NO.PZ2019070101000063
问题如下：
Default rates for a given rating increase over time.
选项：
A.The effect is the same for low-rated and high-rated bonds.
B.The effect was even stronger in highly rated bonds.
C.The effect was even stronger in lowly rated bonds.
D.There are not enough studies to prove this effect.
解释：
B is correct.
考点：Through-the-cycle and At-the-point Internal Ratings
解析：对于投资级信用较高的债券，其累积违约概率的增长速度要高于时间增加的速度。因此题干所述的效应在高评级债券中表现的更为明显。
rt
