Get A Test Of The Weak Form Efficiency Of The Zimbabwe Stock

In many of the markets studied, a significant number of stocks rejected the random walk. Only three markets, Namibia, Kenya and Zimbabwe, were found to be relatively weak form efficient.

The weak form of EMH is the lowest form of efficiency that defines a market as being efficient if current prices fully reflect all information contained in past prices. This form implies that past prices cannot be used as a predictive tool for future stock price movements.

Weak form efficiency, also known as the random walk theory, states that future securities' prices are random and not influenced by past events. Advocates of weak form efficiency believe all current information is reflected in stock prices and past information has no relationship with current market prices.

Tests of market efficiency look at the whether specific investment strategies earn excess returns. Some tests also account for transactions costs and execution feasibility. In every case, a test of market efficiency is a joint test of market efficiency and the efficacy of the model used for expected returns.

Three common types of market efficiency are allocative, operational and informational. However, other kinds of market efficiency are also recognised. Arbitrage involves taking advantage of price similarities of financial instruments between 2 or more markets by trading to generate profits.

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.

The weak form of the EMH assumes that the prices of securities reflect all available public market information but may not reflect new information that is not yet publicly available. It additionally assumes that past information regarding price, volume, and returns is independent of future prices.