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Chapter 7 – Risk, Return and the Security Market Line Learning Objectives Calculate Profit and Returns Convert Holding Period Returns (HPR) to APR Appreciate historical returns Calculate standard deviations and variances Calculate standard deviations with future data Understand risk and return tradeoff Interpret risk and return tradeoff Discover how to remove some risk Understand diversification Explain systematic and unsystematic risk Understand Beta and what it measures
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Returns Calculating a return Dollar Return Ending Value + Distributions – Original Cost Example 7.1, Bought Trading Card for $50 and sold it for $55, Dollar Return (Profit) $5 Percentage Return [(Ending Value + Distributions) / Original Cost] – 1 Example 7.1, [$55 +$0 / $50] - 1 = 10% Calculating a return with distributions Example 7.1, Stock with dividend [($47.82 + $0.90) / $42.00] – 1 = 16%
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Holding Period Returns Holding Period Returns (HRP) The return for the length of time that investment is held Not consistent with interest rates from Chapter 4 Need to convert to annual basis for comparison Annualized return = (1 + HRP) 1/n – 1 Warning on extrapolation of holding period returns for less than a year Compounding requires each additional investment period with same holding period return
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Risk as Uncertainty Risk is the uncertainty in the outcome of an event (potential good and bad outcomes) An event where the outcome is known before the event is free of uncertainty or risk-free Trading Card could go down in value over time Bought at $50 but sell at $41.50 Return = [($41.50 - $50.00) / $50.00] -1 = -17% Holding period return loss of -17% (bad outcome)
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Historical Returns Year by Year Returns (See Table 7.1) Four different investments 3-Month Treasury Bill Long-Term Government Bonds Large Company Stocks Small Company Stocks What do we notice? Large Swings from year to year Most consistent performer, 3-Month Treasury Relationship of average return and standard deviation – first look at risk and return tradeoff
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Measuring Risk Using Variance Measure of the swing from year to year: Variance (σ 2 ) Greater the variance the greater the potential outcomes Standard Deviation (σ) = Variance 1/2 [(σ 2 ) 1/2 ]
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Historical Returns and Variances Four Financial Instruments Highest Return and Highest Variance – Small Stocks Lowest Return and Lowest Variance – U.S. Treasury Bill See Figure 7.3 page 196 Linear relationship of risk and return The greater the return the greater the variance Relationship of risk and return
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Returns in an Uncertain World Investments or bets are made prior to the event Need to calculate the expected outcome of the event Need the list of all potential outcomes Need the chance of each potential outcome Expected Return = Σ outcome i x probability i Payoff or return for investment is the outcome Example 7.3, Expected Return on a bond
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Example 7.3 States of the Economy (World) Four potential economic states Each has positive probability Bond has different “outcome” in each state Expected return is weighed average 15% x 2% + 45% x 5% + 30% x 8% + 10% x 10% On average we expect 5.95% return Variance uses same probabilities of the states of the economy
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Risk and Return Tradeoff Objective: Maximize Return and Minimize Risk Must tradeoff increases in risk and return with decreasing risk and return Investment Rule #1 – Two assets with same expected return, pick one with lower risk Investment Rule #2 – Two assets with the same risk, pick one with higher return What to do when one investment has both higher return and more risk versus another asset? Must look to individual choice
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Diversification – Eliminating Risk Don’t put all your eggs in one basket Spread out your investment over a series of investments If a “bad outcome” should hit one investment a “good outcome” in another investment could offset the bad outcome Combining Zig and Zag When one is up the other down Consistent return from period to period Spreading investment lowers risk
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When Diversification Works Co-movement of stock returns Correlation Coefficient Covariance of two assets divided by their standard deviations (equation 7.10) Positive Correlation No benefit if perfectly positively correlated Example Peat and Repeat Companies Negative Correlation Eliminate all risk if perfectly negatively correlated Example Zig and Zag Companies
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Systematic and Unsystematic Risk Systematic Risk – risk you cannot avoid Unsystematic Risk – risk you can avoid Adding more and more stocks As you add more stocks to portfolio you reduce more of the unsystematic or firm-specific risk Marginal decline in elimination Around 25 to 30 stocks can eliminate nearly all unsystematic risk Variance or Standard Deviation is measure of both systematic and unsystematic risk
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Beta – Measure of Risk in a Portfolio Using Beta for finding the risk of a portfolio In a well diversified portfolio only systematic risk remains Systematic risk of portfolio is weighted betas Example 7.4 (Henry and Rosie’s Betas) Henry average risk and beta is 1.0 0.25 x 0.8 + 0.25 x 1.2 + 0.25 x 0.6 + 0.25 x 1.4 Rosie is slightly conservative (investments) and beta is 0.94 0.35 x 0.8 + 0.15 x 1.2 + 0.30 x 0.6 + 0.20 x 1.4
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Using Beta Beta Facts Beta of zero means no risk (i.e. T-Bill) Beta of 1 means average risk (same as market risk) Beta < 1, risk lower than market Beta > 1, risk greater than market Expected Return and Beta use asset weights in portfolio for portfolio e(r) and β Expected Return = Σ w i x return i Beta = Σ w i x β i
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Using Beta Beta also determines expected return of individual asset Known, risk-free rate Estimate, expected return on market Each asset’s expected return function of its risk as measured by beta and the risk-reward tradeoff (slope of SML)
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Company: A Portfolio of Projects All companies are a portfolio of individual projects (or products and services) Concept of portfolio helps explain Viewing each project or product with different level of risk (project β) and contribution (expected return) Different project or product combinations can lower overall risk of the firm Projects plotting above the SML (buy) Projects plotting below the SML (sell)
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Risk and Return in a Portfolio that is Not Well Diversified George Jetson investing choice Only four assets in portfolio (equally weighted) Expected return = 9.35% Standard Deviation = 4.29% Weighted average standard deviations of four assets = 4.4% Little benefit from diversification Portfolio needs more assets for benefits of diversification
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Security Market Line Assumptions #1 – There is a reward for waiting #2 – The greater the risk the greater the expected reward #3 – There is a constant tradeoff between risk and reward E(return) = risk-free rate + slope (level of risk) Trick is to find the level of risk for an investment and the reward for risk
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CAPM Capital Asset Pricing Model (CAPM) Expected return of an asset is a function of The time value of money Reward for taking on risk Amount of risk Security Market Line is application of CAPM All firms plot on SML (ex-ante) Firms above the line are under priced Firms below the line are over priced Security Market Line estimates expected returns
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Applications of SML Two assets on the SML (two points) Find slope (reward for risk) Find intercept (risk-free rate) Equation of the line in general form Assets plotting off the line Find the “expected return” for the level of risk If the anticipated return is greater than the expected return for that level of risk (asset plots above the line), buy asset If return less, plots below the line, sell asset
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Homework Problem 6 –Returns Problem 12 – Variance and Standard Deviation Problem 15 – Portfolio Expected Return Problem 16 – Portfolio Expected Variance and Standard Deviation Problem 24 – SML application Problem 30 – SML application Problem 32 – Combining Assets
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