DSCR Non-QM Mortgages: Debt Service Coverage Ratio Calculation & Real Estate Investor Loan Limits
A lending guide to non-QM residential investor mortgages, Debt Service Coverage Ratio (DSCR) underwriting formulas, and interest-only options.
DSCR Rental Mortgage Calculator
Evaluate rental property PITIA ratios and solve for minimum qualification rent
Empirical Analysis & Findings
## Non-QM DSCR Mortgage Architecture for Real Estate Investors
Debt Service Coverage Ratio (DSCR) loans enable residential rental property investors to scale portfolios without submitting personal W-2 tax returns, paystubs, or debt-to-income (DTI) calculations.
### 1. The Underwritten DSCR Formulation
Underwriting evaluates exclusively the cash flow capacity of the collateralized asset:
$$\text{DSCR} = \frac{\text{Gross Monthly Rental Income}}{\text{Monthly PITIA Debt Service}}$$
- **Qualifying Rent**: Lower of executed lease agreement or independent appraiser Form 1007 fair market rent schedule.
- **PITIA**: Principal + Interest (amortizing or interest-only) + Property Taxes + Homeowners Insurance + HOA Dues.
| DSCR Tier | Maximum Permitted LTV | Minimum FICO Score | Pricing Spread vs SOFR |
|:----------|:---------------------:|:------------------:|:----------------------:|
| >= 1.25x | 80% | 680 | +325 bps |
| 1.00x - 1.24x | 75% | 700 | +375 bps |
| 0.75x - 0.99x | 70% | 720 | +450 bps |
| < 0.75x | 65% (Strict Escrow) | 740 | +550 bps |
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Frequently Asked Questions
How is DSCR calculated for residential investor mortgage loans?
DSCR equals Gross Monthly Market Rent (certified on appraisal form 1007) divided by Total Monthly PITIA (Principal, Interest, Taxes, Insurance, HOA).
Can an investor qualify for a DSCR loan with a ratio below 1.00x?
Yes, select non-QM programs allow 'No-Ratio' or DSCR < 1.00x loans for prime borrowers with 720+ FICO, compensating with lower LTV limits (65%-70%) and 12 months cash reserves.
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