为什么考虑交易成本可能会阻碍基金经理将投资组合重新调整到最佳水平

问题如下：

There are several statements with respect to considering transactions costs in the portfolio construction process :

I.      considering transactions costs may hinder manager from rebalancing the portfolio to the optimum level.
II.     the transactions costs usually occur at a specific point in time.

III.    managers need to specify rules to regulate how transaction costs are amortized over the benefit time period.

Which of the following is correct :

选项：

A.

None.

B.

Only II.

C.

Both I and II.

D.

All.

解释：

D is correct.

考点：transactions cost

解析：statement I 说法正确，考虑交易成本可能会阻碍基金经理将投资组合重新调整到最佳水平。

statement II 说法正确，交易成本通常发生在特定的时间点。

statement III 说法正确，基金经理需要制定规则来明确交易成本在受益时间段内的摊销方式。所以，选项D正确。