IRS Form 706: The Federal Estate Tax Return Explained

Form 706 is the United States Estate Tax Return, filed for the estates of deceased individuals whose gross assets exceed the federal exemption threshold. With the current exemption at $13.61 million per person (2024), only about 4,000 estates file this return each year. But the stakes are enormous: the top estate tax rate is 40%, and the exemption is set to be cut roughly in half after 2025 when the Tax Cuts and Jobs Act provisions sunset. Understanding Form 706 matters for high-net-worth families and the advisors who serve them.

History and Origin

The federal estate tax was first enacted in 1916 to help fund American involvement in World War I. However, the concept of taxing wealth transfers at death has far older roots; inheritance taxes existed in various forms since the Roman Empire, and the United States imposed temporary inheritance taxes during the Civil War and the Spanish-American War.

The 1916 estate tax started with rates ranging from 1% to 10% on estates above $50,000 (roughly $1.4 million in today's dollars). Since then, the tax has been a political flashpoint, with rates and exemptions swinging dramatically depending on the political climate. The top rate reached 77% in 1941 and remained above 70% for decades.

The modern era of estate tax reform began with the Economic Growth and Tax Relief Reconciliation Act of 2001 (EGTRRA), which gradually increased the exemption and reduced the top rate, culminating in a complete repeal of the estate tax for one year; 2010. The 2010 repeal created the bizarre situation where people who died that year paid no estate tax regardless of wealth, while those who died in 2009 or 2011 were subject to the tax.

The Tax Cuts and Jobs Act of 2017 doubled the exemption from roughly $5.5 million to $11 million per person (indexed for inflation). This notable increase means that only the wealthiest 0.1% of estates owe any federal estate tax. However, this doubled exemption is temporary; it is scheduled to revert to approximately $7 million (inflation-adjusted) after 2025.

Who Files It and When

Form 706 must be filed for the estate of every U.S. citizen or resident whose gross estate; combined with adjusted taxable gifts and specific exemption amounts; exceeds the filing threshold. For 2024, the threshold is $13.61 million.

The gross estate includes far more than just probate assets. It encompasses:

• Real estate, stocks, bonds, and business interests
• Life insurance proceeds on policies owned by the decedent
• Retirement accounts (IRAs, 401(k)s)
• Property in revocable trusts (the trust avoids probate but not estate tax)
• Joint property (usually 50% for married couples, potentially 100% if the surviving owner didn't contribute)
• Powers of appointment, if the decedent had the power to direct who receives property, its value may be included

The filing deadline is nine months after the date of death. An automatic six-month extension is available using Form 4768, but the extension is for filing only — estimated tax must be paid by the original due date. The executor or personal representative of the estate is responsible for filing.

Even when no tax is owed, Form 706 may need to be filed to elect portability; the ability to transfer any unused estate tax exemption to the surviving spouse.

Key Sections Explained

• Part 1; Decedent and Executor: Basic information about the deceased, the executor, and the attorney handling the estate.
• Part 2; Tax Computation: The core calculation that starts with the gross estate, subtracts deductions, applies the unified credit, and determines the net estate tax due.
• Schedules A through I; Asset Schedules:Each schedule covers a different category of assets: real estate (Schedule A), stocks and bonds (Schedule B), mortgages and notes (Schedule C), insurance on the decedent's life (Schedule D), jointly owned property (Schedule E), other miscellaneous property (Schedule F), transfers during the decedent's life (Schedule G), powers of appointment (Schedule H), and annuities (Schedule I).
• Schedule J-L; Deductions: Funeral and administration expenses (Schedule J), debts of the decedent (Schedule K), and net losses during administration (Schedule L).
• Schedule M; Marital Deduction:Property passing to the surviving spouse, which qualifies for the unlimited marital deduction. This deduction can eliminate estate tax entirely at the first spouse's death.
• Schedule O; Charitable Deduction: Bequests to qualifying charities, which are fully deductible.
• Portability Election: Part 6 of the form allows the estate to transfer any unused exemption (the Deceased Spousal Unused Exclusion Amount, or DSUE) to the surviving spouse.

Common Mistakes

Failing to file for portability is one of the most consequential oversights in estate planning. If the first spouse to die has an estate below the exemption threshold, no estate tax is due, but the unused exemption is lostunless Form 706 is filed to elect portability. Many families skip the filing because no tax is owed, not realizing they're forfeiting millions in future exemption. The IRS has granted late portability election relief in many cases, but it requires a private letter ruling or meeting specific revenue procedure requirements.

Undervaluing assets; particularly closely held businesses, real estate, and art; is a frequent audit trigger. The IRS has specialized appraisers and economists who review valuations on estate tax returns. Discounts for lack of marketability and minority interests are legitimate but must be well-supported by qualified appraisals. Aggressive discounts without adequate documentation invite challenge.

Missing the stepped-up basis opportunityis a planning failure rather than a filing error. When someone dies, the tax basis of their assets is "stepped up" to fair market value at the date of death. This means unrealized capital gains accumulated during the decedent's lifetime are permanently eliminated. Not accounting for this benefit, or worse, inadvertently structuring ownership to avoid it, can cost heirs significant capital gains tax.

Not coordinating the estate return with income tax returnscan lead to errors. Deductions can sometimes be taken on either the estate tax return (Form 706) or the estate's income tax return (Form 1041), but not both. The executor must make strategic decisions about where to claim deductions for maximum benefit.

Recent Changes

The most pressing issue is the scheduled sunset of the TCJA's doubled exemption after 2025. Unless Congress acts, the exemption will revert from approximately $14 million per person to roughly $7 million (indexed for inflation). This change would increase the number of taxable estates — potentially from 4,000 per year to 30,000 or more.

In anticipation of the sunset, the IRS issued final regulationsconfirming that gifts made under the current higher exemption will not be "clawed back" if the exemption later decreases. This anti-clawback rule has prompted a wave of estate planning activity, with wealthy individuals making large gifts to take advantage of the higher exemption before it potentially drops.

The IRS has also expanded late portability election relief, issuing Revenue Procedure 2022-32, which allows estates to file a late portability election within five years of the decedent's death (up from two years). This has provided relief to thousands of surviving spouses whose estates failed to file Form 706 on time.

There continues to be legislative interest in modifying the stepped-up basis rules. Some proposals have called for eliminating the step-up or replacing it with carryover basis (where heirs take the decedent's original basis). While no changes have been enacted, this remains an active area of policy debate.

For more information, see the official IRS page: About Form 706.

This article is educational and does not constitute tax advice. Consult a qualified tax professional for guidance specific to your situation.