问题如下：
With respect to capital market theory, which of the following assumptions allows for the existence of the market portfolio? All investors:
选项：
A.are price takers.
B.have homogeneous expectations.
C.plan for the same, single holding period.
解释：
B is correct.
The homogeneous expectations assumption means that all investors analyze securities in the same way and are rational. That is, they use the same probability distributions, use the same inputs for future cash flows, and arrive at the same valuations. Because their valuation of all assets is identical, they will generate the same optimal risky portfolio, which is the market portfolio.
为什么不选C呢？何老师上课说相同一期holding period也是CAPM CML的共同点呀
