Chapter 7 Sources of Risks and Their Determination By Cheng Few Lee Joseph Finnerty John Lee Alice C Lee Donald Wort Chapter Outline • • • • • 2 7.1 RISK CLASSIFICATION AND MEASUREMENT • 7.1.1 Call Risk • 7.1.2 Convertible Risk • 7.1.3 Default Risk • 7.1.4 Interest-Rate Risk • 7.1.5 Management Risk • 7.1.6 Marketability (Liquidity) Risk • 7.1.7 Political Risk • 7.1.8 Purchasing-Power Risk • 7.1.9 Systematic and Unsystematic Risk 7.2 PORTFOLIO ANALYSIS AND APPLICATION • 7.2.1Expected Return on a Portfolio • 7.2.2Variance and Standard Deviation of a Portfolio • 7.2.3The Two-Asset Case • 7.2.4 Asset Allocation among Risk-Free Asset, Corporate Bond, and Equity 7.3 THE EFFICIENT PORTFOLIO AND RISK DIVERSIFICATION • 7.3.1 The efficient Portfolio • 7.3.2 Corporate Application of Diversification • 7.3.3 The Dominance Principle • 7.3.4 Three Performance Measures • 7.3.5 Interrelationship among Three Performance Measure 7.4 DETERMINATION OF COMMERCIAL LENDING RATE 7.5 THE MARKET RATE OF RETURN AND MARKET RISK PREMIUM 7.1 RISK CLASSIFICATION AND MEASUREMENT • • • • • • • • • 3 Call Risk Convertible Risk Default Risk Interest-Rate Risk Management Risk Marketability (Liquidity) Risk Political Risk Purchasing-Power Risk Systematic and Unsystematic Risk Figure 7-1 Probability Distributions Between Securities A and B 4 ( Convertible Risk ) TABLE 7-1 Types of Risk Risk Type Description Call risk The variability of return caused by the repurchase of the security before its stated maturity. Convertible risk The variability of return caused when one type of security is converted into another type of security. Default risk The probability of a return of zero when the issuer of the security is unable to make interest and principal payments—or for equities, the probability that the market price of the stock will go to zero when the firm goes bankrupt. Interest-rate risk The variability of return caused by the movement of interest rates. Management risk The variability of return caused by bad management decisions; this is usually a part of the unsystematic risk of a stock, although it can affect the amount of systematic risk. Marketability risk (Liquidity risk) The variability of return caused by the commissions and price concessions associated with selling an illiquid asset. Political risk The variability of return caused by changes in laws, taxes, or other government actions. Purchasing-power risk The variability of return caused by inflation, which erodes the real value of the return. Systematic risk The variability of a single security’s return caused by the general rise or fall of the entire market. Unsystematic risk The variability of return caused by factors unique to the individual security. 5 Types of Risk (Continued) • • 6 Business risk refers to the degree of fluctuation of net income associated with different types of business operations. This kind of risk is related to different types of business and operating strategies. Financial risk refers to the variability of returns associated with leverage decisions. The question then arises as to how much of the firm should be financed with equity and how much should be financed with debt. 7.2 PORTFOLIO ANALYSIS AND APPLICATION • Expected Return on a Portfolio • Variance and Standard Deviation of a Portfolio • The Two-Asset Case • Asset Allocation among Risk-Free Asset, Corporate Bond, and Equity 7 7.2.1 Expected Return on a Portfolio Portfolio analysis is used to determine the return and risk for these combinations of assets. • The rate of return on a portfolio is simply the weighted average of the returns of individual securities in the portfolio. • R p Wa Ra Wb Rc Wc Rc (0.4)(0.1) (0.3)(0.5) (0.3)(0.12) 0.091 in which Wa ,Wb , andWc are the percentages of the portfolio invested in securities A, B, and C, respectively. 