Property-transfer structure where the buyer takes title subject to an existing mortgage without formally taking over the debt in the same way as an assumption.
A subject-to mortgage transaction is a property transfer in which the buyer takes title subject to an existing mortgage while the old loan remains in place and the buyer does not step into the debt in the same formal way as a true mortgage assumption.
Subject-to transactions matter because they can preserve an attractive existing loan without going through a standard new-origination process. But they also create a sharper legal and credit-risk split between who owns the property, who makes the payments in practice, and who is still directly liable on the original note.
The buyer takes ownership of the property while the existing mortgage stays attached to it. In practical terms, the buyer may make or fund the ongoing payments, but the seller often remains the original borrower on the debt.
| Structure | Title transfer | Formal debt transfer | Core risk |
| — | — | — | — |
| Subject-to mortgage | Yes | Usually no | Seller liability and due-on-sale exposure remain |
| Assumption of mortgage | Yes | Yes | Buyer must qualify and lender approval usually matters |
| Wraparound mortgage | Yes | New financing wraps the old debt | Layered credit and payment-structure risk |
That distinction is why subject-to deals are often discussed in the same breath as Assumption of Mortgage, but they are not the same transaction.
A buyer wants a property with an attractive existing loan but does not formally assume the mortgage through the lender’s approval process. The buyer acquires the property and makes payments associated with the old mortgage, while the original loan itself still remains tied to the seller’s borrower position.
The buyer may control the property and make the payments, but the seller can still remain directly exposed on the original mortgage note.
A Due-on-Sale Clause can give the lender the right to demand payoff after transfer, which is one reason subject-to structures can be riskier than they look at first glance.
An Assumption of Mortgage formally moves responsibility in a way subject-to usually does not.
Assumption of Mortgage: The cleaner formal alternative where the buyer actually takes over the debt obligation.
Assumable Mortgage: The loan feature that can make formal transfer possible.
Due-on-Sale Clause: A central contract risk in subject-to transactions.
Wraparound Mortgage: Another property-financing structure built around an existing underlying loan.
Purchase-Money Mortgage: A different seller-financing structure that creates new financing instead of leaning on the old debt in the same way.