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Stock Market Prices Follow the Random Walks: Evidence from the Efficiency of Karachi Stock Exchange

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This study describes the behavior of the Karachi Stock Exchange (KSE) regarding the movement of share prices of the companies listed at KSE-100 Index as well as how the share price at KSE follows Random Walk. Moreover, this study pinpoints that the prices of the securities are co-integrated and cannot always be predicted. However, the historical data of KSE-100 Index from January 2, 2001 to November 15, 2011 was collected which contains 2672 observations of the closing share price index of the top 100 companies listed with KSE. Simple unit root – Augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) – tests and Johansen Co-integration test was used which discusses the efficiency of the market. Empirical findings of this study suggest that KSE-100 Index follows the Random Walk Hypothesis (RWH) and Efficient Market Hypothesis (EMH). However, KSE is an efficient financial market that can adjust to any new information very quickly and efficiently and the prices of the securities listed for trading at KSE-100 Index cannot be predicted. Hence, KSE cannot be beaten to gain any abnormal return. This research will provide a better understanding about the behavior of KSE as it applies advance econometric techniques which tends to produce more reliable results.
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European Journal of Economics, Finance and Administrative Sciences
ISSN 1450-2275 Issue 51 (2012)
© EuroJournals, Inc. 2012
http://www.eurojournals.com/EJEFAS.htm
Stock Market Prices Follow the Random Walks:
Evidence from the Efficiency of Karachi Stock Exchange
Mian Saqib Mehmood
Corresponding Author, Department of Commerce and Finance
Superior University Lahore, Pakistan
Tel: +92-3338169169
E-mail: miansaqibmehmood@hotmail.co.uk
Asif Mehmood
Department of Commerce and Finance
Superior University Lahore, Pakistan
Tel: +92-3006419833
E-mail: mianasifmehmood@hotmail.co.uk
Bahaudin G. Mujtaba
The H. Wayne Huizenga School of Business and Entrepreneurship
Nova Southeastern University, Ft. Lauderdale, Florida USA 33314
Tel: 954 262-5045
E-mail: mujtaba@nova.edu
Abstract
This study describes the behavior of the Karachi Stock Exchange (KSE) regarding the
movement of share prices of the companies listed at KSE-100 Index as well as how the
share price at KSE follows Random Walk. Moreover, this study pinpoints that the prices of
the securities are co-integrated and cannot always be predicted. However, the historical
data of KSE-100 Index from January 2, 2001 to November 15, 2011 was collected which
contains 2672 observations of the closing share price index of the top 100 companies listed
with KSE. Simple unit root – Augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) –
tests and Johansen Co-integration test was used which discusses the efficiency of the
market. Empirical findings of this study suggest that KSE-100 Index follows the Random
Walk Hypothesis (RWH) and Efficient Market Hypothesis (EMH). However, KSE is an
efficient financial market that can adjust to any new information very quickly and
efficiently and the prices of the securities listed for trading at KSE-100 Index cannot be
predicted. Hence, KSE cannot be beaten to gain any abnormal return. This research will
provide a better understanding about the behavior of KSE as it applies advance
econometric techniques which tends to produce more reliable results.
Keywords: Random Walk Hypothesis (RWH), Efficiency Market Hypothesis (EMH),
Unit Root Test, Co-integration Test, KSE, Pakistan.
72 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
1. Introduction
Karachi Stock Exchange (KSE) is the first share market of Pakistan where almost 70-80% of the
trading is taking place. The KSE gained momentum in 1960s in listing the companies and market
capitalization. However, it faced challenges regarding the economic and political ups and downs in the
country and most of the times these fluctuations have had a direct effect on its trading activities over
the past sixty years. The share prices of the stock market take direct effect of these changes and show
both positive and negative impacts accordingly. Stock exchanges play its key role in economic
development of a country (Oskooe, 2011). Some of the markets prove efficient and the others
inefficient in responding and adjusting to the sudden and prediction free information coming from
changing political and economic conditions. Markets which do not adjust to or absorb these kinds of
information would lead to a financial crisis that could be harmful for the small investors as well as for
the national economy (Mujtaba, 2006). The market efficiency and inefficiency is discussed by Fama
(1970) on the topic of the Efficient Market Hypothesis (EMH). This hypothesis defines efficient
market(s) as a market where there can be a large number of rational, profit-maximize activities with a
motivation of competing with each other by predicting the future market values of securities. However,
all participants have access to the current information. In an efficient market, there is competition
among the professionals who have relevant expertise which leads to a situation where at any point in
time, actual prices of individual securities reflect the effects of information based both on events that
have already occurred and on events which the market expects to take place in the near future. In other
words, an efficient market will be a good estimate of the intrinsic value of a security at any point in
time. The efficiency of the market is very necessary because if a market is inefficient in adjusting to the
new information then the profit-maximizers can outperform the market by knowing the undervalued or
overvalued securities and can gain abnormal returns. However, the inefficiency of the stock market can
cause harm to the small investors as well as to the entire economic system of a country. On the basis of
the information adjustment and availability of this information to the participants in the trading
activities of the stock market, the efficiency of the stock market can be classified into three levels.
