What Is a 1231 Exchange and How Are Gains Taxed?

A “1231 exchange” is almost always a mix-up of two different tax provisions. Section 1231 of the Internal Revenue Code is not an exchange at all. It is the rule that decides how the IRS characterizes gains and losses when you sell business property: net gains get long-term capital gains rates, and net losses are fully deductible against ordinary income like wages. The provision people usually mean when they say “exchange” is Section 1031, which lets you swap business real estate and defer the tax entirely. The two often work together, but they do different jobs.

Section 1231 vs. a 1031 Like-Kind Exchange

Section 1031 defers gain. When you swap one piece of business real estate for another of like kind, no gain or loss is recognized on the exchange itself. Your basis carries over into the new property, and you settle up when you eventually sell without reinvesting.¹

Section 1231 has nothing to do with deferring anything. It sits one step later in the process, sorting the character of the gain or loss when a taxable sale actually happens. You can use both on the same property: 1031 defers, and 1231 characterizes the gain when the deferral finally ends.

What Qualifies as Section 1231 Property

An asset qualifies if you used it in a trade or business and held it for more than one year. The holding period begins the day after you acquire the property, so a sale on day 365 falls short. The statute covers depreciable personal property such as machinery, vehicles, and equipment, along with real property like office buildings, warehouses, and business land.²

Several less obvious categories also qualify:

Timber, coal, and iron ore, when the specific rules under Section 631 are met.³
Cattle and horses held at least 24 months for draft, breeding, dairy, or sporting purposes.
Other livestock held at least 12 months for the same purposes.³
Unharvested crops sold together with the underlying land to the same buyer at the same time.²

Inventory held for sale to customers is excluded. A construction company’s bulldozer qualifies; a car dealership’s inventory of sedans does not. Copyrights, literary works, artistic compositions, and similar intellectual property created by the taxpayer are also excluded, as are accounts receivable from services or sales.² The provision is aimed at the physical capital that supports operations, not the goods those operations produce.

How the Gains and Losses Are Taxed

At year-end you add up all your Section 1231 gains and losses. If the total is a net gain, every dollar is treated as a long-term capital gain, taxed at 0%, 15%, or 20% depending on your taxable income and filing status.⁴

If the total is a net loss, the whole thing is an ordinary loss. This is where the real advantage lives. Ordinary losses offset any type of income — wages, self-employment earnings, interest — with no annual cap. Regular capital losses, by contrast, can only offset $3,000 of ordinary income per year, or $1,500 for married filing separately, with the rest carried forward.⁵ A business owner who sells equipment at a $50,000 loss can use the full amount that year rather than stretching it over 17.

Depreciation Recapture Comes First

Before Section 1231’s favorable rates apply, the IRS recaptures some or all of the depreciation you claimed while you owned the asset. You got deductions each year for that depreciation. When you sell at a gain, the government wants a portion of those deductions back at ordinary rates. Two separate provisions handle this, depending on the type of property.

Section 1245: Personal Property

When you sell equipment, vehicles, machinery, or other depreciable personal property at a gain, the gain is taxed as ordinary income to the extent of all depreciation you claimed. Only the portion of gain above total depreciation qualifies for Section 1231 capital gains treatment.⁶ Buy a $100,000 machine, claim $60,000 in depreciation, sell it for $120,000: $60,000 is recaptured as ordinary income, and only the remaining $20,000 gets capital gains treatment.

Section 1250: Real Property

Buildings and structural improvements follow a friendlier path. Section 1250 only recaptures depreciation as ordinary income to the extent an accelerated method exceeded straight-line depreciation.⁷ Most commercial real estate placed in service after 1986 must use straight-line, so this recapture amount is often zero.

The remaining depreciation on real property falls into a special category called unrecaptured Section 1250 gain, taxed at a maximum of 25%.⁸ Any gain beyond total depreciation gets the ordinary long-term capital gains rate under Section 1231. If you bought a commercial building for $500,000, claimed $150,000 in straight-line depreciation, and sold it for $700,000, the first $150,000 of the $350,000 gain is taxed at up to 25%, and the remaining $200,000 gets the standard capital gains rate.

