The phone call comes. A client has died, and the family wants to know what happens next. For many CPAs, particularly those who don’t specialize in estates, the immediate question is practical: which forms get filed, when are they due, and who is responsible for filing them?
Here’s the filing roadmap.
The Final Individual Return: Form 1040
The decedent’s final Form 1040 covers January 1 through the date of death. It reports all income earned through that date: wages, interest, dividends, capital gains from sales completed before death. The surviving spouse or personal representative files it by the standard deadline (April 15 of the following year, or October 15 with an extension). “DECEASED” is written across the top of the return along with the date of death (IRS Publication 559).
Medical expenses present an either/or choice at this stage. They can be deducted on the final Form 1040 as an itemized deduction, or they can be claimed on the estate tax return as an administration expense. Not both. The right answer depends on the numbers at play in each return.
The Estate Income Tax Return: Form 1041
If the estate generates more than $600 in gross income during any tax year, it files Form 1041. The estate becomes a separate taxpayer on the date of death. Income earned after that date (interest accruing, rental income, business income from estate-owned assets) belongs to the estate, not the decedent (IRS Form 1041 instructions).
One detail that trips up practitioners unfamiliar with fiduciary returns: estates can elect a fiscal year. Unlike trusts, which generally follow a calendar year, an estate’s first Form 1041 can cover any period ending on the last day of a month within 12 months of the date of death. This fiscal year election creates deferral opportunities for beneficiaries receiving distributions.
Income that flows to beneficiaries arrives via Schedule K-1 and is reported on their individual returns. Income retained by the estate is taxed at the estate level, where compressed brackets push rates to the highest marginal rate at a much lower threshold than individual returns.
The Estate Tax Return: Form 706
Form 706 is required when the decedent’s gross estate, combined with adjusted taxable gifts, meets or exceeds the applicable exclusion amount. For 2026 deaths, that threshold is $15 million. The return is due nine months after the date of death. A six-month extension is available through Form 4768, but it extends the filing deadline only, not the payment deadline (Form 706 instructions).
Even estates below the threshold may file Form 706 for one reason: the portability election. Filing allows the surviving spouse to claim the decedent’s unused estate tax exemption (the DSUE amount). For estates that skip this filing, the unused exemption disappears. Revenue Procedure 2022-32 provides a five-year late election window for estates that weren’t otherwise required to file, but that relief has limits and shouldn’t be treated as a default plan.
Other Returns and Notifications
Depending on the estate’s composition, additional filings may apply. The decedent’s final state income tax return follows the same date-of-death cutoff as the federal return. If the decedent owned an interest in a partnership or S corporation, the entity’s return reflects the ownership change and the K-1 allocations split at the date of death. Gift tax returns (Form 709) may be due if the decedent made reportable gifts during the year of death.
The executor or personal representative also files for a new EIN for the estate (Form SS-4), notifies Social Security, and contacts financial institutions holding the decedent’s accounts. These aren’t tax filings, but they’re part of the same initial wave of administrative tasks that hit within the first few weeks.
A Filing Summary
| Return | Due Date | Filed By |
| Final Form 1040 | April 15 following year of death (extension to Oct 15) | Surviving spouse or personal representative |
| Form 1041 (estate income) | 15th day of 4th month after fiscal year-end | Executor or personal representative |
| Form 706 (estate tax) | 9 months after date of death (6-month extension via Form 4768) | Executor |
| State income tax return | Follows state-specific deadlines | Surviving spouse or personal representative |
| Form 709 (gift tax, if applicable) | April 15 following year of death | Executor |
The filing obligations after a client’s death are mechanical but interconnected. Decisions made on one return (medical expense placement, portability election, fiscal year selection) directly affect the others. For CPAs who get the call, knowing which forms are due and when they’re due is the starting point. The planning comes after.