Who fills this out
The executor or personal representative is responsible for filing. Most families work with a CPA or estate tax attorney because the asset valuations, marital deduction, and portability election are technical.
When to file
Due 9 months after the date of death. A 6-month extension is available via IRS Form 4768. Portability-only returns (filed solely to preserve the surviving spouse's exemption) can be filed up to 5 years late under Rev. Proc. 2022-32.
What you will need
- Certified death certificate and letters testamentary.
- Date-of-death appraisals for every asset (real estate, business interests, collectibles).
- Account statements as of the date of death.
- Schedule of gifts made during the decedent's life (carries to line 7).
- Marital deduction documentation for assets passing to a spouse.
- Prior 709 gift tax returns (used to track lifetime exemption).
Common mistakes
- Missing the portability election. The surviving spouse loses millions in future exemption if the first-spouse 706 was never filed.
- Skipping date-of-death appraisals. The IRS rejects "estimates"; every illiquid asset needs a qualified appraisal.
- Miscalculating the marital deduction. A QTIP election must be made on the return; missing it can convert tax-free transfers to taxable.
- Filing late without an extension. Late filing penalties run 5% per month up to 25%.
- Forgetting Arizona has no separate estate tax. No Arizona return is needed; the 706 covers federal only.
Questions families ask
Do most Arizona families file Form 706?
No. Only estates above the federal exemption ($15 million per person in 2026) owe estate tax. But many surviving spouses file a 706 anyway just to elect portability of the deceased spouse's unused exemption.
Does Arizona have its own estate tax return?
No. Arizona repealed its estate tax in 2005, so only the federal Form 706 applies.
Related forms
IRS Form 1041 is the income tax return for an estate or trust. The personal representative files it for any tax year in which the estate has gross income of $600 or more or any taxable income. It also issues Schedule K-1 to each beneficiary reporting distributable net income. The first return is due 3.5 months after the fiscal year ends.
IRS Form 709 is the federal gift tax return filed by any donor who gives more than the annual exclusion ($18,000 per recipient in 2024) to one person in a year, who gifts to a trust, or who wants to split gifts with a spouse. The return is due April 15 of the year after the gift. No tax is usually owed; the form just tracks the donor's lifetime exemption use.
IRS Form SS-4 applies for an Employer Identification Number for an estate, an irrevocable trust, or a revocable trust that became irrevocable at the grantor's death. The personal representative or trustee applies online at IRS.gov and receives the EIN immediately. Every Arizona estate and most post-death trusts need one before opening an estate bank account or filing Form 1041.