First Year a Widow: 7 Tax Decisions Before December 31

The decision in front of you

Margaret, 64, lost her husband Tom in March 2026. They lived in Ohio, a state with no estate tax. Their combined assets — house, two IRAs, a brokerage account, and Tom’s 401(k) — total about $3.4 million. No federal estate tax is due; they are nowhere near the $13.99M exemption. Margaret’s accountant told her “you don’t need to file an estate-tax return.” That advice is technically correct and financially expensive.

By filing Form 706 to elect portability, Margaret banks Tom’s unused $13.99M exemption onto her own. She now carries a combined $27.98M federal estate-tax shield. If her assets grow, or if the exemption is ever cut, that locked-in DSUE protects her heirs from a 40% estate tax on everything above the limit. The election costs her a tax-preparer fee and a few hours of records. Skipping it could cost her family seven figures decades from now. That single decision — among seven that sit on a deadline this year — is why first-year survivor planning matters far more than the grief-numbed first months suggest.

Decision 1: File one last joint return (and capture the wider brackets)

The IRS treats you as married for the entire year your spouse dies. You can file Married Filing Jointly for 2026 even though Tom died in March. This is your last MFJ return — starting in 2027 Margaret files as a single taxpayer (or Qualifying Surviving Spouse if she had a dependent child at home).

Why it matters in dollars: the 2026 MFJ standard deduction is $31,500 versus $15,750 single, and the joint brackets are roughly twice as wide. The 22% bracket starts at $96,950 of taxable income on a joint return but at just $48,475 single. On the final 1040, write “deceased,” your spouse’s name, and the date of death across the top. If a refund is owed and you are not the surviving spouse signing jointly, attach Form 1310 to claim it.

The jump from MFJ to single rates the following year is what planners call the “widow’s penalty” — the same income gets taxed in narrower brackets. That makes 2026 the right year to consider accelerating income (a Roth conversion, harvesting a gain) while the joint brackets still apply.

Decision 2: File Form 706 to elect portability — even with no tax due

This is the decision with the largest dollar tail. The federal estate-tax exemption for 2026 is $13.99M per individual (IRC §2010). When the first spouse dies and does not use their full exemption, the unused amount — the Deceased Spousal Unused Exclusion, or DSUE — can transfer to the survivor. But it does not transfer automatically. You must elect it by filing Form 706 and checking the portability box.

Tom used $0 of his exemption (everything passed to Margaret under the unlimited marital deduction). His full $13.99M DSUE is available to port. Once Margaret elects it, her exemption becomes $27.98M — her own $13.99M plus Tom’s $13.99M DSUE. Above that combined figure, the estate-tax rate is 40% (IRC §2001(c)).

• You file even if no tax is owed. Portability is the one reason a sub-threshold estate files Form 706 at all. The return is “portability-only.”
• The DSUE is locked at the dollar amount, not a percentage. If the exemption is ever cut, Margaret keeps Tom’s $13.99M figure as elected.
• Remarriage risk. If Margaret remarries and that spouse also dies, she can only use the DSUE of her most recent deceased spouse. Electing now preserves Tom’s while she has it.

The deadline you probably haven’t missed

Form 706 is ordinarily due 9 months after death, with a 6-month automatic extension (15 months total). Many widows hear “you missed the 9-month deadline” and give up. Don’t. Under Rev. Proc. 2022-32, an estate that was not otherwise required to file (because it is below the filing threshold) gets a simplified extension to file a portability-only Form 706 up to 5 years from the date of death. Most survivors qualify for this relief. The election is recoverable years later — but do not let it lapse past five years.

Decision 3: Do the spousal IRA rollover before the rules change on you

You are the only beneficiary the tax code lets do a true spousal rollover. Other heirs — children, siblings — are non-eligible designated beneficiaries who must drain an inherited IRA within 10 years (IRC §401(a)(9)(H)). As the surviving spouse you can instead move your late spouse’s IRA into your own IRA, treating it as if it were always yours.

Tom’s traditional IRA holds $480,000. If Margaret rolls it into her own IRA, the transfer is tax-free, and she does not have to start required minimum distributions on it until her own RMD age — 73 for someone born 1951–1959, 75 for someone born 1960 or later (SECURE 2.0 §107). She is 64, so she defers RMDs for nearly a decade and keeps the balance compounding.

1. If you are under 59½ and may need the money soon, weigh keeping it as an inherited IRA first — distributions from an inherited IRA escape the 10% early-withdrawal penalty, while distributions from your own rolled-over IRA do not until you reach 59½.
2. If you are over 59½ (Margaret’s case), the spousal rollover is almost always the right move: tax-deferred growth and RMDs pushed to your own later age.
3. Roth IRAs inherited from a spouse roll into your own Roth with no RMDs during your lifetime — the cleanest outcome of all.

Decision 4: Document every date-of-death basis step-up now

IRC §1014 resets inherited assets to their fair market value on the date of death. This is one of the largest breaks in the code, and it is use-it-or-lose-it on documentation: you need the date-of-death value on file to prove the new basis when you eventually sell.

