Inherited 401k Rules: What Beneficiaries Need to Know

Key Takeaways

• The SECURE Act's 10-year rule applies to most non-spouse beneficiaries of inherited 401k plans.
• Spouses get more flexibility: they can roll the money into their own IRA or 401k.
• 2024 IRS final regulations require annual RMDs for some beneficiaries — get professional help.

The 10-Year Rule

For deaths after December 31, 2019, the SECURE Act compressed the old "stretch" IRA into the 10-year rule: most non-spouse beneficiaries must withdraw the entire inherited balance by December 31 of the 10th year after the owner's death. The rule applies to inherited 401k balances just as it does to IRAs. The 2024 IRS final regulations added a crucial detail: if the original owner had already reached their Required Beginning Date (age 73, or 75 for those born in 1960+), the beneficiary must also take annual RMDs during those 10 years — the account must be emptied by year 10 and drained gradually along the way. Failure to take a required distribution triggers a 25% excise tax (reduced to 10% if corrected promptly under SECURE 2.0).

Spouse vs Non-Spouse Beneficiaries

A surviving spouse has the best options. You can treat the inherited 401k as your own by rolling it into your own IRA or your own 401k, deferring RMDs until your own age 73 — or you can stay as a beneficiary and use the more lenient rules. Non-spouse beneficiaries cannot roll inherited money into their own accounts; they must hold it in an inherited IRA titled with both names, and the 10-year rule applies. Special "eligible designated beneficiary" status (minor children, disabled or chronically ill individuals, or beneficiaries less than 10 years younger) allows distributions over their life expectancy instead — but minor children lose that status at age 21, at which point the 10-year clock starts.

Roth 401k and After-Tax Money

Inherited Roth 401k balances follow the same 10-year timeline, but qualified distributions remain tax-free for beneficiaries provided the original owner satisfied the five-year rule. The practical consequence is different, though: a Roth inherited account should be drained as late as possible to maximize tax-free growth, while a Traditional account is often drained strategically to manage the beneficiary's own tax brackets. If the owner had after-tax 401k contributions, the basis passes to the beneficiary tax-free but must be documented — the plan or custodian can provide the basis records.

Action Steps

1. Confirm who is named as beneficiary on every retirement account — outdated designations override wills.
2. If you inherit a 401k, open an inherited IRA and request a direct transfer from the plan.
3. Mark the December 31 deadline of the 10th year on your calendar.
4. Check whether annual RMDs apply to you under the 2024 final regulations.
5. Consult a CPA or tax attorney — inherited-account mistakes are among the most expensive tax errors.

Common Inherited-401k Mistakes

• Cashing out without checking the tax: an inherited Traditional 401k distribution is fully taxable — a $150,000 inheritance can trigger $30,000+ of tax if taken in one year. Stretch it across the 10-year window.
• Missing the annual RMD: under the 2024 final regulations, if the owner was past their RBD, beneficiaries must take annual RMDs during the 10 years — the 25% excise tax on a missed RMD is brutal.
• Rolling into your own IRA: non-spouse beneficiaries cannot — the money must go into an inherited IRA, or the whole balance becomes taxable immediately.
• Forgetting beneficiary updates: an ex-spouse or an outdated estate can override your intentions; review designations every few years.
• Ignoring Roth money: inherited Roth 401k balances should be drained last — they grow tax-free for the full 10 years.

Choosing Between the Options

Your choice depends on your age and your relationship to the deceased. A spouse has the most flexibility: treat the 401k as your own, roll it into your own IRA, or take the life-expectancy option. A non-spouse beneficiary generally cannot roll the money into their own IRA — it must go into an inherited IRA titled in the deceased's name, and the 10-year rule applies for most designated beneficiaries. Under the 10-year rule (post-SECURE Act), the entire account must be emptied by December 31 of the year containing the 10th anniversary of death. Eligible designated beneficiaries — minor children, disabled or chronically ill individuals, and beneficiaries within 10 years of the deceased's age — can stretch distributions over their own life expectancy. A practical caution: RMDs not taken by the deadline trigger a 25% excise tax (reduced to 10% if corrected promptly), so set calendar reminders the year you inherit.