1.1. Strong-Form of Efficient Market
In this form of efficient market all the relevant information both public and historical is reflected in the
share prices being traded in such markets and no one can beat the market.
1.2. Semi-Strong Form of Efficient Market
In this form of efficient market all the relevant information to the public is reflected in the share prices
being traded in markets. In such markets with some insider information an investor can gain abnormal
returns by judging the undervalued or overvalued securities.
1.3. Weak-Form of Efficient Market
In this form of market all the historical data and prices of the shares and securities are reflected in the
current prices and by analyzing the past prices future prices can be predicted if such markets are
inefficient in the weak form.
Form the definitions of three forms of efficient markets the most important form is weak form
efficient market and it is the main consideration point of the researchers because by technical analysis
in weak form inefficient markets future prices of the securities can be predicted on the basis of the past
and historic prices of the securities. If the security prices in a market follow the random walk that no
future price takes any influence from the past prices than we can say that market is efficient in the
weak form. Bachelier (1900), in his theory of speculation, conclude that the mathematical expectation
of the speculator is zero and this condition is described as a “Fair Game”. However, he also presented
EMH theory – Random Walk Theory – which states that in financial markets the prices evolve
randomly and are not connected. However, they are independent of each other and, therefore, by
73 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
identifying the patterns and trends of price changes in a market could not be used to predict the future
value of financial instruments.
This study is based on the random walk hypothesis using some statistical tests to find out if
KSE is an efficient market in the weak form and whether securities traded in KSE follow the random
walk or not. This study also highlights that rational investor by analyzing the past prices can predict the
future prices accurately to beat the market. Hence, if KSE proves to be efficient there could be the
following benefits to the economy of a country:
Foreign investment can be increased
National savings can be increased
Capital availability and pricing can also be increased
Capital can be efficiently allocated in the economy which will result into economic and
national development.
This paper intends to investigate whether the stock prices movements follow the Random
Walks and this will help to know that KSE is efficient or inefficient as a whole in the weak form.
Moreover, this study also pin points whether the prices of the securities are co-integrated and if they
can be predicted. Hence the analysis of daily closing stock prices of the KSE-100 Index is made by
taking the sample period of January 2
nd
, 2001 to November, 15-2011 through Unit Root Test and
Johansen Co-integration Trace Test. This study attempts to analyze the behavior of KSE and presents a
review of literature, data description and research methodology, along with the results and discussions.
2. Literature Review
The Random Walk Hypothesis (RWH) is a financial theory which states that the prices prevailing in a
stock market cannot be predicted because these prices follow a unique random patron that cannot be
fully analyzed due to the availability of all the information to each and every individual with the stock
market. The randomness in the prices restricts the investors to outperform the market to gain abnormal
returns. The concept of the RWH can be traced to Regnault (1863) and then Bachelier (1900) as “The
Theory of Speculation” included remarkable insights and commentary. Same ideas were later
developed by Cootner (1964) in “The Random Character of Stock Market Prices”. The term was
popularized by Malkiel (1973) through his research work namely “A Random Walk Down Wall
Street” and was used earlier in Fama’s (1965) research entitled “Random Walks in Stock Market
Prices”. The theory that stock prices move randomly was earlier proposed by Kendall (1953) in the
research entitled “The Analytics of Economics Time Series”.
This information describes the basis for the random walk availability in the stock market prices
which is tested and empirically analyzed by many researchers all over the world. However, some of
them find that the stock prices proves inefficient in following the random walk, few of them confirm
the random walk existence and a weak form market efficiency in developed, less developed and
emerging stock markets of the developed and underdeveloped countries.
By applying different statistical techniques on the Kuwait stock market (KSM), Al-Loughani
(1995) concluded that KSM does not follow the random walk as it shows stationarity in its results.
Song and Weigen (1995) used average return of 29 stocks listed on Shanghai Stock Exchange (SSE).
The findings of this study reveals that SSE is weaker than efficient over 1993-1994. Lo and Mackinaly
(1988) tested the RWH for weekly stock market returns by comparing variance estimators derived
from data sampled at different frequencies. However, this study rejects the random walk model for the
entire sample period (1962-1985) and for all sub periods for a variety of aggregate returns indexes and
size sorted portfolios. Wu (1996) evaluated the weak-form efficiency of Shanghai and Shenzhen stock
market, and the findings of this study didn’t conclude weak form efficiency at bottom line.
