Cost or other basis usually means original cost plus improvements. Subtract any postponed gain from the sale of a previous main home. Special rules apply to property received as a gift or inheritance. See Pub. 551, Basis of Assets, for details.

Enter on this line the amount of insurance or other reimbursement you received or expect to receive for each property. Include your insurance coverage whether or not you are filing a claim for reimbursement. For example, your car worth $2,000 is totally destroyed in a collision. You are insured with a $500 deductible, but decide not to report it to your insurance company because you are afraid the insurance company will cancel your policy. In this case, enter $1,500 on this line.

If you expect to be reimbursed but have not yet received payment, you must still enter the expected reimbursement from the loss. If, in a later tax year, you determine with reasonable certainty that you will not be reimbursed for all or part of the loss, you can deduct for that year the amount of the loss that is not reimbursed.

If you are entitled to an insurance payment or other reimbursement for any part of a casualty or theft loss but you choose not to file a claim for the loss, you cannot realize a gain from that payment or reimbursement. Therefore, figure the gain on line 4 by subtracting your cost or other basis in the property (line 2) only from the amount of reimbursement you actually received. Enter the result on line 4, but do not enter less than zero.

If you filed a claim for reimbursement but did not receive it until after the year of the casualty or theft, include the gain in your income in the year you received the reimbursement.

Fair market value (FMV) is the price at which the property would be sold between a willing buyer and a willing seller, each having knowledge of the relevant facts. The difference between the FMV immediately before the casualty or theft and the FMV immediately after represents the decrease in FMV because of the casualty or theft.

The FMV of property after a theft is zero if the property is not recovered.

FMV is generally determined by a competent appraisal. The appraiser's knowledge of sales of comparable property about the same time as the casualty or theft, knowledge of your property before and after the occurrence, and the methods of determining FMV are important elements in proving your loss.

The appraised value of property immediately after the casualty must be adjusted (increased) for the effects of any general market decline that may occur at the same time as the casualty or theft. For example, the value of all nearby property may become depressed because it is in an area where such occurrences are commonplace. This general decline in market value is not part of the property's decrease in FMV as a result of the casualty or theft.

Replacement cost or the cost of repairs is not necessarily FMV. However, you may be able to use the cost of repairs to the damaged property as evidence of loss in value if:

To figure a casualty loss to real estate not used in a trade, business, or for income-producing purposes, measure the decrease in value of the property as a whole. All improvements, such as buildings, trees, and shrubs, are considered together as one item. Figure the loss separately for other items. For example, figure the loss separately for each piece of furniture.

If line 14 is more than line 13:

The holding period for long-term gains and losses is more than 1 year. For short-term gains and losses, it is 1 year or less. To figure the holding period, begin counting on the day after you received the property and include the day the casualty or theft occurred.

Estates and trusts figure adjusted gross income in the same way as individuals, except that the costs of administration are allowed in figuring adjusted gross income.

Partnerships (other than electing large partnerships) and S corporations that have a casualty or theft involving property for which the section 179 expense deduction was previously claimed and passed through to the partners or shareholders must not use Form 4684 to report the transaction. Instead, see the Instructions for Form 4797 for details on how to report it. Partners and S corporation shareholders who receive a Schedule K-1 reporting such a transaction should see the Instructions for Form 4797 for details on how to figure the amount to enter on Form 4684, line 20.

Cost or adjusted basis usually means original cost plus improvements, minus depreciation allowed or allowable (including any section 179 expense deduction), amortization, depletion, etc. Special rules apply to property received as a gift or inheritance. See Pub. 551 for details.

See the instructions for line 3.

See the instructions for line 4.

See the instructions for lines 5 and 6 for details on determining FMV.

Loss on each item figured separately.   Unlike a casualty loss to personal use real estate, in which all improvements are considered one item, a casualty loss to business or income-producing property must be figured separately for each item. For example, if casualty damage occurs to both a building and to trees on the same piece of real estate, measure the loss separately for the building and for the trees.

If the amount on line 28 includes losses on property held 1 year or less, and losses on property held for more than 1 year, you must allocate the amount between lines 29 and 34 according to how long you held each property. Enter on line 29 all gains and losses on property held 1 year or less. Enter on line 34 all gains and losses on property held more than 1 year, except as provided in the instructions for line 33.

Use a separate line for each casualty or theft.

Enter the part of line 28 from trade, business, rental, or royalty property (other than property you used in performing services as an employee).

Enter the part of line 28 from income-producing property and from property you used in performing services as an employee. Income-producing property is property held for investment, such as stocks, notes, bonds, gold, silver, vacant lots, and works of art.

If Form 4797, Sales of Business Property, is not otherwise required, enter the amount from this line on page 1 of your tax return, on the line identified as from Form 4797. Next to that line, enter “Form 4684.”

Estates and trusts, enter on the “Other deductions” line of your tax return. Partnerships (except electing large partnerships), enter on Form 1065, Schedule K, line 13d. Electing large partnerships, enter on Form 1065-B, Part II, line 11. S corporations, enter on Form 1120S, Schedule K, line 12d. Next to that line, enter “Form 4684.”

If you had a casualty or theft gain from certain trade, business, or income-producing property held more than 1 year, you may have to recapture part or all of the gain as ordinary income. See the instructions for Form 4797, Part III, for more information on the types of property subject to recapture. If recapture applies, complete Form 4797, Part III, and this line, instead of Form 4684, line 34.

Taxpayers, other than partnerships and S corporations, if Form 4797 is not otherwise required, enter the amount from this line on page 1 of your tax return, on the line identified as from Form 4797. Next to that line, enter “Form 4684.”