很清楚，很有帮助

被误导了所以来纠正，反对黑色忧郁的答案。两者都是以无风险利率为标准。风险溢价是超额收益的期望值。
The difference in any particular period between the actual rate of return on a risky asset and the actual risk-free rate is called the excess return. Therefore, the risk premium is the expected value of the excess return, and the standard deviation of the excess return is a measure of its risk.
摘自Investments_bodie_10th_edition，page129

楼上是正确的