100 PSA baseline; sector-adjusted (5%-15% CPR FNMA, 3%-8% CPR GNMA II); calibration pending
| source | Internal placeholder; calibration deferred to PL-07 sweep |
| derivation | expert_judgment |
| quality | estimated |
| evidence | documented_internal |
| regulatory frameworks | asop_27, asop_56 |
| set | 2026-05-04 |
| next review due | 2026-12-31 |
PSA 100 = textbook baseline; sector adjustments are placeholder. Material model risk per §6.3: 10%-of-notional sensitivity per 25-PSA shift on long-dated FNMA pools is plausible. Free-source candidates (DR-007 binds): (1) FRED MBA refi index + mortgage rate spread for refi-driven CPR; (2) FNMA Connect historical CPR by vintage / coupon (free public data); (3) Bloomberg PSA model is paid (excluded). Calibration plan: use FNMA Connect monthly CPR by vintage as ground truth; fit one-factor PSA scaler against current 30Y refi spread.