An installment sale under IRC Section 453 allows you to receive the purchase price for your business over multiple years rather than all at once at closing, and to recognize the capital gain proportionally in each year you receive payment. This defers your tax liability across several years, potentially keeping you in a lower tax bracket each year and reducing your total tax burden compared to recognizing the entire gain in a single year.
In a standard business sale, the entire purchase price lands in your account at closing, and you owe tax on the full gain in that year, regardless of whether the liquidity event pushes you into the highest capital gains bracket. An installment sale changes the timing by treating the sale as a series of payments, each carrying a proportionate share of your gain.
The mechanics work as follows: you calculate the gross profit percentage (gain ÷ total contract price). Each payment you receive is multiplied by that percentage to determine how much of it's recognized gain. The rest is a return of your basis (tax-free). You also receive interest on the outstanding balance, which is taxed as ordinary income.
Installment sales are most effective when they spread your income across years when your marginal tax rate is lower, for example, before Social Security begins, before you take required minimum distributions, or before Medicare IRMAA thresholds kick in. They're less effective if you're already in the 20% capital gains bracket regardless of the sale.
The tradeoff is credit risk. You're effectively lending money to the buyer, if the buyer defaults, your recourse is legal action against the business assets, which may have declined in value. For this reason, installment sales are most common with buyers who have strong financials, in smaller transactions, or when secured by a lien on business assets. They should always be structured with a proper promissory note and security agreement.
Key facts
- Installment sales are governed by IRC Section 453
- Gain is recognized proportionally each year based on the gross profit percentage (gain ÷ contract price)
- Interest charged to the buyer is taxed as ordinary income each year, separate from the capital gain portion
- Depreciation recapture income (Section 1245 / 1250) must generally be recognized in full in the year of sale, even in an installment sale
- You can elect out of installment treatment if lump-sum recognition is preferable (e.g., to use capital loss carryforwards)
- Payments due within one year of sale may be treated differently, consult a CPA on the specifics
What is a seller note in a business sale?
A seller note (or seller financing) is the formal mechanism for an installment sale, the buyer signs a promissory note agreeing to pay you the remaining purchase price over a set period, typically at an agreed interest rate. The note should be secured by a lien on business assets or other collateral, and the terms should be documented in your purchase agreement.
Can I use an installment sale to avoid the Net Investment Income Tax?
Spreading income across years can help if doing so keeps your MAGI below the $200,000 / $250,000 NIIT threshold in any individual year. However, if the business is large enough that even a single year's installment payment exceeds those thresholds, the NIIT will apply proportionally to the gain recognized each year.
