A 401(k) beneficiary is the person, people, or entity you name on your plan’s beneficiary form to receive the account balance when you die. That form controls the money. It overrides your will, it skips probate, and it triggers a specific set of federal rules on who can inherit, when they must take the money out, and how it gets taxed. If you are married, federal law limits your choices unless your spouse signs off in writing.
How the Designation Works
You fill out a beneficiary form through your plan administrator. Whatever that form says at the time of your death is what the plan pays, even if your will, a divorce decree, or a letter to your family says something else. The Supreme Court reinforced this in Kennedy v. Plan Administrator for DuPont, holding that plan administrators must follow the beneficiary form on file even when a divorce decree tried to waive the ex-spouse’s rights.1Justia Law. Kennedy v. Plan Administrator for DuPont Savings and Investment Plan
Name a primary beneficiary and a contingent beneficiary. The primary is your first choice. The contingent inherits only if the primary has already died or formally declines the inheritance. If both are gone and no valid designation is on file, the plan document itself decides. Most plans default to the surviving spouse, then to the estate. When the estate ends up as beneficiary, the money runs through probate and the payout options get worse.
You can also say what happens if one of several named beneficiaries dies before you do. A “per stirpes” designation sends a deceased beneficiary’s share down to their children. A “per capita” designation splits it among the remaining living beneficiaries. Not every plan form offers both, so read what your administrator provides.
Review your form after any major life change: marriage, divorce, a birth, a death. File the update with the plan administrator and keep a copy. The estate plan sitting in your lawyer’s office does not pay the account. The form on file does.
Spousal Rights if You Are Married
Under the Employee Retirement Income Security Act (ERISA), a married participant’s spouse is automatically entitled to 100% of the 401(k) at death unless the spouse agrees in writing to give up that right.2U.S. Department of Labor. FAQs about Retirement Plans and ERISA You cannot simply write your children or a sibling on the form and call it done. Without proper spousal consent, that designation is invalid.
The consent requirements are specific. Your spouse must sign a written waiver that names the alternate beneficiary, and the signature must be witnessed by either a plan representative or a notary public.3Office of the Law Revision Counsel. 29 USC 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity If your spouse consents to let you change the alternate freely later on, that broader permission has to be in the original waiver. A conversation does not count. Even a plain signed letter that skips the witnessing step does not count.
Prenups Do Not Waive These Rights
A prenuptial agreement cannot waive ERISA spousal rights. The person signing the prenup is not yet a spouse, and the statute only recognizes a waiver from a current spouse. If your prenup addresses retirement benefits and you want that arrangement to hold, you need a postnuptial agreement signed after the wedding that follows the same witness and documentation rules.
Divorce and the Beneficiary Form
Divorce is where beneficiary mistakes cause the most damage. Most plans do not automatically remove an ex-spouse from the form after a divorce, and ERISA requires the administrator to pay whoever is named. In Kennedy, the ex-wife had waived her pension rights in the divorce decree, but the plan was still required to pay her because the participant never updated the form.1Justia Law. Kennedy v. Plan Administrator for DuPont Savings and Investment Plan
The reliable way to redirect 401(k) benefits during a divorce is a Qualified Domestic Relations Order (QDRO). A QDRO is a court order that tells the plan administrator to pay a specific portion of the account to a former spouse, child, or other dependent. It must identify the participant and the alternate payee by name and address and specify either a dollar amount or a percentage.4Internal Revenue Service. Retirement Topics – QDRO Qualified Domestic Relations Order A former spouse who receives benefits through a QDRO can roll them tax-free into their own IRA.
If you are going through a divorce, updating the beneficiary form the day the divorce is final should sit at the top of your list. Trusting the decree alone is not enough under federal law.
What Surviving Spouses Can Do
Surviving spouses have the most flexible options of any beneficiary, and the choice can save tens of thousands in taxes over time.
- Roll the funds into your own IRA or 401(k). The account keeps growing tax-deferred, required minimum distributions do not start until you reach your own RMD age (currently 73, rising to 75 in 2033), and you can name your own beneficiaries.5Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
- Keep it as an inherited account. This can make sense if you are younger than 59½ and need access without the 10% early withdrawal penalty. Inherited-account distributions avoid that penalty regardless of your age.
- Take a lump sum. The full balance counts as ordinary income for the year and often pushes the recipient into a much higher bracket.
Surviving spouses are eligible designated beneficiaries, which exempts them from the 10-year deadline that hits most other individual beneficiaries. A spouse who keeps the money as an inherited 401(k) can stretch distributions over their own life expectancy.
The 10-Year Rule for Everyone Else
Before 2020, most non-spouse beneficiaries could stretch withdrawals over their own life expectancy, sometimes for decades. The SECURE Act of 2019 ended that. Most non-spouse individual beneficiaries now have to empty the inherited account by December 31 of the tenth year after the owner’s death.5Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
What confused beneficiaries for years was whether annual withdrawals were required inside that window. The IRS finalized regulations in 2024 that settled it. If the account owner had already started taking RMDs, the beneficiary must take annual distributions in years one through nine and clear whatever remains by the end of year ten.6Fidelity. Inherited 401(k) Rules If the owner died before reaching RMD age, the beneficiary can time withdrawals however they choose inside the 10-year window as long as the account is empty by the deadline.
