Capital Budgeting under Risk and Uncertainties^159
that is acceptable to management. This is quite understandable. If the profitability index
is high, one profitability that the net present value is negative (profitability index is less
than 1) is negligible even if the dispersion is wide.
Risk Adjusted Discount Rate Method
The risk adjusted discount rate method calls for adjusting the discount rate to reflect
project risk. If the risk of the project is equal to the risk of the existing investments of
the firm, the discount rate used is the average cost of capital of the firm, if the risk of
the project is greater than the risk of the existing investments of the firm, the discount
rate used is higher than the average cost of capital of the firm; if the risk of the project
is less than the risk of the existing investment of the firm the discount rate used is less
than the average cost of capital of the firm. The risk adjusted discount rate is :
rk = i + n + dk
where rk = risk-adjusted discount rate for project k
i = risk-free rate of interest
n = adjustment for the firmís normal risk
dk = adjustment for the differential risk of project k
It may be noted that (1 + n) measures the firmís cost of capital dk may be positive or
negative depending on how the risk of the project under consideration compares with
the existing risk of the firm.
The adjustment for the differential risk of project, k quite understandably, depends on
managementís perception of the project risk and managementís attitude towards towards
risk (risk return preference). A large pharmaceutical concern, for example, uses the
following riskadjusted discount for various types of investments.
Investment category Risk-adjusted discount rate
Replacement investments Cost of capital
Expansion investments Cost of capital + 3%
Investment in related lines Cost of capital + 6%
Investment in new lines Cost of capital + 10%
Once the projectís risk-adjusted discount rate (rk) is specified, the project is accepted
if its net present value, calculated as follows, is positive.
NPV =
A
rk
t
t
t
n
( 1 )
1
1 +
- =
I ...(8.7)
where NPV = net present value of project k