Updated July 28, 2026. Quick answer: A surviving spouse generally files as single from the year after the death, on income that has often barely fallen — and now controls a combined retirement balance. Same money, narrower brackets, higher IRMAA exposure.
What actually changes
| Before | After | |
|---|---|---|
| Filing status | Married filing jointly | Single (generally from the following year) |
| Household income | Two Social Security benefits, two RMD streams | Often only modestly lower |
| Retirement balance to draw | Split across two people | Combined, in one person’s brackets |
| IRMAA thresholds | Joint | Single — materially lower |
Why it compounds with an inherited account
A surviving spouse who also inherits accounts from a parent or sibling faces both at once: narrower brackets and a 10-year emptying obligation layered on top of their own required distributions.
The year of death is usually the last joint return. That makes it a genuinely valuable planning year — and it is the year nobody is thinking about tax.
What can be done in advance
Roth conversions during the joint years, when brackets are wider, are the main lever. It is one of the strongest arguments for converting earlier than feels necessary — the wider brackets are not permanent, and which spouse dies first is not knowable.
Sources
SECURE Act (2019); SECURE 2.0 (2022); final RMD regulations published 19 July 2024; IRC §401(a)(9); IRC §1014 (basis of property acquired from a decedent); IRC §664 (charitable remainder trusts). Cross-checked July 2026 against professional analyses from Kitces, Grant Thornton, Ascensus, Charles Schwab and Kiplinger. Indexed figures and state-specific rules are flagged rather than asserted.
This states what the cited authority says. It is not tax or legal advice, and beneficiary planning turns on family facts and state law that no page can see.