Installment Sale Tax Treatment: Recapture, NIIT, and Form 6252

An installment sale lets you spread the taxable gain from a sale of property across the years you actually receive payments, rather than paying tax on the full profit in the year of the sale. The installment method applies automatically to any qualifying sale where at least one payment arrives after the tax year the deal closed, so no election or checkbox is needed to use it.¹ The tax treatment of an installment sale rests on a fixed gross profit percentage applied to each principal payment, separate ordinary-income treatment for interest, and a set of rules that can accelerate the deferred tax when depreciation, related-party resales, or large outstanding balances enter the picture.

Which Sales Qualify

The installment method covers sales of real property such as land and buildings, and personal property such as equipment and vehicles, sold outside the ordinary course of business, whenever at least one payment is received after the close of the sale year.¹

Some categories are off-limits:

Inventory and property held for sale to customers in the ordinary course of business.²
Publicly traded stock and securities, where the entire gain must be recognized in the year of sale.³
Sales at a loss. Losses are reported in full in the year of the sale.⁴

You can also choose to opt out and report the full gain up front, but that election is essentially permanent once made and can only be revoked with IRS approval.¹

How Each Payment Is Taxed

The engine of installment reporting is the gross profit percentage (GPP). You calculate it once at the time of sale, and it stays fixed for every payment you receive afterward.¹

Two figures go into it. Gross profit is the selling price minus your adjusted basis (typically the purchase price plus improvements, minus any depreciation claimed). Contract price is the total amount the buyer will pay you, which is generally the selling price but can shrink when the buyer takes over existing debt.

The GPP equals gross profit divided by contract price. In each year you receive a payment, you multiply the principal portion of that payment by the GPP to get the taxable gain for the year. The rest of the principal is a nontaxable return of your basis.

When the buyer assumes a mortgage, the contract price is reduced by the assumed debt, but only up to your adjusted basis. Any assumed debt above basis is treated as a payment received in the year of sale.¹

A Worked Example

Say you sell undeveloped land on October 1, 2025 for $500,000. Your adjusted basis is $200,000, and the buyer takes on no existing debt. You collect $100,000 at closing and four annual principal payments of $100,000 from 2026 through 2029, plus interest at a market rate.

Gross profit is $500,000 minus $200,000, or $300,000. Contract price is $500,000. GPP is $300,000 ÷ $500,000, or 60%.

In 2025, the $100,000 down payment produces $60,000 of recognized capital gain (60% of $100,000). The other $40,000 is a return of basis. The same math applies to each $100,000 payment in 2026, 2027, 2028, and 2029. Total recognized gain over the five years comes to $300,000, matching the original gross profit. Interest is reported separately each year as ordinary income.

Interest on the Note

Only the principal portion of each payment runs through the GPP. Interest the buyer pays on the deferred balance is taxed as ordinary income in the year received, at your regular federal rate, and it never changes the GPP or the capital gain figure.¹

If the note charges little or no interest, sections 1274 and 483 of the Internal Revenue Code require the IRS to impute interest at the applicable federal rate (AFR), which is published monthly and varies with the note’s term. Imputed interest reclassifies part of each payment from principal to interest. That reduces the capital gain flowing through the GPP but raises ordinary income by the same amount, and because ordinary rates are usually higher than long-term capital gains rates, a below-market note can cost more in tax than expected. Limited exceptions apply, including sales of farms by individuals and small businesses at $1,000,000 or less, and sales where total payments (including debt instruments received) don’t exceed $250,000.⁵

Depreciation Recapture Is Not Deferred

If the property you sold was depreciated (a rental building, business equipment, commercial vehicles), the installment method’s deferral carries a major carve-out. All depreciation recapture must be recognized as ordinary income in the year of the sale, regardless of how much cash you actually collected that year.² Only the gain above the recapture amount can be spread over the note.

The recaptured amount is then added back to your adjusted basis for purposes of the GPP calculation, which reduces the gross profit used in the formula and lowers the percentage applied to future payments. For example, if you sell a commercial building for $800,000 with an original cost of $600,000 and $150,000 of depreciation claimed, your total gain is $350,000. The $150,000 of recapture hits year one as ordinary income; the remaining $200,000 of gain gets spread across future payments through a recalculated GPP.

For real property such as buildings and rental houses, the recapture attributable to straight-line depreciation is treated as unrecaptured Section 1250 gain and taxed at a maximum rate of 25%, rather than at full ordinary rates.⁶ Gain above that layer still qualifies for regular long-term capital gains rates.

Rate Brackets and the Net Investment Income Tax

Deferral changes when you recognize gain, not its character. Long-term capital gain recognized through an installment sale keeps preferential capital gains rates. For 2026, those are 0%, 15%, or 20% depending on taxable income and filing status. A single filer, for example, pays 0% on long-term gain up to $49,450 of taxable income and reaches the 20% rate above $545,500.

