IRC Section 453: The Installment Sale Tax Playbook

A founder sells a rental property for $900,000. Her adjusted basis is $300,000 and selling expenses run $20,000: the gain is $580,000. The buyer puts $100,000 down and pays $100,000 a year for seven years. Without section 453 she owes tax on the full $580,000 in the year of sale — on money she has not received. With it, she recognizes $72,500 a year for eight years.

The statute: what counts as an installment sale

Section 453(a) states the general rule: income from an installment sale is taken into account under the installment method. Section 453(b)(1) defines the sale: a disposition with at least one payment after the close of the year of disposition. Section 453(c) defines the method: the income recognized for any year is the proportion of the payments received which the gross profit bears to the total contract price.

The ratio — the gross profit percentage — is computed once, in the year of sale, and does not change. Section 453(b)(2) excludes dealer dispositions and inventory personal property; per Publication 537, gain from stock or securities traded on an established market must be reported in full in the year of the trade date.

The math: one ratio, eight years

Form 6252, Part I, for the founder's sale: selling price $900,000, including a $100,000 mortgage the buyer assumes; adjusted basis $300,000; selling expenses $20,000.

Contract price is the selling price minus the mortgage assumed (the excess of basis and expenses over the mortgage is zero here):

That 72.5% — line 19 of Form 6252 — governs every year of the note. The buyer pays $100,000 down and $100,000 a year for seven years, and each payment produces the same income:

Eight payments recognize the full $580,000. At an assumed 20% rate, the annual tax is $14,500, not a single $116,000 bill. Interest is separate ordinary income, never on Form 6252.

Form 6252: the filing mechanics

Form 6252 (2026) is filed for the year of disposition and every year after, until the final payment or disposition of the obligation — even in a year with no payment. Part I, Gross Profit and Contract Price (lines 5–18), builds the ratio. Part II (lines 19–26) applies it: line 19 the gross profit percentage, line 24 installment sale income, line 26 the amount carried to Schedule D or Form 4797. Do not file it for a sale that produces no gain, for stock or securities traded on an established market, or where the taxpayer elects out — report those on Form 4797, Form 8949, or Schedule D.

Who is in the room: entities, advisers, and the note

The entity changes the paperwork, not the ratio. A single-member LLC reports the sale on the owner's return; a multi-member LLC files Form 1065 as a partnership unless it elects corporate treatment; a C-Corp files Form 1120; an S-Corp files Form 1120-S, passing the gain to shareholders on Schedule K-1. Each needs an EIN, a CPA who has filed a § 453 return before, and books kept on a GAAP basis. The note is usually tracked on a SaaS platform — a seller-financing or loan-servicing API that follows the amortization schedule and interest split — and a B2B seller should confirm it reports interest separately, because only principal is multiplied by the gross profit percentage. The pricing calculator models the cash side of a financed sale; the tax side belongs on Form 6252.

The dealer exclusion and the timeshare exception

A dealer cannot use the installment method — with one narrow exception. Dealers of timeshares and residential lots may treat certain sales as installment sales if they elect to pay a special interest charge under § 453(l): interest on the deferred tax, the same economic idea as the § 453A charge below.

Related persons: the two traps

Selling to family or a controlled entity is where installment sales most often collapse. The first trap is § 453(e), the second-disposition rule. Sell to a related person — spouse, child, grandchild, parent, sibling, or a related corporation, S corporation, partnership, estate, or trust under § 453(f)(1) — and if that person disposes of the property before you have received all payments, the amount realized is treated as received by you then. For property other than marketable securities, the rule applies only if the second disposition occurs within two years of the first. Exceptions: an involuntary conversion threatened after the first disposition, a disposition after the death of the seller or buyer, or a showing that tax avoidance was not a principal purpose. Form 6252, Part III, reports it for the year of sale and the two years after.

The second trap is § 453(g). An installment sale of depreciable property between related persons — § 1239(b), plus partnerships related under § 707(b)(1)(B) — cannot use the installment method unless tax avoidance is shown not to have been a principal purpose. Where denied, all payments are treated as received in the year of disposition, except contingent payments whose fair market value cannot be reasonably ascertained, for which basis is recovered ratably. The purchaser may not increase basis before the amount is includible in the seller's gross income.

Electing out: when deferral is the wrong answer

Section 453(d) lets the taxpayer elect out — report the entire gain in the year of sale. To elect out, report the selling price on a timely filed return, including extensions, on Form 4797, Form 8949, or Schedule D. If the original return was filed on time without the election, it can still be made on an amended return filed no later than six months after the due date, excluding extensions, with "Filed pursuant to section 301.9100-2" at the top.

Imputed interest: §§ 1274 and 483

A note with no interest, or interest below the market rate, does not escape interest treatment. Section 1274 re-prices the deal: with no adequate stated interest, the issue price is the imputed principal amount — the sum of the present values of all payments due, discounted at the applicable Federal rate compounded semiannually. The difference between the face amount and the imputed principal amount is original issue discount, taxed as interest over the note's life. In a potentially abusive situation, including a tax shelter, the imputed principal amount is the property's fair market value. Section 483 covers the contracts § 1274 does not reach: total unstated interest — the excess of the sum of payments due over the sum of their present values, discounted at the AFR — is interest where a payment is due more than six months after the sale, some or all payments are due more than one year after the sale, and there is total unstated interest. Either way, the interest portion is ordinary income when it accrues.

