Involuntary Conversion Rules: Replacement Property, Deadlines, and Basis

Involuntary conversion rules, set out in Section 1033 of the Internal Revenue Code, let you postpone tax on a gain when property is destroyed, stolen, condemned, or seized, provided you reinvest the proceeds in qualifying replacement property within a fixed window and make the election on your return. Miss any of the three requirements (a qualifying event, qualifying replacement, and the deadline) and the gain becomes taxable in the year you first received the money.

Which Events Qualify

Section 1033 covers four kinds of forced loss: casualty, theft, condemnation, and government seizure or requisition. The common thread is that the transfer must be forced on you. A voluntary sale under financial pressure never qualifies.

A casualty is the sudden, unexpected destruction of property — fire, hurricane, earthquake, flood. Gradual damage from termites, dry rot, or ordinary wear does not count, however bad it looks by the time you find it.

Theft means a criminal taking under your state’s law. Property that is lost or misplaced is not theft for tax purposes.

Condemnation is the most common trigger and, for real estate, the most flexible. It occurs when a government body exercises eminent domain for public use. A formal proceeding is not required. A sale made because you reasonably believed the property would be condemned if you refused also qualifies, but you need evidence of that threat: official correspondence, published plans, or statements from officials. A rumor about a highway expansion is not enough.¹

Figuring the Gain

Before deferral matters, you need to know what gain you have. Take the compensation you received (insurance payout, condemnation award, or settlement), subtract expenses tied directly to the conversion such as attorney or appraisal fees, and then subtract your adjusted basis in the property. Adjusted basis is what you originally paid, plus capital improvements, minus depreciation claimed.

An example. You bought a rental building for $100,000 and claimed $50,000 in depreciation, leaving an adjusted basis of $50,000. Fire destroys it and net insurance proceeds come to $120,000. Realized gain is $70,000. That is the number you will either recognize or defer.

If the conversion produces a loss on business or investment property, it is generally deductible in the year of the conversion. For personal-use property, a casualty or theft loss is deductible only if it resulted from a federally declared disaster, a limit in place since 2018.²

Making the Election and How Much You Can Defer

Deferral is not automatic. You elect it on the tax return for the year you first realize gain, attaching a statement that describes the conversion, the gain, and your plan to acquire replacement property.³ Skip that step and the whole gain is taxable.

How much you defer depends on how much you reinvest. To defer the entire gain, you must spend at least as much on replacement property as you received. Gain is recognized only to the extent the amount realized exceeds the cost of the replacement.¹

Back to the fire example. If you received $120,000 and spent $120,000 or more on replacement, the full $70,000 gain defers. Spend only $100,000, and you leave $20,000 in proceeds unreinvested. You recognize $20,000 and defer $50,000. The recognized portion is always the lesser of the realized gain or the shortfall in reinvestment.

What Counts as Replacement Property

This is where most elections fall apart. The replacement must be “similar or related in service or use” to what you lost, and the IRS reads that standard differently depending on how you used the property.

If You Used the Property Yourself

The replacement must serve the same function. A manufacturer whose factory burns needs another factory, not a retail store. The IRS looks at what the property physically did for the business, not just whether the replacement sits in the same asset class.

If You Held It as an Investment

For landlords and passive investors, the standard is more forgiving. The IRS focuses on the nature of the investment activity: tenant type, management involvement, financial risk. A landlord whose apartment building is destroyed can potentially replace it with a rental office building, so long as the investment profile is comparable.

The Broader Rule for Condemned Real Estate

When business or investment real property is taken through condemnation or the threat of it, you can use the “like-kind” standard that applies to Section 1031 exchanges.⁴ Condemned farmland could be replaced with a commercial building, provided both are held for business or investment.⁵ The like-kind standard does not apply to casualties or theft, and it does not cover buying stock in a corporation, even one that owns like-kind property.

Stock as Replacement

You can also acquire stock in a corporation that owns qualifying property, and that counts as replacement. But you must acquire at least 80% of the voting power and 80% of every other class of stock.¹ A minority stake does not work.