Spreading gain across years can keep you in a lower bracket each year rather than stacking everything into one return and pushing into the 20% tier. That bracket management is one of the method’s main practical benefits.

Higher-income sellers also face the 3.8% net investment income tax on the lesser of net investment income or the amount by which modified adjusted gross income exceeds $200,000 for single filers or $250,000 for joint filers.⁷ Capital gain from an installment sale counts as net investment income in the year recognized, so deferring gain into years when other income is lower can keep more of it below the threshold.

Selling to a Related Party

Sales on installment terms to family members, controlled entities, or certain partnerships come with an anti-abuse rule aimed at preventing a two-step cash-out. If the related-party buyer resells the property within two years of the original sale, you are treated as having received those resale proceeds at the time of the second sale, which accelerates your deferred gain.¹

Related parties for this purpose include family members whose stock ownership would be attributed to you under the constructive ownership rules, along with entities you control.² The two-year rule does not apply to involuntary dispositions such as condemnations and casualty losses, and you can avoid it if you can show the IRS that neither the original sale nor the resale had a principal purpose of tax avoidance.¹

Even without a resale, related-party sales carry an extra reporting duty: Part III of Form 6252 must be completed for the year of sale and the two years that follow.¹

Interest Charges on Large Installment Notes

Section 453A imposes an additional interest charge when the sale price exceeds $150,000 and the total face amount of your outstanding installment obligations arising during the tax year exceeds $5,000,000 at year-end.⁸ The $5,000,000 threshold is fixed by statute and not indexed for inflation. Once you cross it, you owe interest to the IRS on the deferred tax attributable to the portion of the outstanding balance above $5,000,000, calculated at the IRS underpayment rate set each quarter. For very large sales, this charge can erode the benefit of deferral significantly.

Section 453A also contains a pledging rule. If you pledge an installment obligation as collateral for a loan, the net loan proceeds are treated as a payment received on the note, triggering tax on the associated gain immediately.⁸ This applies whenever the sale price exceeds $150,000, whether or not you’re above the $5,000,000 threshold. Actual payments received later on the note are then ignored to the extent they overlap with the amount already triggered.

Buyer Default and Repossession

If the buyer defaults and you repossess real property, the sale is not simply unwound. Repossession has its own gain calculation, and the taxable gain is the lesser of:¹

Total payments received (or treated as received) before repossession, minus the gain you’ve already reported; or
The original gross profit, minus the gain already reported, minus your repossession costs (legal fees, court costs, recording fees, and similar).

The character of that gain (capital or ordinary) matches the original sale. Your basis in the repossessed property becomes the adjusted basis of the installment note (unpaid balance minus the profit portion), plus repossession costs, plus the gain recognized on repossession.¹ That basis matters if you later resell.

Disposing of or Modifying the Note

Selling, gifting, canceling, or otherwise disposing of the installment obligation before it’s fully paid triggers immediate recognition. The gain equals what you receive (or the note’s fair market value in a gift or cancellation) minus your basis in the note, which is its face value minus the income you would have reported had it been paid in full.

If a note is canceled or becomes unenforceable and the buyer is a related party, its fair market value is treated as no less than its face amount, so you can’t claim worthlessness simply because you chose to forgive.¹

Agreeing with the buyer to reduce the selling price without canceling the note is different. It’s not a disposition. Instead, you recalculate the GPP using the lower selling price and apply the revised percentage to payments received after the reduction.¹

Reporting on Form 6252

Every installment sale is reported on IRS Form 6252, Installment Sale Income.⁹ Part I, filed in the year of the sale, walks through the GPP calculation: selling price, adjusted basis, gross profit, and contract price.¹ Part II is filed each subsequent year a payment is received and applies the established GPP to that year’s principal. Part III tracks related-party resales during the two-year monitoring window.

From Form 6252, the gain flows to the right place on your return based on what you sold. Capital assets go to Schedule D.¹⁰ Business property that was subject to depreciation goes to Form 4797. When a sale involves both capital gain and depreciation recapture, the recapture is reported as ordinary income on Form 4797 and the remaining capital gain on Schedule D.

1
Internal Revenue Service. Publication 537 (2025), Installment Sales
2
Office of the Law Revision Counsel. 26 U.S. Code 453 – Installment Method
3
GovInfo. 26 USC 453
4
Internal Revenue Service. Topic No. 705, Installment Sales
5
Office of the Law Revision Counsel. 26 USC 1274
6
Internal Revenue Service. Topic No. 409, Capital Gains and Losses
7
Internal Revenue Service. Topic No. 559, Net Investment Income Tax
8
Office of the Law Revision Counsel. 26 U.S. Code 453A – Special Rules for Nondealers
9
Internal Revenue Service. About Form 6252, Installment Sale Income
10
Internal Revenue Service. Instructions for Schedule D (Form 1040)