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Underwriting Subject-To and Wrap Deals

10 min
2/6

Key Takeaways

  • Rate arbitrage is the primary subject-to value driver.
  • Wrap underwriting evaluates two financing layers.
  • Escrow/servicing essential for wraps.
  • Model base, downside, and upside scenarios.

Subject-to and wrap deals require evaluating existing financing terms alongside new deal economics.

Subject-To Underwriting

Evaluate: Can rent cover the existing payment? Is the rate meaningfully below market? What equity payment is needed? What is the remaining term? The key metric is rate arbitrage—the savings versus a new market-rate loan.

Rate Arbitrage
Existing: $180K at 3.5% = $808/mo New: $180K at 7.5% = $1,259/mo Savings: $451/mo | $5,412/yr | $135,300 over 25 years

Wrap Underwriting

Evaluate two layers: underlying payment (cost) and wrap payment (revenue). The spread is the seller's income. Escrow/servicing essential for payment compliance.

Scenario Modeling

Base case: all payments made, value stable. Downside: 10-20% rent decline, due-on-sale invocation cost. Upside: appreciation + favorable financing.

Go / No-Go Decision Framework

Go Indicators

  • Rate arbitrage is the primary subject-to value driver.
  • Wrap underwriting evaluates two financing layers.

No-Go Indicators

  • Calculating rate arbitrage without considering the full holding cost picture: Overstated returns that ignore insurance, taxes, maintenance, and vacancy
  • Not having a refinance contingency plan for subject-to acquisitions: If the lender invokes due-on-sale, the investor has no ability to refinance quickly

Scenario: Subject-To: Capturing a 3.25% Mortgage

Seller has $175K balance at 3.25%, 27 years remaining. Value $195K. Needs $5K to relocate. Market rent $1,500/mo.

Outcome

$268/mo positive vs. negative with market-rate. $462/mo savings, $149,700 total interest savings over loan life.

Common Mistakes to Avoid

Calculating rate arbitrage without considering the full holding cost picture

Consequence: Overstated returns that ignore insurance, taxes, maintenance, and vacancy

Correction: Calculate net cash flow after all expenses, not just the mortgage payment savings from rate arbitrage.

Not having a refinance contingency plan for subject-to acquisitions

Consequence: If the lender invokes due-on-sale, the investor has no ability to refinance quickly

Correction: Maintain refinancing capacity (credit, equity, documentation) to pay off the existing mortgage within 90 days if needed.

Test Your Knowledge

1.What is the primary value driver in a subject-to acquisition?

2.What is essential for wrap mortgage compliance?

3.What scenarios should be modeled for every creative deal?