问题如下：
3. In the current interest rate environment, using a required return estimate based on the short-term government bond rate and a historical equity riskpremium defined in terms of a short-term government bond rate would be expected to:
选项：
A.bias long-term required return on equity estimates upwards.
B.bias long-term required return on equity estimates downwards.
C.have no effect on long-term required return on equity estimates.
解释：
A is correct.
The required return reflects the magnitude of the historical equity risk premium, which is generally higher when based on a short-term interest rate (as a result of the normal upward sloping yield curve), and the current value of the rate being used to represent the risk-free rate. The short-term rate is currently higher than the long-term rate, which will also increase the required return estimate. The short-term interest rate, however, overstates the long-term expected inflation rate. Using the short-term interest rate, estimates of the long-term required return on equity will be biased upwards.
re=rf+beta(rm-rf)
1、当前利率曲线是inverted,说明短期利率大于长期利率，因此公式第一项rf较大。----- 为什么这个rf 用现在的数据？
2、rm-rf用历史ERP，历史上利率曲线是normal形态-upward sloping（短期小于长期），因此rm-r-----f较大为什么这个rf 用历史的数据？
综上，用当前rf和历史ERP，会高估re
