Wells Fargo issues a CMBS. The mortgage pool consists of interest only loans, with a total loan amount of $15 million. Assume the mortgage rate is 11%, the mortgages are annually compounded, and the loan maturity is 4 years. There are three tranches in the CMBS: 1. Tranche A, with an amount of $10 million at 8% coupon rate, 2. Tranche B, with $3 million at 10% coupon rate, and 3. the residual tranche, with $2 million. The maturity of the MBS securities is 4 years. Suppose the value of the properties in the mortgage pool at the end of 4th year is worthy of only 70% of the original loan amount indicated above. What is the investor return for Tranche B for the 4 year period?