The “in duplum” rule originated from the South African common law and has been applied through South African case law for over 100 years. This common law rule specifies that interest on a debt will cease to run (or accrue) when the total amount of arrear interest equals the amount of the principal debt outstanding. A statutory “in duplum” rule was later introduced into South African law in the National Credit Act[1]  which came into effect on 1 June 2007. This rule however does not only apply to unpaid interest but also limits, together with the unpaid interest, other finance […]