IDGT (Intentionally Defective Grantor Trust)
An IDGT is an irrevocable trust that is treated as the grantor's for income tax purposes but as separate from the grantor's estate for gift and estate tax purposes — a mismatch used to shift appreciation and pay tax from the estate, both of which reduce the taxable estate.
Definition
An Intentionally Defective Grantor Trust (IDGT) is an irrevocable trust designed to be treated, for federal tax purposes, as two different entities:
- Income tax: the grantor is treated as the owner — so all trust income is taxed to the grantor personally (the “defect”)
- Gift and estate tax: the trust is a separate entity, with assets removed from the grantor’s taxable estate
This deliberate mismatch — intentional in design, “defective” only in the quirky tax-code sense — is the engine of a powerful estate-planning toolkit.
Why the mismatch matters
Two consequences follow from grantor-trust status on a completed gift:
- The grantor pays the trust’s income taxes — out of their own funds, not trust funds. This is an additional indirect gift to the trust (not a taxable gift under the IRS’s current position), because it depletes the grantor’s taxable estate while allowing the trust’s assets to compound pre-tax.
- Transactions between the grantor and the trust are ignored for income tax purposes. Sales of assets to the trust are not taxable events. This is the basis of the classic “sale to an IDGT” technique.
The sale-to-IDGT technique
A standard play:
- Grantor seeds the IDGT with approximately 10% of the asset value (to give the trust “economic substance”) — often funded using lifetime gift tax exemption
- Grantor sells appreciated assets to the IDGT in exchange for a promissory note at the applicable federal rate (AFR), currently a minimum hurdle set monthly by the IRS
- Because of grantor-trust status, the sale is not a taxable event for income tax purposes — no capital gains
- The trust uses the asset’s cash flow or eventual sale to pay down the note
- Any appreciation above the AFR hurdle accrues to the trust, outside the grantor’s estate
The technique is particularly powerful for pre-IPO stock, private company interests, or real estate with strong expected appreciation.
IDGT vs GRAT
Both structures transfer future appreciation out of the estate. Key differences:
| IDGT | GRAT | |
|---|---|---|
| Estate inclusion risk on death | Generally none | Full if death during term |
| Uses lifetime exemption | Yes, on the seed gift | Can be zeroed out |
| Interest rate | AFR (generally lower than 7520) | Section 7520 rate |
| Works well with discounts | Yes | Yes, but more scrutinized |
| Best for | Larger transfers, longer horizons | Volatile assets, shorter horizons |
Both are often used in parallel: GRATs for short-term opportunistic gifting, IDGTs for the larger structural transfer of appreciating assets.
Discounts and valuation
IDGTs are often funded with interests that qualify for lack-of-marketability and minority-interest discounts — family limited partnership interests, non-voting LLC units, or minority equity in a family business. Properly executed, a $30 million interest may be valued at $20 million for gift tax purposes, amplifying the transfer.
Discount planning requires careful appraisal work, genuine economic arrangements (not purely cosmetic), and advisors familiar with IRS scrutiny in this area. Many aggressive discount plays have been challenged; well-structured ones have held up in Tax Court.
Generation-skipping
IDGTs are commonly drafted to last for multiple generations, allocated GST exemption at funding, and situated in states with favorable trust laws (South Dakota, Nevada, Delaware, New Hampshire) to extend duration. Combined with dynasty trust principles, a well-designed IDGT can hold assets across centuries.
Turning off grantor-trust status
Grantor-trust status is driven by specific trust provisions (typically a power of substitution or the ability to borrow without adequate security). A grantor who no longer wants to pay the trust’s income taxes can, if the trust is properly drafted, “toggle off” grantor-trust status — at which point the trust becomes a separate taxpayer and the grantor stops bearing the income tax burden.
Best candidates for IDGT use
- Pre-IPO or early-stage company stock expected to appreciate substantially
- Family business interests headed for transfer
- Appreciating real estate portfolios
- Households with remaining lifetime exemption they want to deploy before future reduction
Limitations
- Legislative risk. Proposed legislation has periodically targeted grantor-trust rules, including measures that would include grantor-trust assets in the grantor’s estate or treat sale transactions as taxable events.
- Complexity. IDGTs require coordinated income, gift, and estate tax planning plus careful trust drafting.
- Valuation scrutiny. Sales at below-market valuations invite IRS challenge.
- Cash flow burden on the grantor from paying the trust’s income tax — which is the point, but requires planning.
Related on QP List
Nothing on this page is legal or tax advice. IDGT mechanics depend on current IRS rules and evolving legislative proposals.