Testing the Random Walk Behavior and Efficiency of the Gulf Stock Markets

Inferences drawn from tests of market efficiency are rendered imprecise in the presence of infrequent trading. As the observed index in thinly traded markets may not represent the true underlying index value, there is a systematic bias toward rejecting the efficient market hypothesis. For the three emerging Gulf markets examined in this paper, correction for infrequent trading significantly alters the results of market efficiency and random walk tests. The Beveridge–Nelson (1981) decomposition of index returns is done to estimate the underlying index.     

Variance ratio tests of the random walk hypothesis for European emerging stock markets

The hypothesis that stock market price indices follow a random walk is tested for five European emerging markets, Greece, Hungary, Poland, Portugal and Turkey, using the multiple variance ratio test. In four of the markets, the random walk hypothesis is rejected because of autocorrelation in returns. For the Istanbul market, which had markedly higher turnover than the other markets in the 1990s, the stock price index follows a random walk. This contrasts with the results of earlier research, carried out for periods of lower turnover, which rejected the random walk hypothesis.     

Random Walks and Market Efficiency Tests of Latin American Emerging Equity Markets: A Revisit

The few existing studies on equity price dynamics and market efficiency for Latin American emerging equity markets show conflicting results. This study uses multiple varianceratio and auto-regressive fractionally integrated moving-average tests and new data (U.S. dollar-based national equity indices for the 1987–1997 period) to clarify these results. Documented evidence shows that equity prices in major Latin American emerging equity markets — Argentina, Brazil, Chile and Mexico—follow a random walk, and that they are, generally, weak-form efficient. In sum, therefore, the evidence suggests that international investors in these markets cannot use historical information to design systematically profitable trading schemes because future long-term returns are not dependent on past returns.     

Random Walks and Market Efficiency Tests: Evidence from Emerging Equity Markets

We use the multiple variance-ratio test of Chow and Denning (1993) to examine the stochastic properties of local currency- and US dollar-based equity returns in 15 emerging capital markets. The technique is based on the Studentized Maximum Modulus distribution and provides a multiple statistical comparison of variance-ratios, with control of the joint-test's size. We find that the random walk model is consistent with the dynamics of returns in most of the emerging markets analyzed, which contrasts many random walk test results documented with the use of single variance-ratio techniques. Further, a runs test suggests that most of the emerging markets are weak-form efficient. Overall, our results suggest that investors are unlikely to make systematic nonzero profit by using past information in many of the examined markets, thus, investors should predicate their investment strategies on the assumption of random walks. Additionally, our results suggest exchange rate matters in returns' dynamics determination for some of the emerging equity markets we analyzed.     

Using Daily High/Low Time to Test for Intraday Random Walk in Two Index Futures Markets

This paper investigates the time of the daily high/low price in the Hang Seng and S&P 500 index futures and uses it to test for deviation from the predictive behavior of an intraday random walk model. Theoretical distributions of the daily high/low time under the random walk model are derived assuming either uniform or time-varying intraday trading speed. We show that under a random walk model, daily high/low time is more likely to occur near market open/close than in the middle of the trading day. Empirical distributions of the daily high/low time are compared with its theoretical distributions to test for the random walk model. It is found that for the intraday movement of the S&P 500 futures, the random walk hypothesis cannot be rejected. However, it is discovered that in the Hong Kong market, daily high/low time tends to appear significantly more often than is predicted by the random walk model in the first 15-minute time interval when the market opens in the morning or in the afternoon. The results remain valid even after we have taken the time-varying trading speed into account. By comparing the price behavior across markets, we can better understand the microstructure of the futures market.     

Efficient Markets Hypothesis and the Emerging Capital Market in Sri Lanka: Evidence from the Colombo Stock Exchange – A Note

The behaviour of stock prices on the Colombo Stock Exchange (CSE) is examined with a view to determine its consistency with the weak form of the Efficient Markets Hypothesis (EMH). Runs, Autocorrelation and Cointegration tests are applied to daily, weekly and monthly CSE index data for the period of January 1991–November 1996. Results of Runs, Correlation and Cointegration tests overwhelmingly reject the serial independence hypothesis, leading to the conclusion that the behaviour of stock prices in the Colombo Stock Exchange is not consistent with the weak form of the Efficient Markets Hypothesis. Tests of the-day-of-the-week-effect, however, show that there is no evidence of such a phenomenon on the Colombo Stock Exchange stock prices. Results of the tests of the-month-of-the-year-effect lead to the conclusion that CSE prices do not display any month-specific behaviour.     

Globalization and Investment Opportunities: A Cointegration Study of Arab,U.S., and Emerging Stock Markets

Using a sample of Arab, U.S., and emerging stock markets from 1997 to 2002, this study is designed to determine if international diversification is still possible despite growing globalization and the consequent integration among various stock markets. Our results show that within Arab markets, Kuwait cointegrates individually with Jordan, Tunisia, and Saudi Arabia and between Tunisia and Jordan, thus offering investors possible continued diversification opportunities. On the other hand, only Jordan, Kuwait, and Morocco are cointegrated with the U.S. general market index, implying that these markets offer a probable substitute for those investing in the U.S. markets.     

MENA stock market volatility persistence: Evidence before and after the financial crisis of 2008

The global financial crisis began with a financial meltdown in the United States in early 2008 and then it had spread to the rest of the world. In this paper we test whether the MENA equity market volatility presents a different behavior before and after the financial crisis of 2008. Using long range dependence techniques we test for long memory in the returns, absolute and squared returns of the MENA equity markets. We subject the series to unit root tests that allow for structural breaks and use the Bai and Perron (1998, Econometrica, 66, 47; 2003a, J. Appl. Econometrics, 6, 72; 2003b, Econometrics J., 18, 1) to test for multiple breaks in the mean returns. The results indicate that the volatility measures represented by absolute and squared returns show evidence of long memory for the full and subsample periods, while the returns show a weak evidence of long memory. Considering the shift dates and corresponding to the 2008 financial crisis, the returns and volatility measures display less evidence of long memory in the after crisis period as opposed to the before crisis period. The change in the returns and volatility dynamics of these markets was due to financial and economic conditions that took place in the MENA region after the crisis.