Final answer:
To achieve their desired expected returns, Bart, Lisa, and Maggie must allocate 87%, 65%, and 43% of their portfolios to the equity portfolio, respectively. Their resulting portfolio betas would be approximately 1.11 for Bart, 0.96 for Lisa, and 0.86 for Maggie.
Step-by-step explanation:
To determine the combination of the two assets that will give the desired expected return for Bart, Lisa, and Maggie, we use the following formula to find the weight (w) of the equity portfolio in each combination:
Desired return = w * Return on equity + (1 - w) * Return on bonds
For Bart:
15% = w * 15.8% + (1 - w) * 7.1%
w = (15% - 7.1%) / (15.8% - 7.1%)
w ≈ 0.87 (87% in equity, 13% in bonds)
For Lisa:
13% = w * 15.8% + (1 - w) * 7.1%
w = (13% - 7.1%) / (15.8% - 7.1%)
w ≈ 0.65 (65% in equity, 35% in bonds)
For Maggie:
11% = w * 15.8% + (1 - w) * 7.1%
w = (11% - 7.1%) / (15.8% - 7.1%)
w ≈ 0.43 (43% in equity, 57% in bonds)
To find each investor's beta, we apply the formula:
Beta of combination = w * Beta of equity + (1 - w) * Beta of bond
Using the weights calculated above, we get:
- Bart's beta ≈ 0.87 * 1.2 + 0.13 * 0.6 ≈ 1.11
- Lisa's beta ≈ 0.65 * 1.2 + 0.35 * 0.6 ≈ 0.96
- Maggie's beta ≈ 0.43 * 1.2 + 0.57 * 0.6 ≈ 0.86
Therefore, each investor can adjust their portfolio allocation to achieve their desired expected return and associated beta.