願聞其詳

前者是指预期值，后者也许是实际值。

In corporate finance, the cost of equity is the return (often expressed as a rate of return) a firm theoretically pays to its equity investors, i.e., shareholders, to compensate for the risk they undertake by investing their capital.
the return on equity (ROE) is a measure of the profitability of a business in relation to the book value of shareholder equity, also known as net assets or assets minus liabilities.
简单来讲，股权资本成本就是公司以权益方式融资所需要股东创造的最低回报率，而Equity return是净资产回报，是企业实际的收益问题，后者度量方式为净利润除以净资产。前者的计算方式非常复杂，分为事前和事后的股权资本成本。