8 7.2.1 Expected Return on a Portfolio n R p RiWi (7.1) i 1 where: n W i 1 i 1 W i the proportion of the individual's investment allocated to security i;and R i the expected rate of return for security i. 9 7.2.2 Variance and Standard Deviation of a Portfolio N Cov (W1 R1 , W2 R2 ) t 1 (W1 R1t W1 R1 )(W2 R2t W2 R2 ) N 1 ( R1t R1 )(R2t R2 ) W1W2 N 1 t 1 W1W2 Cov ( R1 , R2 ) N where: (7.2) R1t t he rat eof ret urnfor t hefirst securit yin periodt ; R2t t he rat eof ret urnfor t hesecondsecurit yin periodt ; R1 and R2 averagerat esof ret urnfor t hedirst securit yand t he secondsecurit y,respect ively; and Cov ( R1 , R2 ) t hecovariancebet ween R1 and R2 . 10 7.2.2 Variance and Standard Deviation of a Portfolio The covariance as indicated in Equation (7.2) can be used to measure the covariability between two securities (or assets) when they are used to formulate a portfolio. With this measure the variance for a portfolio with two securities can be derived: N Var (W1 R1t W2 R2t ) t 1 11 [(W1 R1t W2 R2t ) (W1 R1 W2 R2 )]2 N 1 (7.3) 7.2.2 Variance and Standard Deviation of a Portfolio • The general formula for determining the number of terms that must be computed (NTC) to determine the variance of a portfolio with N securities is N2 N NTC N variances + covariances 2 12 Sample Problem 7.1 Security 1 Security 2 W1 40% W2 60% t 1 R1t 10% t 1 R2t 5% 2 15% 2 10% 3 20% 3 15% R1 10% R1 15% N Var (W1 R1t W2 R2t ) t 1 [(W1 R1t W2 R2t ) (W1 R1 W2 R2 )]2 N 1 [(0.4)(0.1) (0.6)(0.05) (0.4)(0.15) (0.6)(0.1)]2 / 2 [(0.4)(0.1 5) (0.6)(0.1) (0.4)(0.15 ) (0.6)(0.1) ]2 / 2 [(0.4)(0.2 ) (0.6)(0.15 ) (0.4)(0.15 ) (0.6)(0.1) ]2 / 2 (0.07 0.12) 2 (0.12 0.12) 2 (0.17 0.12) 2 2 2 2 Var port folio 0.0025 13 Sample Problem 7.1 14 Sample Problem 7.1 • The riskiness of a portfolio can be measured by the standard deviation of returns as: N p 2 ( R R ) pt p t 1 (7.6) N 1 where p is the standard deviation of the portfolio’s return and Rp is the expected return of the n possible returns. 15 7.2.3 The Two-Asset Case • To explain the fundamental aspect of the riskdiversification process in a portfolio, consider the two-asset case: (7.7) (R R ) N 2 p t 1 pt N 1 N p [W t 1 2 1 ( R1t R1 ) 2 W22 ( R2t R2 ) 2 2W1W2 ( R1t R1 )(R2t R2 )] N 1 W12 Var( R1t ) W22 Var ( R2t ) 2W1W2 Cov( R1 , R2 ) where W1 W2 1 16 7.2.3 The Two-Asset Case By the definitions of correlation coefficients between R1 and R2 , ( 12 ), the Cov( R1 , R2 ) can be rewritten: Cov( R1 , R2 ) 12 1 2 (7.8) Where 1 and 2 are the standard deviations of the first and second security, respectively. • From Equations (7.7) and (7.8), the standard deviation of a two-security portfolio can be defined as • p Var (W1 R1t W2 R2t ) W (1 W1 ) 2W1 (1 W1 ) 12 1 2 2 1 17 2 1 2 2 2 (7.9) Sample Problem 7.2 For securities 1 and 2 used in the previous example, applying Equation (7.9), we get: Security 1 Security 2 12 0.0025 W1 0.4 12 1 22 0.0025 W2 0.6 p (0.4) 2 (0.0025) (0.6) 2 (0.0025) 2(0.4)(0.6)(1)(0.05)(0.05) 0.0025 p 0.05 or Var portfolio = 0.0025, the same answer as for Sample Problem 7.1. 