NO.PZ2016031002000037
问题如下：
Brown owns a mortgage pass-through security, when interest rates decline, it is most likely affected by:
选项：
A.Extension risk.
B.Contraction risk.
C.Operation risk.
解释：
B is correct.
Contraction risk is the risk that loan principal will be repaid more rapidly than expected, typically when interest rates have declined. Homeowners will refinance at the available lower interest rates.
请问pass-through security是啥？我印象之前老师讲过MBS的return是pass-through ratio，这又是为什么呢？
