2020 mock exam（A）第40题
Statement 1 The effective convexity of a putable bond cannot be less than that
of an otherwise identical option-free bond.
Statement 2 The effective convexity of a callable bond can be negative in some
circumstances, but the effective convexity of a putable bond is
always positive.
Statement 3 The effective duration of a callable bond cannot be greater than
that of an otherwise identical option-free bond, and the effective
duration of a putable bond cannot be less than that of the option
free bond.
Which of the statements made by the Klang Analytics developer is most likely
correct?
答案是Statement 2
我知道Statement 2是正确的，不明白为什么Statement 1是错的，putable bond的effective convexity在利率上升价格下降时是比普通债权more convexity的呀