18 Sample Problem 7.2 If 12 = 1.0, Equation (7.6) can be simplified to the linear expression: p W1 1 W2 2 whereW2 (1 W1 ). Since Equation (7.9) is a quadratic equation, some value of W1 minimizes p . To obtain this value, differentiate Equation (7.9) with respect to W1 and set this derivative equal to zero. Then we get: 2 ( 2 12 1 ) W1 2 1 22 2 12 1 2 19 (7.10a) Sample Problem 7.2 If 12 1, Equation (7.10a) reduces from: p W1 [W12 12 (1 W1 ) 2 22 2W1 (1 W1 ) 12 1 2 ] 1 / 2 [2W1 12 2(1 W1 ) 22 2(1 2W1 ) 12 1 2 ] W1 [ 12 22 2 12 1 2 ] [ 12 12 1 2 ] [W12 12 (1 W1 ) 2 22 2W1 (1 W1 ) 12 1 2 ] To 2 ( 2 1 ) 2 W1 ( 2 1 )( 2 1 ) 2 1 20 (7.10b) Sample Problem 7.2 • If12 1 , Equation (7.10a) reduces to: W1 • 2 ( 2 1 ) 2 ( 1 2 )( 1 2 ) ( 2 1 ) However, if the correlation coefficient between 1 and 2 is –1, then the minimum-variance portfolio must be divided equally between security 1 and security 2—that is: 0.05 W1 0.05 0.05 0.5 21 (7.10c) Sample Problem 7.2 As an expanded form of Equation (7.9), a portfolio can be written: p W12 12 2 i 1 i 1 n 1 n j 1 n where: n i 1 WiW j ij i j j i 1 n WiW j Cov( Rit , R jt ) | 1/ 2 (7.11) 1/ 2 Wi andW j theinvestor's investmentallocatedto securityi and security j , respectively; ij thecorrelation coefficient between securityi and security j ; and n the number of securitiesincluded in theportfolio. 22 Sample Problem 7.3 Consider two stocks, A and B:RA 10%, RB 15%, A 4, and B 6. (1) If a riskless portfolio could be formed from A and B, what would be the expected return of R p ? (2) What would the expected return be if AB 0 ? Solution 2 2 2 2 1/ 2 ( W ( 1 W ) 2 W ( 1 W ) ) 1. p A A A B A A AB A B If we let AB 1 p [WA A (1 WA ) B ], p 0 4WA 6(1 WA ) RB WA 3 / 5 So 23 3 2 R p WA RA (1 WA ) RB (10%) (15%) 12% 5 5 Sample Problem 7.3 Solution 2. If we let AB 0 p [WA2 A2 (1 WA ) 2 B2 ]1/2 p 1 [2WA A2 2(1 WA ) B2 (1)][WA2 A2 (1 WA ) 2 B2 ]1/2 0 WA 2 Then, WA A2 (1 WA ) B2 0 WA B2 / ( A2 B2 ) 62 / (42 62 ) 9 /13 9 4 RP (10%) (15%) 11.54% 13 13 24 7.2.4 Asset Allocation among Risk-Free Asset, Corporate Bond, and Equity 25 • The most straightforward way to control the risk of the portfolio is through the fraction of the portfolio invested in Treasury bills and other safe money market securities versus risky assets. • The capital allocation decision is an example of an asset allocation choice — a choice among broad investment classes, rather than among the specific securities within each asset class. • Most investment professionals consider asset allocation as the most important part of portfolio construction. Sample Problem 7.4 • Private fund $500,000 investing in a risk-free asset $100,000, risky equities (E) $240,000, and long-term bonds (B) $160,000. • Current risky portfolio consists 60% of E and 40% of B, and the weight of the risky portfolio in the mutual fund is 80%. 26 Sample Problem 7.4 27 • Suppose the fund manager wishes to decrease risk portfolio from 80% to 70%, then should sell $400,000-0.7 ($500,000)=$50,000 of risky holdings, with the proceed used to purchase more shares in risk-free asset. • To keep the same weights of E and B (60% and 40%)in the risky portfolio, the fund manager should sell • 0.6×50,000=$30,000 in E • 0.4×50,000=$20,000 in B 7.3 THE EFFICIENT PORTFOLIO AND RISK DIVERSIFICATION • The efficient Portfolio • Corporate Application of Diversification • The Dominance Principle • Three Performance Measures • Interrelationship among Three Performance Measure 28 7.3.1 The Efficient Portfolio • Definition: A portfolio is efficient, if there exists