Market efficiency and global issues: A case of Indonesia

Efficient market hypothesis (EMH) states that financial markets are “informationally efficient”, implying that current prices fully reflect all available information. The present study aims at testing the weak form of market efficiency of the individual stocks listed on the Bahrain Bourse for the period 2011 to 2015. Weak form of EMH is tested using the Kolmogorov-Smirnov goodness of fit test, run test and autocorrelation test. The K-S test result concludes that in general the stock price movement does not follow random walk. The results of the runs test reveals that share prices of seven companies do not follow random walk. Autocorrelation tests reveal that share prices exhibit low to moderate correlation varying from negative to positive values. As the study shows mixed results, it is difficult to conclude the weak form of efficiency of Bahrain Bourse.

The study identifies the features of the USD/UAH exchange rate dynamics for the period from January 2014 to May 2020. The main purpose of the empirical analysis is to determine the current trend of the USD/UAH exchange rate (is it random or permanent), indicate the presence of seasonality in foreign exchange rate dynamics and evaluate its sensitivity to external shocks. Three hypotheses are tested using several methods of time series analysis (autocorrelation analysis, ADF, Phillips-Perron and Granger tests), including a trend-season model using a time series of one variable (ARMA), a multifactor VAR-model, impulse functions. The results show that, the movement of the hryvnia exchange rate against the US dollar is a stochastic process. Its trend has a random component and tends to change sharply over time. Moreover, exchange rate fluctuations are seasonal. It depreciates in the first and second quarters, and strengthens in the third and fourth. Some macroeconomic indicators cause a positive or negative reaction of the USD/UAH exchange rate. This indicates that today the Ukrainian foreign exchange market is relatively efficient, but stable, since its reaction to external shocks is short-term, insignificant and tends to fade out. Although the findings are controversial, they support the generally accepted view that the exchange rate formation is a multifactorial process that depends on several macroeconomic factors. However, high volatility and random walk specification indicate that it is almost impossible to predict its future value at this time.

Acknowledgment
The material was prepared within the framework of the scientific research Modeling and Forecasting the Behavior of Financial Markets as an Information Base for Ensuring Financial Stability and Security of the State, No. 0117U003936 (supervisor Alex Plastun).

The Saudi Arabia Stock Exchange (Tadawul) is one of the biggest emerging Stock Exchanges in the Middle East region. Therefore, this research aims to apply Fama and French (2015) 5-factor model on Tadawul, and compares it with the Fama and French 3-factor model and CAPM to check the applicability of the models in Tadawul and the identity of the factors that can affect stock returns. Furthermore, the Generalized Method of Moments (GMM) regression has been implemented to examine the impact between the variables in the models. Empirically, the results show that Fama and French (2015) 5-factor model is the most consistent model in comparison to the other two models in terms of explaining the cross-section of average stock returns in Tadawul. However, it is not the best according to the intercepts results of all the regressions in 2x3, 2x2, or 2x2x2x2 sorts. Besides, Fama and French (2015) 5-factor model has the highest explanatory power in most of the portfolios based on the adjusted R2 regardless of the sort (2x3, 2x2, or 2x2x2x2). Finally, the results conclude that Fama and French (2015) 5-factor model can be an applicable model in Tadawul but only market and size can affect the stock returns, while the value, profitability, and investment cannot. Accordingly, the author recommends that, as a continuation of this research, further research can be done, which investigates a model with additional factors like momentum and illiquidity.