Risk Adjustment in the Capital Budgeting Analysis
The APV model we presented and demonstrated is suitable for use in analyzing a capital
expenditure that is of average riskiness in comparison to the firm as a whole. Some
projects may be more or less risky than average, however. The risk-adjusted discount
method is the standard way to handle this situation. This approach requires adjusting
the discount rate upward or downward for increases or decreases, respectively, in the
systematic risk of the project relative to the firm as a whole. In the APV model presented
in Equation 18.7, only the cash flows discounted at K incorporate systematic
risk; thus, only K needs to be adjusted when project risk differs from that of the firm
as a whole.
A second way to adjust for risk in the APV framework is the certainty equivalent
method. This approach extracts the risk premium from the expected cash flows to convert
them into equivalent riskless cash flows, which are then discounted at the risk-free
rate of interest. This is accomplished by multiplying the risky cash flows by a certainty-equivalent
factor that is unity or less. The more risky the cash flow, the smaller is the
certainty-equivalent factor. In general, cash flows tend to be more risky the further into
the future they are expected to be received. We favor the risk-adjusted discount rate
method over the certainty-equivalent approach because we find that it is easier to adjust
the discount rate than it is to estimate the appropriate certainty-equivalent factors.