Empirical Evidence for the Efficient Market Hypothesis

Capital markets provide a function which facilitates the buying and selling of long-term financial securities to increase liquidity and their value, Watson & Head (2013). Hence, the Efficient Market Hypothesis (EMH) explains the relationship that exists with the prices of the capital market securities, where no individual can beat the market by regularly buying securities at a lower price than it should be. This means that in order to be an efficient market prices of securities will have to fairly and fully reflect all available information, Fama (1970). Consequently, Watson & Head (2013) believe that market efficiency refers to the speed and quality of how share price adjusts to new information. Nevertheless, the testing of the efficient markets has led to the recognition of three different forms of efficiency in which explains how information available is used within the market. In this essay, the EMH will be analysed; testing of EMH will show that the model does provide strong evidence to explain share behaviour but also anomalies will be discussed that refutes the EMH. Therefore, a judgment will be made to see which structure explains the efficient market and whether there are some implications with the EMH, as a whole.

It is believed that Efficient Market Theory is based upon some fallacies and it does not provide strong grounds of whatever that it proposes. More importantly the Efficient Market theory is perceived to be too subjective in its definition and details and because of this it is close to impossible to accommodate this theory into a meaningful and explicit financial model that can actually assist investors in making the investment decisions (Andresso-O’Callaghan, B., 2007).

As Chapter 10 questions, if further evidence continues to surface that capital markets do not always behave in accordance with the efficient market hypothesis, then should we reject the research that has embraced the EMH as a fundamental assumption? In this regard we can return to earlier chapters of this book in which we emphasised that theories are abstractions of reality. Capital markets are made of individuals and as such it would not (or perhaps, should not) be surprising to find that the

The Efficient-Market Hypothesis (EMH) states that it is impossible to beat the market because stock market efficiency causes existing share prices to always incorporate and reflect all relevant information.

It was previously assumed that economic investors and regulators (agents) utilised all available information and thus market prices were a reflection of this information with assets representing their fundamental value, encouraging the position that agents’ actions were rational. The 2007-2008 Global Financial Crisis (GFC) is posited to have originated from the notion that all available information was utilised, causing agents to fail to thoroughly investigate and confirm “the true values of publicly traded securities,” leading to a failure to register the presence of an asset price bubble preceding the GFC (Ball 2009).

The efficient markets theory, according to NASDAQ (n.d.) is the, “Principle that all assets are correctly priced by the market, and that there are no bargains,” (para. 1). This theory implies that supply and demand dictate the reasonable market value for products. Without high demand, the supply will be greater and prices will be lower. Respectively, as demand increases so do the prices until the supply and demand are at equilibrium.

This document is authorized for use only by Yen Ting Chen in FInancial Markets and Institutions taught by Nawal Ahmed Boston University from September 2014 to December 2014.

Financial theory accepts the belief that a share’s return should be proportional to the risk received by its holder. There is a need of a risk-return equilibrium model. Since the nativity of the efficient market hypothesis (EMH), an equilibrium model was only the Capital Asset Pricing Model (CAPM). The CAPM constitutes of two types of returns, the risk free rate of returns of the Treasury bills and beta times the return on the market portfolio. The following equation is the basis of this model:

Allocating the ownership of economy’s stock capital is the primary role of capital market. In an ideal market the price would provide accurate signals for allocation of resources. Ideal market is one in which firm’s production-investment decisions and investor’s decision regarding securities will depend on the assumption that the security prices fully reflect available information at any point in time. A market in which prices always “fully reflect” available information is called efficient.1

The efficient-market hypothesis (EMH) is one of the well-known methods for measuring the future value of stock prices. According to this hypothesis, the market is efficient if its prices are formed on the basis of all disposable information. According to EMH if there is a possibility to predict the future price of shares, that is the first sign of an inefficient market.

information in the previous prices. In short, they simply imply that in the long run, no one

Efficient Market Hypothesis has been controversial issues among researcher for decades. Until now, there is no united conclusion whether capital markets are efficiency or not. In 1960s, Fama (1970) believed that market is very efficient despite there are some trivial contradicted tests. Until recently, both empirical and theatrical efficient market hypothesis was being disputed by behavior finance economist. They have found that investor have psychological biases and found evidences that some stocks outperform other stocks. Moreover, there are evidences prove that market are not efficient for instance financial crisis, stock market bubble, and some investor can earn abnormal return which happening regularly in stock markets all over the world. Therefore, the purpose of this essay is to demonstrate that Efficient Market Hypothesis in stock (capital) markets does not exist in the real world by proofing four outstanding unrealistic conditions that make market efficient: information is widely available and cost-free, investor are rational, independent and unbiased, There is no liquidity problem in stock market, and finally stock prices has no pattern.

The efficient market hypothesis (EMH) has been subject to professional and academic debate and analysis for many years, and refers to the theory proposing that stock prices show all information regarding a firm’s value. An efficient market is a market in which investors with the same information and similar investment goals compete actively (Sewell, 2012). Many private investors and investors aiming to make profits are involved with the stock market and often make low risk investments while aiming for high rates of return. However, the efficient market hypothesis states that it is impossible to consistently outperform the stock market as the market is able to quickly adjust to new information. The Efficient Market Hypothesis also addresses

The weak-form efficiency cannot explain January effect. In semi-strong-form efficient market, to test this hypothesis, researchers look at the adjustment of share prices to public announcements such as earnings and dividend announcements, splits, takeovers and repurchases. As time goes, later tests tend to be not supportive to EMH. For instance, semi-strong-form efficiency cannot explain the pricing/earning effect. In strong-form efficiency, the highest level of market efficiency, Fama (1991) pointed out the immeasurability of market efficiency and suggested that it must be tested jointly with an equilibrium model of expected. However, perfect efficiency is an unrealistic benchmark that is unlikely to hold in practice.

Market efficiency is the way in which information is shared and absorbed quickly by the market ensuring stock prices reflect all the available information Atrill (2012).