Assumption

The undertaking of the repayment of a debt or the performance of an obligation owed by another.

When a purchaser of real property assumes the mortgage of the seller, he or she agrees to adopt the mortgage debt, becoming personally liable for its full repayment in case of default. If a foreclosure sale of the mortgaged property does not satisfy the debt, the purchaser remains financially responsible for the outstanding balance.

In contrast, a purchaser who takes subject to the seller's mortgage agrees to repay the mortgage debt, but that person's liability is limited only to the amount that the mortgaged property is sold for in the case of foreclosure. If the property is sold for less than the mortgage debt, the mortgagee must seek the remaining balance due from the seller, the original mortgagor.