Finance that is based on rational and logical theories, such as the capital asset pricing model (CAPM) and the efficient market hypothesis (EMH). These theories assume that people, for the most part, behave rationally and predictably. The Efficient market hypothesis assumes that financial markets incorporate all public information and assets that share prices reflect all relevant to the firm information (Fama, 1970).
Relevant information includes past information, publicly available information and private information. Efficient market is divided into three categories. Weak form efficiency is when stock prices reflect only the past information, semi-strong form is when past information and all publicly available information is reflected and strong form is when all the past, publicly available and information only available to company insiders is reflected on the stock prices. However, there are some anomalies and behaviors that couldn't be explained by EMH. Market participants often behaved very unpredictably. However there is a new study called behavioral finance that is trying to explain all these anomalies. Behavioral finance studies the irrational behavior of the investors. Weber (1999) makes the following observation: ‘Behavioral Finance closely combines individual behavior and market phenomena and uses the knowledge taken from both the psychological field and financial theory’. Behavioral finance attempts to identify the behavioral biases commonly exhibited by investors and also provides strategies to overcome them. Some of the main problems with EMH may be cause by heuristic responses to new information, psychological anchors, overconfidence, social fads, framing and regret avoidance and herd behavior.
Overconfidence: According to Nevins (2004), overconfidence suggests that investors overestimate their ability to predict market