What makes a grantor trust intentionally defective?

The trust is intentionally designed with a provision—such as the power to substitute assets of equivalent value—that causes it to be treated as owned by the grantor for income tax purposes while remaining a completed gift for estate and gift tax purposes. This dual treatment is the planning feature, not a flaw.

Why is the grantor paying the trust income tax a benefit?

When the grantor pays income tax on the trusts income, it effectively transfers additional wealth to the trust beneficiaries tax-free. The tax payment reduces the grantors taxable estate without being treated as an additional gift, allowing the trust assets to grow undiminished by income taxes.

Tax Planning with Intentionally Defective Grantor Trusts (IDGTs) | Lynch Law

The intentionally defective grantor trust—commonly known by its acronym, IDGT—is one of the most powerful estate planning techniques available to high-net-worth individuals. Despite the somewhat alarming name, there is nothing defective about the planning. The "defect" is intentional: the trust is designed to be treated as a separate entity for gift and estate tax purposes but as a grantor trust for income tax purposes. This dual treatment creates significant planning opportunities, particularly in the current environment of elevated gift and estate tax exemptions.

How an IDGT Works

An IDGT is an irrevocable trust that contains a provision causing it to be treated as a grantor trust under Sections 671 through 679 of the Internal Revenue Code. Common "defect" provisions include retaining the power to substitute assets of equivalent value (Section 675(4)(C)) or the power to borrow trust assets without adequate security. These provisions trigger grantor trust status without causing the trust assets to be included in the grantor's estate for estate tax purposes.^[1]

The result is a trust that removes assets from the grantor's taxable estate (achieving the transfer tax goal) while the grantor continues to pay income tax on the trust's income (achieving the income tax goal). The grantor's payment of the trust's income tax is itself a tax-free gift—the grantor is paying a liability that would otherwise reduce the trust assets, effectively transferring additional value to the trust beneficiaries without using any additional gift tax exemption.

The Installment Sale to an IDGT

The most common planning technique involving IDGTs is the installment sale. The grantor sells an appreciated asset—typically an interest in a closely held business or investment entity—to the IDGT in exchange for a promissory note bearing interest at the applicable federal rate (AFR). Because the trust is a grantor trust, the sale is disregarded for income tax purposes: there is no capital gain recognition on the sale, and the interest payments on the note are not taxable income to the grantor or deductible by the trust.^[2]

The planning works because the AFR—which is the minimum interest rate required to avoid gift treatment—is typically far below the actual rate of return on the transferred assets. If the assets in the trust appreciate at a rate exceeding the AFR, the excess appreciation passes to the trust beneficiaries free of gift and estate tax. This is the "spread" that makes the technique work, and in a low interest rate environment, the spread can be enormous.

Seeding the Trust

For the installment sale to be respected as a bona fide sale rather than a disguised gift, the IDGT must have economic substance independent of the note. The general practice is to "seed" the trust with assets equal to at least 10% of the value of the property being purchased. This seed capital is typically a taxable gift by the grantor, using a portion of the gift tax exemption. The seed gives the trust a meaningful equity cushion and supports the argument that the trust could service the note even if the purchased assets underperformed.^[3]

Valuation Considerations

The transferred asset is typically a minority interest in an LLC or limited partnership, which qualifies for valuation discounts for lack of control and lack of marketability. These discounts—which can range from 20% to 40% or more depending on the facts—allow the grantor to transfer a larger share of the underlying assets for a smaller gift and estate tax cost. The IRS has challenged aggressive discounts in numerous cases, so the valuation must be supported by a qualified independent appraisal.^[4]

Current Planning Window

IDGT planning is particularly attractive in the current environment because of the historically high gift and estate tax exemption ($13.99 million per person in 2025). If the exemption is reduced—whether by legislative action or the scheduled TCJA sunset—the opportunity to seed IDGTs with large gifts and execute installment sales at current exemption levels will be lost. This creates urgency for high-net-worth individuals who have not yet taken advantage of the current exemption levels. Working with an experienced estate planning attorney is essential to ensure these complex structures are properly implemented.^[5]

References

^[1] IRC §§ 671-679 (grantor trust rules); § 675(4)(C) (substitution power as common IDGT trigger).
^[2] Rev. Rul. 85-13 (grantor trust is disregarded for income tax purposes; sale between grantor and grantor trust is not a taxable event).
^[3] The 10% seed capital requirement is not a statutory rule but a widely accepted planning convention. See Karmazin v. Comm'r, T.C. Memo. 2003-41 (discussing bona fide sale requirement for sales to grantor trusts).
^[4] See, e.g., Estate of Holliday v. Comm'r, T.C. Memo. 2016-51 (discussing valuation discounts for interests in family LLCs).
^[5] See Estate Planning (discussing IDGT planning and other advanced estate planning techniques).