小编导读：报名高顿网课的学员，可通过高顿网校学习更多精品课程，练习更多免费题目，享受更多教学服务；更多详情请拨打高顿网校客服电话400-825-0088。
　　Under a 200% PSA model, what is the single monthly mortality (SMM) for, respectively, month 20 and month 40
　　A.      8% and 12%
　　B.      8% and 16%
　　C.      0.69% and 1.44%
　　D.      0.69% and 1.06%
　　Answer: D
　　The base PSA model assumes that prepayments begin at a rate of 0.2% CPR in the first month and increase at a rate of 0.2% CPR per month until they reach 6.0% CPR in month 30.