The taxpayer bears the burden of proving and substantiating his claim for deduction for loss and should comply with the following substantiation requirements:
1. A sworn declaration of loss must be filed within the period prescribed; and
2. Proof of the elements of the loss claimed, such as the actual nature and occurrence of the event and the amount of the loss.
1. A sworn declaration of loss must be filed within the period prescribed; and
2. Proof of the elements of the loss claimed, such as the actual nature and occurrence of the event and the amount of the loss.
