Specialized Returns for Individuals · Estate tax

Estate filing requirements and due dates (Form 706, Form 1041)

A death produces up to three separate returns, filed by the same person, on three different schedules, under three different thresholds. Two of them are income tax returns and one is a transfer tax return, and the commonest administrative failure is treating the last as optional because no tax is owed. It is often optional. It is also the return on which the portability election lives, and the one whose threshold lifetime gifts have quietly lowered.

The rule

Three returns. The decedent’s final Form 1040 for the part of the year up to death; Form 1041 for the estate as a taxable entity from the day after death; and Form 706 for the estate tax. The personal representative signs and files all three where each is required.

Form 1041: when. $600 of gross income for the taxable year for a domestic estate; a trust files on any taxable income, or on $600 of gross income whatever the taxable income; and either files where any beneficiary is a nonresident alien, whatever the income (IRC § 6012(a)(3), (4), (5))^TY2026Verified 2026-08-20IRC § 6012(a), read at law.cornell.edu/uscode/text/26/6012 And the 15th day of the fourth month following the close of the taxable year — 15 April for a calendar year estate (IRC § 6072(a))^TY2026Verified 2026-08-20IRC § 6072(a), read at law.cornell.edu/uscode/text/26/6072

Form 1041: an estate may choose its year. an estate may adopt a fiscal year, and a fiscal year must be a period of 12 months ending on the last day of a month other than December — so an estate's first year can be short but cannot end mid-month (IRC § 441(e))^TY2026Verified 2026-08-20IRC § 441(e), read at law.cornell.edu/uscode/text/26/441 This is the one election in estate administration that is genuinely free and frequently missed — a fiscal year lets income and distributions be aligned across two calendar years, and the choice is made simply by filing the first return on that basis.

Form 706: when. a return is required where the gross estate of a citizen or resident exceeds the basic exclusion amount in effect for the calendar year of death — $60,000 of United States situs property for a nonresident who is not a citizen (IRC § 6018(a))^TY2026Verified 2026-08-20IRC § 6018(a), read at law.cornell.edu/uscode/text/26/6018 9 months after the date of death (IRC § 6075(a))^TY2026Verified 2026-08-20IRC § 6075(a), read at law.cornell.edu/uscode/text/26/6075

And the threshold is not what it appears. the filing threshold is reduced, but not below zero, by post-1976 adjusted taxable gifts and by any specific exemption allowed under the repealed IRC § 2521 for gifts after 8 September 1976 — so an estate below the basic exclusion amount can still be required to file (IRC § 6018(a)(3))^TY2026Verified 2026-08-20IRC § 6018(a)(3), read at law.cornell.edu/uscode/text/26/6018 An estate of $15,000,000 for a decedent dying in calendar year 2026 — the IRC § 2010(c)(3)(A) basic exclusion amount as raised by Pub. L. 119-21 § 70106, indexed from calendar year 2026 and rounded to the nearest $10,000 under § 2010(c)(3)(B)^TY2026Verified 2026-08-19IRC § 2010(c)(3) read at law.cornell.edu/uscode/text/26/2010 and Rev. Proc. 2025-32 § 2.14 read at irs.gov/pub/irs-drop/rp-25-32.pdf less the client’s lifetime taxable gifts is the real line, and the executor will not know where it sits without the gift tax history.

One election merges two of the returns. where the executor and the trustee of a qualified revocable trust both elect, the trust is treated and taxed as part of the estate rather than as a separate trust (IRC § 645(a))^TY2026Verified 2026-08-20IRC § 645(a), read at law.cornell.edu/uscode/text/26/645 It runs until 2 years after the date of death where no estate tax return is required, and 6 months after the final determination of the chapter 11 liability where one is (IRC § 645(b)(2))^TY2026Verified 2026-08-20IRC § 645(b)(2), read at law.cornell.edu/uscode/text/26/645

Extensions of time to file. the Secretary may grant a reasonable extension of time to file, and outside the case of taxpayers abroad no such extension may exceed 6 months (IRC § 6081(a))^TY2026Verified 2026-08-20IRC § 6081(a), read at law.cornell.edu/uscode/text/26/6081

Extensions of time to pay are separate, and longer. up to 12 months for estate tax shown on the return under the general rule, and for reasonable cause up to 10 years from the IRC § 6151(a) payment date — with a separate 4-year limit for a deficiency, unavailable where the deficiency is due to negligence, intentional disregard or fraud (IRC § 6161(a)(1), (a)(2), (b)(2), (b)(3))^TY2026Verified 2026-08-20IRC § 6161, read at law.cornell.edu/uscode/text/26/6161 Where the estate holds a closely held business, where an interest in a closely held business exceeds 35 percent of the adjusted gross estate, the executor may elect to pay the attributable share of the tax in up to 10 equal installments (IRC § 6166(a))^TY2026Verified 2026-08-20IRC § 6166(a), read at law.cornell.edu/uscode/text/26/6166

Current figures

How it works in practice

Fix the dates in the first meeting. Death on a given day sets three clocks: the final Form 1040 on the ordinary individual schedule for that calendar year; Form 706 at nine months; and the estate’s first Form 1041 at the fourth month after whatever year end the executor chooses. Only one of those is negotiable, and it has to be chosen before the first return goes in.

