Installment Sale Tax: How Section 453 Spreads the Gain

How an installment sale works

An installment sale is any sale where at least one payment arrives after the end of the tax year of the sale (IRC 453(b)(1)). The installment method applies automatically; you do not elect into it. You elect out if you would rather report everything now.

The math rests on three numbers:

• Gross profit: selling price minus adjusted basis, selling expenses and any depreciation recapture already reported.
• Contract price: generally the selling price, less any existing mortgage the buyer assumes up to your basis.
• Gross profit ratio: gross profit divided by contract price. That share of every principal dollar you receive is gain; the rest is your basis coming back.

The buyer's promissory note is not a payment when you receive it (IRC 453(f)(3)). Cash at closing, the down payment, and buyer funds used at closing to pay off your mortgage are payments in the year of sale (Temp. Reg. 15a.453-1(b)(3)(i)). A note payable on demand or readily tradable counts as a payment (453(f)(4)), and so does a note secured by cash or a cash equivalent. Interest on the note is separate: it is ordinary income in the year received, and it must be at least the applicable federal rate or the IRS recharacterizes part of the principal as interest (IRC 483 and 1274).

Who it fits, and who it does not

Strong fit:

• Owners of rentals, land or a closely held business whose one-year gain would push them into the 20% capital gain bracket plus the 3.8% net investment income tax.
• Sellers about to retire, whose other income drops in the years the payments arrive.
• Farm sellers: farm property is exempt from the Section 453A interest charge (IRC 453A(b)(3)(B)).
• Sellers who want a steady interest-paying asset and know and trust the buyer, such as a key employee, a tenant or a neighbor.

Poor fit:

• Publicly traded stock or securities (453(k)(2)), dealer property and inventory (453(b)(2)): the installment method is not available.
• Sellers who need all the cash now, or who cannot get comfortable with the buyer's credit.
• Property with heavy cost segregation: the recapture is taxed in year one whether or not cash arrives.
• Depreciable property sold to a controlled entity or other related party: 453(g) generally denies the method.
• Sales at a loss: the method only spreads gain.

Worked example: one year versus ten

Assumptions (illustration only): married couple filing jointly, Texas residents (no state income tax), $100,000 of other ordinary income every year. They sell investment land held for many years for $1,500,000; adjusted basis $500,000, so the gain is $1,000,000 and the gross profit ratio is two-thirds. No selling costs, no depreciation. 2026 federal law and brackets (Rev. Proc. 2025-32) held flat for every year. Tax shown is the added federal income tax plus net investment income tax on the gain, computed with the Big Sale Tax engine. Interest on the note is ordinary income and is left out to isolate the gain.

Same gain, $99,755 less federal tax in this illustration, because most of the gain lands in the 0% and 15% brackets instead of the 20% bracket, and stays under the $250,000 joint threshold for the net investment income tax. Your numbers depend on your income, state and terms. Try the one-year versus spread estimator or see the scenario comparisons.

What is still taxed in the year of sale

• Depreciation recapture. Ordinary recapture under Sections 1245 and 1250, including recapture on cost-segregated components, is recognized in full in the year of sale even if no cash arrives (IRC 453(i)). Unrecaptured Section 1250 gain on a straight-line building is different: it is deferred, but it comes out first, at up to 25% (Treas. Reg. 1.453-12).
• Mortgage payoff at closing. Buyer funds that pay off your loan are a payment to you.
• Debt above basis. If the buyer assumes a mortgage larger than your basis, the excess is a year-one payment.
• Down payment and any cash at closing.

IRS stance and audit risk

The installment method is long-settled law. Section 453 in its current form dates to the Installment Sales Revision Act of 1980, and the IRS explains it in Publication 537. A plain installment sale to a real buyer is not a listed transaction and carries no special disclosure. Audits focus on mechanics:

• Section 453A interest. For sales over $150,000, if the face amount of installment notes arising in the year and still outstanding at year end exceeds $5,000,000, you owe interest each year on the deferred tax tied to the excess. The rate is the IRS underpayment rate (IRC 6621(a)(2)) and the deferred tax uses the top rate. Example of the ratio: $8,000,000 outstanding means 37.5% of the deferred tax bears interest. Farm property and personal-use property are exempt.
• Pledge rule. Borrowing against the note is treated as receiving payment (453A(d)).
• Disposing of the note. Selling, gifting or cancelling the note triggers the remaining gain (IRC 453B). Transfers to a spouse are excepted.
• Related parties. If a related buyer resells within two years, you are treated as paid in full (453(e)).
• Interest below AFR gets recharacterized (IRC 483, 1274).
• Death. The unpaid note is income in respect of a decedent: no step-up, heirs report the gain as paid (IRC 691).

Do not confuse it with a monetized installment sale, which adds an intermediary and a loan and which the IRS proposed to identify as a listed transaction in 2023 (REG-109348-22).

Protecting yourself from buyer default

With a direct installment sale you are the bank. The protections that matter most:

• Down payment: real buyer equity, often 20% or more, so walking away costs the buyer.
• Security: a first-position deed of trust or mortgage on real estate; a UCC lien on business assets, stock or membership interests.
• Personal guarantee from the buyer's owners when the buyer is an entity.
• Note terms: a rate at or above the AFR, amortization, any balloon, acceleration on default and a due-on-sale clause, cure periods, prepayment terms, covenants and annual financial reporting.
• Collateral upkeep: a lender's title policy, required property insurance naming you, and tax payments kept current; escrow or holdbacks where useful.

If the buyer defaults on real estate, IRC 1038 limits the tax on taking it back. The seller financing analysis walks through each protection and a repossession example.

Costs and fees

• Attorney fees to draft the note, deed of trust or security agreement, and any personal guarantee.
• Title and escrow charges, including a lender's title policy.
• Optional loan servicing company to collect payments, track escrow for taxes and insurance, and issue Forms 1098 and 1099.
• Annual Form 6252 reporting by your CPA for every year a payment arrives.
• Section 453A interest, if it applies.
• The economic cost: your money sits in one note at one rate instead of a diversified portfolio.

How it compares with the other tools

For a direct head-to-head, see 1031 vs installment sale and deferred sales trust vs installment sale. If a single year would be cheaper, electing out is allowed through the due date of the return, including extensions.

Frequently asked questions