The Capital Asset Pricing Model (CAPM):
What Is It? How Does It Work? And Does It Work Effectively?
In 1960, a doctoral candidate in economics at the University of California, Los Angeles by the name of William F. Sharpe needed a dissertation topic. After reading a 1952 paper on portfolio theory by Harry Markowitz entitled Portfolio Selection, Sharpe had found his idea. Markowitz's paper presented the notion of an "efficient frontier" of optimal investment that advocated a diversified portfolio to reduce risk. However, his theory did not develop a practical means to assess how various holdings operate together, or correlate. Sharpe took Markowitz's theoretical work and greatly simplified it by connecting investment risk and reward to a single risk factor (beta) (Burton, 1998). With the publication of his 1963 dissertation A Simplified Model of Portfolio Analysis, Sharpe introduced the world to the Capital Asset Pricing Model (CAPM). Today, CAPM has become an integral part of investment theory and is used on a daily basis by investment practitioners and managers. The concept was deemed so important that in 1990, Sharpe was awarded the Nobel Prize in Economics for his contributions to the development of the CAPM theory. Since its introduction, there have been many questions concerning the relevance of the assumptions upon which the theory is based. CAPM has been and continues to be tested within the academic research, however, although other alternative pricing models have been developed in an attempt to combat the shortcomings of CAPM, the Capital Asset Pricing Model is the most widely used and accepted model within the current financial community.
The Capital Asset Pricing Model is an economic model for valuing stocks, securities, and ...