When the grantor of a revocable living trust dies, the trust becomes a separate taxpayer, and the taxes on a decedent’s trust fall into two tracks: income tax on anything the trust earns after the date of death, reported on Form 1041, and potentially federal estate tax if the total estate tops $15 million. The income tax side is where most trustees get burned, because trusts hit the top 37% federal bracket at just $16,000 of taxable income in 2026. Nearly every timing and distribution decision the successor trustee makes turns on that fact.
What Changes at the Grantor’s Death
During the grantor’s lifetime, a revocable living trust is invisible to the IRS. Income flows through to the grantor’s personal return under the grantor’s Social Security number, and the grantor can amend or dissolve the trust at will. Death ends that. The trust locks into an irrevocable structure, its assets separate permanently from the decedent’s personal finances, and it becomes its own taxpayer from that day forward.
The successor trustee named in the document steps in immediately. That person owes fiduciary duties to the beneficiaries: every choice about investments, distributions, and expenses has to serve their interests. First tasks are securing assets, notifying financial institutions, and re-titling accounts held in the decedent’s individual name into the trust’s name under the new trustee.
Assets already titled to the trust stay put. If the decedent had a pour-over will directing personal assets into the trust, those items pass through probate first before they land in the trust.
Setting Up the Trust’s Tax Identity
The trust needs its own taxpayer ID number now that it is irrevocable. The trustee applies for an Employer Identification Number by filing Form SS-4, which can be done online, by fax, or by mail.1Internal Revenue Service. About Form SS-4 The EIN has to be in hand before the trustee can open bank accounts under the trust, receive investment income, or file the trust’s return.
The trustee should also file Form 56 to formally notify the IRS of the fiduciary relationship, which puts the agency on notice that the trustee is now the responsible party for the trust’s tax matters.2Internal Revenue Service. About Form 56, Notice Concerning Fiduciary Relationship
Separate bank accounts under the trust’s new EIN receive all post-death income (rent, dividends, interest) and pay all administrative expenses. Commingling trust funds with personal money is one of the fastest routes to personal liability for a trustee.
The Step-Up in Basis, and What Doesn’t Get It
The biggest tax break triggered by death is the step-up in basis. Under federal law, the cost basis of assets acquired from a decedent resets to fair market value as of the date of death.3Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired From a Decedent Property held in a revocable trust qualifies because the grantor retained the right to revoke or amend during life.
The effect is dramatic. If the decedent bought stock decades ago for $10,000 and it was worth $200,000 at death, the $190,000 of unrealized gain simply disappears. A beneficiary who sells the next day at $200,000 has zero taxable gain. So the trustee has to establish fair market value for every trust asset as of the date of death, because those numbers are the starting point for every future capital gains calculation.
Not everything steps up. Items classified as income in respect of a decedent (IRD) keep the decedent’s original tax character. The common IRD assets are traditional IRA and 401(k) balances, unpaid wages, and deferred compensation. When those get distributed, the recipient pays ordinary income tax on the full amount, just as the decedent would have.4Office of the Law Revision Counsel. 26 USC 691 – Recipients of Income in Respect of Decedents Identifying and segregating IRD items early prevents reporting mistakes later.
The Alternative Valuation Date
If the estate owes federal estate tax, the executor can elect under Section 2032 to value all assets six months after death instead of on the date of death. The election is available only when it reduces both the gross estate and the total estate tax owed. It also resets the stepped-up basis to the six-month value, so in a declining market, estate tax savings could come at the cost of a lower basis for beneficiaries. Both sides have to be weighed.