Dahel and Laabas (1999) examine the efficiency of Gulf Cooperation Council (GCC) equity
markets. By taking the data from 1994-1998, this study concludes that the stock market of Kuwait
follows the weak form of efficiency. However, the rest of the markets reject the weak form of the
74 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
EMH. Abraham et al., (2002) tested the RWH and market efficiency hypothesis for Saudi Arabia,
Kuwait and Bahrain. The results of this study shows that Saudi and Bahraini markets follow the
hypothesis of random walk but market of Kuwait is inefficient and hence couldn’t follow RWH.
Malkiel (2003) states that in case of fully efficient markets, present period is not effected by the past
information. However, the investors are not allowed by the efficient stock markets to earn more
average returns without facing more average risks. Narayan and Smyth (2004) apply Zivot and
Andrews (1992) and Lumsdaine and Papell’s (1997) one and two structural break unit root tests
respectively to analyze the random walk hypothesis for stock prices in South Korea. The findings of
this study narrate that stock prices in South Korea has unit root, hence are consistent with the RWH.
Chakraborty (2006) evaluated the weak form efficiency of KSE-100 index. Findings of this study
reject the random walk hypothesis which depicts that KSE is not an efficient stock market. Hassan and
Abdullah (2007) examined the weak form market efficiency of KSE. The result shows that prices
pattern didn’t follow random walks and are not weak form efficient. Marashdeh and Shrestha (2008)
highlight the efficiency in emerging markets of United Arab Emirates (UAE) by applying Perron’s
(1997) model to test for a unit root. Empirical results show that UAE securities markets follow the
RWH and are efficient in the weak form. Liu (2010) examines the stock market development and
market efficiency on China Stock Market (CSM). By applying EGRACH test, the findings of this
study reveals that the CSM are not weak form efficient and do not follow the RWH. Zaubia and
Nahlehb (2010) tested the financial market efficiency in the Middle East and North African Countries
(MENA). The results of this study show that MENA markets follow the RWH and are efficient
weakly. Irfan, M. et al. (2010) determine the existence of weak from efficiency in the Karachi Stock
Exchange (KSE), either it is efficient market or not. This study uses daily and monthly closing prices
of KSE-100 indexes over the period of January 011999 to August 31, 2009. Results of this study show
that the Karachi Stock Market of Pakistan is not efficient in weak from. Oskooe (2011) tested the
RWH for Iran Stock Market (ISM). Findings of this study reveal that that ISM follows the RWH or in
other words ISM is efficient in the weak form. Mishra (2011) conducted a study to find out the weak
form market efficiency in the emerging and developed world capital markets. By applying unit root test
and GARCH (1, 1), this study concludes that these markets are not weak form efficient and do not
follow the RWH. Bashir et al., (2011) examined the weak form hypothesis in the stock prices of banks
listed in KSE. The findings of this study concludes that KSE is inefficient and do not follow the RWH.
However, the prices of banking sector for KSE are being predictable or its pattern can be judged based
on its inefficiency at bottom line. Above given scenario depicts the mixed results about different stock
exchanges behavior. However, this study fills the gap by examining the behavior of KSE by analyzing
the random walk hypothesis.
3. Data Description and Methodology
3.1. Data Collection and Analysis
The study about the random walk nature of the share prices of the firms listed at KSE-100 Index
consists upon the historical data of KSE-100 Index from January 2, 2001 to November 15, 2011 which
contains 2672 observations of the closing share price index of the top 100 companies listed with KSE.
For the first time share prices of the KSE as a whole are considered for the analysis of market
efficiency or randomness in the share prices of the KSE and almost all the research conducted for this
purpose are based on the sector wise analysis. However, all the data required for this study is gathered
from official web site of the KSE and this data does not include the share prices of public holidays and
sessions when the market is off.
3.2. Econometric Methodology
3.2.1. Unit Root Test
There is a need of stationarity checking before applying any econometric work. However, Granger and
Newbold (1974) narrates that working with non-stationary variables often bring spurious results and
75 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
that may observe incorrect inferences in this regard. It is compulsory that the series should be
stationary. This study applies two unit root tests namely, Augmented Dickey-Fuller (ADF) and
Phillips-Perron (PP) tests for investigating the order of integration of the variables.
3.2.2. Johansen Cointegration Test
Cointegration is considered as a statistical property that depicts the long-run relationship of economic
time series. Johansen (1988) proposed an approach to examine the long-run relationship among
variables. However, this study uses Johansen and Juselius’s (1990) cointegration approach for
estimating the co-integration among the stock prices of the firms listed at KSE-100 index. The
hypothesis of efficient stock market in weak form narrates that price movements of stock are
independent and hence successive stock price shows their independence in this scenario. However, for
examining the efficiency of stock market in weak form, this study examines the randomness of stock
prices by taking the RWH as base. Past precedence and trends of stock price did not help to predict the
future stock price movements.
