Among the foremost to apply digital computers to perform empirical research in the field of finance, Fama operationally defined the EMH by pointing structure on several information sets accessible to market players. The efficient-market hypothesis necessitates that the agents should expect rationally that on average the overall population is correct (although if no individual is) and each time new pertinent information comes out, the agents should update their anticipations appropriately. Moreover, agents are not needed to be rational. EMH permits that on facing novel information, some investors may under react while some, on the other hand may over react. But, they are necessitated by EMH to react in a random manner that follows standard normal distribution. So, the overall impact on market prices may not be constantly exploited to attain more than usual profit, particularly, while keeping into consideration the transaction costs (including spreads and commissions). Therefore, any individual may be perceived to be incorrect regarding the market but, market, on the contrary, as a whole is considered to be always correct.
Three levels of hypothesis
The efficient market hypothesis can be commonly stated in three basic forms. These include weak-form, semi-strong form and strong form efficiency. Each of these provides distinct implications for the way market performs. Weak-Form Efficiency This form of EMH specifies that current prices of assets reflect past volume and price information. The information incorporated in the past series of a security’s prices is completely reflected in its present market price. It is called as weak because the market price is the most accessible information available to individuals and the utilization of technical analysis is forbidden by this form of EMH. Semi-Strong Form Efficiency This form submits that entire available information to the public is incorporated into the prices of asset. Thus the market price of that asset is a complete reflection of all information accessible to the public. This publicly known information includes the past prices as well as the data reported by the company in its financial statements, announcement along with economic and other factors. The Strong-Form Efficiency This form implies that along with the publicly available information, the insider or private information is also reflected in an asset’s market price. Thus, such a market restricts the inside organization members from gaining unusual returns. Thus, all forms of EMH restrict individuals from attaining unusual returns due to unavailability of information and inhibit the possibility of arbitrage or risk free profit (Fama, 1991). Firm’s pricing of debt and equity decisions and EMH The 2007-2012 financial disaster has contributed to renewed criticism and scrutiny of the efficient market hypothesis. It has been even dismissed as being an ineffective way to study the functioning of financial markets in reality by various economists and financial analysts. Critics have proposed that corporations and financial institutions have the