27) Assume that Widget Repair Corporation provides services to 100 customers whose decision
to change suppliers is uncorrelated. The portfolio effect suggests that the entrepreneur/owner of
Widget, who is compensated on the basis of the firm’s profits, may have lower cash-flow risk
than a clerk who works full-time for Widget on a fixed salary.
28) Insurance companies take advantage of the portfolio effect by insuring many different
homeowners against loss. However, the risks of loss for individual homes in hurricane-prone or
earthquake-prone areas such as Florida and California are highly correlated. This suggests that
insurance companies should avoid writing (or consider canceling) some customers’ policies in
Florida and California, even when the policies are both needed by homeowners and expected to
be highly profitable to the insurer.
29) When choosing portfolios of assets, management should try to achieve the highest possible
return at a given level of risk.