Friday, June 26, 2020

Capital Asset Pricing Essay Example Pdf - Free Essay Example

Living in challenging and high competition world, most investors aimed to maximize their return of investment. Various approaches and methods used to estimate value of financial instruments. Characteristics such as risk involved, price, cash flows and others were included in order to derive potential value of an instrument. Volatility of instruments and securities values also affects investors estimation. It is important for investors to choose appropriate approach to estimate the actual value of instruments or securities. Capital asset pricing model, referred as CAPM, is a model that explains relationship between risk and expected return, which is used in pricing securities. Relationship exists in this model serves two vital functions. The function including provide a benchmark rate of return for evaluating possible investments. Other than that, the model helps investors to make an appropriate and sufficient guess for the expected return of securities which are not yet been traded in the marketplace. CAPM has been used widely since its accuracy is deemed acceptable to be applied for pricing securities. 2. ASSUMPTION Several assumptions made in order to use basic version of CAPM. This is to ensure that investors are as alike as possible, with the notable exceptions of initial wealth and risk aversion. Assumptions including: 1. There are many investors, which each of them own relatively small wealth compared with total endowment of all investors. Investors considered as price taker, act as though securities prices unaffected by their trades. This assumption based on perfect competition assumption stated in microeconomics. 2. Investors will plan for one identical holding period. This behavior called as myopic, which it ignores everything that could happen after the end of the single period horizon. 3. Investments are limited to a universe of publicly traded financial assets, such as risk free borrowing and lending arrangements. Assumption also believed to rules out investment for non-traded assets like education, private enterprises, international airport and others. Investors also may b orrow or lend any amount at fixed, risk free rate. 4. Investors will not pay for taxes on returns and no transaction costs on trades in securities. 5. Investors are rational mean-variance optimizers, where the Markowitz portfolio selection model applicable. 6. Investors have the same economic view and analyze securities in the same way. Estimation of probability distribution of future cash flow for available securities is similar. For any set of security prices, investors will derive the same input list fit with Markowitz model. This assumption also referred as homogenous expectations or beliefs. With these six assumptions, we can than come out with some powerful insight of the nature of equilibrium in security markets. In equilibrium; a) The investors will hold a portfolio of risky assets in the market portfolio. The market portfolio includes all traded assets whereby it generally refers to the stocks. b) The market portfolio will be on the efficient frontier and tangent to the optimal capital allocation line (CAL). As a results from this, Capital Market Line (CML) is establish, where the investor holds M (market portfolio) as their optimal risky portfolio. c) The risk premium on the market is depends on degree of investors risk aversion. d) Thus, the risk premium on individual assets will directly proportionate to the market risk premium and beta coefficient. Beta is define as szlig; = Cov (ri rM)s2M and the risk premium of individual securities is 3. MARKET RISK PREMIUM The equilibrium risk premium on the market portfolio, E(r M ) r f, will be proportional to the average degree of risk aversion of the investor population and the risk of the market portfolio. The difference between a rate of return and the risk free rate of return is a risk premium. Risk premiums may be calculated for a particular security, a class of securities, or a market. In the simplified CAPM economy, risk-free investments involve borrowing and lending among investors. Risk-free rate is a rate that someone can earn by leaving money in risk-free assets such as T Bills, money market funds or the banks. Any borrowing position must be offset by the lending position of the creditor. This means that net borrowing and lending across all investors must be zero. The difference in any particular period between the actual rate of return on risky asset and the risk-fee asset is called excess return. Therefore, the risk premium is the expected value of the excess return, and the stan dard deviation of the excess return is an appropriate measure of its risk. The market risk premium is one of the most important but elusive parameters in finance. It is also called as equity premium market premium and risk premium. Market risk premium has three concepts consists of required market risk premium, historical market risk premium and expected market risk premium. Required market risk premium is the incremental return of the diversified portfolio (the market) over the risk free rate (return of treasury bonds) required by an investor. Historical market premium is the historical differential return of the stock market to the treasury bonds while expected market risk premium is the expected differential return of the stock market over the treasury bonds. However, the CAPM assumes that the required market risk premium is equal to the expected market risks premium. The three concepts are different because the historical market risk premium is equal for all investors but the required and the expected market risk premium are different for different investors. 