Intentionally Defective Grantor Trust (IDGT): 2026 Installment Sale Guide

An intentionally defective grantor trust is one of the most powerful estate-freezing tools available to HNW households — yet it's poorly understood because the name sounds like a flaw rather than a feature. The "defect" is deliberate: the trust is structured to be irrevocable for estate tax purposes (assets leave your estate) but a grantor trust for income tax purposes (you pay the income taxes). That combination, paired with a sale to the trust using a promissory note at the IRS's Applicable Federal Rate, allows appreciation above the AFR to accumulate in the trust and pass to your heirs with no gift tax, no estate tax, and no recognition of gain on the sale — while your annual income tax payments serve as an additional tax-free gift to the trust.

What makes a trust "intentionally defective"?

Under IRC §§ 671–677, a trust is treated as a "grantor trust" for income tax purposes when the grantor retains certain powers or interests that the IRS considers incompatible with a completed transfer. Normally, estate planners avoid grantor trust status because it means paying taxes on income you don't receive. But when paired with an installment sale, grantor trust status is the point — it creates a powerful wealth transfer mechanism.¹

The most commonly used "defects" that create grantor trust status without causing estate inclusion:

• Swap power (IRC § 675(4)(C)): The grantor retains the right to reacquire trust assets by substituting assets of equivalent value. This creates grantor trust status for income tax (grantor controls the trust's investment) without causing estate inclusion under IRC § 2036 — because the power must be exercised at fair market value.
• Power to add charitable beneficiaries (IRC § 674): Grantor retains right to add charitable organizations as beneficiaries. Creates grantor trust status; doesn't cause estate inclusion because the power is limited to charitable additions.
• Spousal access (IRC § 677(a)): If the grantor's spouse can benefit from the trust, this triggers grantor trust status. Combined with careful drafting, it doesn't necessarily cause estate inclusion — though divorce risk makes this defect less commonly used.

The installment sale mechanics

The IDGT's power comes from combining grantor trust status with an installment sale. Here is how a typical IDGT installment sale works, step by step:

1. Seed the trust. The grantor funds the trust with an initial gift — typically 10–15% of the intended note value — to give the trust economic substance. This seed gift ($500K on a $5M note) uses some of the $15M lifetime exemption but is necessary for the IRS to respect the debt as a genuine arm's-length obligation rather than a disguised gift.²
2. Transfer the asset at fair market value. The grantor sells the target asset — concentrated stock, a business interest, FLP units, or real estate — to the IDGT at its current appraised FMV. Because grantor and grantor trust are treated as the same taxpayer under Rev. Rul. 85-13, this is not a taxable event. No capital gains tax is triggered on the sale.³
3. Receive a promissory note at the AFR. In exchange for the asset, the trust issues a promissory note at the applicable federal rate (AFR). The note can be interest-only with a balloon payment at maturity, or fully amortizing. Interest-only structures are most common because they maximize the amount left in the trust to grow for beneficiaries.
4. Asset appreciates inside the trust. While the note is outstanding, the asset grows inside the IDGT. The trust is outside the grantor's estate, so appreciation above the AFR accumulates for beneficiaries entirely estate-tax-free.
5. Grantor pays income taxes on trust income (the hidden gift). Because the IDGT is a grantor trust, all investment income — dividends, interest, and capital gains — flows through to the grantor's personal tax return. The grantor pays these taxes from their own estate. This is a significant benefit: every dollar of income tax the grantor pays is a dollar removed from their estate and preserved in the trust, without using any gift tax exemption and without counting as a taxable gift.
6. Note is repaid at maturity. At the end of the term, the trust repays the note principal (and any remaining interest). The trust retains the appreciated asset, net of the repaid note. That net appreciation — everything above the original sale price — has passed to beneficiaries with no estate or gift tax.

July 2026 AFR rates

The applicable federal rate is the minimum interest rate required on intra-family loans and installment sales to the IRS under IRC § 7872. Using below-AFR rates converts the excess into a taxable gift. The IRS publishes new AFR rates monthly; always use the rate for the month the note is signed.⁴

The July 2026 §7520 rate — used for GRATs, CLATs, and similar split-interest trusts — is 5.20%. The mid-term AFR for IDGT sales (3.29%) is substantially lower than the §7520 hurdle rate, which means an IDGT installment sale requires a lower minimum return than a GRAT to generate meaningful wealth transfer.

Interactive IDGT installment sale calculator

Enter your asset's current value, expected growth rate, and note structure to see how much appreciation transfers to your beneficiaries — and how much estate tax you avoid versus holding the asset until death.

IDGT vs. GRAT vs. SLAT: which tool fits your situation?

Who benefits most from an IDGT installment sale?

1. Business owners before a sale or liquidity event

The IDGT installment sale shines when the grantor transfers closely-held business interests at a current appraised value — which may include minority interest discounts and lack-of-marketability discounts of 20–40% — and the business later sells at a premium. Because there is no gain recognition on the sale to the IDGT (Rev. Rul. 85-13), and because appreciation above the 3.29% note rate passes to beneficiaries tax-free, a business owner who sells $5M of interests (discounted from $7M enterprise value) and watches the company sell for $15M in year 5 has transferred the bulk of that appreciation outside the estate at minimal gift tax cost. Coordinate with the business exit planning guide for the interaction with IRC § 453 installment sales and §1042 ESOP elections.