P
t
= µ
t
+P
t-1
+ ε
t
(1)
Whereas, P
t
is the stock price index at time t, µis the expected price change, P
t-1
depicts the
stock price index at time t-1 and ε
t
is error term.
4. Empirical Results and Discussion
By using the Eviews-7, the descriptive statistical summary is obtained to view the data as a whole with
the help of Histogram and statistical results about the KSE-100 Index share prices.
Figure 1: KSE-100 Index Share Prices
4.1. Descriptive Statistical Analysis
Table 1: Series: Closing KSE-100 Index
Sample: 01-02-2001 to 11-15-2011
Obs. Mean Median Max Min SD Skewness Kurtosis
Jarque-
Bera
Prob.
2672 7693.209 8470.810 15676.34 1075.160 4093.154 -0.152 1.803 169.735 0.000
76 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
The descriptive statistical values of the KSE-100 Index shows that there is variation in the share
prices of the 100 companies listed with the KSE and the data sample is negatively skewed. Table 1
depicts the stochastic properties of the KSE prices index. The sample mean for stock return series is
7693.209. Standard deviation is 4093.154. However, the Kurtosis in KSE-100 index is 1.803 which is
smaller than the normal value of 3. The Jarque-Bera statistics also reject the null hypothesis that KSE
stock prices series is normally distributed.
4.2. Augmented Dickey-Fuller (ADF) Unit Root Test
Share prices always have a trend which means there could be a major observation that can affect the
results which we normally want to obtain. Before applying the desired econometric test, data should be
made stationary or its trend should be reduced to minimize the effect of such major observations which
are normally caused by the market crises as faced by market in 2008 and recently in October, 2011.The
KSE-100 index during the outgoing week (October, 2011) shed almost 463 points or 3.9% to close at
11,525.25 index points as compared to 11,988.09 index points of the previous week. Such sudden
changes affect the desired result and to minimize the effect of such unwanted ups and downs, this study
uses ADF unit root test for this purpose and it is depicted in table-2.
Table 2: Augmented Dickey-Fuller Unit Root Test Results for KSE-100 Index
Unit Root t-statistics Critical Value at 5% Critical Value at 1%
Level -1.459 -3.411 -3.961
1
s
t
Difference -25.427 -3.411 -3.961
Hypothesis
KSE-100 Index Series is Non-Stationary
As can be seen from table 2, at level the results of the ADF test of null hypothesis is true but at
the 1
st
difference of ADF unit root test, null hypothesis is rejected as the t-statistic value of the ADF is
greater than their critical values both at 5% and 1% level of significance which means the KSE-100
Index series data becomes stationary. However, KSE-100 Index share prices move along time within a
stochastic process which means that there exists a sense of randomness among the share prices of the
KSE-100 Index. In other words, KSE-100 Index follows the random walk and is an efficient market.
4.3. Phillips-Perron (PP) Unit Root Test
Phillips-Perron (PP) test is another test which is mostly used by the analysts to de-trend the series data
to minimize the effects of the major variations in the data same as the ADF unit root test as applied and
interpreted thus far. Table-3 shows the results of the PP unit root test.
Table 3: Phillips-Perron Unit Root Test Results for KSE-100 Index
Unit Root Adj. t-statistics Critical Value at 5% Critical Value at 1%
Level -1.509 -3.411 -3.961
1
s
t
Difference -25.504 -3.411 -3.961
Hypothesis
KSE-100 Index Series is Non-Stationary
The results of the PP test fails to reject the null hypothesis as the value of the PP Adj. t-statistic
remain less than the critical values but the at 1
st
difference the null hypothesis is rejected as the value of
PP test becomes greater than the critical values at 5% and at 1% level of significance which means
KSE-100 Index has no trend and series is now stationary. The results of PP test also confirms the
outcome of ADF test which shows that series data of the KSE-100 index follows the random walk and
KSE is an efficient market. Figures 2 and 3 also show two different lines of the KSE-100 index sample
77 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
data series. Figure-2 shows the raw data which is not stationary and has a trend in its movement but
figure-3 shows the stationary data line which has no trend movement. However, Figure-2 shows that
KSE-100 index share prices are at normal and Figure-3 depicts it at 1
st
difference stationary.
Figure 2: KSE-100 Index Share Price Data
Figure 3: KSE-100 Index Share Price Data
4.4. Johansen Cointegration Test
Cointegration is a property of the times series data which normally shows the correlated accelerations
or a stochastic drift among the observations of the data. It means the cointegration shows that each
previous value puts some of its influence on the next observation which helps in predicting the future
values. This study of share prices at KSE follows a random walk or KSE is an efficient market.
