. Research limitations/implications – The theoretical model is a simple two firm model and not generalized to n number of firms. The empirical test considers only two state elections and applies simple statistical test. The study is restricted to one country only. Practical implications – The paper has practical implications for stock market. It has implications for corporate governance and for political governance. This is important since political connection of firms has emerged as an important issue in India. Social implications – The paper is important as it addresses the issue of political connection of firms, which have ramifications for social equilibrium. In a democratic country like India any nexus between political party and firms may adversely affect not only corporate governance but also political governance. Originality/value – This paper looks at political connectedness theoretically in a federal structure, an issue not addressed so far in the literature. Second it considers not so discussed topic of market perception of political connection in India. The originality of the paper is that it presents a theory and also verifies the theoretical results with empirical test.

scholarly journals Adaptive market hypothesis: An empirical analysis of the Wine Market

2021 ◽  
Vol 10 (2) ◽  
pp. 99-109
Author(s):  
Anoop S Kumar
Keyword(s):  
Linear Dependence ◽  
Statistical Tests ◽  
Weak Form ◽  
Informational Efficiency ◽  
Variance Ratio ◽  
Full Dataset ◽  
Long Run ◽  
Hurst Coefficient ◽  
Non Linear ◽  
Wine Market

We test the nature of weak form informational efficiency present in the wine market using daily return of LIV-EX 50 index from 1/1/2010 to 12/6/2020. First, we employ a number of statistical tests including variance ratio tests, tests for linear and non-linear dependence and Hurst coefficient. The tests are applied on the full dataset and on four non overlapping sub-samples of equal length. The variance ratio tests provide a mixed regarding informational efficiency. Evidence of non-linear dependence in the return series was found. The Hurst coefficient values confirm the presence of long run persistence in the wine market. Based on the mixed evidence, we test the possibility of adaptive nature of the wine market. We employ the newly proposed Adaptive Index (AI) to quantify the degree of information inefficiency in the wine market at any instance. Our results confirm that wine market is adaptive and periodically shifts between states of efficiency and inefficiency. The wine market is found to be relatively free from the Covid-19 induced shock and the safe haven property of wine is thus confirmed. Finally, impact of various macroeconomic and financial events on wine market efficiency is identified by using AI. 

scholarly journals Testing Weak-Form Market Efficiency of Dhaka Stock Exchange

2015 ◽  
Vol 4 (2) ◽  
pp. 79-90
Author(s):  
Md.‬ Abu Hasan‬‬‬‬‬‬‬‬
Keyword(s):  
Random Walk ◽  
Stock Market ◽  
Stock Prices ◽  
Stock Exchange ◽  
Weak Form ◽  
Jel Classification ◽  
Ratio Test ◽  
Daily Return ◽  
Classification Code ◽  
Augmented Dickey Fuller

Measuring the efficiency of the stock market is an important research topic as there are various implications for investors. This paper investigates the weak form efficiency in the framework of the random walk hypothesis for the stock market in Bangladesh, employing both Non Parametric tests (Runs test and Phillips-Perron test) and Parametric tests (Autocorrelation test, Augmented Dickey-fuller test, and Variance Ratio test). The study uses daily return data for the three stock indices of Dhaka Stock Exchange such as DSI (from 02 January 1993 to 27 January 2013) with a total of 4823 daily return observations, DGEN (from 01 January 2002 to 31 July 2013) with a total of 2903 daily return observations, and DSE-20 (from 01 January 2001 to 27 January 2013) with a total of 3047 daily return observations. The evidence suggests that all the return series do not follow the random walk model, and thus the Dhaka Stock Exchange is inefficient in weak form. Thus, historical stock prices can be used to achieve superior gains from the stock markets in Bangladesh. JEL Classification Code: C22, G10, G14

Variance Ratio Test of Random Walk in Indian Stock Market

2015 ◽  
Vol 2 (2) ◽  
pp. 89-107
Author(s):  
Saloni Gupta ◽  
Neha Bothra
Keyword(s):  
Random Walk ◽  
Stock Market ◽  
Stock Returns ◽  
Ratio Test ◽  
Variance Ratio ◽  
Random Walk Hypothesis ◽  
Variance Ratio Test ◽  
Indian Stock Market ◽  
High Degree ◽  
The Relationship

We conduct tests of the null hypothesis of a random walk at the aggregate level of market indices and disaggregate level of individual shares to the Indian stock market over various data periods and a comparison of two sub-periods namely the pre liberalization and the post liberalization period. For this, we use the Lo-MacKinlay (1988) variance ratio test. Although the oldest test i.e. the serial correlation coefficient test is also applied to the same data to establish the relationship between the two tests but its results are not elaborated in this paper. The strength of this paper lies in the voluminous data base and a powerful testing tool that it makes use of. It is observed that the market is highly inefficient at daily returns level, thus imbibing high degree of predictability in stock returns, and even the weekly returns show the existence of trend. Monthly returns, however, support the random walk hypothesis across all periods. Thus it is concluded that further refinement of reform measures is required.

FRACTALITY EVIDENCE AND LONG-RANGE DEPENDENCE ON CAPITAL MARKETS: A HURST EXPONENT EVALUATION

Fractals ◽  
2014 ◽  
Vol 22 (04) ◽  
pp. 1450010 ◽  
Author(s):  
CAMELIA OPREAN ◽  
CRISTINA TĂNĂSESCU
Keyword(s):  
Random Walk ◽  
Stock Returns ◽  
Long Range ◽  
Capital Markets ◽  
Hurst Exponent ◽  
Efficient Market Hypothesis ◽  
Long Range Dependence ◽  
Fluctuation Analysis ◽  
Random Walk Hypothesis ◽  
Detrended Fluctuation

Since the existence of market memory could implicate the rejection of the efficient market hypothesis, the aim of this paper is to find any evidence that selected emergent capital markets (eight European and BRIC markets, namely Hungary, Romania, Estonia, Czech Republic, Brazil, Russia, India and China) evince long-range dependence or the random walk hypothesis. In this paper, the Hurst exponent as calculated by R/S fractal analysis and Detrended Fluctuation Analysis is our measure of long-range dependence in the series. The results reinforce our previous findings and suggest that if stock returns present long-range dependence, the random walk hypothesis is not valid anymore and neither is the market efficiency hypothesis.

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