An investment manager at TD Ameritrade is making a decision about a $10,000,000 investment. There are four portfolio options available and she is looking at annual return of these portfolios to choose one. Market has four possible situations: bad, average, good, and excellent. Each portfolio may have a different estimated rate of return under a known market situation. For "Bad", "Average", "Good", and "Excellent" market, "Option 1" has return rates of 33%, 28%, 1%, and loss of 15% respectively. These numbers are 22%, 12%, 17%, and loss of 5% for "Option 2", 8%, 9%, 14%, and 16% for "Option 3", and finally for "Option 4" these rates are loss of 2%, 5%, 12%, and 35% under "Bad", "Average", "Good", and "Excellent" market situations.
a. Compare the outcomes for all portfolios under any market situation. What is the best portfolio under Minimax Regret rule?
b. Does the outcome change if the investment decision was made based on the expected value of portfolios? Why? Probabilities for bad, average, good, and excellent market situations are 35%, 22%, 25%, and 18% respectively.