Missing a required annual distribution triggers a 25% excise tax on the amount you should have withdrawn. The penalty drops to 10% if you correct the shortfall within two years.7Internal Revenue Service. Required Minimum Distributions (RMDs)
A non-spouse beneficiary can also take a lump sum at any time, but the full balance is taxed as ordinary income in that year. For a large account, spreading withdrawals across the 10-year window almost always produces a better tax result.
Beneficiaries Who Escape the 10-Year Rule
The tax code exempts a short list of “eligible designated beneficiaries” from the 10-year rule, letting them stretch distributions over their life expectancy:5Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
- A surviving spouse.
- A minor child of the account owner. Only biological or legally adopted children qualify, and only until they turn 21. Once the child hits 21, the 10-year clock starts on whatever is left.
- A disabled individual, using the definition in IRC Section 72(m)(7), which generally requires inability to engage in any substantial gainful activity due to a medically determinable condition expected to be long-lasting or fatal.
- A chronically ill individual under IRC Section 7702B(c)(2), generally someone unable to perform at least two activities of daily living for a period reasonably expected to be lengthy.
- An individual not more than 10 years younger than the deceased.
Status is determined as of the date the account owner dies. Disability and chronic illness both require medical certification. If an eligible designated beneficiary dies before the inherited account is fully distributed, their own beneficiaries do not inherit the exemption and have to follow the 10-year rule for whatever remains.
When No Beneficiary Is Named
If nothing valid is on file at your death, the plan document decides. Most plans default first to a surviving spouse and, failing that, to the estate. The estate is the worst-case outcome. The money passes through probate, which is public, slow, and expensive, and the payout timeline tightens. If the owner died before RMD age, the whole balance generally has to be distributed within five years. If RMDs had started, distributions can only be stretched over the owner’s remaining statistical life expectancy, not the heir’s.5Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
Naming a Trust
Some owners name a trust to control how the money is spent, protect assets for a minor child, or provide for a beneficiary with a disability. The strategy works, but the trust has to meet specific requirements or the tax picture gets significantly worse.
For the trust’s individual beneficiaries to be treated as the designated beneficiaries for distribution purposes (a “look-through” or “see-through” trust), four conditions have to be met:
- The trust is valid under state law.
- The trust is irrevocable, or becomes irrevocable at the owner’s death.
- The trust’s beneficiaries are individuals identifiable from the trust document.
- A copy of the trust reaches the plan administrator by October 31 of the year after the owner’s death.8Internal Revenue Service. IRS Private Letter Ruling 202035010
Fail any of these and the trust is treated as having no designated beneficiary, which forces the five-year payout or the owner’s remaining life expectancy depending on when the owner died. That accelerated timeline defeats the point of using a trust. For minor children specifically, a trust also avoids the need for a court-appointed guardian to manage the money. Given the mix of federal tax, state trust law, and plan administration, this is not a do-it-yourself setup.
How Distributions Are Taxed
Every dollar distributed from a traditional inherited 401(k) is taxed as ordinary income in the year the beneficiary receives it. There is no capital gains rate and no special discount. A $500,000 inherited 401(k) taken as a lump sum adds $500,000 to the beneficiary’s taxable income for that year, which can push someone into the top federal bracket in a single move.
That is why the timing of withdrawals matters so much inside the 10-year window. A beneficiary who spreads distributions relatively evenly can often stay in a lower bracket each year compared with taking the whole account at once or back-loading it into year ten.
Inherited Roth 401(k) accounts follow a different path. Because contributions went in after tax, qualified distributions to beneficiaries are generally tax-free. The 10-year deadline still applies to non-spouse beneficiaries, but the timing pressure is far lighter because the withdrawals are not taxed. Many beneficiaries drain inherited Roth accounts last and let the tax-free growth run as long as the rules allow.
One practical wrinkle: distributions paid directly from an inherited 401(k) may carry mandatory 20% federal income tax withholding. Rolling the inherited 401(k) into an inherited IRA first gives the beneficiary more control over withholding.
Creditor Protection
Money inside an ERISA-covered 401(k) has strong creditor protection, even after the owner dies. ERISA’s anti-alienation rules generally shield the account from creditors as long as the funds stay in the plan, and there is no dollar cap on that protection.
The protection can vanish the moment the beneficiary moves the money. In Clark v. Rameker, the Supreme Court held that inherited IRAs are not “retirement funds” for bankruptcy purposes, so a non-spouse beneficiary who rolls an inherited 401(k) into an inherited IRA loses federal bankruptcy protection for those assets.9Justia Law. Clark v. Rameker, Trustee A surviving spouse who rolls the inherited 401(k) into their own IRA (not an inherited IRA) keeps the standard IRA bankruptcy exemption, which is capped and adjusted periodically. If creditor concerns are on the table, leaving the funds inside the 401(k) plan as long as possible preserves the stronger ERISA shield. State rules on inherited IRAs vary widely, so anyone in that spot should talk to an attorney who knows both federal and local law.