Choose the fiscal year deliberately. A death in, say, October gives a choice between a short year to 31 December and a fiscal year running to the following 30 September. The second defers the estate’s first return by nine months, gives income time to be identified, and lets distributions carried out in the second calendar year be reported in the estate’s first year. It is worth a conversation, and it disappears once a calendar year return has been filed.

Check the gift history before concluding no Form 706 is required. Section 6018(a)(3) reduces the threshold by post-1976 adjusted taxable gifts. A client who gave away a substantial amount during life and left a modest estate may still be over the line, and the executor has no way to know without the prior Forms 709.

File Form 706 anyway if there is a surviving spouse. This is the recurring point across this section and it belongs here too: made by the executor of the estate of the deceased spouse, on an estate tax return for that estate on which the amount is computed, filed within the time prescribed including extensions — and once made it is irrevocable (IRC § 2010(c)(5)(A))^TY2026Verified 2026-08-20IRC § 2010(c)(5)(A), read at law.cornell.edu/uscode/text/26/2010 An estate that files nothing loses that permanently.

Separate the two extensions. An extension of time to file Form 706 does not extend the time to pay the estate tax. Where liquidity is the problem, the request is under § 6161 — up to twelve months as of right on the amount shown, or up to ten years for reasonable cause — or under § 6166 if a closely held business qualifies.

Consider the § 645 election where there is a revocable trust. Most modern estates are administered through one, and without the election the trust files its own Form 1041 on a mandatory calendar year while the estate files on whatever year it chose. The election collapses them into one return with one year end, and the fiscal year advantage extends to the trust’s income as well.

How this has changed

The mechanics are old. Sections 6012, 6018, 6072, 6075, 6081 and 6161 have been substantially in their present form for decades, and Pub. L. 119-21 amended none of them. Section 645 arrived in 1997 and has not been materially altered since.

What has changed is the population of estates that file. The Form 1041 threshold is $600 — the IRC § 6012(a)(3) gross income threshold for an estate, which is not indexed and has stood at that figure since the 1954 Code, so inflation alone has steadily widened the population of estates required to file^TY2026Verified 2026-08-20IRC § 6012(a)(3), read at law.cornell.edu/uscode/text/26/6012 — so the number of estates required to file an income tax return has grown with inflation alone, and an estate holding a modest bank balance can clear it. The Form 706 threshold has moved in the opposite direction: at $15,000,000 for a decedent dying in calendar year 2026 — the IRC § 2010(c)(3)(A) basic exclusion amount as raised by Pub. L. 119-21 § 70106, indexed from calendar year 2026 and rounded to the nearest $10,000 under § 2010(c)(3)(B)^TY2026Verified 2026-08-19IRC § 2010(c)(3) read at law.cornell.edu/uscode/text/26/2010 and Rev. Proc. 2025-32 § 2.14 read at irs.gov/pub/irs-drop/rp-25-32.pdf very few estates are required to file at all, which is precisely why the portability election is missed so often.

The practical shape of the topic has therefore inverted. Form 706 used to be the return an executor worried about and Form 1041 the afterthought. Now Form 1041 is the return most estates actually have to file, and Form 706 is the one most estates should file voluntarily and do not.

Exam focus

Expect a date computation. Form 706 is nine months from death (IRC § 6075(a)); Form 1041 is the 15th day of the fourth month after the close of the estate’s taxable year (§ 6072(a)). Watch for a fiscal year in the facts, because the four-month count is from the year end and not from death.

Know the two thresholds and what they are measured against: gross income for Form 1041, and the gross estate against the basic exclusion amount for Form 706 — reduced by lifetime adjusted taxable gifts under § 6018(a)(3), which is the detail that distinguishes a prepared candidate.

Know that the personal representative signs all three returns, that an extension to file is not an extension to pay, and that a fiscal year must end on the last day of a month.

Check yourself

1. A domestic estate has gross income of $700 and taxable income of nil after deductions. Must it file Form 1041?

Answer: Yes. IRC § 6012(a)(3) requires a return from every estate whose gross income for the taxable year is $600 or more, regardless of what taxable income comes to after deductions.

2. A decedent dies on 8 June. The executor selects a fiscal year ending 31 March. When is the estate’s first Form 1041 due?

Answer: 15 July of the following year. IRC § 6072(a) sets the date at the 15th day of the fourth month following the close of the fiscal year, and the four months run from 31 March, not from the date of death.

3. A decedent’s gross estate is $3,000,000 and she made post-1976 adjusted taxable gifts of $13,500,000. Is a Form 706 required?

Answer: Yes. IRC § 6018(a)(3) reduces the filing threshold by adjusted taxable gifts, so the applicable figure is the basic exclusion amount less $13,500,000, and the gross estate exceeds it.

4. An executor obtains an extension of time to file Form 706. Does the estate tax remain due at nine months?

Answer: Yes. IRC § 6081 extends the time to file only. An extension of time to pay must be sought separately under § 6161, and interest runs from the original date in any event.

5. May an estate adopt a taxable year ending on 15 September?

Answer: No. IRC § 441(e) defines a fiscal year as a period of 12 months ending on the last day of a month other than December, so a year end must fall on the last day of a month.