FIRE Modeling Assumptions

How FIRE Models Purchasing Power

FIRE combines your Financial Position with published market and eligibility benchmarks, then applies a small set of Cashare planning assumptions so everyone starts from a consistent model.

Effective as of 2026-09-10Sources last checked 2026-09-16

Current FIRE assumptions

FIRE evaluates the listed down-payment structures and uses the one that supports the highest modeled purchase price for your plan. The winning structure is a modeling result, not a financing recommendation.

Primary home

Down payments FIRE evaluates: 5%, 10%, 15%, 20% ^2,4
Modeled rate: 6.76% ^1,4; 6.76% Freddie Mac PMMS benchmark.
Protected reserve: 3 months modeled household obligations ⁴

Primary home · 2–4 units

Down payments FIRE evaluates: 5%, 10%, 15%, 20% ^2,4
Modeled rate: 6.76% ^1,4; 6.76% Freddie Mac PMMS benchmark.
Protected reserve: Greater of 3 months modeled household obligations or 6 months subject-property payment ^3,4

Second home

Down payments FIRE evaluates: 10%, 15%, 20% ^2,4
Modeled rate: 7.26% ^1,4; 6.76% Freddie Mac PMMS + 0.50% Cashare planning adjustment.
Protected reserve: Greater of 3 months modeled household obligations or 2 months subject-property payment ^3,4

Investment property · 1 unit

Down payments FIRE evaluates: 15%, 20%, 25% ^2,4
Modeled rate: 7.76% ^1,4; 6.76% Freddie Mac PMMS + 1.00% Cashare planning adjustment.
Protected reserve: Greater of 3 months modeled household obligations or 6 months subject-property payment ^3,4

Investment property · 2–4 units

Down payments FIRE evaluates: 25%, 30% ^2,4
Modeled rate: 7.76% ^1,4; 6.76% Freddie Mac PMMS + 1.00% Cashare planning adjustment.
Protected reserve: Greater of 3 months modeled household obligations or 6 months subject-property payment ^3,4

Shared planning assumptions

Monthly financing benchmark

45% DTI ⁴

Estimated closing costs

3% of purchase price ⁴

Mortgage insurance estimate

0.8% annually below 20% down ⁴

Property tax estimate

1.2% annually ⁴

Homeowners insurance estimate

0.4% annually ⁴

Loan term

30 years ⁴

Sources

Published guidance establishes market and eligibility reference points. Cashare assumptions turn those references into a consistent educational model. FIRE does not present Cashare assumptions as agency requirements.

1 — Freddie Mac PMMS. 30-year fixed national market-rate benchmark, 2026-09-10. Official source
2 — Freddie Mac eligibility guidance. Maximum LTV/TLTV/HTLTV reference used for owner-occupied 2–4-unit modeling. Official source
3 — Fannie Mae Eligibility Matrix. Occupancy and property-type eligibility reference. Official source
4 — Fannie Mae reserve guidance. Reserve reference used for owner-occupied 2–4-unit, second-home, and investment modeling. Official source
5 — Cashare planning assumptions. Planning spreads, candidate structures, household reserve policy, DTI, closing-cost, tax, insurance, and mortgage-insurance estimates used by FIRE.

What changes over time?

Market benchmarks and agency guidance change. This page establishes the public framework for FIRE's current approved assumptions. The values shown here are projected from the same governed Purchase Plan modeling data used by FIRE's Purchasing Power and property-scenario defaults. Future versioning can preserve approvals and change history without creating a second set of assumptions.

FIRE is an educational planning model. Actual lender pricing, underwriting, reserve requirements, mortgage insurance, taxes, insurance, and eligibility can differ based on the borrower, lender, property, loan structure, and market.