IRS Publication 547 - Casualties, Disasters, and Thefts
Authored By: IRS
This explains the tax treatment of casualties, thefts, and losses on deposits. A casualty occurs when your property is damaged as a result of a disaster such as a storm, fire, car accident, or similar event. A theft occurs when someone steals your property. A loss on deposits occurs when your financial institution becomes insolvent or bankrupt.