Updated August 3, 2026. Quick answer: if your spouse is more than ten years younger and is the sole beneficiary of the account, your required minimum distribution is calculated from a different, more favourable table — and it produces a smaller required withdrawal every year for the rest of your life. Most people in this position never find out.
The rule
the employee’s surviving spouse who is more than 10 years younger than the employee is the employee’s sole beneficiary … the sole beneficiary of the employee’s entire interest at all times during the distribution calendar year … If the employee and the employee’s spouse are married on January 1 of a distribution calendar year, but do not remain married throughout that year (that is, the employee or the employee’s spouse dies or they become divorced during that year), the employee will not fail to have a spouse as the employee’s sole beneficiary for that year merely because they are not married throughout…
— 26 CFR 1.401(a)(9)-5(c) (rule for which table applies); 26 CFR 1.401(a)(9)-9 (the tables themselves); IRS Pub 590-B
Three conditions, and all of them must hold:
- Your spouse must be more than ten years younger. Exactly ten does not qualify.
- Your spouse must be the sole beneficiary of the entire account.
- That must be true at all times during the distribution calendar year — not just on one date.
The carve-out that catches people out
The regulation anticipates the year going wrong. If you are married on 1 January and the marriage ends during that year through death or divorce, you do not lose the treatment for that year merely because you were not married throughout it.
Note what that does not cover: changing the beneficiary designation. Adding a child alongside your spouse, or naming a trust, breaks the sole-beneficiary condition — and it breaks it for the whole year, not from the date of the change. This is the quietest way to lose the benefit, because updating beneficiaries feels like good housekeeping.
Why it is worth real money
The default table is built on an assumption about your beneficiary’s age. When the actual beneficiary is much younger, the joint table reflects a longer combined life expectancy, so the account is spread over more years and each year’s required withdrawal is smaller. Less forced income means a lower tax bill, and it keeps more of the balance growing tax-deferred for the spouse who will very likely inherit it.
It compounds in a second way that matters for exactly these households: less forced income can mean a lower income figure for Medicare purposes, which steps up at thresholds rather than phasing in.
What to check
- Confirm the age difference is more than ten years, on the definition your plan or custodian applies.
- Check the beneficiary designation actually says what you think. Custodians hold the controlling record, not your will, and stale designations are extremely common.
- Ask your custodian which table they are applying. Many default to the standard table unless told otherwise; the calculation is theirs but the facts are yours.
- Re-check after any beneficiary change, and before making one.
We are not reproducing the tables here. They are published by the IRS, they are revised, and a table copied onto a web page is exactly the kind of figure that goes quietly out of date. Use the current IRS tables and ask your custodian to show you the factor they used.
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Related: the whole age-gap picture · pension elections.
General information drawn from the Internal Revenue Code, IRS regulations and IRS publications, not legal, tax or financial advice. Contribution limits, tax brackets and life-expectancy tables change and are not reproduced here; use the current IRS figures. Retirement plan rules are set by each plan within federal limits, so what your plan permits may be narrower than what federal law allows – your summary plan description controls.