One year ago, Matt bought 100 shares of ABC Corp. stock for $5.619 including commission. He is about to sell the ABG stock for $6.528 net of commissions. When he made the purchase the S&P 500 index was at 907; now it is 1070. The beta of ACE stock is 0.98, and the market's risk-free rate is 4.0%. No dividends were paid. a. Evaluate the role of portfolio revision in the process of managing a portfolio.