The Five-Year Lookback

Section 1231(c) prevents taxpayers from alternating loss years and gain years to game the character of each. When you have a net Section 1231 gain in the current year, the IRS looks back at the five preceding tax years. If you claimed net Section 1231 losses in that window, your current gain is recharacterized as ordinary income to the extent of those prior unrecaptured losses.²

Say you claimed a $10,000 net Section 1231 loss three years ago and used it against your ordinary income that year. This year you have a $25,000 net Section 1231 gain. The first $10,000 is taxed at ordinary rates, effectively paying back the earlier benefit. Only the remaining $15,000 qualifies for long-term capital gains rates. Once the $10,000 has been recaptured it no longer counts. If you had ordinary losses in more than one prior year within the window, all must be fully recaptured before any current gain gets capital gains treatment.

Casualty and Theft Losses Get Their Own Netting

Involuntary conversions from fire, storms, theft, or similar events run through a separate calculation before touching the main Section 1231 pool. If your recognized losses from those events exceed your gains from them during the year, all the casualty gains and losses are pulled out of Section 1231 entirely and treated as ordinary.² Only when casualty gains exceed casualty losses do those amounts flow into the broader Section 1231 netting alongside your voluntary sales. The result is that a large uninsured fire loss is not trapped by the capital loss limitations; it lands in ordinary loss territory where it can offset your full income.

The 3.8% Net Investment Income Tax

High earners face an additional 3.8% surtax on net investment income, which includes Section 1231 gains treated as long-term capital gains. The surtax applies when modified adjusted gross income exceeds $200,000 for single filers or $250,000 for married couples filing jointly, and it is calculated on the lesser of net investment income or the amount by which income exceeds those thresholds.⁹ A married couple with $300,000 in income and a $100,000 Section 1231 gain would owe the 3.8% on $50,000, the portion above the $250,000 threshold.

Reporting on Form 4797

Section 1231 transactions are reported on IRS Form 4797, Sales of Business Property. The form has three parts that must be worked in a specific order.¹⁰

Part III comes first for depreciable property. You calculate depreciation recapture here. The recaptured portion flows to Part II as ordinary income, and any gain above the recapture flows to Part I.
Part I is where all Section 1231 gains and losses are netted. Voluntary sales, qualifying involuntary conversions, and the non-recaptured portion of Part III gains land here. A net gain moves to Schedule D as long-term capital gain; a net loss is ordinary.
Part II holds ordinary gains and losses, including the recapture amounts from Part III.³

Form 4797 is filed with your federal return: Form 1040 for individuals, Form 1120 for corporations, or the appropriate partnership or S corporation return. Given the five-year lookback, keeping records for at least seven years after the final sale is prudent, since you may need to prove the character of prior-year losses long after those returns were filed.¹¹

When Section 1031 and Section 1231 Actually Meet

These two provisions interact more often than owners realize. A 1031 like-kind exchange defers recognition of gain on qualifying real property swaps, but deferral is not forgiveness. When you eventually sell the replacement property in a taxable transaction, Section 1231 determines how the accumulated gain is characterized, and Sections 1245 and 1250 determine how much of it is recaptured as ordinary income.

After several rounds of 1031 exchanges the deferred gain can grow large, and so can the accumulated depreciation, because your basis in each replacement property carries over from the original. A taxpayer who started with a $200,000 building and exchanged through several properties over two decades could face a substantial ordinary income hit from recapture on the final sale, even if each individual exchange looked painless. Planning the exit from a chain of 1031 exchanges is where the Section 1231 analysis matters most.

1
Office of the Law Revision Counsel. 26 USC 1031 – Exchange of Real Property Held for Productive Use or Investment
2
Office of the Law Revision Counsel. 26 USC 1231 – Property Used in the Trade or Business and Involuntary Conversions
3
Internal Revenue Service. Instructions for Form 4797
4
Tax Foundation. 2026 Tax Brackets and Federal Income Tax Rates
5
Office of the Law Revision Counsel. 26 USC 1211 – Limitation on Capital Losses
6
Office of the Law Revision Counsel. 26 USC 1245 – Gain From Dispositions of Certain Depreciable Property
7
Office of the Law Revision Counsel. 26 USC 1250 – Gain From Dispositions of Certain Depreciable Realty
8
Office of the Law Revision Counsel. 26 USC 1 – Tax Imposed
9
Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax
10
Internal Revenue Service. About Form 4797, Sales of Business Property
11
Internal Revenue Service. How Long Should I Keep Records