返回列表 发帖

Stock A has a standard deviation of 4.1% and Stock B has a standard deviation of 5.8%. If the stocks are perfectly positively correlated, which portfolio weights minimize the portfolio’s standard deviation?

Stock A Stock B

A)
100% 0%
B)
63% 37%
C)
0% 100%



Because there is a perfectly positive correlation, there is no benefit to diversification. Therefore, the investor should put all his money into Stock A (with the lowest standard deviation) to minimize the risk (standard deviation) of the portfolio.

TOP

Adding a stock to a portfolio will reduce the risk of the portfolio if the correlation coefficient is less than which of the following?

A)
0.00.
B)
+1.00.
C)
+0.50.



Adding any stock that is not perfectly correlated with the portfolio (+1) will reduce the risk of the portfolio.

TOP

An investor has a two-stock portfolio (Stocks A and B) with the following characteristics:

  • σA = 55%
  • σB = 85%
  • CovarianceA,B = 0.9
  • WA = 70%
  • WB = 30%

The variance of the portfolio is closest to:

A)
0.39
B)
0.59
C)
0.54



The formula for the variance of a 2-stock portfolio is:

s2 = [WA2σA2 + WB2σB2 + 2WAWBσAσBrA,B]

Since σAσBrA,B = CovA,B, then

s2 = [(0.72 × 0.552) + (0.32 × 0.852) + (2 × 0.7 × 0.3 × 0.9)] = [0.14822 + 0.06502 + 0.378] = 0.59124, or approximately 0.59.

TOP

An investor’s portfolio currently consists of 100% of stocks that have a mean return of 16.5% and an expected variance of 0.0324. The investor plans to diversify slightly by replacing 20% of her portfolio with U.S. Treasury bills that earn 4.75%. Assuming the investor diversifies, what are the expected return and expected standard deviation of the portfolio?

ERPortfolio

σPortfolio

A)

14.15%

14.40%

B)

14.15%

2.59%

C)

10.63%

2.59%




Since Treasury bills (T-bills) are considered risk-free, we know that the standard deviation of this asset and the correlation between T-bills and the other stocks is 0. Thus, we can calculate the portfolio expected return and standard deviation.

Step 1: Calculate the expected return
Expected ReturnPortfolio = (wT-bills × ERT-bills) + (wStocks × ERStocks)
= (0.20) × (0.0475) + (1.00-0.20) × (0.165) = 0.1415, or 14.15%.

Step 2: Calculate the expected standard deviation
When combining a risk-free asset and a risky asset (or portfolio or risky assets), the equation for the standard deviation, σ1,2 = [(w12)(σ12) + (w22)(σ22) + 2w1w2 σ1 σ2ρ1,2]1/2, reduces to: σ1,2 = [(wStocks)(σStocks)] = 0.80 × 0.03241/2 = 0.14400, or 14.40%. (Remember to convert variance to standard deviation).

TOP

Which of the following measures is NOT considered when calculating the risk (variance) of a two-asset portfolio?

A)
Each asset’s standard deviation.
B)
The beta of each asset.
C)
Each asset weight in the portfolio.



The formula for calculating the variance of a two-asset portfolio is:

σp2 = WA2σA2 + WB2σB2 + 2WAWBCov(a,b)

TOP

Assets A (with a variance of 0.25) and B (with a variance of 0.40) are perfectly positively correlated. If an investor creates a portfolio using only these two assets with 40% invested in A, the portfolio standard deviation is closest to:

A)
0.3742.
B)
0.3400.
C)
0.5795.



The portfolio standard deviation = [(0.4)2(0.25) + (0.6)2(0.4) + 2(0.4)(0.6)1(0.25)0.5(0.4)0.5]0.5 = 0.5795

TOP

As the correlation between the returns of two assets becomes lower, the risk reduction potential becomes:

A)
greater.
B)
smaller.
C)
decreased by the same level.



Perfect positive correlation (r = +1) of the returns of two assets offers no risk reduction, whereas perfect negative correlation (r = -1) offers the greatest risk reduction.

TOP

返回列表