 If a property with a due-on-sale clause in the mortgage loan is transferred and the loan is not paid off, the bank could call the loan and then foreclose on the property if the buyer is unable to immediately tender the entire remaining balance on the loan.How likely this is depends on how the real estate economy is doing.If the buyer continues to pay the loan payments when due, it is less likely that the bank would actually call the loan due but it is still the bank's choice.