Filing Form 1041 and the Compressed Brackets
Income the trust earns after the grantor’s death gets reported on Form 1041, U.S. Income Tax Return for Estates and Trusts. A trust must file Form 1041 if it has any taxable income for the year, gross income of $600 or more, or a beneficiary who is a nonresident alien.5Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 This return is completely separate from the decedent’s final personal return on Form 1040, which covers January 1 through the date of death and still has to be filed by the surviving spouse or personal representative.6Internal Revenue Service. How to File a Final Tax Return for Someone Who Has Passed Away
The rate schedule is brutal. For 2026, taxable income up to $3,300 is taxed at 10%; $3,301 to $11,700 at 24%; $11,701 to $16,000 at 35%; and everything over $16,000 at 37%.7Internal Revenue Service. 2026 Form 1041-ES An individual doesn’t hit 37% until well over $600,000 of taxable income. A trust gets there at $16,000. On top of that, the 3.8% net investment income tax applies to trusts once adjusted gross income exceeds the threshold where the 37% bracket begins, which for 2026 is $16,000.8Internal Revenue Service. Topic No. 559, Net Investment Income Tax Undistributed investment income inside a trust can face a combined federal rate above 40%.
Whether the Trust or the Beneficiary Pays
The mechanism that shifts tax off the trust and onto beneficiaries is distributable net income (DNI). DNI is broadly the trust’s net income available to pass through. When the trustee distributes income, the trust claims a corresponding deduction on Form 1041, and the liability moves to the beneficiaries, who report their shares on their own returns, usually at lower rates because their brackets are so much wider.9Office of the Law Revision Counsel. 26 USC 643 – Definitions Applicable to Subparts A, B, C, and D
Each beneficiary’s share is reported on Schedule K-1 (Form 1041), which has to be furnished to the beneficiary by the date Form 1041 is due.5Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 The K-1 breaks income out by type (interest, dividends, capital gains, rental income) so each category keeps its tax character on the beneficiary’s return.10Internal Revenue Service. Instructions for Schedule K-1 (Form 1041) for a Beneficiary Filing Form 1040 or 1040-SR
The IRS categorizes trusts as simple or complex. A simple trust must distribute all income annually and cannot distribute principal or make charitable gifts; because income leaves each year, beneficiaries generally pay the tax. A complex trust can accumulate income, distribute principal, or make charitable contributions. Most irrevocable trusts created from a formerly revocable living trust are complex because the trustee has discretion.
Capital gains behave differently. Under fiduciary accounting rules, gains from selling appreciated trust assets are generally treated as principal, not income, so they stay at the trust level and get taxed there instead of passing through in DNI. Exceptions: the trust document specifically allocates gains to income, the gains are distributed with principal, or the trust is in its final year, at which point remaining gains flow out to beneficiaries on their K-1s.9Office of the Law Revision Counsel. 26 USC 643 – Definitions Applicable to Subparts A, B, C, and D
Elections That Cut the Bill
The Section 645 Election
If the decedent also had a probate estate, the trustee and executor can jointly elect under Section 645 to treat the revocable trust as part of the estate for income tax purposes. Estates can choose a fiscal year rather than a calendar year, which can defer income into a later period and give beneficiaries more time before the first K-1 arrives.11Office of the Law Revision Counsel. 26 USC 645 – Certain Revocable Trusts Treated as Part of Estate
The election runs until the earlier of the date all assets are distributed or the “applicable date.” If no estate tax return is required, the applicable date is two years after death. If Form 706 is required, it is the later of two years after death or six months after the estate tax liability is finally determined.12eCFR. 26 CFR 1.645-1 – Election by Certain Revocable Trusts to Be Treated as Part of Estate It has to be made by the due date, with extensions, of the estate’s first income tax return, and it cannot be revoked.
The 65-Day Rule
Under Section 663(b), a trustee can elect to treat distributions made within the first 65 days after the close of the tax year as if they were made on the last day of the prior tax year.13eCFR. 26 CFR 1.663(b)-1 – Distributions in First 65 Days of Taxable Year That gives the trustee until early March to look at the trust’s income for the year just ended and push income out to beneficiaries retroactively, avoiding the top bracket. The election applies only to the year it’s made and cannot exceed the trust’s DNI for that year.