4. RETURN AND RISK FOR INDIVIDUAL SECURITIES The risk premium on individual securities is a function of the individual securitys contribution to the risk of the market portfolio which means that it is a function of the covariance of returns with the assets that make up the market portfolio. (From lectures Note) Risk is consists of systematic risk and unsystematic risk. The risk of a portfolio is comprises with systematic risk and unsystematic risk. Commonly, the risk of all securities is systematic risk. And systematic risk cannot be diversified. On the other hand, unsystematic risk is the risk associated with individual assets and it can be diversified. Therefore, as a rational investor should not take any diversifiable risk, as only non-diversifiable risks are rewarded within the scope of this model. Therefore, the required rate of return on an asset, that is, the return that compensates for risk taken, must be linked to its riskiness in a portfolio context. Thus, in the CAPM context, the beta of the portfolio is defi ning the factor in rewarding the systematic exposure taken by an investor. 5. THE SECURITY MARKET LINE (SML) Security Market Line (SML) is a expected return-beta relationships graph. This is because the markets beta is 1, the slope is the risk premium of the market portfolio such as the figure shown in figure1. Equation for calculating SML: Slope of SML = E (rM ) r f SML = r f   + szlig;[E (rM ) r f] Mostly, SML use to compare with Capital Market Line (CML). This is because CML graphs show the valid measure of risk premiums of efficiency of the diversify portfolios that the investors overall portfolio. On the other hand, SML graphs show the individual asset risk premium as a function of asset risk. Thus, SML is valid for efficient portfolios and individual assets. The SML provides the following information: 1) Benchmark for evaluation of investment performance 2) Required rate of return Therefore, their expected returns are commensurate with their risk. If a stock is underpriced, so it will plot above of the SML: Given their betas, their expected returns are greater than dictated by the CAPM, and vice versa. 6. INDEX MODEL AND REALIZE RETURNS From the beginning we know that CAPM analysis is only results in expected return of the securities. However, in the real life practice, everyone can easily observe directly its realize returns compare to expected returns. By simplifying the model, the single-index model of CAPM is form as Ri = ai + szlig;iRM + ei While; Ri = return of the stocks ai = return due to macroeconomic and microeconomic events szlig;iRM = market stock returns modified by Beta ei = non-systematic risks By the definition, the firm non-systematic components is independent of market thus the Cov(RM, ei) = 0. With this the covariance of the excess rate of return on security I with market index is Cov (Ri, RM) = Cov(szlig;iRM + ei, RM) =szlig;iCov(RM, RM) + Cov(ei, RM) =szlig;is2M We can see that, a is drop from the covariance because ai is constant, thus have zero covariance for all variables. Since Cov (Ri, RM) = szlig;is2M , the sensitivity coefficient, szlig;i equals At the e nd, the index model of beta coefficient turns out to be the same as beta of the CAPM expected return-beta relationship. 7. CAPM AND REAL LIFE PRACTICAL When the CAPM is valid, than the single-index model which includes all traded securities also would be valid as well. Thus the all alpha values in risk premium would be identically zero. However in market, if all alpha is zero, there would be no incentive for analyst to analyse the security. So, the market equilibrium will be only near to the proper values, which the alpha is nearly zero values but with some differences. It is to induce and motivate the analyst to continue their effort to analyse the securities. Moreover, CAPM is the best available model to explain the rate of return on the securities portfolio, which means that one should take security alpha as zero. If the securities are misprice the alpha will be non-zero. Alpha is positive when the securities are underpriced and alpha is negative when securities are overpriced. After all analysis, the investors will select the best investment by assumption of all the alpha would be zero values.

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