Consider the following CMO: - Tranche A issued for $12 million with a coupon of 6.5% - Tranche B issued for $4 million with a coupon of 6.5% - Z-Tranche issued for $4 million with a coupon of 6.5% The securities are backed by a pool of fully amortizing 30 -year fixed rate mortgages with WAC equal to 6.5% and monthly payments. There is assumed to be a 5% CPR in this pool and no servicing fee. What does the y-axis graph represent? Note that the x-axis is month. Consider the following CMO: - Tranche A issued for $12 million with a coupon of 6.5% - Tranche B issued for $4 million with a coupon of 6.5% - Z-Tranche issued for $4 million with a coupon of 6.5% The securities are backed by a pool of fully amortizing 30 -year fixed rate mortgages with WAC equal to 6.5% and monthly payments. There is assumed to be a 5% CPR in this pool and no servicing fee. What does the y-axis graph represent? Note that the x-axis is month