However, our main objective is to know if any chance exists that KSE-100 share prices can be
predicted on the basis of the previous market prices or KSE can be outperformed. To judge this
characteristic of the KSE-100 index Johansen Cointegration Test is also used and the results obtained
from this test are given in table-4.
78 European Journal of Economics, Finance and Administrative Sciences - Issue 51 (2012)
Table 4: Johansen Cointegration Test of the KSE-100 Index
Trace Statistics Critical Value at 5% Critical Value at 1%
1.580 3.76 6.65
*Trace test indicates no cointegration at both 5% and 1% levels
From the values shown in table-4, the trace statistic value is less than the critical values of 5%
and 1% significance, which means there exists no cointegration among the observations of the KSE-
100 Index share prices. It means that no future value is influenced by the previous value of the market
share price so future prices at the KSE cannot be predicted on the basis of the previous share market
prices. However, KSE cannot be outperformed to gain an abnormal return from the share prices at
KSE-100 Index.
5. Concluding Remarks
Each investor is profit-oriented and wants to gain the highest possible returns and different researches
are conducted about beating the market for earning some abnormal return. However, most of the time
markets prove efficient against the strategies of the investment gurus and the prices of the market
cannot be predicted accurately. For the accomplishment of the purpose of this study, Augmented
Dickey-Fuller (ADF) and Phillips-Perron (PP) Unit Root Test was applied to check the stationarity of
the data. Hence the data included in this study is 1
st
difference stationary for both ADF and PP unit root
test and that become the cause of applying Johansen Cointegration Test. Form our analysis of the KSE-
100 Index – prices of the sample period – we conclude that KSE is an efficient financial market that
can adjust any new information very quickly and efficiently and the prices of the securities listed for
trading at KSE-100 Index cannot be predicted as KSE cannot be beaten to gain any abnormal
return.KSE-100 Index follows the Random Walk Hypothesis (RWH) and Efficient Market Hypothesis
(EMH) according to the results of the tests used. Securities and Exchange Commission of Pakistan
(SECP) can enhance the efficiency of KSE by improving infrastructure and through proper policy
making that result in attracting foreign investments, which become the cause of soundness and
uplifting the economy of Pakistan. However, security conditions and economic solidarity of Pakistan
has major concerns in this regard and it needs much attention from government, policy makers and of
all other stakeholders who hold offices regarding the administration. The results of this study may
exhibit a lack of generalizability in case of other stock exchanges working in Pakistan. Further study is
recommended in case of comparative analysis for getting ground breaking results about rest of the
stock exchanges behavior working in Pakistan.
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251-270.
... The efficient market hypothesis states that financial markets are efficient and that prices already reflect all known information concerning stock prices. There are three forms of the efficient market hypothesis that differ in what information is considered (Dupernex, 2007;Mehmood, Mehmood, & Mujtaba, 2012). Firstly, weak-form efficiency, where past market trading information, such as stock prices, trading volume, and short interest are considered. ...
... The results from the univariate LM unit root tests and panel LM unit root test with one structural break suggest that stock prices in each country is characterized by a random walk, but the findings from the panel LM unit root test with two structural breaks suggest that stock prices in the eight countries are mean reverting. Mehmood et al. (2012) describe the movement of share prices of companies listed at Karachi Stock Exchange (KSE) from January 2, 2001 to November 15, 2011 with 2672 observations. Simple unit root -Augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) tests -and Johansen Co-integration test findings suggest that KSE-100 Index follows the Random Walk Hypothesis (RWH) and Efficient Market Hypothesis (EMH). ...
... Simply, the daily closing stock price follows a random walk during the January 2015-December 2019 period and the Philippine stock market is an efficient market (i.e., regarded as weak-form efficient). These findings are consistent with the results of Mehmood et al. (2012), Lean and Smyth (2007), and Worthington and Higgs (2006) that there exists a sense of randomness among the stock prices. The explanation of the existence of a random walk in weak-form efficiency can be attributed to market liquidity (Lima & Tabak, 2004;Go & Lau, 2014;Camba & Camba, 2020) because of policies that promote continuous development and modernization of an equity market (Kim & Shamsuddin, 2008;Rufino, 2013). ...
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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.
... Then, the less informed investors tend to overreact and the analysts as well as the savvy investors leave behind the market by receiving overvalued and undervalued securities information. Consequently, they earn abnormal returns in that period (Mehmood et al., 2012). Research in experimental psychology asserts that when an investor violates Bayes' rule that would subsequently tend to overreact to unanticipated news. ...
... Henceforth, the results of these three different time series unit root tests exhibit that the Pakistan stock market follows random walk and proves that PSX is a weak form of an efficient market. The result of the study is consistent with the finding of the existing studies (see, for instance, Karan & Kapusuzoglu, 2010;& Mehmood et al., 2012). ...