The § 453A interest charge: deferral above $5,000,000

Section 453A applies to a nondealer obligation with a sales price over $150,000, and the interest charge applies only if the obligation is outstanding at year-end and the face amount of all such obligations arising during and outstanding at year-end exceeds $5,000,000. Farm property and personal-use property of an individual are excepted; § 52 single-employer groups count as one person. The charge is computed in three factors under § 453A(c):

Deferred tax liability is the gain not yet recognized at year-end, times the maximum rate under § 1 or § 11 — with the § 1(h) net capital gain rate for long-term capital gain. The applicable percentage is the portion of the aggregate face amount above $5,000,000, divided by the aggregate face amount. The underpayment rate is the § 6621(a)(2) rate for the month with or within which the tax year ends, published quarterly in the Internal Revenue Bulletin.

Publication 537 works it on ABC, Inc., a C corporation that sold intellectual property with a $0 basis on November 15, 2022 for $15,000,000, with $500,000 of expenses and payments of $1,000,000 in 2022, $5,000,000 in 2023, and $9,000,000 in 2024. Gross profit is $14,500,000 and the percentage is 96.67%. At the end of 2022, recognized gain is $966,667, unrecognized gain $13,533,333, deferred tax liability at 21% $2,842,000, and face amount outstanding $14,000,000 — so the applicable percentage is 64.29% and the 2022 interest, at the 6% rate quoted in the publication, is $109,620.

The applicable percentage is fixed in the year of sale, so the 2023 charge uses the same 64.29% times the 2023 rate (8% as of December 31, 2023). The interest is not figured on Form 6252: individuals report it on Schedule 2 (Form 1040), line 15; corporations on Form 1120, Schedule J, line 9f. A corporation may deduct it when paid or accrued; an individual may not.

The pledge rule: borrowing against the note

Section 453A(d) closes the obvious workaround: borrowing against the note. If indebtedness is secured by an installment obligation, the net proceeds are treated as a payment on the obligation, as of the later of the time the debt becomes secured or the proceeds are received. The amount treated as received cannot exceed the excess of the total contract price over payments received before the secured debt was obtained. The note is not a line of credit: pledge it and the deferral ends to the extent of the borrowing.

Repossession: when the buyer stops paying

For personal property, gain or loss on repossession is the property's fair market value minus the seller's basis in the installment obligation and any repossession costs. Publication 537's Worksheet C example: FMV $1,400, unpaid balance $800, gross profit percentage 40%, unrealized profit $320, basis $480, repossession costs $75, gain $845.

For real property the rules are mandatory — but only where the repossession protects the seller's security rights, the obligation was received in the original sale, and no additional consideration was paid unless the original contract provided for it. Gain is the total payments received minus the total gain already reported, and taxable gain is limited to the gross profit on the original sale minus the gain already reported. No bad-debt deduction is allowed on a real-property repossession, and one taken in an earlier year is recovered as income in the year of repossession.

Installment sale or like-kind exchange

Section 453(f)(6) adjusts the installment computation where the exchange is described in § 1031(b): total contract price and gross profit are both reduced for the property received without recognition of gain. The section 1031 like-kind exchange playbook covers the exchange side: § 1031 defers gain by swapping into replacement property, while § 453 defers gain by taking a note instead of cash. A seller exiting the asset takes the note; a seller entering a different asset takes the exchange. Where the gain qualifies, the IRC 1202 QSBS 100 percent gain exclusion rules can eliminate it outright, when the stock and the holding period qualify.

Filing sequence

1. Compute selling price, adjusted basis, selling expenses, and any mortgage assumed before the note is signed.
2. Draft the note with adequate stated interest at or above the applicable Federal rate.
3. If the buyer is related, confirm the § 453(e) two-year exposure and the § 453(g) bar for depreciable property.
4. Test the § 453A thresholds: sales price over $150,000 and aggregate obligations over $5,000,000 at year-end trigger the interest charge.
5. File Form 6252 for the year of sale — Parts I and II, plus Part III if the buyer is related — and every year until the final payment.
6. Report interest separately as ordinary income, and the § 453A charge on Schedule 2, line 15, or Form 1120, Schedule J, line 9f.

Execution checklist

• [x] At least one payment after the close of the year of sale
• [x] Gross profit percentage computed on Form 6252, Part I
• [x] § 453(e) two-year clock and § 453(g) bar checked
• [x] § 453A thresholds tested: $150,000 sales price, $5,000,000 aggregate obligations

The decision in advance

Section 453 rewards the seller who plans the note before signing it: compute the gross profit percentage, price interest at or above the applicable Federal rate, clear the related-party rules, test the $5,000,000 threshold, never pledge the note. This playbook is for the seller of real property, a business, or other non-inventory property financing the buyer — not for a dealer, a seller of inventory or marketable securities, or a seller who cannot afford the buyer's default.