RISK+AND+RETURN+I.ppt
- 1. Chapter 3 – Risk and Return I
- 2. Outline • Portfolios • Announcements, Surprises, and Expected Returns • Risk: Systematic and Unsystematic • Diversification and Portfolio Risk • Systematic Risk and Beta • The Security Market Line
- 3. Portfolios • A portfolio is a collection of assets • An asset’s risk and return is important in how it affects the risk and return of the portfolio • The risk-return trade-off for a portfolio is measured by the portfolio expected return and standard deviation, just as with individual assets
- 4. 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
- 5. 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
- 6. 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
- 7. Systematic Risk • Risk factors that affect a large number of assets • Also known as non-diversifiable risk or market risk • Includes such things as changes in GDP, inflation, interest rates, etc.
- 8. Unsystematic Risk • Risk factors that affect a limited number of assets • Also known as unique risk and asset-specific risk • Includes such things as labor strikes, part shortages, etc.
- 9. Diversification • Portfolio diversification is the investment in several different asset classes or sectors • Diversification is not just holding a lot of assets • Diversification can reduce the variability of returns without a reduction in expected returns • This reduction in risk arises if worse than expected returns from one asset are offset by better than expected returns from another • The risk that cannot be diversified away is called systematic risk
- 10. Diversifiable Risk • The risk that can be eliminated by combining assets into a portfolio • Often considered the same as unsystematic, unique or asset-specific 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
- 11. 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
- 12. Measuring 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
- 13. Total versus Systematic Risk • Consider the following information: Standard Deviation Beta • Security C 20% 1.25 • Security K 30% 0.95 • Which security has more total risk? • Which security has more systematic risk? • Which security should have the higher expected return?
- 14. Example: Portfolio Betas • Consider the following example • Security Weight Beta • DCLK .133 3.69 • KO .2 0.64 • INTC .167 1.64 • KEI .4 1.79 • What is the portfolio beta? • .133(3.69) + .2(.64) + .167(1.64) + .4(1.79) = 1.61
- 15. Beta and the Risk Premium • Remember that the risk premium = expected return – risk-free 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!
- 16. Example: Portfolio Expected Returns and Betas 0% 5% 10% 15% 20% 25% 30% 0 0.5 1 1.5 2 2.5 3 Beta Expected Return Rf E(RA) A
- 17. Reward-to-Risk Ratio: Definition and Example • The reward-to-risk ratio is the slope of the line illustrated in the previous example • Slope = (E(RA) – Rf) / (A – 0) • Reward-to-risk ratio for previous example = (20 – 8) / (1.6 – 0) = 7.5 • What if an asset has a reward-to-risk ratio of 8 (implying that the asset plots above the line)? • What if an asset has a reward-to-risk ratio of 7 (implying that the asset plots below the line)?
- 18. Market Equilibrium • In equilibrium, all assets and portfolios must have the same reward-to-risk ratio and they all must equal the reward-to-risk ratio for the market M f M A f A R R E R R E ) ( ) (
- 19. Security Market Line • The security market line (SML) is the representation of market equilibrium • The slope of the SML is the reward-to-risk 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
- 20. 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
- 21. Factors Affecting Expected Return • Pure time value of money – measured by the risk- free rate • Reward for bearing systematic risk – measured by the market risk premium • Amount of systematic risk – measured by beta