Does a stable growth rate have to be constant over time?
The assumption that the growth rate in dividends has to be constant over time is a
difficult assumption to meet, especially given the volatility of earnings. If a firm has an
average growth rate that is close to a stable growth rate, the model can be used with little real
effect on value. Thus, a cyclical firm that can be expected to have year-to-year swings in
growth rates, but has an average growth rate that is 5%, can be valued using the Gordon
growth model, without a significant loss of generality. There are two reasons for this result.
First, since dividends are smoothed even when earnings are volatile, they are less likely to be
affected by year-to-year changes in earnings growth. Second, the mathematical effects of
using an average growth rate rather than a constant growth rate are small