The Replacement Deadline

Missing the deadline is the fastest way to lose the deferral. The clock starts on the earlier of the date you actually disposed of the property or the date a threat of condemnation first became real.¹ The end depends on the type of conversion:

Casualty or theft: two years after the close of the first tax year in which any part of the gain was realized. Gain realized in 2025 means a December 31, 2027 deadline.¹
Condemnation of business or investment real property: three years after the close of that year.⁴
Principal residence destroyed in a federally declared disaster: four years after the close of that year.⁶

Asking for More Time

The IRS will consider a request for up to one additional year if you show reasonable cause, such as construction delays on a replacement building. Being unable to find something you like, or facing high prices, will not persuade them.⁷

Submit the request before the replacement period expires if you can, or shortly after with an explanation. Send it by fax to 877-477-9193 or by mail to the IRS at 985 Michigan Ave., Stop 16, Detroit, MI 48226. Include your name, taxpayer identification number, a legal description of the converted property, its adjusted basis, the dates and amounts of payments received, and a description of your search for replacement property.⁷

The Basis of Your Replacement Property

Deferral is not forgiveness. The deferred gain follows you through a mandatory basis reduction. Basis in the replacement equals its cost minus the deferred gain, so a future sale will trigger a larger taxable gain than it otherwise would.

In the fire example, if you spent $100,000 and deferred $50,000, the replacement’s basis is $50,000. If you spent $120,000 and deferred the full $70,000, the basis is still $50,000. The deferred amount always comes off.

Homes, Livestock, and Depreciable Property

When the property is your principal residence, Section 121 can exclude up to $250,000 of gain, or $500,000 on a joint return, if you owned and used it as your main home for at least two of the five years before the conversion. The statute treats an involuntary conversion as a “sale” for this purpose. Any gain above the exclusion can then be deferred under Section 1033, and the amount realized for the deferral calculation is reduced by the excluded portion.⁸ In a federally declared disaster, insurance proceeds for unscheduled personal property are excluded from gain entirely, and all other proceeds for the home and contents are treated as a single lump sum for reinvestment purposes.⁶

Ranchers and farmers get a special rule. If drought forces you to sell livestock held for draft, breeding, or dairy purposes above your normal annual volume, the excess sales qualify for Section 1033 deferral even without a casualty, theft, or condemnation. Poultry is excluded, and replacement livestock must serve the same function: dairy cows for dairy cows, not breeding stock swapped for draft animals. The sale does not have to occur in a drought area, but drought must be the reason.⁹

If the converted property was depreciable, recapture under Sections 1245 and 1250 still applies. When you fully defer the gain by reinvesting everything, recapture is generally deferred as well, but any additional depreciation not reported in the year of the conversion carries over to the replacement and surfaces when you eventually sell it.³

Reporting, and What Happens If You Miss the Deadline

Casualties and thefts are reported on Form 4684. For condemnations, attach a statement to the return for the year you realized the gain, describing the property, the date and circumstances of the conversion, the compensation received, and your intent to acquire replacement property. When you buy the replacement in a later year, attach a second statement to that year’s return with details on the purchase.³

If the deadline passes without qualifying replacement, file an amended return (Form 1040-X for individuals) for the year you originally realized the gain. Report the full gain, pay the deferred tax, and pay interest running from the original due date. The same amended return is required if you did buy replacement property but spent less than you initially planned. In that case, you report only the portion that can no longer be deferred.³

One point for entities: only the partnership or corporation can make the election, not individual partners or shareholders. If the entity misses the deadline, the gain flows through on the amended return.³

1
Office of the Law Revision Counsel. 26 U.S. Code 1033 – Involuntary Conversions
2
Internal Revenue Service. Topic No. 515, Casualty, Disaster, and Theft Losses
3
Internal Revenue Service. Publication 544 – Sales and Other Dispositions of Assets
4
Justia Law. 26 U.S.C. 1033 – Involuntary Conversions
5
eCFR. 26 CFR 1.1033(g)-1
6
Office of the Law Revision Counsel. 26 U.S.C. 1033 – Involuntary Conversions
7
Internal Revenue Service. Involuntary Conversion: Get More Time to Replace Property
8
Office of the Law Revision Counsel. 26 U.S. Code 121 – Exclusion of Gain from Sale of Principal Residence
9
eCFR. 26 CFR 1.1033(e)-1