问题如下：
The KMV model produces a measure called expected default frequency. Which of the following statements about this variable is correct?
选项： It
decreases when the leverage of the firm falls.
It increases when the stock price of the firm has been rising.
C.It is the risk-neutral probability of default from Merton’s model.
D.It tells investors how the default risk of a bond is correlated with the default risk of other bonds in the portfolio
解释：
ANSWER: A
The EDF, similarly to the risk-neutral PD, decreases when the stock price goes up, when the leverage goes down, or when the volatility goes down. It is a transformation of the PD from a Merton-type model. The KMV framework can be extended to finding correlations, but the EDF is not sufficient.
为什么当stock price goes up，or leverage goes down时，dd会下降？
