CRE: HOME-funded affordable multifamily
A 29-year affordable multifamily underwriting from HUD's HOME Multifamily template, with restricted rents reverting to market at year 15 and a first mortgage, stated from its sizing terms, that stops paying before the hold ends.
Every number below is checked against an independent reference implementation on every commit — period by period, and on each metric, inside a declared tolerance. See benchmark methodology.
The case
A 29-year affordable multifamily underwriting. Rents are restricted under a federal HOME subsidy and revert to market in year 15; four operating expense lines each escalate on their own schedule; a replacement reserve accrues; and a permanent mortgage, stated from its sizing terms, carries mortgage insurance as a separate agreement rather than as part of one payment.
The reference
A federal agency's HOME multifamily underwriting template, published as a spreadsheet together with a populated example. It publishes a full annual cash flow. The model runs monthly, as the mortgage pays, and its annual rollup reproduces the published rows year by year.
Freely downloadable, and a populated example ships with it.
What it exercises
| Pack | cre |
| Declared | five states, two contracts, eight native streams |
| Language features | declared state for each escalating expense line and the reserve; a monthly calendar reconciled to an annual pro forma through the results' annual rollup |
| Contracts | cre.permanent_debt, cre.mortgage_insurance |
| Conventions | restricted rents reverting to market mid-hold, per-line escalation, a replacement reserve, mortgage insurance as an agreement of its own |
The five states carry the four operating expense lines and the reserve, each compounding at its own rate once a year. The two contracts state the first mortgage as the template's sizing tab states it: $150,000 at 4.00% over 180 months, and mortgage insurance at 0.450% of the original principal. Together they reproduce the tab's monthly payment of 1,165.7819 to the fourth decimal.
The result
Net operating income and debt service reproduce the template's own figures:
domain.cre.noi = 1,886,475 and domain.cre.debt_service = 195,846.
Asserted: nine stream and subtotal columns at eleven anchor months across 29 years, the coverage ratio at six of them, plus the two lifetime aggregates.
The delta
The per-month tolerance is 0.05 — a twelfth of half a dollar — because the template publishes money to whole dollars a year while compounding on unrounded balances. Its debt service coverage ratio, which the template quotes to sixteen figures, agrees to five decimal places and is asserted far more tightly than the money lines.
The template's mortgage payment is principal, interest and mortgage insurance, rounded to whole dollars a year. The contracts pay the unrounded payment, 0.38 a year more, and the lifetime debt service is asserted at the template's figure within that rounding.
Run configuration
{"deterministic":{"annual_discount_rate":0.10}}Verified results
Checked period by period: 13 series across 11 periods — 138 values in all, each within the tolerance shown.
cre.unit.base_rent.home— within ±0.05cre.vacancy.loss— within ±0.05cre.ops.revenue— within ±0.05cre.opex.line.management— within ±0.05cre.opex.line.maintenance— within ±0.05cre.opex.line.utilities— within ±0.05cre.opex.line.taxes_insurance— within ±0.05cre.opex.line— within ±0.05cre.mortgage_insurance.premium— within ±0.05domain.cre.debt_service— within ±0.05domain.cre.egi— within ±0.1domain.cre.noi— within ±0.1domain.cre.dscr— within ±1.0e-4
Summary metrics for the base run:
| Metric | Value | Tolerance |
|---|---|---|
domain.cre.noi | 1,886,475 | ±130 |
domain.cre.debt_service | 195,846 | ±6 |