A debenture is an unsecured debt. It is simply a promise by the borrower to repay the lender. A debenture will mature on a specific day and state an interest rate. This rate may be fixed, or tied to some sort of index, such as LIBOR or the Federal Funds rate. | A debenture is an unsecured debt. It is simply a promise by the borrower to repay the lender. A debenture will mature on a specific day and state an interest rate. This rate may be fixed, or tied to some sort of index, such as LIBOR or the Federal Funds rate. |