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Recently, the investor overreaction catches the attention of the academicians and practitioners. The topic comes under the limelight of academicians and policymakers. This study, therefore, addresses investor overreaction and its relationship with the global financial crisis for the period of 2004–15. The study used stratified random sampling technique; equal allocation method of Krejcie and Morgan. By adopting the methodology of Debondt and Thaler, the study finds that there is highly significant overreaction (distinct reversal) in the stock market in the global-financial crisis period, which may attribute to the aggressive behavior of individual investors in the market. Overreaction has also been shown in the line graph shaded area which opposes the efficient market hypothesis and verifies the presence of a weak form of efficiency. Econometric tests are applied for robustness check that confirms weak form of efficiency in the PSX. The study has implications for both the investors and policymakers. This study is quintessential for those investors who have the aptitude to look introspectively and to evaluate their behavioral biases. Further, investors would learn to transmute behaviors and to build portfolios which will help them to stick to their long-term investment strategies and hence achieve their investment goals.
... Efficient market is a worthy estimate of the stock market security intrinsic value at a specific period of time. The market efficiency is indispensible in a country because when the market is inefficient in adjustment to the new-fangled news, then the analysts/market proficient can outperform the stock market by receiving information about over and undervalued securities and as a result earns abnormal returns in that period (Mehmood, Mehmood, & Mujtaba, 2012). ...
... Hence the results of time series unit root Kwiatkowski-Phillips-Schmidt-Shin test exhibits that the stock prices of thirty firms in Pakistan stock market follows random walk. The results of the study are consistent with the existing literature of (Karan & Kapusuzoglu, 2010;Mehmood, Mehmood & Mujtaba, 2012). ...
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Research in behavioral finance put forward that in violation of Bayes’ theorem rule and involving in Noise trading, majority of the investors in stock market tend to underreact or overreact to unanticipated bad and good news. One of the investor anomalies “Overreaction effect” in 30 firms listed in Pakistan Stock Exchange has been investigated in this study with the help of the portfolios of Loser and Winner Average Cumulative Abnormal Return’s. Moreover, the Random Walk is checked over the average prices of the same 30 firms listed in Pakistan stock market. This research of market efficiency took stocks data of randomly selected 30 firms listed in Pakistan Stock Exchange on weekly basis whether such investor’s anomalies affect stock prices. The result presents that there exist weak form of efficiency where the investor Overreaction present over many periods especially in global financial crises. Along with it, the Econometric test confirms the presence of Random Walk in the thirty firms of Pakistan stock market. Finally, the portfolios of loser Average Cumulative Abnormal Return’s outperformed that of portfolios of winner Average Cumulative Abnormal Return’s.
... Asset prices must follow a random walk process, resulting from the movement of many investors attempting to capitalize on the opportunity of the received information for the EMH to be valid. Many studies (e.g., Lee 1992;Elliott et al. 1996;Mehmood et al. 2012;Valera and Lee 2016;Mensi et al. 2017;Lee et al. 2018;Tiwari et al. 2019;Dias et al. 2020) have found that prices pursue a random walk by investigating the foreseeability of asset returns based on past price movements. ...
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This study aims to examine the time-varying efficiency of the Turkish stock market’s major stock index and eight sectoral indices, including the industrial, financial, service, information technology, basic metals, tourism, real estate investment, and chemical petrol plastic, during the COVID-19 outbreak and the global financial crisis (GFC) within the framework of the adaptive market hypothesis. This study employs multifractal detrended fluctuation analysis to illustrate these sectors’ multifractality and short- and long-term dependence. The results show that all sectoral returns have greater persistence during the COVID-19 outbreak than during the GFC. Second, the real estate and information technology industries had the lowest levels of efficiency during the GFC and the COVID-19 outbreak. Lastly, the fat-tailed distribution has a greater effect on multifractality in these industries. Our results validate the conclusions of the adaptive market hypothesis, according to which arbitrage opportunities vary over time, and contribute to policy formulation for future outbreak-induced economic crises.
... However, according to [17], empirical results are still debatable due to the inconsistency of the macroeconomic determinants employed in the model's formulation. To avoid the difficulty of which macroeconomic determinant(s) to be employed into the RMs, [18] argued that the stock price or returns mimics a random walk hypothesis and it is a difficult task to predict or forecast the accurate future returns; but numerous studies in the area of stock returns prediction or forecasting have dedicated on the usage of classical statistical methods (ARIMA) which has dominated the field of financial dataset as a popular choice model that can be used to model the accurate future stock price [19]. In this regard, this study employs the Box-Jenkins approach as an alternative to the RMs in stock market re- ...
