663(b) Election: 65-Day Rule, Form 1041, and Beneficiary Impact

A fiduciary makes the 663(b) election by checking the box at Question 6 in the Other Information section of IRS Form 1041 and filing the return by its due date, including extensions. The election lets a complex trust or estate treat distributions paid to beneficiaries within the first 65 days of the new tax year as if they were paid on the last day of the prior year. Because an estate or trust reaches the top 37% federal rate at just $16,000 of taxable income in 2026, while a single individual doesn’t reach that rate until $640,600, shifting income out to beneficiaries through this election can produce real savings.¹²

Who Can Make the Election

The election under Section 663(b) is available to the executor of a decedent’s estate or the fiduciary of a complex trust.³ Simple trusts are not eligible. A simple trust’s governing instrument requires all income to be distributed currently, so there is no retained income for the election to address.

Complex trusts and estates may retain income or make discretionary distributions. These are the entities that face the compressed bracket problem, and the election exists for them. Estates that have adopted a fiscal year rather than a calendar year use the same 65-day rule, measured from the close of the fiscal year.

The 65-Day Window

Distributions covered by the election must be properly paid or credited to the beneficiary within the first 65 days after the close of the entity’s tax year.³ For a calendar-year trust or estate, the deadline is March 6 of the following year (March 5 in a leap year).

The clock runs from the actual date the money leaves the entity, not from when the fiduciary decides to make the election or files the return. A distribution mailed on the 65th day but received after it could create problems, so fiduciaries who wait until the end of the window should build in a cushion.

The election is annual and optional. A fiduciary can use it one year and skip it the next. Once made for a given tax year, however, it is irrevocable for that year.

How to Make the Election on Form 1041

The election is made on the entity’s annual Form 1041. On the 2025 return (filed in 2026), the fiduciary checks the box for Question 6 in the Other Information section.⁴ Checking that box tells the IRS that distributions made in the first 65 days of 2026 should be treated as paid on December 31, 2025.

The fiduciary must designate the specific amount to which the election applies. It can cover the full amount distributed during the 65-day window or only part of it. The designated amount flows through Schedule B of Form 1041, where the income distribution deduction is calculated.

The deadline to make the election is the Form 1041 due date, including any extensions. For a calendar-year entity, the original due date is April 15.⁵ With a valid extension, the filing deadline moves to September 30, giving the fiduciary additional time to finalize the tax picture before committing. That extended window is one reason tax advisors routinely file extensions for trusts and estates.

How Much You Can Elect

The amount that can be elected back is capped. Treasury regulations limit the election to the greater of the trust’s accounting income or its distributable net income (DNI) for the year, reduced by amounts actually paid, credited, or required to be distributed during the year itself.⁶

In practice, the election fills the gap between what was already distributed during the year and the maximum distributable amount. If a trust had $80,000 in DNI for 2025 and distributed $50,000 during the year, the fiduciary could elect to treat up to $30,000 of early-2026 distributions as 2025 payments. Anything paid out beyond that cap during the 65-day window is simply a 2026 distribution.

The formula uses the greater of accounting income or DNI because the two can differ. Accounting income is defined by the trust instrument and state law; DNI is a federal tax concept. Taking the higher figure gives the fiduciary maximum flexibility.

Effect on the Trust or Estate

The immediate benefit for the entity is a larger income distribution deduction on Schedule B.⁴ The elected distribution is treated as paid on the last day of the prior tax year, reducing that year’s taxable income even though the cash moved weeks later.

Because the entity’s distribution deduction cannot exceed its DNI, the election effectively shifts income from compressed entity-level rates to beneficiaries, who are usually in lower brackets.⁷ At 2026 rates, retained taxable income above $16,000 inside the entity is taxed at 37%. Pushing that income to a beneficiary in the 22% or 24% bracket saves 13 to 15 cents on the dollar.¹

Net Investment Income Tax

The election can also reduce or eliminate the 3.8% Net Investment Income Tax that applies to trusts and estates. The NIIT kicks in when adjusted gross income exceeds the dollar amount at which the highest ordinary income bracket begins.⁸ For 2026, that threshold is $16,000.¹

The NIIT applies to the lesser of the entity’s undistributed net investment income or its AGI over that threshold. A 663(b) election that pushes investment income out to beneficiaries reduces both numbers. A trust with $60,000 of investment income that distributes $50,000 under the election may drop below the NIIT threshold entirely, saving 3.8% on income that would otherwise be hit by both the 37% rate and the surcharge. That combined 40.8% rate starts at just $16,000 inside a trust.

