UpTrajectory Review

Selling a business on an installment note lets the owner spread capital gains tax across the years he actually collects the payments. Congress built one exception into that deferral: once a seller's installment obligations for the year top $5 million, Section 453A imposes an annual interest charge on the deferred tax. Whitehead's piece in CPA Practice Advisor walks through what sellers must model before they sign. The charge applies to non-dealer dispositions of property used in a trade or business or held for production of income, and it runs from the date of sale until the tax is paid. The rate tracks the federal short-term rate plus three percentage points, compounded daily.

For a small-business owner who expects to retire on the proceeds of a sale, the threshold changes the math on every term sheet. A $4.9 million note keeps the deferral clean; a $5.1 million note triggers an interest bill the seller must pay each year, in cash, before he has collected enough to cover the underlying tax. Owners who plan to sell in 2026 or 2027 should pull the note balance into the negotiation now, not after the letter of intent. The buyer cares too, because a seller who faces an interest charge will push for a bigger down payment or a shorter payout, and that pressure lands on the buyer's financing.

The $5 million figure is not indexed for inflation, which makes it a smaller gate every year. Whitehead's guidance is sound: model the interest charge against the after-tax proceeds under alternative structures, including a smaller note, an earnout, or a partial installment sale combined with a cash component. We agree with the emphasis on modeling. The piece underplays one point, though. The charge applies to the face amount of the obligation, not the gain, so a seller with a high basis still pays interest on deferred tax that may never come due if the buyer defaults. That risk belongs in the model.

Second-order effects reach beyond the two parties. A seller who structures around the threshold may shift income into years when other deductions or credits no longer apply, which raises the effective rate. A seller who ignores the threshold may face a liquidity squeeze in year two or three, when the interest bill arrives but the buyer has fallen behind on payments. The advisor who drafts the note also faces exposure, because a client who learns about Section 453A after closing will ask why no one raised it. The cleanest fix is often a written model, signed by the client, that shows the charge under realistic collection scenarios.

Watch for two developments. First, any proposal to index the $5 million threshold or to repeal Section 453A, which surfaces in tax bills every few years and gains traction when sale volumes rise. Second, the IRS's guidance on how the charge applies to contingent payments and wraparound notes, an area where the rules remain thin. An owner who plans to sell should ask his CPA to run the Section 453A calculation on the proposed terms before he signs the letter of intent, and he should revisit the model if the buyer asks to restructure the note after closing.

“Once a seller’s installment obligations for the year top $5 million, Section 453A imposes an annual interest charge on the deferred tax.” — CPA Practice Advisor

Takeaway: Model Section 453A interest on any installment note above $5 million before you sign the letter of intent.