[求助] 关于CFA level I Notes里的Binomial Tree Factor的算法

himawari

今天在看notes book 1 page 187的时候,讲到binominal tree, 他说over the next period, the stock price will either increase by 1% or decrease by 1%. 然后就说所以the up-move facor U=1.01, the down-move factor D=1/1.01. 可是在学校以前上课学binomial tree的时候, 如果stock会decrease in value by 1%,好像是说down-move factor = 99%的...是CFA的算法不同还是Notes写错了? 

之所以会这么问是听有人说过Notes里面有可能有些小知识点会写错,所以想上来问问前辈们,以免在考试时白白丢分~ 

请高手指教~~谢谢~

himawari

那么down-move  factor就应该是1/1.01? 可是如果stock price会decrease by 1% over the next period，下一个period的价钱不是应该是现在的价钱*(1-0.01) = 99%么？@_@