Andrew wants to invest in two securities Alpha and Omega and
Andrew wants to invest in two securities, Alpha and Omega, and the relevant information is below:
State of the Economy
Probability
Return on Alpha (%)
Return on Omega (%)
Bear
0.25
-15%
4%
Moderate
0.5
5%
4%
Bull
0.25
20%
4%
Calculate expected returns and standard deviations of two securities.
Andrew shorts $1,000 of Omega and invests all proceeds from this short sale as well as $3,000 of her own money into Alpha. What is the expected return and the standard deviation of her portfolio?
| State of the Economy | Probability | Return on Alpha (%) | Return on Omega (%) |
| Bear | 0.25 | -15% | 4% |
| Moderate | 0.5 | 5% | 4% |
| Bull | 0.25 | 20% | 4% |
Solution
Expected return on Alpha = 3.75%
Standard dev = 12.44%
Expected return on Omega = 4%
Standard dev = 0%
weight of Omega = -1000/3000 = =1/3
weight of Alpha = 4/3
expected return = 4/3*3.75% - 1/3*4% = 3.67%
standard dev = 4/3 * 12.44% = 16.59%
| p(x) | return | p*x | p*(x - mean)^2 |
| 0.25 | -15% | -0.0375 | 0.0087891 |
| 0.5 | 5% | 0.025 | 0.0000781 |
| 0.25 | 20% | 0.05 | 0.0066016 |