no other portfolio having the same expected return at a lower variance of returns, or, if no other portfolio has a higher expected return as the same risk of returns. • This suggests that given two investments, A and B, investment A will be preferred to B if: E (A) E (B) and Var A Var B or E (A) E (B) and Var A Var B Where E(A) and E(B) = the expected returns of A and B, Var(A) and Var(B) = their respective variances or risk. 29 7.3.1 The efficient Portfolio 30 Sample Problem 7.5 • Monthly rates of return for April, 2001 to April, 2010 for Johnson & Johnson (JNJ) and IBM are used as examples. The basic statistical estimates for these two firms are average monthly rates of return and the variance-covariance matrix.in Table 7.3: Variance-Covariance Matrix 31 JNJ IBM JNJ 0.0025 0.0007 IBM 0.0007 0.0071 Sample Problem 7.5 From Equation (7.10), we have: 0.0071 .0007 0.0064 0.5818 0.0025 0.0071 2(0.0007) 0.011 W2 1.0 0.5818 0.4182 W1 Using the weight estimates and Equations (7.2) and (7.3): E ( RP ) (0.5818)(0.0080) (0.4182)(0.0050) 0.0067454 P2 (0.5818)2 (0.0025) (0.4182) 2 (0.0071) 2(0.5818)(0.4182)(0.0007) 0.0024 P 0.0493 When 12 is less than 1.00 it indicates that the combination of the two securities will result in a total risk less than their added respective risks. 32 7.3.2 Corporate Application of Diversification 33 • The effect of diversification is not necessarily limited to securities but may have wider applications at the corporate level. • Instead of “putting all the eggs in one basket,” the investment risks are spread out among many lines of services or products in hope of reducing the overall risks involved and maximizing returns. • The overall goal is to reduce business risk fluctuations of net income. 7.3.3 The Dominance Principle • The dominance principle has been developed as a means of conceptually understanding the risk/return tradeoff. • As with the efficient-frontier analysis, we must assume an investor prefers returns and dislikes risks. 34 7.3.4 Three Performance Measures The Sharpe measure (SP) (Sharpe, 1966) is of immediate concern. Given two of the portfolios depicted in Figure 7.4, portfolios B and D, their relative risk-return performance can be compared using the equations: SP D RD R f D and SP B RB R f B where SP D , SP B Sharpe performanc e measures; RD , RB theaveragereturnof each portfolio; R f risk - free rate;and D , B therespectivestandarddeviationon risk of each portfolio. 35 Sharpe measure (SP) If a riskless rate exists, then all investors would prefer A to B because combinations of A and the riskless asset give higher returns for the same level of risk than combinations of the riskless asset and B. 36 Sample Problem 7.6 Table 7.4 Smyth Fund Jones Fund Average return R (%) 18 16 Standard deviation (%) 20 15 Risk-free rate R f (%) 9.5 Using the Sharpe performance measure, the risk-return measurements for these two firms are: 0.18 0.095 SPSmyth 0.425 0.20 0.16 0.095 SP Jones 0.433 0.15 Jones fund has better performance based on Sharpe measure. 37 Sample Problem 7.7 The performances of portfolios A-E shown in Table 7.5. Portfolio Return (%) Risk (%) A 50 50 B 19 15 C 12 9 D 9 5 E 8.5 1 R Rf By using Sharpe measure SP M , assume risk-free rate is 8%, the rank of M portfolios is A>B>E>C>D: SPA 0.84,SPB 0.73,SPC 0.44,SPD 0.20,SPE 0.50 Protfolio A is the most desirable. However, for risk-free rate 5%, the order changes to E>B>A>D>C: SPA 0.90,SPB 0.933,SPC 0.77,SPD 0.80,SPE 0.35 Now E is the best portfolio. 