slippage cost定义是什么？并请详细解释~

NO.PZ201809170400000503问题如下 Whifunin Exhibit 1 most likely hthe greatest implicit costs to implement its strategy? A.Fun1B.Fun2C.Fun3 A is correct. Because Fun1 ha large AUM but focuses on small-cstocks, hol a relatively small number of securities in its portfolio, anprefers to make large tras, Fun1 likely hthe highest implicit costs. Eaof these characteristiserves to increase the market impaof its tras. Market impais a function of the security’s liquity antra size. The larger a tra size relative to a stock’s average ily volume, the more likely it is ththe tra will affeprices. The relatively low level of trang volume of small-cstocks ca significant implementation hure for a manager running a strategy with significant assets unr management ansignificant positive active weights on smaller companies. 最后一句提到 fun3 prefer 大单交易。本身small cap流动性就要低一些，大单交易不是会有slippage cost吗

NO.PZ201809170400000503问题如下 Whifunin Exhibit 1 most likely hthe greatest implicit costs to implement its strategy? A.Fun1 B.Fun2 C.Fun3 A is correct. Because Fun1 ha large AUM but focuses on small-cstocks, hol a relatively small number of securities in its portfolio, anprefers to make large tras, Fun1 likely hthe highest implicit costs. Eaof these characteristiserves to increase the market impaof its tras. Market impais a function of the security’s liquity antra size. The larger a tra size relative to a stock’s average ily volume, the more likely it is ththe tra will affeprices. The relatively low level of trang volume of small-cstocks ca significant implementation hure for a manager running a strategy with significant assets unr management ansignificant positive active weights on smaller companies. 老师，这道题我定位在“fun2 buil up its positions slowly\",所以我认为fun很大可能有slippage cost，请问这样想哪里错了？

NO.PZ201809170400000503 Fun2 虽然是大盘股，但是他建仓也慢，为什么不选Fun2

fun为什么不对？