Kuwait Court of Cassation principle number 3539

A commercial obligation for a sum of money. When its subject matter is ascertainable in amount at its inception, even if the debtor disputes its amount. Statutory interest is compensation for delay in performing the obligation to pay a sum of money; it runs as soon as the debt falls due, without proof of damage or agreement upon it, and the debtor is not exempted from it except by his agreement or a custom providing otherwise.