The Section 645 election lets the trustee of a decedent’s revocable trust and the executor of the estate treat the trust as part of the estate for income tax purposes, filing one combined Form 1041 instead of two separate returns. The election is made on IRS Form 8855, attached to the estate’s first income tax return. Beyond cutting the paperwork in half, it opens the door to tax benefits that are normally reserved for estates: a fiscal tax year, a $600 personal exemption, a two-year holiday from estimated tax payments, and favorable treatment for rental real estate losses and S corporation stock.
What the Election Does
When someone with a revocable living trust dies, the trust becomes irrevocable and turns into its own taxable entity. Without the election, the executor files a Form 1041 for the estate and the trustee files a separate Form 1041 for the trust. Two returns, two sets of professional fees, and two separate pools of income and deductions that cannot offset each other.
The election collapses the two entities into one for federal income tax purposes. All income, deductions, and credits from the trust flow onto a single Form 1041 filed under the estate’s name and taxpayer identification number, and the trust is treated and taxed as part of the estate for the entire election period.1Office of the Law Revision Counsel. 26 U.S.C. 645 – Certain Revocable Trusts Treated as Part of Estate Once made, the election is irrevocable, so both fiduciaries should model the tax picture before committing.
Which Trusts Qualify
Only a “qualified revocable trust” is eligible. That means a trust the decedent was treated as owning during life because they held the power to revoke it, the same trust type described in Section 676 of the tax code.2Office of the Law Revision Counsel. 26 U.S.C. 676 – Power to Revoke The standard revocable living trust drafted for probate avoidance qualifies in almost every case.
A trust that was already irrevocable before the decedent’s death does not qualify, even if it held most of the decedent’s assets. If only a portion of a trust was revocable, only that portion is eligible.
Who Makes the Election
If a court has appointed an executor or personal representative, both the executor and the trustee must agree. Neither can force it on the other. The executor takes responsibility for filing the combined Form 1041 under the estate’s name and EIN, and that return picks up all items from both the estate and the electing trust.3Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 (2025)
Many revocable trust plans are designed specifically to avoid probate, so no executor is ever appointed. In that case the trustee can make the election alone. The trustee files Form 1041 as if the trust were an estate, using the TIN the trust obtained after the decedent’s death, and gets the same fiscal year flexibility and $600 exemption an estate would receive.3Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 (2025)
How to File Form 8855
The election is made on IRS Form 8855, “Election to Treat a Qualified Revocable Trust as Part of an Estate.”4Internal Revenue Service. About Form 8855, Election to Treat a Qualified Revocable Trust as Part of an Estate It asks for the decedent’s name and Social Security number, plus the names, addresses, and employer identification numbers of the estate and the trust. If either entity does not yet have an EIN, obtain one from the IRS online before filing.
Form 8855 is not filed on its own. It must be attached to the first Form 1041 filed for the estate, or, when there is no executor, the first Form 1041 filed by the trustee acting as the estate. The deadline is the due date of that first return, including extensions.5Internal Revenue Service. Form 8855 (Rev. December 2020) Election to Treat a Qualified Revocable Trust as Part of an Estate Miss the deadline and the election is gone for good. There is no late-filing relief, so putting the first Form 1041 on extension early in the administration is a simple way to protect the option.
Why the Election Is Worth Considering
The real value of Section 645 is the set of estate-only rules the trust gets to borrow during the election period. Several of them can move the needle on the tax bill.
A Fiscal Tax Year
Trusts are locked into a calendar year by statute.6GovInfo. 26 U.S.C. 644 – Taxable Year of Trusts Estates can choose any fiscal year-end. Under the election, the trust rides on the estate’s fiscal year. If a decedent dies in November, the executor can pick a January 31 year-end and push most of the first year’s income into a return that is not due until the following May. That creates room to gather brokerage statements, rental records, and partnership K-1s before the first return has to be filed.
With the right year-end, the entire administration sometimes fits inside a single Form 1041, which cuts professional fees. The fiscal year is chosen on the first 1041, so run projections before locking it in.
A Larger Personal Exemption
Estates get a $600 exemption on Form 1041. A trust required to distribute all income gets $300, and any other trust gets $100.7Internal Revenue Service. Instructions for Form 1041 and Schedules A, B, G, J, and K-1 (2025) – Section: Line 21—Exemption The dollar difference is modest, but during the election period the trust gets the full $600 too.
