Section 6166 Installment Payments for Farm Estates — Five-Year Deferral and Annual Installments

Why Farm Estates Need a Payment Plan

Federal estate tax is generally due nine months after the date of death. For a farm estate that owes tax, that timeline can create a cash flow problem. The 2026 basic exclusion is $15 million per decedent; estates above their available exclusion may still face tax while much of their wealth is in land, equipment, and livestock.

Section 6166 of the Internal Revenue Code lets an eligible estate defer principal for up to five years from the original payment due date, then pay in up to ten annual installments. Interest is due each year during the deferral and installment periods.

The 35% Threshold

To qualify, the value of the decedent's interest in a closely held business must exceed 35% of the adjusted gross estate. A sole proprietorship can qualify. A partnership qualifies if the estate's capital interest is at least 20% or the partnership has 45 or fewer partners; a corporation qualifies if the estate holds at least 20% of its voting stock or it has 45 or fewer shareholders. The entity must have carried on a trade or business at the date of death.

Do not assume the threshold is met because the estate owns farmland. Calculate the value of the qualifying business interest against the adjusted gross estate. A farm held only as a passive investment may not satisfy the trade-or-business requirement.

How the Interest Rate Works

The interest rate on deferred estate tax under Section 6166 is below the standard underpayment rate. For decedents dying in 2026, the IRS-indexed amount used to calculate the 2% portion is $1.94 million; this is a calculation amount, not a taxable-value slice. Interest on the remaining deferred tax is charged at 45% of the standard IRS underpayment rate.

That preferential rate makes Section 6166 one of the cheapest forms of financing available to a farm estate. Compare it to the alternative: a commercial bank loan secured by farmland, typically at prime plus 1-2%, or forced liquidation of land at a below-market auction price.

The Payment Schedule

Here is how the deferral and installment schedule works:

Deferral period: Principal is deferred for up to five years from the original estate tax due date. Interest is due annually.

Installments: Up to ten annual payments of principal, plus interest on the remaining balance.

The executor can accelerate payments without penalty at any time — for example, if a strong crop year or a strategic land sale generates surplus cash.

What Triggers Acceleration

The IRS can demand the entire remaining balance in a lump sum if certain events occur:

• Qualifying dispositions of interests in the closely held business reach or exceed 50% of the value of the estate's interest
• An installment or interest payment remains unpaid for six months after its due date

The IRS may require a surety bond or a special lien on estate property as security. A partial disposition below the statutory 50% threshold does not by itself require proportional prepayment.

Combining Section 6166 With Section 2032A

Many farm estates qualify for both Section 6166 (installment payments) and Section 2032A (special use valuation). Using both in combination can reduce the taxable value of land and spread the remaining eligible tax into installments.

The elections are made on the estate tax return (Form 706), generally due nine months after death. Form 4768 provides an automatic six-month filing extension. Section 6166 requires a timely filed return, including an allowed extension. Section 2032A has a separate rule allowing an election on a late-filed return if it is the first return filed.

Practical Steps for the Executor

First, determine whether the farm qualifies as an active business. Pull the most recent Schedule F (Form 1040), FSA farm operating plans, crop insurance records, and any crop-share lease agreements. Document that the decedent or the estate was actively engaged in farming — not just collecting rent.

Second, calculate the 35% threshold using the value of the decedent's qualifying closely held business interest included in the gross estate and the adjusted gross estate. If that ratio exceeds 35%, continue checking the other eligibility requirements.

Third, coordinate with the estate's tax advisor on timing. The Section 6166 election is made on Form 706. During the deferral period, monitor business dispositions and payment deadlines because they can accelerate the remaining tax.

The Farm & Agricultural Estate Settlement Guide walks through both the 6166 and 2032A elections step by step, including the documentation checklist and the interaction between the two when both apply.