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This paper developed a short-term stock exchange prediction model using the Box-Jenkins approach. In this study, monthly data from Ghana Stock Exchange market report that spans from March 2013 to February 2018 were used to develop the model. ARIMA (0, 2, 1) model was fitted to the data based on the Bayesian Information Criterion (BIC) for model selection. Diagnostic checks showed that the residuals of the fitted model were uncorrelated. The developed model was used for forecasting for a period of six months. The trend of the forecasted values showed a significant increase in the Ghana Stock Exchange performance for the next six months.
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Forecasting the stock market trend and movement is a challenging task due to multiple factors, including the stock’s natural volatility and nonlinearity. It concerns discovering the market’s hidden patterns with respect to time to enable proactive decision-making and better futuristic insights. Recurrent neural network-based methods have been a prime candidate for solving complex and nonlinear sequences, including the task of modeling multivariate time series forecasts. Due to the lack of comprehensive and reference work in short-term forecasts for the Saudi stock price and trends, this article introduces a comprehensive and accurate forecasting methodology tailored to the Saudi stock market. Two steps were configured to render effective short-term forecasts. First, a custom-built feature engineering streamline was constructed to preprocess the raw stock data and enable financial-related technical indicators, followed by a stride-based sliding window to produce multivariate time series data ready for the modeling phase. Second, a well-architected Gated Recurrent Unit (GRU) model was constructed and carefully calibrated to yield accurate multi-step forecasts, which was trained using the recently published historical multivariate time-series data from the primary Saudi stock market index (TASI index), in addition to being benchmarked against a suitable baseline model, namely Vector Autoregression Moving-Average with Exogenous Regressors (VARMAX). The output predictions from the proposed GRU model and the VARMAX model were evaluated using a set of regression-based metrics to assess and interpret the model precision. The empirical results demonstrate that the proposed methodology yields outstanding short-term forecasts of the Saudi stock price trends price compared to existing efforts related to this work.
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This study aimed at revisiting and divulging the existing empirical evidence regarding the informational efficiency and random walk in stock markets of developed and emergent markets. The critical analysis of statistical tools used is out of the purview of this study. Most of the empirical literature on the topic after the seminal work of Fama (1965a) is based on the developed markets. However, emergent markets received greater attention of the researchers after the huge inflow of capital in these markets after financial liberalization. Review of literature reveals varied results for efficiency and random walk in case of developed and emerging markets. Developed markets empirically found to be more efficient than emergent markets. Highly contradictory results are observed for emerging markets depending on the size, influence of insider trader, market integration, liberalization, trading volume, trading process, and infrequent trading. Empirical evidence in favour or against efficiency is a major contribution towards the strategic trading adeptness of a portfolio manager and of a proficient investor.
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The construction industry’s work process can lead to the generation of waste which does not add value to the operational performance. The purpose of this research is to study the operational performance of the Malaysian construction industry. Based on the analysis of 296 responses from Grade 7 construction organizations, the data revealed that these construction organizations have applied some lean manufacturing principles in their day-to-day operations. This study revealed that there is a correlation between lean manufacturing concepts and operational performance (OP), thus making a useful contribution to the industry, academia, and society. The future agenda is to improve construction industry performance, which requires joint initiatives between governments, educators, university administration, and industry leaders.
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This paper aims to focus weekly stock market prices from the CEECs (Lithuania, Hungary, Romania, Croatia, Slovenia, Poland, Bulgaria, the Slovak Republic, Latvia, Estonia, and the Czech Republic) markets for evidence of weak-form market efficiency. This is complemented by the use of comprehensive unit root tests to test for abnormal return behaviour in these stock markets. For this purpose, Harvey et al. (2008) linearity test was applied in order to determine the characteristics of the series. The results indicate that the series with linear characteristics are Slovenia, Bulgaria, the Slovak Republic, Estonia, and the Czech Republic and those with non-linear characteristics are Lithuania, Hungary, Romania, Croatia, Poland, and Latvia. Then, in order to examine the weak-form market efficiency, DF-GLS (1996), Phillips-Perron (1988) and Lee-Strazicich (2003) unit root tests are applied to linear series and Kapetanios et al. (2003) and Kruse (2011) tests were applied to nonlinear series. The linear and nonlinear unit root tests evidence that all the selected stock markets in CEECs have a unit root, in other words, are non-stationary. In the period analyzed, the results suggest that the weak-form efficient market hypothesis holds in the CEECs. Accordingly, the results indicate support for the validity of the random walks hypothesis in all the selected stock markets in CEECs. It means that investors should not be able to earn abnormal returns by carrying out the same analysis and analysing historical prices in CEECs. The finding of weak-form market efficiency has notable implications from the point of capital allocation, stock price predictability, and the influence of shocks to stock prices.