No Estimated Tax Payments for Two Years
Estates are exempt from estimated tax payments for any tax year ending within two years of the decedent’s death.8Office of the Law Revision Counsel. 26 U.S.C. 6654 – Failure by Individual to Pay Estimated Income Tax Without the election, the trust would need to start quarterly payments right away. The election extends the estate’s exemption to the trust, eliminating the risk of underpayment penalties during a period when income is hard to project and cash may be tied up.
Rental Real Estate Losses
If the decedent actively managed rental property before death, the estate can deduct up to $25,000 in passive rental real estate losses against other income during the two tax years following the death.9Office of the Law Revision Counsel. 26 U.S.C. 469 – Passive Activity Losses and Credits Limited That allowance does not normally extend to trusts. Under the election, the trust is treated as part of the estate and can use the estate’s active participation status to claim those losses.10Internal Revenue Service. Publication 925, Passive Activity and At-Risk Rules For a decedent who owned rental properties throwing off depreciation losses, this one benefit can pay for the election several times over.
S Corporation Stock
An estate is an eligible S corporation shareholder for the duration of its administration. A regular irrevocable trust must fit into one of the narrow categories (an electing small business trust or a qualified subchapter S trust, for instance) to hold S corporation stock without blowing the company’s S election.11eCFR. 26 CFR 1.1361-1 – S Corporation Defined During the Section 645 election period, the trust is treated as part of the estate for shareholder purposes, which keeps the stock in safe harbor without restructuring the trust or rushing a distribution.12eCFR. 26 CFR 1.645-1 – Election by Certain Revocable Trusts to Be Treated as Part of Estate The trustee will need a plan for the stock once the election period ends.
Charitable Set-Aside Deduction
Estates can deduct amounts permanently set aside for charity under the governing instrument, even before the money is paid out.13Office of the Law Revision Counsel. 26 U.S.C. 642 – Special Rules for Credits and Deductions Trusts created after 1969 generally cannot take a set-aside deduction; they can only deduct charitable amounts actually distributed during the year. A revocable trust with charitable provisions gains access to the estate’s set-aside rule during the election period.
How Long the Election Lasts
The election period runs from the date of death until the “applicable date,” which depends on whether the estate is large enough to require a federal estate tax return.1Office of the Law Revision Counsel. 26 U.S.C. 645 – Certain Revocable Trusts Treated as Part of Estate
- No Form 706 required: the election ends two years after the date of death. For 2026 deaths, Form 706 is only required when the gross estate exceeds $15,000,000, so most estates land here.14Internal Revenue Service. What’s New — Estate and Gift Tax
- Form 706 required: the election ends six months after the final determination of the estate tax liability, or two years after the date of death, whichever is later. Estate tax audits and litigation can push the final determination date out considerably.
The election also ends early if both the estate and the electing trust have distributed all their assets before the applicable date.12eCFR. 26 CFR 1.645-1 – Election by Certain Revocable Trusts to Be Treated as Part of Estate
What Happens When the Election Ends
Once the period terminates, the trust stops being treated as part of the estate and reverts to its own taxable existence. If it still holds assets and will keep operating, several things need to happen at once.
The trust needs a new taxpayer identification number. When an executor was involved, the trust may need a new TIN; when there was no executor and the trustee had been filing under a TIN obtained after the decedent’s death, a new TIN is required.15GovInfo. 26 CFR 1.645-1 – Election to Treat Trust as Part of an Estate The estate, if it continues to exist, keeps its original TIN.
The trust also loses its fiscal year. Trusts must use a calendar year, so the first post-election return covers a short period running from the day after the election ends through December 31. After that, calendar-year Form 1041s continue for as long as the trust holds assets or earns income.
Every other estate-only benefit disappears at the same time. Estimated tax payments kick in, the exemption drops to $100 or $300, the passive loss allowance for rental real estate is gone, and any S corporation stock held in the trust needs to sit inside a qualifying trust structure or be distributed to a qualifying shareholder. Plan for the handoff well before the applicable date, especially when rental property or S corporation stock is in the mix.