Here's the information you'll need to have handy to complete your unsecured promissory note, interest-only with balloon final payment. A Promissory Note with Balloon Payments is a loan contract that enables a lender set loan terms with one or more larger payments at the end.Here's the information you'll need to have handy to complete your secured promissory note, interest-only with balloon final payment. This form is perfect for anyone looking to create a legally binding document for a loan with a balloon payment structure. A balloon payment is a large one-time amount due at the end of a loan. Mortgages, auto loans, and business loans have been structured for balloon payments.