When a Borrower Gets Six Months of Forbearance: One Event, Six Different Consequences

1. The event

A borrower on a 30-year fixed mortgage receives six months of payment forbearance starting in month 60 under a declared structure: accrued interest capitalizes at exit, the loan re-amortizes over its remaining term, and the servicer advances scheduled principal and interest to investors during the window. Programme-specific treatments can differ.

2. Starting mortgage state

$350,000 at 5.25%, 360 months, payment $1,932.71. By month 60 the balance is $323,042.61. The full pre-event schedule is frozen and hashed.

3. What changes in the loan / servicing state

Two explicit ledger postings:

• Servicer advances (month 60): $1,932.71 × 6 = $11,596.28 advanced to investors, financing cost $289.91, processing $250 — total $12,136.19.
• Interest capitalization (month 67): $8,479.87 — exactly balance × rate × months — added to the loan. Pre-posting balance $319,358.73, post-posting $327,838.60.

4. Cash-flow consequences

The loan re-amortizes: payment rises to $1,984.03, matching the closed-form annuity on the capitalized balance over the remaining 294 months to the cent, and the loan retires to exactly $0.00 at month 360. The schedule contains zero unexplained roll-forward breaks — the one balance step is the posted capitalization.

5. Downstream consequences — six positions, one schedule

6. Why positions differ

Each position consumes the same modified schedule through its own contract: the IO strip sees only the larger interest stream, the PO only the re-timed principal, the MSR and g-fee strips their basis-point strips on the higher balance. The decomposition reconciles exactly: ΔIO + ΔPO = ΔPT to the cent.

7. What EVA computes

Deterministic state transformation with explicit postings, machine reconciliation and byte-identical replay. The sign of the result follows from the arithmetic of the declared structure: investors are kept whole during the window and additional interest accrues.

8. Outside the demonstrated scope

Post-forbearance credit-risk elevation; borrower-side missed-payment ledger during the window (represented via the advance postings, not a borrower sub-ledger); programme-specific agency variations.

9. Evidence / replay coordinate

US_HOUSING_V14 ledger path, POST /api/v1/cashflow/apply-events, source commit 422ea36a; verbatim requests/responses, duration controls (3/6/12 m, exactly linear), payoff non-target control, and the native-UI schedule frame (period 66 → 67 showing the posted capitalization and new payment) accompany this case.