In: Finance
Consider a portfolio with three assets E[rA]=10% E[rB]=12% E[rC]=8%; σA2 =0.008 σB2 =0.010 σC2 =0.005; ρA,B =0.2 ρB,C = 0.0 ρA,C = −0.2
a) Consider the portfolio weights xA = 0.3 and xB = 0.3. Calculate the portfolio weight xC , the expected portfolio return, and the variance of the portfolio returns.
b) Consider the portfolio weights xA = 0.3. Calculate the expected portfolio return as a function of xB
c) Consider the portfolio weights xA = 0.3. Calculate the portfolio return variance as a function of xB
d) Calculate the portfolio which has the smallest variance, for which xA = 0.3.
a) | Total Weight =1 | |||||||||||
XA+XB+XC=1 | ||||||||||||
0.3+0.3+Xc=1 | ||||||||||||
Xc=1-0.3-0.3=0.4 | ||||||||||||
W | R | W*R | ||||||||||
Weight | Return(%) | Weight*Return | ||||||||||
StockA | 0.3 | 10 | 3 | |||||||||
StockB | 0.3 | 12 | 3.6 | |||||||||
StockC | 0.4 | 8 | 3.2 | |||||||||
SUM | 9.8 | |||||||||||
Expected PortfolioReturn | 9.80% | |||||||||||
Expected Portfolio variance: | ||||||||||||
(XA^2)*(VarianceA)+(XB^2)*(VarianceB)+(XC^2)*(VarianceC)+2XA*XB*CovarianceA,B+2XA*XC*Covaraince,A,C+2XB*XC*Covariane,B,C | ||||||||||||
XA=0.3, XB=0.3, XC=0.4 | ||||||||||||
Variance A=0.008 | ||||||||||||
Variance B=0.01 | ||||||||||||
Variance C=0.005 | ||||||||||||
Covariance A,B=0.2*SQRT (0.008*0.01) | 0.001789 | |||||||||||
Covariance A,C=-0.2*SQRT (0.008*0.005) | -0.00126 | |||||||||||
Covariance B,C= | 0 | |||||||||||
Expected Portfolio variance: | ||||||||||||
(0.3^2)*(0.008)+(0.3^2)*(0.01)+(0.4^2)*(0.005)+2*0.3*0.3*0.001789+2*0.3*0.4*(-0.00126) | ||||||||||||
Expected Variance of the portfolio Return | 0.00244 | |||||||||||
Expected Standard Deviation of the portfolio | 0.049393 | (SQRT (0.00244) | ||||||||||
b. | ||||||||||||
XA=0.3 | ||||||||||||
XC=1-XA-XB=1-0.3-XB=0.7-XB | ||||||||||||
RP=Expected Portfolio Return (Percentage) | ||||||||||||
XA*10+XB*12+XC*8 | ||||||||||||
0.3*10+XB*12+(0.7-XB)*8 | ||||||||||||
RP=3+12XB+5.6-8XB | ||||||||||||
RP=4XB+8.6 | ||||||||||||
RP=Expected Portfolio Return (Percentage) | ||||||||||||
XB=Weight of StockB in the portfolio | ||||||||||||
VP=Portfolio Variance: | ||||||||||||
(XA^2)*(VarianceA)+(XB^2)*(VarianceB)+(XC^2)*(VarianceC)+2XA*XB*CovarianceA,B+2XA*XC*Covaraince,A,C+2XB*XC*Covariane,B,C | ||||||||||||
XA=0.3,XC=0.7-XB | ||||||||||||
Variance A=0.008 | ||||||||||||
Variance B=0.01 | ||||||||||||
Variance C=0.005 | ||||||||||||
Covariance A,B=0.2*SQRT (0.008*0.01) | 0.001789 | |||||||||||
Covariance A,C=-0.2*SQRT (0.008*0.005) | -0.00126 | |||||||||||
Covariance B,C= | 0 | |||||||||||
VP=Portfolio Variance: | ||||||||||||
(0.3^2)*(0.008)+(XB^2)*(0.01)+((0.7-XB)^2)*(0.005)+2*0.3*XB*0.001789+2*0.3*(0.7-XB)*(-0.00126) | ||||||||||||
Vp=Portfolio Variance=0.00072+0.01*(XB^2)+(0.49+(XB^2)-1.4XB)*0.005+0.001073XB-0.00053-0.00076XB | ||||||||||||
Vp=Portfolio Variance=0.00072+0.01*(XB^2)+0.00245+(XB^2)*0.005-0.007XB+0.001073XB-0.00053-0.00076XB | ||||||||||||
Vp=Portfolio Variance=0.015(XB^2)-0.00669XB+0.00264 | ||||||||||||
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