Behavioral Finance: How psychological factors can influence the stock market

Behavioral finance, a sub-field of behavioral economics, proposes that psychological influences and biases affect the financial behaviors of investors and financial practitioners. Moreover, influences and biases can be the source for an explanation of all types of market anomalies and specifically market anomalies in the stock market, such as severe rises or falls in stock price.

Behavioral finance can be analyzed from a variety of perspectives. Stock market returns are one area of finance where psychological behaviors are often assumed to influence market outcomes and returns but there are also many different angles for observation. The purpose of the classification of behavioral finance is to help understand why people make certain financial choices and how those choices can affect markets. Within behavioral finance, it is assumed that financial participants are not perfectly rational and self-controlled but rather psychologically influential with somewhat normal and self-controlling tendencies.

One of the key aspects of behavioral finance studies is the influence of biases. Biases can occur for a variety of reasons. Biases can usually be classified into one of five key concepts. Understanding and classifying different types of behavioral finance biases can be very important when narrowing in on the study or analysis of industry or sector outcomes and results.

The efficient market hypothesis (EMH) says that at any given time in a highly liquid market, stock prices are efficiently valued to reflect all the available information. However, many studies have documented long-term historical phenomena in securities markets that contradict the efficient market hypothesis and cannot be captured plausibly in models based on perfect investor rationality.

The EMH is generally based on the belief that market participants view stock prices rationally based on all current and future intrinsic and external factors. When studying the stock market, behavioral finance takes the view that markets are not fully efficient. This allows for observation of how psychological factors can influence the buying and selling of stocks.

The understanding and usage of behavioral finance biases are applied to stock and other trading market movements daily. Broadly, behavioral finance theories have also been used to provide clearer explanations of substantial market anomalies like bubbles and deep recessions. While not a part of EMH, investors and portfolio managers have a vested interest in understanding behavioral finance trends. These trends can be used to help analyze market price levels and fluctuations for speculation as well as decision-making purposes.