Supersedes Undertaking on Appeal is a legal document that is signed by a party appealing a court's decision in order to stop the enforcement of a judgment against them until the appeal is heard. The appealing party must provide security (usually in the form of a bond) for the payment of any costs, damages, or other liabilities that may be imposed on them should the appeal be unsuccessful. There are two types of Supersedes Undertaking on Appeal: a fixed sum and a variable sum. A fixed sum is an amount of money predetermined by the court which must be paid by the appealing party if their appeal is unsuccessful. A variable sum is an amount that can vary depending on the outcome of the appeal. If the appeal is successful, the appealing party will be refunded the full amount of security they provided; if the appeal is unsuccessful, they will be liable for any amount they owe as a result of the judgment.