A balloon payment mortgage is a mortgage which does not fully amortize over the term of the note, thus leaving a balance due at maturity. A balloon mortgage allows you to enjoy low monthly payments for several years — with a big catch.In California, your promise to repay is ordinarily in the form of a promissory note and the mortgage is ordinarily in the form of a deed of trust. Loan and Shared Appreciation is due on sale, title transfer, first mortgage repayment, or in 30 years as a balloon payment. A balloon loan is a type of mortgage financing that differs in its payment structure. What is a Balloon Payment Mortgage?