关于Level I 2015 Notes Book 2 第238页 第二个Example的小疑问。 exchange, forward

ncfanshaopeng

如题，在Level I 2015 Notes Book 2 第238页，有一个Example如下：
The spot ABE/DUB exchange rate is 4.5671, the 90-day riskless ABE rate is 5%, and the 90-day riskless DUB rate is 3%. What is the 90-day forward exchange rate that will prevent arbitrage profits?

它的解是：

forward=4.5671[(1+0.05/4) / (1+0.03/4)]=4.5898.

但是题目是给出90-day的rate，要求90-day的forward exchange rate，它为什么要除以4呢？？ 难道不应该是给出一年的rate，要求90-day的rate，这才要除以4吗？？    用90-day的rate除以4再算这是什么含义呢？？

望大家能够答疑解惑~~

感激不尽！

dyzhang37

题目给出来的都是annualized rate， 而且90天的无风险利率有5%也不太实际

lvjingru

楼主，可以问一个不相干的问题吗。。。你的2015note哪买的啊？谢谢~

rut

all the rate given in the CFA is annualized rate

rut

Sorry not annualized rate(Compound), it is MMY rate, Money market yearly rate(without compound)