Here's the information you'll need to have handy to complete your unsecured promissory note, interest-only with balloon final payment. Promissory note is the written contract between the borrower and the lender that is the promise to repay the debt including interest payments.Here's the information you'll need to have handy to complete your secured promissory note, interest-only with balloon final payment. There are four types of loan: 1. Balloon Payment Loan 2. A mortgage that permits the lender to adjust its interest rate periodically on the basis of changes in a specified index. George has a loan that is amortizing over 30 years, but he will be required to pay the remaining principal in 15 years. What is this called?