这里的spread是价值还是波动率的意思？

NO.PZ2020033002000076问题如下 A synthetic C comprises two tranches, a 50% junior tranche pricea spreJ, ana 50% senior tranche pricespreS. If the fault correlations between the invireferencret names crease how woulspreJ anspreS change accorngly? Both sprea remain the same. S increases relative to J. J increases relative to S. The effecannot terminegiven the ta supplie C is correct.考点C解析 相关性降低，senior层会变得安全，它的sprea降低；junior承担损失的可能性变大，所以value会变小，junior sprea大。 两个部分那个是债券，哪个是C？为什么有相应的变动？xie xie

NO.PZ2020033002000076 问题如下 A synthetic C comprises two tranches, a 50% junior tranche pricea spreJ, ana 50% senior tranche pricespreS. If the fault correlations between the invireferencret names crease how woulspreJ anspreS change accorngly? Both sprea remain the same. S increases relative to J. J increases relative to S. The effecannot terminegiven the ta supplie C is correct.考点C解析 相关性降低，senior层会变得安全，它的sprea降低；junior承担损失的可能性变大，所以value会变小，junior sprea大。 相关性降低，senior层会变得安全，它的sprea降低；junior承担损失的可能性变大，所以value会变小，junior sprea大。我的理解是，组合内成分债券的相关性降低，组合的违约概率降低，所以风险补偿应该减少，YTM减少，Cret sprea对于senior tranche 和junior tranche 都减少，但是junior tranche的减少程度大于senior tranche，所以是S靠近J 这样理解有啥不对啊？而且老师的我也不太看得懂，为什么相关性降低junior承担损失的可能性变大，麻烦了，谢谢！