How much you step up depends on your state. In the 41 common-law states, you step up the deceased’s half of jointly titled property. In the 9 community-property states — CA, AZ, ID, LA, NV, NM, TX, WA, WI — you get a full 100% step-up on both halves of community property. Margaret is in Ohio (common-law), so the brokerage account jointly held with Tom steps up on his half only.

On the brokerage account, Tom’s half steps up from $100,000 to $300,000, erasing $200,000 of embedded gain. At the 15% long-term capital-gains rate that is roughly $30,000 in tax Margaret never pays — but only if she has the date-of-death statement on file. Pull broker date-of-death valuations and a real-estate appraisal now, while they are easy to obtain.

Decision 5: Re-file every beneficiary designation

Your spouse was almost certainly the named primary beneficiary on your 401(k), your IRAs, and your life insurance. Those forms now point to a deceased person. Beneficiary designations override your will — so until you update them, the contingent beneficiary inherits, or if there is none, the asset drops into probate and is governed by your state’s intestacy rules.

• Your own 401(k), 403(b), and IRAs — name a new primary and a contingent.
• Life insurance policies — both yours and any survivor benefit.
• Transfer-on-death (TOD) and payable-on-death (POD) bank and brokerage accounts.
• Your will and any revocable trust — coordinate them with the new beneficiary forms so they don’t conflict.

This is the same mechanic that bites people after a divorce: the form, not the will, controls. The fix is identical — re-file the designation with each custodian and keep the dated confirmation.

Decision 6: Decide whether to accelerate income this year

Because 2026 is the last year of the wide joint brackets, it is often the best year to convert traditional IRA dollars to Roth or to realize capital gains. A married couple stays in the 12% bracket up to $96,950 of taxable income; a single filer hits 22% at $48,476. Filling the cheap joint brackets now — with a partial Roth conversion, for example — can lock in a lower lifetime tax bill before the widow’s-penalty single rates arrive.

Run the math against the survivor’s expected post-2026 income. If Margaret will sit in the 22% single bracket every year going forward, converting up to the top of the 2026 joint 12% bracket is nearly free arbitrage. Roth conversions must be completed by December 31, 2026 — not April 15 — and cannot be undone (recharacterization of conversions was eliminated by the TCJA).

Decision 7: Confirm the survivor’s Social Security and Medicare moves

A surviving spouse can claim a Social Security survivor benefit as early as age 60 (50 if disabled), or switch to it from a smaller benefit, and can let their own retirement benefit grow with 8%/year delayed credits to age 70 before switching. The optimal sequence often is: take the survivor benefit first, let your own benefit grow, then switch at 70.

Watch the Medicare IRMAA surcharge. A large one-time event in the year of death — selling appreciated stock, a big Roth conversion — spikes your MAGI and can push you into a higher Part B premium tier two years later (2026 IRMAA tiers start above $103K single / $206K MFJ). If a death-year sale shoves the survivor over a threshold, file Form SSA-44 to request a life-changing-event adjustment; loss of a spouse is a qualifying event.

What most people get wrong: “the estate is too small to bother”

The single most common — and most expensive — mistake is skipping Form 706 because the estate is well under $13.99M and owes no tax. The accountant is right that no tax is due. The accountant is wrong that nothing needs filing. Portability is the entire reason a small estate files Form 706, and it is irreversible once the 5-year window closes.

Consider the downside: Margaret’s $3.4M estate grows to $14M over 25 years through ordinary market appreciation and an inheritance of her own. Without the ported DSUE, only her single $13.99M exemption (or whatever it has become) shields the estate — and the excess is taxed at 40%. With Tom’s DSUE banked, the first $27.98M passes free. The cost of capturing that protection today is one tax return. The cost of skipping it is borne by her children. That asymmetry — near-zero cost, seven-figure potential payoff — is why portability is the default recommendation for nearly every surviving spouse, regardless of estate size.

A second myth: “I have plenty of time.” Three of these seven decisions carry hard deadlines this calendar year — the final MFJ return, any Roth conversion, and the practical window to capture clean date-of-death valuations. The portability election has the 5-year runway, but the records you need to support it are easiest to gather in the first months.

The lever to pull this year

• File the 2026 return Married Filing Jointly — $31,500 standard deduction and joint brackets — and write “deceased” plus the date of death on Form 1040.
• File a portability-only Form 706 to bank your late spouse’s $13.99M DSUE, lifting your exemption to $27.98M. File even though no tax is due; you have up to 5 years under Rev. Proc. 2022-32, but gather records now.
• Do the spousal IRA rollover into your own IRA (tax-free) to escape the 10-year drain rule and defer RMDs to your own age 73 or 75 — unless you are under 59½ and may need penalty-free access.
• Capture date-of-death fair-market values on every asset for the §1014 step-up; in community-property states (CA, AZ, ID, LA, NV, NM, TX, WA, WI) you get a full 100% step-up.
• Re-file every beneficiary designation — they override the will — on retirement accounts, life insurance, and TOD/POD accounts.
• Use the final joint brackets to consider a Roth conversion (deadline December 31), and coordinate the survivor’s Social Security claiming and Medicare IRMAA before a death-year sale spikes MAGI.