Tuning Support

MBS Prepayment Model Tuning Parameter Recommendations
[5.2e version]

Please note that some vendor systems have specific instructions for adjusting AD&Co tuning parameters. Please click here for vendor-specific information.

FIXED RATE AGENCY LOAN TYPES

Loan Type	Slide	Turnover	Refi	Tuning Start Year	Tuning Start Month	Tuning End Year	Tuning End Month	Tuning Ramp Months	Tuning Fade Months
FNMA, FHLMC 20	50	1.00	1.00	2007	6	2010	6	12	24
FNMA, FHLMC 30	50	0.70	0.50	2007	6	2010	6	12	24
GNMA 15	50	1.00	1.00	2007	6	2010	6	12	24
GNMA 30	50	0.85	0.85	2007	6	2010	6	12	24
RELO 15	50	1.00	1.00	2007	6	2010	6	12	24
RELO 30	50	0.75	0.75	2007	6	2010	6	12	24

ADJUSTABLE RATE AGENCY LOAN TYPES

Loan Type	Slide	Turnover	Refi	Lag	Tuning Start Year	Tuning Start Month	Tuning End Year	Tuning End Month	Tuning Ramp Months	Tuning Fade Months
FNMA, FHLMC 3/1	150	0.9	0.5	0.5	2007	6	2009	12	12	24
FNMA, FHLMC 5/1	100	0.9	0.5	0.5	2007	6	2009	12	12	24
FNMA, FHLMC 7/1	100	1	0.8	0.5	2007	6	2009	12	12	24
FNMA, FHLMC 10/1	50	1	0.8	0.5	2007	6	2009	12	12	24

All Agency loan types with parameters not listed above should be set to 1.0 with the exception of slide which should be set to 0.

FIXED RATE NON-AGENCY LOAN TYPES

Loan Type	Slide	Turnover	Refi	Aging	Tuning Start Year	Tuning Start Month	Tuning End Year	Tuning End Month	Tuning Ramp Months	Tuning Fade Months
Non-Agency Prime 30 Fixed	175	1.0 (default)	0.75	1.0 (default)	2007	6	2009	12	12	24
Non-Agency Prime 15 Fixed	50	1.0 (default)	0.75	1.0 (default)	2007	6	2009	12	12	24
Sub-Prime 30 Fixed	200	0.85	0.85	1.0 (default)	2007	6	2009	12	12	24

ADJUSTABLE RATE NON-AGENCY LOAN TYPES

Loan Type	Slide	Turnover	Refi	Aging	Tuning Start Year	Tuning Start Month	Tuning End Year	Tuning End Month	Tuning Ramp Months	Tuning Fade Months
Non-Agency Prime ARM	200	0.85	0.75	0.2	2007	6	2009	12	12	24
Sub-Prime ARM	125	0.85	1.0 (default)	0.2	2007	6	2009	12	12	24
Option ARM	125	0.85	0.5	1.0	2007	6	2009	12	12	24

All Non-Agency loan types with parameters not listed above should be set to 1.0 with the exception of slide which should be set to 0.