38 Treynor measure (TP) Treynor measure (TP), developed by Treynor in 1965, examines differential return when beta is the risk measure. The Treynor measure can be expressed by the following: • TP Rj Rf j (7.13) where: R j average return of jth portfolio; R f risk free rate; and j beta coefficient for jth portfolio. • 39 The Treynor performance measure uses the beta coefficient (systematic risk) instead of total risk for the portfolio as a risk measure. Jensen’s measure (JM) • Jensen (1968, 1969) has proposed a measure referred to as the Jensen differential performance index (Jensen’s measure or JM). • JM is the differential return which can be viewed as the difference in return earned by the portfolio compared to the return that the capital asset pricing line implies should be earned. • CAPM: • • 40 RP R f (RM R f ) P JM RP [R f (RM R f ) p ] (7.14) (7.15) Sample Problem 7.8 Portfolio Ri (%) i (%) A 50 50 2.5 B 19 15 2.0 C 12 9 1.5 D 9 5 1.0 E 8.5 1 0.25 Rank portfolios based on JM: JM ( Ri R f ) i ( RM R f ) (1)When RM=10% and Rf=8%, JM A 37 %,JM B 7 %,JM C 1%,JM D 2 %,JM E 0 % A>B>C>E>D (2)When RM=12% and Rf=8%, JM A 32%,JM B 3 %,JM C 2 %,JM D 3 %,JM E 0.5 % A>B>E>C>D 41 Sample Problem 7.8 Portfolio Ri (%) i (%) A 50 50 2.5 B 19 15 2.0 C 12 9 1.5 D 9 5 1.0 E 8.5 1 0.25 Rank portfolios based on JM: JM ( Ri R f ) i ( RM R f ) (3)When RM=8% and Rf=8%, JM A 42%,JM B 11 %,JM C 4 %,JM D 1 %,JM E 0.5 % A>B>C>D>E (4)When RM=12% and Rf=4%, JM A 26 %,JM B 1 %,JM C 4 %,JM D 3 %,JM E 2.5 % A>E>B>D>C 42 Since 7.3.5 Interrelationship among Three Performance Measure Since p pm / m2 and pm pm / p m The JM must be multiplied by equivalent SM: JM P 1/𝜎𝑃 in order to derive the [ RP R f ] [ RM R f ] ( pm ) P m m p [ RP R f ] [ RM R f ] SPP SPm P m (7.16) (7.17) (commom constant) If the JM divided by 𝛽𝑃 ,it is equivalent to the TM plus some constant common to all portfolios: JM [ RP R f ] [ RM R f ] P (7.18) P P P TM P [ RM R f ] TM P commom constant 43 Sample Problem 7.9 Continuing with the example used for the Sharpe performance measure in Sample Problem 7.6, assume that in addition to the information already provided the market return is 10 percent, the beta of the Smyth Fund is 0.8, and the Jones Fund beta is 1.1. Then, according to the capital asset pricing line, the implied return earned should be: RSmyth 0.095 (0.10 0.095)(0.8) 0.099 RJones 0.095 (0.10 0.095)(1.1) 0.1005 Using the Jensen measure, the risk-return measurements for these two firms are: JM Smyth 0.18 0.099) 0.081 JM Jones 0.16 0.1005 0.0595 44 7.4 Determination of Commercial Lending Rate Based upon the mean and variance Equations (7.1) and (7.2) it is possible to calculate the expected lending rate and its variance. Using the information provided in Table 7.8, the weighted average and the standard deviation can be calculated: (A) (B) (C) (D) ( B D ) (A+C) Economic Conditions Boom Rf (%) 12 Probability 0.25 Normal 10 0.50 Poor 8 0.25 Rp (%) 3.0 5.0 8.0 3.0 5.0 8.0 3.0 5.0 8.0 Probability 0.40 0.30 0.30 0.40 0.30 0.30 0.40 0.30 0.30 Joint Lending Probability Rate of Occurrence (%) 0.100 15 0.075 17 0.075 20 0.200 13 0.150 15 0.150 18 0.100 11 0.075 13 0.075 16 R (0.100)(15%) (0.075)(17%) (0.075)(20%) (0.200)(13%) (0.150)(15%) (0.150)(18%) (0.100)(11%) (0.075)(13%) (0.075)(16%) 15.1% [(0.100)(15 15.1) 2 (0.075)(17 15.1) 2 (0.075)(20 15.1) 2 (0.200)(13 15.1) 2 (0.150)(15 15.1) 2 (0.150)(18 15.1) 2 (0.100)(11 15.1) 2 (0.075)(13 15.1) 2 (0.075)(16 15.1) 2 ]1/2 2.51% 45 According to lending rates in Table 7.8 The weighted average and the standard deviation are: R 15.1%, 2.51% 46 7.5 The Market Rate Of Return And Market Risk Premium • • The market rate of return is the return that can be expected from the market portfolio. The market rate of return can be calculated using one of several types of market indicator series, such as the Dow-Jones Industrial Average or the Standard and Poor (S&P) 500 by using the following equation: I t I t 1 Rmt I t 1 where: Rmt marketrateof returnat timet; I t marketindex at t; and I t 1 marketindex at t 1. 47 (7.19) 7.5 The Market Rate Of Return And Market Risk Premium 48 • A risk-free investment is one in which the investor is sure about the timing and amount of income streams arising from that investment. • The reasonable investor dislikes risks and uncertainty and would, therefore, require an additional return on his investment to compensate for this uncertainty. This return, called the risk premium, is added to the nominal risk-free rate. • Table 7.9 illustrates the concept of risk premium by using the market rate of return of S&P 500 index. 7.5 The Market Rate Of Return And Market Risk Premium TABLE 7.9 Market Returns and T-bill by Quarters Quarter S&P 500 (A) Market Return (percent) (B) T-Bill Rate (percent) (A)-(B) Risk Premium (percent) 1980 IV 135.76 1981 49 I 136.00 + 0.18 13.36 -13.18 II 131.21 - 3.52 14.73 -18.25 III 116.18 -12.94 14.70 -27.64 IV 122.55 + 5.48 10.85 - 5.37 7.5 The Market Rate Of Return And Market Risk Premium TABLE 7.9 Market Returns and T-bill by Quarters (Continued) S&P 500 (A) Market Return (percent) (B) T-Bill Rate (percent) (A)-(B) Risk Premium (percent) I 152.96 + 8.76 8.35 0.41 II 168.11 + 9.90 8.79 1.11 III 166.07 - 1.22 9.00 -10.22 IV 164.93 - 0.69 9.00 - 9.69 I 159.18 - 3.49 9.52 -13.01 II 153.18 - 3.77 9.87 -13.64 III 166.10 + 8.43 10.37 - 1.94 IV 167.24 + 0.68 8.06 - 7.37 Quarter 1983 1984 50 7.5 The Market Rate Of Return And Market Risk Premium TABLE 7.9 Market Returns and T-bill by Quarters (Continued) S&P 500 (A) Market Return (percent) (B) T-Bill Rate (percent) (A)-(B) Risk Premium (percent) I 180.66 + 8.02 8.52 - 0.50 II 188.89 + 4.55 6.95 - 2.4 III 184.06 - 2.62 7.10 - 9.72 IV 207.26 +12.60 7.07 + 5.53 I 232.33 +12.09 6.56 + 5.53 II 245.30 + 5.58 6.21 - 0.63 III 238.27 - 2.86 5.21 - 8.07 IV 248.61 + 4.33 5.43 - 1.10 Quarter 1985 1986 51 7.5 The Market Rate Of Return And Market Risk Premium TABLE 7.9 Market Returns and T-bill by Quarters (Continued) S&P 500 (A) Market Return (percent) (B) T-Bill Rate (percent) (A)-(B) Risk Premium (percent) I 292.47 +17.64 5.59 +12.05 II 301.36 + 3.03 5.69 - 2.66 III 318.66 + 5.74 6.40 + 0.05 IV 240.96 -24.38 5.77 -30.10 Quarter 1987 52 7.6 SUMMARY This chapter has defined the basic concepts of risk and risk measurement. The efficient-portfolio concept and its implementation was demonstrated using the relationships of risk and return. The dominance principle and performance measures were also discussed and illustrated. Finally, the interest rate and market rate of return were used as measurements to show how the commercial lending rate and the market risk premium can be calculated. Overall, this chapter has introduced uncertainty analysis assuming previous exposure to certainty concepts. Further application of the concepts discussed in this chapter as related to security analysis and portfolio management are explored in later chapters. 53