Your 401(k) is probably one of your largest assets. The average 401(k) balance for Americans aged 55-64 is over $200,000, and many people have balances well into the millions. When you die, who gets that money isn't determined by your will — it's determined by your beneficiary designation form.
This is one of the most commonly misunderstood aspects of estate planning, and getting it wrong can have devastating financial consequences for your family.
Beneficiary Designations Override Your Will
This cannot be stated strongly enough: your 401(k) beneficiary designation is a legal contract between you and the plan administrator. It takes precedence over your will, your trust, and any other estate planning document.
Real-world example: John divorces Sarah and marries Lisa. He updates his will to leave everything to Lisa. But he never updates his 401(k) beneficiary form, which still names Sarah. When John dies, Sarah gets the 401(k) — not Lisa. John's will is irrelevant for the 401(k).
This happens more often than you'd think. Review your beneficiary designations after any major life event: marriage, divorce, birth of a child, or death of a beneficiary.
Special Rules for Spouses
Federal law (ERISA) gives surviving spouses special protections with 401(k) plans:
Automatic Spousal Rights Under ERISA, your spouse is automatically entitled to be the beneficiary of your 401(k), even if you name someone else. To name a non-spouse beneficiary, your spouse must sign a written waiver. This protects spouses from being unknowingly disinherited.
Note: This rule applies to 401(k) plans and other ERISA-qualified plans. It does NOT apply to IRAs, which are not governed by ERISA.
Spouse's Options After Inheriting
A surviving spouse has the most options of any 401(k) beneficiary:
Option 1: Roll Over to Their Own IRA The spouse can roll the inherited 401(k) into their own IRA. The money is then treated as their own — they take RMDs based on their own age, can make contributions, and can name their own beneficiaries. This is usually the best option for spouses who don't need the money immediately.
Option 2: Roll Over to Their Own 401(k) If the surviving spouse has their own employer 401(k), they may be able to roll the inherited funds into that plan. This can be useful for creditor protection (401(k)s generally have stronger creditor protection than IRAs in some states).
Option 3: Leave It in the Deceased Spouse's 401(k) Some plans allow the surviving spouse to keep the funds in the deceased's 401(k). RMDs would be based on the surviving spouse's life expectancy. This can be useful if the surviving spouse is under 59½ and needs access to funds without the 10% early withdrawal penalty (401(k) distributions to beneficiaries are not subject to the early withdrawal penalty, while IRA rollovers would be).
Option 4: Take a Lump Sum The spouse can withdraw the entire balance at once. The full amount (for traditional 401(k)s) is taxable as ordinary income in the year of withdrawal. This is rarely the best option due to the tax impact, but it's available.
Option 5: Elect the 10-Year Rule The spouse can choose to use the 10-year distribution rule, emptying the account within 10 years. This is rarely optimal for spouses who have better options available.
Non-Spouse Beneficiary Rules
Non-spouse beneficiaries — adult children, siblings, friends, non-married partners — have fewer options and are generally subject to the SECURE Act's 10-year rule.
The 10-Year Rule Most non-spouse beneficiaries must distribute the entire inherited 401(k) within 10 years of the participant's death. The full distribution is taxable as ordinary income for traditional 401(k) balances.
Annual RMDs Within the 10 Years If the 401(k) participant died on or after their required beginning date (generally April 1 after turning 73), annual RMDs are required in years 1-9, with the remaining balance distributed in year 10.
If the participant died before their required beginning date, no annual RMDs are required — the beneficiary just needs to empty the account by the end of year 10.
For full details on the 10-year rule, including exceptions and strategies, see our inherited IRA rules guide — the same rules apply to inherited 401(k)s.
Exceptions to the 10-Year Rule The following non-spouse beneficiaries can still stretch distributions over their life expectancy: - Minor children of the deceased (until they reach age 21, then the 10-year clock starts) - Disabled individuals - Chronically ill individuals - Beneficiaries not more than 10 years younger than the deceased
Roth 401(k) Rules
Roth 401(k) contributions are made with after-tax money, so qualified distributions are tax-free. Here's how inherited Roth 401(k)s work:
For Spouses A surviving spouse can roll an inherited Roth 401(k) into their own Roth IRA. The money continues to grow tax-free and qualified distributions are tax-free. No RMDs are required from a Roth IRA (though they would be required if the funds stay in the Roth 401(k)).
For Non-Spouse Beneficiaries The 10-year rule applies, but with a significant benefit: **no annual RMDs are required** during the 10-year period (even if the participant had reached their required beginning date). The beneficiary can let the money grow tax-free for the full 10 years and then withdraw everything tax-free.
This makes inherited Roth 401(k)s particularly valuable. If you have the choice between contributing to a traditional or Roth 401(k), the Roth option provides better outcomes for your beneficiaries.
What Happens If There's No Beneficiary Named?
If no beneficiary is designated — or if all named beneficiaries have predeceased the participant — the plan's default beneficiary provisions apply. Most plans default to:
1. The surviving spouse 2. The participant's children (equally) 3. The participant's estate
When the estate is the beneficiary, the 401(k) loses important tax advantages. The assets must typically be distributed within 5 years (if the participant died before their required beginning date) or based on the participant's remaining life expectancy. This is almost always worse than having a named individual beneficiary.
Tax Implications and Planning
No Step-Up in Basis Unlike stocks, real estate, and crypto, 401(k) assets do **not** receive a step-up in basis. Every dollar distributed from an inherited traditional 401(k) is taxed as ordinary income, regardless of when the original contributions were made. This is because the money was never taxed going in (it was tax-deferred).
State Taxes Don't forget state income taxes. Inherited 401(k) distributions are subject to state income tax in the beneficiary's state of residence (not the deceased's state). If you live in a state with high income taxes, this can significantly impact the effective tax rate on distributions.
Distribution Strategy If you're subject to the 10-year rule, spreading distributions across all 10 years generally produces better tax outcomes than waiting until year 10. Consider: - Taking larger distributions in years when your other income is lower - Coordinating with other inherited account distributions - Accounting for Medicare IRMAA surcharges if you're near those thresholds
Action Steps: Protect Your 401(k) Beneficiaries
1. Check your beneficiary designations today. Log into your 401(k) provider's website or contact your HR department to verify who is named.
2. Update after life events. Marriage, divorce, birth, death — any of these should trigger a beneficiary review.
3. Name contingent beneficiaries. If your primary beneficiary predeceases you, a contingent beneficiary ensures the plan doesn't default to your estate.
4. Document your 401(k) accounts. Make sure your executor knows which 401(k) plans you have, where they're held, and who is named as beneficiary. Passed Plan lets you store all of this securely in one place.
5. Consider Roth conversions. If you want to minimize the tax burden on your beneficiaries, converting traditional 401(k) funds to Roth (either within the plan if available, or via rollover to a Roth IRA after separation from service) shifts the tax burden to you now.
6. Consult a financial advisor. The intersection of beneficiary designations, tax planning, and estate law is complex. Professional guidance can save your beneficiaries significant money.
Your 401(k) may be your largest single asset. Make sure it ends up where you intend — and that your beneficiaries know how to claim it.
Document your accounts in Passed Plan
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