Federal Estate Tax and Form 706
Income tax is only one side of the picture. If the decedent’s total taxable estate exceeds the federal exemption, the estate owes a separate tax of up to 40% on the excess. For 2026, the exemption is $15 million per person after the One Big Beautiful Bill Act, signed July 4, 2025, replaced the expiring TCJA provisions with no sunset date and inflation adjustments starting in 2027.14Internal Revenue Service. What’s New – Estate and Gift Tax
Form 706 is due nine months after the date of death when required. The executor can request an automatic six-month extension by filing Form 4768 before the original deadline, though the estimated tax still has to be paid on time.15Internal Revenue Service. Filing Estate and Gift Tax Returns16Internal Revenue Service. About Form 4768, Application for Extension of Time to File a Return and/or Pay US Estate (and Generation-Skipping Transfer) Taxes
Assets in a revocable living trust are included in the decedent’s gross estate for estate tax purposes even though they avoid probate. That trips up families who assume the trust dodges estate tax entirely. It doesn’t. A revocable trust avoids probate, not the estate tax, and every dollar in it counts toward the $15 million threshold.
Portability for a Surviving Spouse
A married couple effectively has a combined $30 million exemption because the surviving spouse can claim the deceased spouse’s unused exclusion amount. Portability is not automatic. The executor has to file a complete Form 706 to elect it, even if the estate owes zero estate tax and would otherwise be under the filing threshold.17Internal Revenue Service. Instructions for Form 706 Skip the filing and the unused exemption is gone. For estates that miss the nine-month deadline, the IRS allows a late portability election up to five years after the date of death under simplified procedures.
Deductions Available on the Trust Return
The trust can reduce its taxable income with several deductions before the compressed brackets apply. Administrative expenses directly tied to managing trust assets or producing income are deductible: legal fees for trust administration, accounting fees for preparing the return, and trustee compensation.
Trustee compensation has a flip side. The trust deducts the fees, but the trustee reports them as personal income. A family member or friend serving as trustee reports compensation as other income on Form 1040 and does not owe self-employment tax on it. A professional trustee treats the fees as self-employment income subject to both income tax and self-employment tax.
State and local income taxes paid by the trust are also deductible. When the estate is large enough to require Form 706, the trustee has a strategic choice: administrative expenses can be deducted on Form 1041 to reduce income tax, or on Form 706 to reduce estate tax, but not both.18Internal Revenue Service. How Do I Deduct the Administration Expenses of My Father’s Estate? The right answer depends on which return produces the larger savings, which usually means running the numbers both ways.
Deadlines and Penalties
Form 1041 is due by the 15th day of the fourth month after the close of the trust’s tax year. For a calendar-year trust, that is April 15 of the following year.19Internal Revenue Service. Forms 1041 and 1041-A: When to File An extension is available, but any tax owed still has to be paid by the original due date to avoid interest.
Trusts expecting to owe $1,000 or more in tax for the year must make quarterly estimated payments using Form 1041-ES. Missing them triggers underpayment penalties that compound already-high trust tax rates.20Internal Revenue Service. About Form 1041-ES, Estimated Income Tax for Estates and Trusts
Late filing of Form 1041 carries a penalty of 5% of the unpaid tax per month or partial month, up to 25%. If the return is more than 60 days overdue, the minimum penalty is the lesser of $525 or the total tax due. The IRS will waive the penalty for reasonable cause.
Closing the Trust and Filing the Final 1041
Before making final distributions, the trustee should provide beneficiaries with a full accounting: every dollar of income received, every expense paid, every distribution made during administration. Many trustees ask beneficiaries to sign a release and indemnification agreement to protect against later claims. Beneficiaries are not required to sign, but most do once they have reviewed the accounting.
The trust’s legal existence ends with the filing of the final Form 1041, marked as the “Final Return.” Any remaining income, deductions, and tax attributes flow out to the beneficiaries on their final K-1s. The trust is not terminated until every asset has been distributed and that last return is on file with the IRS.