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تمثّل التقلّبات في البورصات أحد القضايا الأكثر نقـــاشاً في الأدبيـّــات المـــاليّة والاقتصـــاديّة الحديثة، خاصة بعد الانفتاح والتكامل المالي الذي شهده الاقتصاد العالمي وتكرار الاهتزازات السعرية والأزمات الماليّة. تهدف هذه الدّراسة إلى قياس كفاءة البورصات العربيّة عند المستوى الضعيف، شملت العينة أربع بورصات عربيّة: السعودية، أبوظبي، قطر والجزائر خلال الفترة الممتدة ما بين 01-01-2007 إلى 31-12-2017، وباستخدام بيانات يوميّة لمؤشرات البورصات وتطبيق اختبارات الاستقرارية والاستقلالية. خلصت الدراسة إلى أن عوائد مؤشرات البورصات العربية لا تتبع التوزيع الطبيعي ولا السير العشوائي، وهذا يعني ضمنياً أن البورصات غير كفؤة عند المستوى الضعيف.
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Many empirical studies examine financial market efficiency; the concept of market efficiency had been anticipated at the beginning of the 20th century by Bachlier (1900) in his PhD in mathematics from the Sorbonne. In his opening paragraph, Bachlier recognized that "past, present and even discounted future events are reflected in market price, but often show no apparent relation to price changes". Bachlier contribution in this field was overlooked until it was circulated to economists by Paul Samuelson in the late 1950s. In the early 1950s, researchers were, for the first time, able to use electronic computers to study the behavior of price series in order to extract from it a long-term movement, or trend, and then use the residual portion for short-term movements and random fluctuations. By applying RWH (Random Walk Hypothesis) on the time series that consist of the major index calculated by stock exchange authority for (Morocco, Tunisia, Egypt, Jordan, and Turkey) financial markets, the time series starts from 1 January 2004 to 31 December 2006 which if it works (RWH) then the expected returns of speculative strategies should be zero. Some other statistical tests will be performed such as testing the normality of returns.
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In an efficient market, all relevant information regarding stock position is reflected in its market price. Lack of consensus among economists and financial analysts regarding market efficiency necessitates the study of EMH. Another significant reason to study market efficiency is the role of stock markets acting as financial intermediary between the saver and borrower for distribution of scarce resources via price mechanism. The present study examines the Weak Form informational efficiency of banking sector in emerging markets of Pakistan. Market efficiency receives high focus within the studies conducted in the context of European, American and Greek capital markets. However, such studies are very scarce in context of the developing world including Pakistan. In Pakistan the stock market is very sensitive to political mayhem, expectations, speculation and insider information, qualifying it logically to test EMH. The present study used the daily closing stock prices for individual firm level which has not been previously used by the researchers in Pakistan. The data from June, 1997 to April 15, 2009 was used from eleven high volume trading banks listed on Karachi Stock Exchange. The statistical techniques used include Augmented Dickey Fuller and Phillips-Perron tests in order to check stationarity, while Cointegration and VAR tests are applied to examine the weak form efficiency. The results refuted the null hypothesis of weak form Efficient Market Hypothesis in banking sector. Moreover the prices exhibit predictable and exploitable patterns concluding inefficiency of banking sector for KSE.
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This study adopts a new unit root test which allows for an unknown number of structural breaks with unknown functional forms and nonlinearity in data generating process of stock prices series to test the random walk hypothesis in an emerging stock market (Iran stock market). The results from nonlinear Fourier unit root test implies that in view of taking into account possible unknown structural breaks and nonlinear behavior in the stock prices series, Iran stock prices index follow random walk theory and is efficient in weak form.
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Recently, Perron has carried out tests of the unit-root hypothesis against the alternative hypothesis of trend stationarity with a break in the trend occurring at the Great Crash of 1929 or at the 1973 oil-price shock. His analysis covers the Nelson-Plosser macroeconomic data series as well as a postwar quarterly real gross national product (GNP) series. His tests reject the unit-root null hypothesis for most of the series. This article takes issue with the assumption used by Perron that the Great Crash and the oil-price shock can be treated as exogenous events. A variation of Perron's test is considered in which the breakpoint is estimated rather than fixed. We argue that this test is more appropriate than Perron's because it circumvents the problem of data-mining. The asymptotic distribution of the estimated breakpoint test statistic is determined. The data series considered by Perron are reanalyzed using this test statistic. The empirical results make use of the asymptotics developed for the test statistic as well as extensive finite-sample corrections obtained by simulation. The effect on the empirical results of fat-tailed and temporally dependent innovations is investigated. In brief, by treating the breakpoint as endogenous, we find that there is less evidence against the unit-root hypothesis than Perron finds for many of the data series but stronger evidence against it for several of the series, including the Nelson-Plosser industrial-production, nominal-GNP, and real-GNP series.