Effect on the Beneficiary

Beneficiaries report the elected distribution on their individual return for the same year the trust or estate claimed the deduction, not the year the money was received. Treasury regulations treat amounts elected back under Section 663(b) as received by the beneficiary in the prior year “for all purposes.”⁹ A payment physically received in February 2026 that gets elected back must appear on the beneficiary’s 2025 return.

That creates a timing headache when the beneficiary has already filed their individual return before the fiduciary makes the election. Since the fiduciary has until September 30 (with an extension) to make the election, a beneficiary who filed in February may not learn about the shifted income until months later. In that case, the beneficiary must file an amended return on Form 1040-X to pick up the additional income.

The fiduciary reports the shifted amount on the beneficiary’s Schedule K-1 (Form 1041) for the prior tax year, combined with any amounts distributed during the year itself.¹⁰ Good practice is to warn beneficiaries early that a 663(b) election is likely so they can delay filing or plan for an amendment.

If You Miss the Election

A fiduciary who fails to check the Question 6 box by the filing deadline (including extensions) has missed the election for that year. Distributions made during the 65-day window become ordinary current-year distributions with no retroactive effect, and the prior year’s tax bill stays as it was.

The IRS has a framework for granting relief on late regulatory elections under the Section 9100 rules. The 663(b) election does not qualify for automatic 12-month relief, so a fiduciary who wants to make a late election must request discretionary relief through a private letter ruling. That process requires showing that the fiduciary acted reasonably and in good faith and that relief won’t prejudice the government. Private letter rulings carry substantial IRS user fees and professional costs, so prevention is the better strategy.

The simplest protection is to file an extension for Form 1041. That moves the election deadline from April 15 to September 30 for calendar-year entities, giving the fiduciary close to ten months after year-end to decide whether the election makes sense.⁵

A Worked Example

Suppose a complex trust has $75,000 of DNI for 2025 and distributed $20,000 to its sole beneficiary during the year. The remaining $55,000 would be taxed inside the trust at rates up to 37%, generating roughly $17,400 in federal income tax before the NIIT. The beneficiary has other income that puts them in the 24% bracket.

In January 2026, the trustee distributes another $40,000 to the beneficiary. The trustee then files the trust’s 2025 Form 1041, checks the box at Question 6, and designates the full $40,000 as a prior-year distribution under Section 663(b). The trust’s total distribution deduction for 2025 becomes $60,000 ($20,000 paid during the year plus $40,000 elected back), leaving only $15,000 taxable at the entity level.³

At $15,000, the trust falls below the $16,000 threshold for both the 37% rate and the NIIT. The beneficiary reports $60,000 from the trust on their 2025 individual return and pays tax at 24%. The election saves the difference between the trust’s 37% rate (plus 3.8% NIIT) on $40,000 and the beneficiary’s 24% rate, roughly $6,300 on a single distribution decision.

1
Internal Revenue Service. 2026 Form 1041-ES Estimated Income Tax for Estates and Trusts
2
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
3
Office of the Law Revision Counsel. 26 USC 663 – Special Rules Applicable to Sections 661 and 662
4
Internal Revenue Service. 2025 Instructions for Form 1041 and Schedules A, B, G, J, and K-1
5
Internal Revenue Service. Forms 1041 and 1041-A When to File
6
eCFR. 26 CFR 1.663(b)-1 – Distributions in First 65 Days of Taxable Year
7
Office of the Law Revision Counsel. 26 USC 661 – Deduction for Estates and Trusts Accumulating Income
8
Internal Revenue Service. Topic No. 559 Net Investment Income Tax
9
eCFR. 26 CFR 1.663(b)-1 – Distributions in First 65 Days of Taxable Year Scope
10
Internal Revenue Service. Instructions for Schedule K-1 (Form 1041) for a Beneficiary Filing Form 1040 or 1040-SR (2025)