问

问题如下：

Which commercial mortgage-backed security (CMBS) characteristic causes a CMBS to trade more like a corporate bond than a residential mortgage-backed security (RMBS)?

选项：

A.

Call protection

B.

Internal credit enhancement

C.

Debt-service coverage ratio level

解释：

A is correct.

With CMBS, investors have considerable call protection. An investor in a RMBS is exposed to considerable prepayment risk, but with CMBS, call protection is available to the investor at the structure and loan level. The call protection results in CMBS trading in the market more like a corporate bond than a RMBS. Both internal credit enhancement and the debt-service coverage (DSC) ratio address credit risk, not prepayment risk.

考点：CMBS

解析：本题问的是CMBS有了下列哪个特性之后，更像公司债，而不是RMBS。

公司债有credit risk，没有prepayment risk（没有特别强调是callable bond），而RMBS是有prepayment risk，同时，agency RMBS几乎不考虑credit risk。

如果含有call protection的CMBS，就相当于把提前偿还的风险cover住了，所以此时更像公司债而不像RMBS。故选项A正确。