Casualties and Thefts - Form 4684
Form 4684 reports casualties and thefts of both personal use property and income-producing business property. Destruction of property by fire, storm, shipwreck, or other casualty and theft by larceny, embezzlement, or robbery is tax deductible.
There are some losses you cannot deduct, however. Lost money or property, items broken under normal conditions, and progressive damage to property caused by insects or disease are not tax deductible.
If you receive more in insurance or other reimbursement than the cost of the destroyed property, then your casualty or theft resulted in a gain, which you must report and pay tax on. You can only deduct the portion of your loss not covered by reimbursement.
If more than 4 items of either personal use property or business and income-producing property were damaged or lost, attach additional sheets.