Ingenta Bank has securitized a pool of 500 interest only mortgages with and average principal of 450,000 each and 30 years to maturity. The mortgage pool pays an aggregate coupon of 3.42%. Ingenta bank sells the pool to an SPV who collects an annual servicing fee of 21bsp. The SPV then purchase GNMA insurance for 4bps per annum. Find the aggregate expected payment to the bond holders, SPV and GNMA at the end of month 4 assuming 75% PSA (all payments are made in arrears).
Recommended: Find the payment to bondholders after one year has passed (at the end of month 12) if loans are fully amortizing.