A Literature Study on the Capital Asset Pricing Model

Abstract

Capital Asset Pricing Model (CAPM) is an important theory in financial economics. It was based on Markowitz's Modern Asset Allocation Theory (MPT) and proposed by Sharpe. This model expresses the relationship between risk coefficient, asset return rate, and systematic risks by simple mathematical formulas. The model has four advantages, handling of risks when evaluating investment behavior, accuracy when estimating equity capital, relatively reliable and better than Weighted Average Cost of Capital (WACC) in investment evaluation. CAPM also has some weakness, consisting of variables and application in investment evaluation. There are three variables in CAPM model, risk-free rate of return, equity risk premium and beta. The weakness about application in investment evaluation shows that in beta of projects and firms are different, complex restructure and periods. The Arbitrage Pricing Theory (APT) can be an option of CAPM, and it is a more flexible and complex model compared with CAPM. However, the latest research proves that Portfolio Theory has very big problems. High-risky assets do not necessarily have high returns. This view may be embodied in "low-risk anomalies" and "Idiosyncratic Volatility". In the future, researchers will introduce more elements for CAPM to improve accuracy, or develop new models.