问题如下：
With any other factors remaining unchanged, which of the following statements regarding bonds is not valid?
选项：
A. The
price of a callable bond increases when interest rates increase.
B. Issuance
of a callable bond is equivalent to a short position in a straight bond plus a
long call option on the bond price.
C. The
put feature in a puttable bond lowers its yield compared with the yield of an
equivalent straight bond.
D. The
price of an inverse floater decreases as interest rates increase.
解释：
ANSWER: A
Answer B is valid because a short position in a callable bond is the same as a short position in a straight bond plus a long position in a call (the issuer can call the bond back). Answer C is valid because a put is favorable for the investor, so it lowers the yield. Answer D is valid because an inverse floater has high duration.
逆浮动的久期为什么更长？？？？？
