Zero-Coupon Mortgage A form of commercial financing in which regular interest and principal payments are deferred until maturity, rather than paid over the course of the loan. While the coupon rate on such a mortgage is technically zero because there are no regular coupon or interest payments, interest accrues and is rolled into the principal amount at maturity. BREAKING DOWN 'Zero-Coupon Mortgage' Zero-coupon mortgages are especially useful for commercial projects where cash flows to service debt may not be available until the project nears completion. As total interest plus principal repayment is only received by the lender when the loan matures, the credit risk is significantly higher than with a conventional loan. As such, lenders may only offer this form of financing to established commercial borrowers with pristine credit records