> The interest rate (as shown on the coupon payment on the bond) will always be positive. Negative coupons would be quite difficult to implement but having a p

> The interest rate (as shown on the coupon payment on the bond) will always be positive. Negative coupons would be quite difficult to implement but having a positive coupon doesn't really mean anything: bonds are not necessarily sold at the nominal price even when they are initially issued. "Henkel and Sanofi sell first negative yielding euro corporate bonds" https://www.ft.com/content/6fdfeee8-2045-3452-a55d-3744a90910b2 https://www.ft.com/content/6fdfeee8-2045-3452-a55d-3744a9091...