What Is the Estate Tax and How Does It Work?

The estate tax is a federal tax imposed on the transfer of property when someone dies. Unlike income tax, which applies to earnings during life, the estate tax applies to the total value of everything you own at the moment of death. For investors with concentrated portfolios or significant real estate holdings, understanding how the estate tax works is critical to preserving wealth across generations. The estate tax can claim as much as 40% of assets that exceed the exemption threshold, making it one of the most consequential taxes in wealth transfer planning.

Quick definition: The estate tax is a federal tax levied on the transfer of a deceased person's property to their heirs. It applies to the total value of the taxable estate and uses a progressive rate structure, with rates as high as 40% on the portion exceeding the exemption threshold.

Key takeaways

• The estate tax applies to the total value of assets at death, including real estate, investments, retirement accounts, and life insurance proceeds.
• As of the mid-2020s, the federal estate tax exemption is approximately $13.6 million per individual, meaning estates below this threshold owe no federal estate tax.
• The estate tax rate is a flat 40% on the taxable portion of estates exceeding the exemption.
• Only estates worth more than the exemption threshold are required to file an estate tax return (Form 706).
• The estate tax exemption is scheduled to sunset and return to lower levels after 2025 unless Congress acts to extend current rules.

How the Estate Tax Works

The estate tax operates on a simple principle: the IRS values all of your property at the date of death and determines whether the total exceeds the exemption. If it does, your estate pays tax on the excess. The tax is "on top of" your assets, not instead of income tax—assets may be subject to both income tax (during life) and estate tax (at death).

The taxable estate includes:

• Real property: your home, investment real estate, mineral interests
• Financial assets: stocks, bonds, mutual funds, brokerage accounts
• Retirement accounts: IRAs, 401(k)s, 403(b)s (full balance, not just after-tax contributions)
• Business interests: closely held businesses, partnership units, LLC stakes
• Life insurance proceeds: full death benefit, even if you're not the policyholder
• Tangible property: art, collectibles, vehicles, jewelry
• Digital assets: cryptocurrency holdings, online accounts, domain names

The IRS does not count unpaid debts or liabilities; your estate can subtract valid mortgages, outstanding loans, and final medical expenses before calculating the tax. For example, if you own a $2 million home with a $1 million mortgage and your total assets are $14 million, the taxable estate is $13 million ($14M − $1M debt), which in the mid-2020s would result in estate tax of approximately $160,000 on the $400,000 excess over the exemption.

The Exemption and Tax Brackets

The federal estate tax exemption is indexed to inflation annually. In 2025, the exemption stands at approximately $13.6 million per individual. This means your estate does not owe any federal estate tax unless the total value of your taxable property exceeds this amount. For married couples, both spouses have their own exemption, allowing a combined exempt amount of roughly $27.2 million—though there are critical planning steps required to preserve both exemptions.

Once an estate exceeds the exemption, the tax applies at a flat rate of 40% on the excess. There are no graduated brackets; unlike income tax, the estate tax does not apply progressively to successive layers. This flat-rate structure means that a $1 million estate worth $14.6 million faces 40% tax on the $1 million excess, or $400,000 in total estate tax, regardless of how that $1 million is apportioned.

Who Must File an Estate Tax Return?

Not every estate requires filing Form 706, the estate tax return. Only estates with a gross value exceeding the exemption threshold must file—the penalty for not filing is substantial, so executors and trustees must be careful. For estates below the exemption, filing is optional, though there can be advantages to filing anyway (such as resetting the income tax basis of inherited assets, discussed in a later section).

The filing deadline is nine months after death, with an automatic six-month extension available if requested before the deadline. The complexity of Form 706 (which often runs 40+ pages with schedules) makes hiring an estate tax attorney or CPA essential for larger estates.

State Estate Taxes and the Decoupling Issue

Roughly 17 states and Washington, D.C., impose their own estate or inheritance taxes, separate from the federal tax. Some states have high exemptions (close to the federal level), while others have exemptions as low as $1 million. An estate that is exempt from federal tax may still owe significant state tax. For example, Massachusetts has an exemption of just $1 million; an investor in Massachusetts with a $5 million estate pays no federal tax but could owe Massachusetts estate tax on the $4 million excess.

Additionally, many states have "decoupled" from the federal exemption, meaning they no longer automatically use the federal exemption amount. After the federal exemption increased substantially in 2017, some states held their exemptions at prior levels. This creates a situation where a New York resident might owe New York estate tax even if the federal estate tax is avoided.

Estate Tax and the Unified Credit

The federal estate and gift taxes are unified under a single lifetime exemption. This means when you give away taxable gifts during life, you reduce the exemption available at death dollar-for-dollar. Conversely, if you use only a portion of your exemption during life, the unused portion carries forward to your estate. The unified credit is the tax benefit equal to the tax that would be imposed on the exemption amount.

Simplified Illustration of Tax Impact

Portability of the Exemption

Married couples can preserve both spouses' exemptions through an election called portability. This strategy is covered in detail in a later chapter, but the basic concept is that when the first spouse dies, their unused exemption can be transferred to the surviving spouse, effectively doubling the exemption for that couple. Without proper planning and timely filing, the first spouse's exemption is wasted.

Real-World Examples

Scenario 1: Investor in a Low-Exemption State

Patricia, a widow living in Massachusetts, owns a portfolio of $6 million in individual stocks, a vacation home worth $1.5 million, and a condo worth $800,000. Her total taxable estate is $8.3 million. The federal exemption in 2025 is $13.6 million, so she owes no federal estate tax. However, Massachusetts has a state exemption of only $1 million. Her estate faces approximately $2.92 million in Massachusetts estate tax on the $7.3 million excess (at Massachusetts's top rate of 16%). This illustrates the critical importance of understanding state-level rules that may impose tax even when federal tax is avoided.

