Proving the Loss

In order to claim a deduction for your casualty loss, you must be prepared to prove it. Specifically, if your tax return is audited, you should be prepared to show all of the following:

• that you owned the property
• the amount of your basis in the property
• the pre-disaster value of the asset
• the reduction in value caused by the disaster
• the lack or insufficiency of reimbursement to cover the costs

To claim the deduction, generally, you must be the owner of the property. For example you can't claim a loss for the destruction of property owned by your manager or employee. If more than one person owns the property, the loss must be allocated among the owners in proportion to their ownership interests. However, if the risk of loss was shifted to you by a contract, you can claim a deduction even if you didn't own the property.

Tip If the rental agreement for your office space says that you must pay for any damages to the building resulting from a casualty, then you are entitled to claim a loss deduction for the damages.

Proving the basis of business property is generally not a problem, since you should have adequate records of the property's original cost or other basis, plus any additions or subtractions to the basis, for tax and accounting purposes.

For personal property, proving the basis may be more difficult. For larger items such as your home, you should have retained the sales contract or closing documents in your safe-deposit box, but for furniture, cars, clothing, household items etc., it's quite impractical to save every sales slip. Perhaps luckily, since these items typically depreciate in value over time, their loss would generally be measured by the fair market value at the time of the casualty, not their cost basis to you.

For very expensive or unusual items, you may need to get an appraisal or other evidence of the amount of your loss.