Unformatted text preview: 13 Return, Risk, and the Security Market Line 1 Key Concepts and Skills Know how to calculate expected returns Understand the impact of diversification Understand the systematic risk principle Understand the security market line Understand the riskreturn tradeoff Be able to use the Capital Asset Pricing Model 2 Chapter Outline Expected Returns and Variances Portfolios Announcements, Surprises, and Expected Returns Risk: Systematic and Unsystematic Diversification and Portfolio Risk Systematic Risk and Beta The Security Market Line The SML and the Cost of Capital: A Preview 3 Expected Returns Expected returns are based on the probabilities of possible outcomes In this context, "expected" means average if the process is repeated many times The "expected" return does not even have to be a possible return E ( R ) = pi Ri
i =1
4 n Example: Expected Returns Suppose you have predicted the following returns for stocks C and T in three possible states of nature. What are the expected returns? State Boom Normal Recession Probability 0.3 0.5 ??? C 15 10 2 T 25 20 1 RC = .3(15) + .5(10) + .2(2) = 9.9% RT = .3(25) + .5(20) + .2(1) = 17.7% 5 Variance and Standard Deviation Variance and standard deviation still measure the volatility of returns Using unequal probabilities for the entire range of possibilities Weighted average of squared deviations
n 2 = pi ( Ri  E ( R)) 2
i =1
6 Example: Variance and Standard Deviation Consider the previous example. What are the variance and standard deviation for each stock? Stock C 2 = .3(159.9)2 + .5(109.9)2 + .2(29.9)2 = 20.29 = 4.5 2 = .3(2517.7)2 + .5(2017.7)2 + .2(117.7)2 = 74.41 = 8.63 Stock T 7 Another Example Consider the following information: State Boom Normal Slowdown Recession Probability .25 .50 .15 .10 ABC, Inc. (%) 15 8 4 3 What is the expected return? What is the variance? What is the standard deviation? 8 Portfolios A portfolio is a collection of assets An asset's risk and return are important in how they affect the risk and return of the portfolio The riskreturn tradeoff for a portfolio is measured by the portfolio expected return and standard deviation, just as with individual assets 9 Example: Portfolio Weights Suppose you have $15,000 to invest and you have purchased securities in the following amounts. What are your portfolio weights in each security? $2000 of DCLK $3000 of KO $4000 of INTC $6000 of KEI DCLK: 2/15 = .133 KO: 3/15 = .2 INTC: 4/15 = .267 KEI: 6/15 = .4
10 Portfolio Expected Returns The expected return of a portfolio is the weighted average of the expected returns of the respective assets in the portfolio j =1 You can also find the expected return by finding the portfolio return in each possible state and computing the expected value as we did with individual securities E ( RP ) = w j E ( R j ) m 11 Example: Expected Portfolio Returns Consider the portfolio weights computed previously. If the individual stocks have the following expected returns, what is the expected return for the portfolio? DCLK: 19.69% KO: 5.25% INTC: 16.65% KEI: 18.24% E(RP) = .133(19.69) + .2(5.25) + .267(16.65) + .4(18.24) = 15.41% 12 Portfolio Variance Compute the portfolio return for each state: RP = w1R1 + w2R2 + ... + wmRm Compute the expected portfolio return using the same formula as for an individual asset Compute the portfolio variance and standard deviation using the same formulas as for an individual asset 13 Example: Portfolio Variance Consider the following information Portfolio 12.5% 7.5% What are the expected return and standard deviation for each asset? What are the expected return and standard deviation for the portfolio?
14 Invest 50% of your money in Asset A State Probability A B Boom .4 30% 5% Bust .6 10% 25% Another Example Consider the following information State Boom Normal Recession Probability .25 .60 .15 X 15% 10% 5% Z 10% 9% 10% What are the expected return and standard deviation for a portfolio with an investment of $6,000 in asset X and $4,000 in asset Z? 15 Expected versus Unexpected Returns Realized returns are generally not equal to expected returns There is the expected component and the unexpected component At any point in time, the unexpected return can be either positive or negative Over time, the average of the unexpected component is zero 16 Announcements and News Announcements and news contain both an expected component and a surprise component It is the surprise component that affects a stock's price and therefore its return This is very obvious when we watch how stock prices move when an unexpected announcement is made or earnings are different than anticipated 17 Efficient Markets Efficient markets are a result of investors trading on the unexpected portion of announcements The easier it is to trade on surprises, the more efficient markets should be Efficient markets involve random price changes because we cannot predict surprises