Scenario 2: Business Owner with Life Insurance

James owns a manufacturing company valued at $9 million and maintains a key-person life insurance policy with a death benefit of $5 million. He has a home worth $2 million and $1 million in liquid investments. When James dies, his taxable estate includes the $9 million business, the $5 million insurance proceeds, the home, and the liquid assets—totaling $17 million. His federal exemption covers $13.6 million, leaving $3.4 million taxable at 40%, or $1.36 million in federal estate tax. His executor may need to sell some company shares to pay the tax, or arrange bank financing.

Scenario 3: Married Couple with Portability Planning

Margaret and her husband Robert each have $8 million in separate property. When Robert dies in 2025, his estate is below the $13.6 million exemption, so no federal tax is owed. However, Robert's executor files Form 706 to elect portability, preserving Robert's unused $13.6 million exemption for Margaret's later use. When Margaret dies five years later with an estate of $12 million, she can use her own $13.6 million exemption plus Robert's preserved exemption of $13.6 million, meaning her heirs owe no estate tax. Without portability, Margaret's estate would have faced $1.36 million in tax.

Common Mistakes

Mistake 1: Ignoring State Estate Tax

Many investors focus solely on the federal exemption and fail to plan for state-level taxes. A $10 million estate in California faces no state estate tax but would face substantial tax in Illinois, Maryland, or Oregon. Failing to account for state rules results in unnecessary tax.

Mistake 2: Not Filing Form 706 to Claim Portability

When the first spouse of a married couple dies, the executor must file Form 706 to elect portability and preserve the deceased spouse's exemption. If this form is not filed within nine months of death (or six months with an extension), the exemption is permanently lost, and the surviving spouse cannot use it. This single omission can cost the family over $5 million in avoidable estate tax.

Mistake 3: Overestimating the Permanence of the Exemption

The current high exemption of $13.6 million is set to sunset and revert to approximately $7 million per person in 2026 unless Congress acts to extend the rules. Investors with estates near the $7 million threshold may face significantly higher tax burdens if they delay planning. Assuming the exemption will remain indefinitely is risky.

Mistake 4: Treating Life Insurance as Avoiding Estate Tax

Many people buy life insurance thinking it avoids estate tax, but life insurance proceeds are fully included in the taxable estate if you own the policy or have incidents of ownership. A $5 million life insurance policy increases the estate tax liability, not decreases it. Life insurance is useful as a tool to pay the tax, not to avoid it.

Mistake 5: Concentrating Assets Without Valuation Discounts

Investors with concentrated portfolios of closely held business interests or real estate can reduce estate tax through valuation discounts (minority discounts, marketability discounts), but these require proper structuring and professional appraisal. Many estates miss these discounts entirely.

FAQ

What happens if my estate exceeds the exemption?

Your executor must file Form 706, the federal estate tax return, and your estate pays tax at 40% on the amount exceeding the exemption. The tax is due nine months after death. Your estate may need to liquidate assets or borrow funds to pay the tax.

Does the estate tax apply to life insurance proceeds?

Yes, if you own the policy or have any incidents of ownership (such as the right to change beneficiaries), the death benefit is included in your taxable estate. However, life insurance can be excluded from the estate if held in an irrevocable life insurance trust (ILIT).

Can I reduce my estate through charitable donations?

Yes, charitable bequests reduce the taxable estate dollar-for-dollar. If you leave $1 million to a qualified charity in your will, your taxable estate is reduced by $1 million. Some investors use charitable remainder trusts or donor-advised funds to achieve both income tax and estate tax benefits.

Is the current exemption permanent?

No. The current exemption of $13.6 million is set to sunset in 2026 and revert to approximately $7 million per person unless Congress extends the rules. Investors should plan for both scenarios.

How is the date-of-death value of assets determined?

The executor values all property at fair market value as of the date of death. For publicly traded securities, this is the closing price on that date. For real estate, closely held businesses, and other illiquid assets, an appraisal is typically required.

Can I give away assets during life to avoid estate tax?

Yes, but you use your lifetime gift exemption, which is unified with your estate exemption. Gifts above the annual exclusion reduce your exemption dollar-for-dollar. Gifting can be useful for specific goals (such as reducing future appreciation or removing life insurance from the estate) but does not eliminate the exemption requirement.

What is the difference between an estate tax and an inheritance tax?

An estate tax is owed by the estate itself; an inheritance tax is owed by heirs based on what they receive. The federal government imposes an estate tax. Iowa, Kentucky, Maryland, Nebraska, New Jersey, and Pennsylvania impose inheritance taxes, where heirs owe tax directly on their bequests (though surviving spouses are often exempt).

Related concepts

• The Federal Estate Tax Exemption
• Step-Up in Basis at Death
• Why Taxes Matter for Investors
• Portability Between Spouses

Summary

The federal estate tax is a 40% tax on the transfer of property at death, but only applies to estates exceeding the exemption threshold of approximately $13.6 million per person in the mid-2020s. Understanding what property is included in your taxable estate, how the exemption works, and the critical role of state estate taxes is essential for preserving family wealth. While most investors will not face federal estate tax, those with significant holdings in real estate, concentrated stock positions, or businesses must plan proactively to minimize tax and ensure smooth transfer of assets to heirs.

Next

→ The Federal Estate Tax Exemption