Answer: decreased by 8.5%
Explanation:
The beta coefficient of a stock is simply used to measure the volatility of a stock which is relative to the market.
From the question, we are informed that investor's portfolio has a beta coefficient of 0.85 and that the overall market declined by 10% over the course of a year.
Based on the information above, the value of the portfolio would have decreased by:
= 0.85/10
= 0.085
= 8.5%