18 Systematic Risk Risk factors that affect a large number of assets Also known as nondiversifiable risk or market risk Includes such things as changes in GDP, inflation, interest rates, etc. 19 Unsystematic Risk Risk factors that affect a limited number of assets Also known as unique risk and assetspecific risk Includes such things as labor strikes, part shortages, etc. 20 Returns Total Return = expected return + unexpected return Unexpected return = systematic portion + unsystematic portion Therefore, total return can be expressed as follows: Total Return = expected return + systematic portion + unsystematic portion 21 Diversification Portfolio diversification is the investment in several different asset classes or sectors Diversification is not just holding a lot of assets For example, if you own 50 Internet stocks, you are not diversified However, if you own 50 stocks that span 20 different industries, then you are diversified 22 Table 13.7 23 The Principle of Diversification Diversification can substantially reduce the variability of returns without an equivalent reduction in expected returns This reduction in risk arises because worse than expected returns from one asset are offset by better than expected returns from another However, there is a minimum level of risk that cannot be diversified away and that is the systematic portion 24 Figure 13.1 25 Diversifiable Risk The risk that can be eliminated by combining assets into a portfolio Often considered the same as unsystematic, unique or assetspecific risk If we hold only one asset, or assets in the same industry, then we are exposing ourselves to risk that we could diversify away 26 Total Risk Total risk = systematic risk + unsystematic risk The standard deviation of returns is a measure of total risk For welldiversified portfolios, unsystematic risk is very small Consequently, the total risk for a diversified portfolio is essentially equivalent to the systematic risk 27 Systematic Risk Principle There is a reward for bearing risk There is not a reward for bearing risk unnecessarily The expected return on a risky asset depends only on that asset's systematic risk since unsystematic risk can be diversified away 28 Table 13.8 29 Measuring Systematic Risk How do we measure systematic risk? We use the beta coefficient to measure systematic risk What does beta tell us? A beta of 1 implies the asset has the same systematic risk as the overall market A beta < 1 implies the asset has less systematic risk than the overall market A beta > 1 implies the asset has more systematic risk than the overall market 30 Total versus Systematic Risk Consider the following information:
Standard Deviation Beta Security C Security K 20% 30% 1.25 0.95 Which security has more total risk? Which security has more systematic risk? Which security should have the higher expected return? 31 Work the Web Example Many sites provide betas for companies Yahoo Finance provides beta, plus a lot of other information under its key statistics link Click on the web surfer to go to Yahoo Finance Enter a ticker symbol and get a basic quote Click on key statistics 32 Example: Portfolio Betas Consider the previous example with the following four securities Security DCLK KO INTC KEI Weight Beta .133 .2 .267 .4 2.685 0.195 2.161 2.434 What is the portfolio beta? .133(2.685) + .2(.195) + .267(2.161) + .4(2.434) = 1.947 33 Beta and the Risk Premium Remember that the risk premium = expected return riskfree rate The higher the beta, the greater the risk premium should be Can we define the relationship between the risk premium and beta so that we can estimate the expected return? YES! 34 Example: Portfolio Expected Returns and Betas
30% 25% Expected Return 20% 15% 10% 5% f 0% 0 0.5 1 Beta 1.5 A E(RA) R 2 2.5 3 35 RewardtoRisk Ratio: Definition and Example The rewardtorisk ratio is the slope of the line illustrated in the previous example Slope = (E(RA) Rf) / ( A 0) Rewardtorisk ratio for previous example = (20 8) / (1.6 0) = 7.5 What if an asset has a rewardtorisk ratio of 8 (implying that the asset plots above the line)? What if an asset has a rewardtorisk ratio of 7 (implying that the asset plots below the line)? 36 Market Equilibrium In equilibrium, all assets and portfolios must have the same rewardtorisk ratio and they all must equal the rewardtorisk ratio for the market E ( RA )  R f A = E ( RM  R f ) M
37 Security Market Line The security market line (SML) is the representation of market equilibrium The slope of the SML is the rewardtorisk ratio: (E(RM) Rf) / M But since the beta for the market is ALWAYS equal to one, the slope can be rewritten Slope = E(RM) Rf = market risk premium 38 The Capital Asset Pricing Model (CAPM) The capital asset pricing model defines the relationship between risk and return E(RA) = Rf + A(E(RM) Rf) If we know an asset's systematic risk, we can use the CAPM to determine its expected return This is true whether we are talking about financial assets or physical assets 39 Factors Affecting Expected Return Pure time value of money measured by the riskfree rate Reward for bearing systematic risk measured by the market risk premium Amount of systematic risk measured by beta 40 Example  CAPM Consider the betas for each of the assets given earlier. If the riskfree rate is 2.13% and the market risk premium is 8.6%, what is the expected return for each? Security DCLK KO INTC KEI Beta 2.685 0.195 2.161 2.434 Expected Return 2.13 + 2.685(8.6) = 25.22% 2.13 + 0.195(8.6) = 3.81% 2.13 + 2.161(8.6) = 20.71% 2.13 + 2.434(8.6) = 23.06%
41 Figure 13.4 42 Quick Quiz How do you compute the expected return and standard deviation for an individual asset? For a portfolio? What is the difference between systematic and unsystematic risk? What type of risk is relevant for determining the expected return? Consider an asset with a beta of 1.2, a riskfree rate of 5%, and a market return of 13%. What is the rewardtorisk ratio in equilibrium? What is the expected return on the asset? 43 13 End of Chapter 44 Comprehensive Problem The risk free rate is 4%, and the required return on the market is 12%. What is the required return on an asset with a beta of 1.5? What is the reward/risk ratio? What is the required return on a portfolio consisting of 40% of the asset above and the rest in an asset with an average amount of systematic risk? 45 ...
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 Spring '08
 JohnWingender
 Standard Deviation, Capital Asset Pricing Model, Modern portfolio theory, systematic risk, DCLK

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