Type of mortgage loan that requires the borrower to pay a large sum of money at the time of maturity. The borrower typically pays regular payments on the loan until the loan reaches maturity. A lot of borrowers accept this type of loan with the goal of selling the property before the maturity date and avoiding the balloon payment. A balloon mortgage is not ideal for borrowers unless they are positive that they will have the money to pay the balloon payment at the time of maturity.