Exam CFA® Level 2 topic 1 question 486 discussion

Samuel Edson, CFA, portfolio manager for Driver Associates, employs a multifactor model to evaluate individual stocks and portfolios. Edson examines several possible risk factors and finds two that are priced in the marketplace. These two factors are investor sentiment (IS) risk and business cycle (BC) risk. Edson manages three equity portfolios (A, Bt and Q and derives the following relationships for each portfolio, as well as for the S&P 500 stock market index:

Portfolios A and B are well-diversified, while C is a less than fully diversified, value-oriented portfolio. FJS is the surprise in investor sentiment, and FBC is the surprise in the business cycle. Surprises in the risk factors are defined as the difference between the actual value and the predicted value.
Exhibit 1 provides data for the actual and predicted values for the investor sentiment and business cycle risk factors.

Driver Associates uses a two-factor Arbitrage Pricing Model to develop equilibrium expected returns for individual stocks and portfolios:

Valry is concerned that the economy did not perform as originally predicted by Driver Associates. She informs Edson that the returns for all the portfolios will likely differ from their expected returns. Use the multifactor equation (1) and the data provided in Exhibit 1 to find the revised returns for Portfolio A.