CMLSML wrote:
Does not make any sense. Risk-free rate is dependent on the investment horizon (e.g. t-bill vs. t-bonds) while the conjecture is that the growth rate is in perpetuity.
Risk-free rate is dependent on time horizon, but the farther out the yield curve you go, the less the change in rate. Additionally, on average with a flat yield curve, the 10-yr and 30-yr rate will be approximately equal. Think about which risk-free rate is used to calculate cost of equity (a source of capital with an infitinite horizon). It is common to use the 10-year treasury bond. While the 30-year bond will give a better estimate of the risk-free rate for an infinite horizon, the 30-year bond is relatively illiquid and will not as accurately reflect market perceptions.
The rational for using the risk-free rate as the long-term growth rate of the economy for modeling is similar. While the estimate is of a perpetuity growth rate, the 10-year rate is probably a reasonable estimate. More importantly, the rate should match the risk-free rate used in the cost of equity. If the 30-year rate is used as an estimate of long-term growth rate, that rate will (currently) be higher than if the 10-year rate is used, increasing the valuation. However, if the same 30-year rate is used as the risk-free rate for cost of equity, WACC will be higher which will offset the increase in the assumed growth rate.
This also addresses the issue of differing risk-free rates in different economic environments. In the 1980’s, using the risk-free rate would result in a very high long-term growth rate. However, the same risk-free rate is used to calculate the cost of equity, increasing WACC and counteracting the high long-term growth rate. Also, embedded in this rate is expected inflation, so it is reasonable to assume that the company will also grow at this rate unless an explicit assumption is made that inflation decreases to a normalized level. However, if this assumption is made, WACC will also have to be adjusted, counteracting the assumption.