NO.PZ2020033002000034
问题如下：
Grapefruit Bank issued two semi-annual interest-bearing credit bonds, of which bond A matures after half a year, the coupon rate is 8.5%, the current price is $ 98, and the corresponding half-year T-bill interest rate is 4.5%. The bond B expires after one year, the coupon rate is 10%, the current price is $ 101, and the corresponding one-year T-bill rate is 5%. Assuming that their recovery rates are all 40%, and they will only default on the coupon payment date, which of the following statements is correct?
选项：
A.The market implied risk-neutral default probability in the first half of the year is higher than that in the second half.
B.The market implied risk-neutral default probability in the first half of the year is lower than that in the second half.C.The market implied risk-neutral default probability is equal in the first half and the second half.
D.
The market implied risk-neutral default probability in the first half and the second half cannot be compared.
解释：
A is correct.
考点：Spread Risk-DVCS and Credit Spread Curve
解析：由bondA可以得出：98=\frac{104.25}{1+{\displaystyle\frac y2}}，解出半年期bond收益率y=12.755%，那么半年期的spread就是12.755%-4.5%=8.255%。
同理得到债券B：一年期bond的收益率y=8.93%，那么一年期的spread就是8.93%-5%=3.93%。当recovery rate是一样的时候，那前半年的违约概率肯定是高于后半年的。
算法都会，结合答案的描述，没有理解这个情景。
发行了两个债券，都是半年付息。A半年后到期，B一年后到期。因为后半年只剩bondB了，所以spread就是Bond B的？算出来的BondA的spread为啥可以当作前半年的spread，
