Did a wrap where the underlying had 19 years left and I was only in the deal for 5, and I never ran a real amortization on what the seller was still carrying

The tail risk you are describing is the part of wrap analysis that most people do with a gut check instead of a spreadsheet, and the gut check is almost always optimistic. What you carried was not just a payment obligation but a continuing lien relationship with your original lender for the full remaining term, and if your buyer defaulted at month 14 you would have been catching up arrears on the underlying, managing a foreclosure on the wrap, and doing both simultaneously with a due-on-sale clause that could have accelerated everything the moment your lender noticed activity. The spread math is easy because it is just two interest rates and a balance. The liability math requires you to model the underlying amortization schedule at every possible default month, calculate the reinstatement cost at that point, and compare it against the equity cushion your wrap buyer had built, because that cushion is the only collateral standing between you and a loss that outlasts your intended hold period by fourteen years in your case.

What I would confirm before doing this again, and with whom: the current balance and amortization schedule directly from the servicer in writing, not from the original note and a calculator, because servicers apply payments in ways that can differ from a standard amortization table, especially if there was ever a modification or a skip-payment arrangement you did not know about. I would also have a real estate attorney in that state confirm whether your wrap instrument gave you a viable path to cure and then foreclose on your buyer faster than the underlying lender could accelerate against you, because that sequencing is jurisdiction-specific and it is the entire ballgame if things go wrong at month 14. Your deal ended cleanly, but the margin for error in that window was determined by documents you may not have stress-tested. What did your wrap instrument actually say about your right to step into the buyer's shoes and cure before acceleration?

Yes, and I think it is one of the most common gaps in how wraps get built.

The spread math is easy to see. You borrow at 4.1, you lend at 6.5, you pocket the difference. That calculation fits on a napkin and it feels good. What is harder to see at signing is the shape of the underlying loan across time, specifically how much principal balance you would still owe the original lender if the deal collapsed at month 14 or month 20.

For anyone reading this who has not done a wrap before: an amortization schedule shows you how a loan balance shrinks month by month. Early payments are mostly interest, so the balance falls slowly. On a 19-year remaining term at even a modest balance, you can be two years in and still owe close to what you started with. If the buyer stops paying, the seller in a wrap is still on the hook to the underlying lender for that balance, because the original loan never went away.

The scenario worth modeling before you close is simple: buyer defaults at the worst possible moment, you have to keep the underlying current out of your own pocket while you work through the legal process to remove them. How many months could you carry that, and what does the balance look like on the day you get the property back?

This is also why wraps sit in the more advanced column of the strategy guide. The spread is the upside, but the underlying tail is a real liability that deserves its own line in the deal model.

One question for you: when you did eventually run the amortization in month eight, did you also model the legal timeline for what removal would have taken in your state, or was it mainly the balance numbers you were looking at?

What was your plan at month 14 if he missed two payments back to back?