2. HNW investors with family limited partnership interests

FLP or LLC interests carrying valuation discounts are ideal IDGT assets for two reasons: (1) the discounted value reduces the note size (and thus the seed gift and required interest payments), and (2) the discount itself is not a taxable event because of the grantor trust exception. A grantor who funds an FLP with $10M of investment assets, receives a 70% LP interest (worth $7M after discounts), and sells that interest to an IDGT for a $7M note at 3.29% has effectively transferred the discount benefit and all future appreciation above 3.29% to beneficiaries — without triggering any gain. Read the family limited partnership guide for the valuation discount mechanics.

3. Executives with concentrated low-basis stock

For executives with large blocks of restricted or unrestricted stock with low cost basis, the IDGT installment sale solves a problem that a direct gift cannot: the sale to the IDGT creates no gain recognition, even if the asset has substantial unrealized appreciation. A direct gift triggers no gain recognition either, but it transfers basis — the donee eventually pays capital gains when they sell. With an IDGT, the grantor continues paying income taxes on the trust's investment income, which functions as a continuing transfer without triggering gift tax. Coordinate with the concentrated stock diversification guide for the exchange fund and hedging alternatives.

4. Estates above $15M or in high-estate-tax states

With the federal estate/gift/GST exemption permanently set at $15M per person by the OBBBA (P.L. 119-21, July 2025), married couples can shelter up to $30M from federal estate tax without using any trust strategies.⁵ But for estates above $30M — or for households in states with lower exemptions (Oregon $1M, Massachusetts $2M, New York $7.35M with cliff) — the IDGT installment sale effectively removes appreciating assets from the taxable estate without requiring any additional exemption. The seed gift (10–15% of note) is the only exemption used.

Risks and limitations

IRC § 2036 estate inclusion risk

If the grantor retains too much control over the IDGT — the right to distributions, the ability to revoke the trust, or implicit power to benefit from trust assets — the IRS may argue under § 2036 or § 2038 that the assets were never truly transferred out of the estate. The swap power (§ 675(4)(C)) is the safest "defect" because it is exercisable only at fair market value, which courts have consistently held does not constitute a retained interest in the trust's economic value. Avoid drafting features that give the grantor practical control over distributions or trust income.

The note must be commercially reasonable

The IRS scrutinizes IDGT installment sales under a "bona fide debt" standard. If the note terms are not commercially reasonable — interest rate below AFR, no fixed repayment schedule, interest forgiveness — the IRS may recharacterize the transaction as a gift equal to the full asset value. Best practices: use the monthly AFR for the month the note is signed, execute a formal promissory note with a fixed payment schedule, make all payments on time, and have the trust hold a diversified asset base rather than just the transferred asset.

The 10% seed gift requirement

Courts and the IRS expect the IDGT to have independent economic substance — the note must be a genuine obligation, not just a paper transfer. The general practitioner guideline is that the trust should hold at least 10% of the note value in seed cash or assets not subject to the note. On a $5M installment sale, that means a seed gift of approximately $500K. This seed gift does use the $15M lifetime exemption, but it is typically a small fraction of the total transfer.

No step-up in basis at grantor's death

Assets held in the IDGT are not included in the grantor's estate, which means they do not receive a stepped-up cost basis at death. Heirs who later sell trust assets will owe capital gains on the full appreciation from the original purchase price. For low-basis assets expected to be held long-term or donated to charity, the IDGT forfeits the step-up. Compare the estate tax savings (40%) against the capital gains tax cost (23.8%) before committing. If charitable giving is part of the plan, see the donor-advised fund and charitable remainder trust guides for how to address low-basis assets without triggering gain.

Legislative risk

Congress has periodically considered legislation that would eliminate the grantor-trust installment sale technique — primarily by requiring gain recognition when a grantor sells to a grantor trust, or by requiring grantor trust assets to be included in the grantor's estate. As of July 2026, no such legislation has been enacted. The OBBBA (July 2025) did not address IDGTs. Practitioners consider the risk real but low in the current political environment. If you are considering an IDGT for a time-sensitive asset (pre-sale business, pre-IPO equity), act on the current law.

Implementation steps

1. Engage an estate attorney. The IDGT must be carefully drafted to include an effective grantor trust "defect" (typically the swap power) while avoiding any provision that causes § 2036/2038 estate inclusion. This is not a DIY document.
2. Obtain a qualified appraisal. If the asset is a closely-held business, FLP interest, or other non-publicly-traded property, an IRS-qualified appraisal is required to establish the FMV for the sale. The appraisal date should be as close to the note execution date as possible.
3. Fund the trust with a seed gift. The seed gift (typically 10–15% of the note value) is reported on Form 709 and counts against the $15M lifetime exemption.
4. Execute the sale and promissory note. Sign the note at the current month's AFR. Use the mid-term AFR (3.29% in July 2026) for notes with terms of 3–9 years. File Form 709 to report the seed gift; the installment sale itself is not a reportable gift if priced at FMV.
5. Make all note payments on time. Missed payments are a significant audit risk. Set up automatic transfers and document every payment. If the trust does not have sufficient liquid assets, it can make in-kind payments (transferring asset shares equal to the payment amount at FMV).
6. Coordinate with your CPA. The grantor reports all IDGT income on their personal Form 1040 each year. The trust files Form 1041 but reports all income and deductions as flowing to the grantor. Your CPA needs to know about the IDGT structure at the start of each tax year.
7. Monitor the §675(4)(C) swap power. If the grantor exercises the swap power, the substituted assets must be of equal FMV, supported by documentation. Sloppy swap-power exercises are an audit trigger and could collapse grantor trust status.