The rules for a 401(k) beneficiary come down to three things: the form you file with your plan administrator controls who inherits (your will does not), your spouse is entitled to the entire account unless they sign a written waiver, and most non-spouse beneficiaries must empty the account within ten years of your death. Everything else, from tax treatment to creditor protection, flows from those three facts.
The Form on File Is What Pays
Your 401(k) beneficiary designation is a form you complete through your plan administrator, and it controls the account regardless of what your will says. The Supreme Court confirmed this in Kennedy v. Plan Administrator for DuPont, holding that plan administrators must pay whoever is named on the beneficiary form, even when a divorce decree had attempted 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 contingent inherits only if the primary has already died or formally declines. If no valid designation exists, the plan’s default rules take over, which usually means the surviving spouse first and then the estate. An estate beneficiary is the worst outcome: the money goes through probate, and the distribution timeline collapses to five years (if you died before reaching RMD age) or to your own remaining life expectancy (if you had already started RMDs).2Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
Review the form after any major life change: marriage, divorce, a birth, or the death of someone you named. File the update directly with your plan administrator and keep a copy. Nothing else counts.
Spousal Consent Is Required
If you are married, the Employee Retirement Income Security Act gives your spouse 100% of your 401(k) at your death unless they agree in writing to give that right up.3U.S. Department of Labor. FAQs about Retirement Plans and ERISA Naming your children, a sibling, or a charity on the form does nothing on its own. Without proper spousal consent, the designation is invalid and the spouse still inherits.
A valid waiver has to meet specific formalities. 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.4Office of the Law Revision Counsel. 29 USC 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity A conversation, an email, or a signed letter that skips the witness requirement does not satisfy ERISA.
A prenuptial agreement cannot waive these rights. The person signing a prenup is not yet a spouse when they sign, and the statute only recognizes waivers from a current spouse. If your prenup addresses retirement benefits, you need a postnuptial agreement executed after the wedding, following the same witness rules, to make the waiver stick for an ERISA plan.
Divorce Does Not Automatically Remove an Ex
Most plans do not strip an ex-spouse off the beneficiary form when a divorce is finalized. That was the painful lesson of Kennedy v. DuPont: the ex-wife had waived her pension rights in the divorce decree, but because the participant never updated the form, the plan administrator was legally required to pay her.1Justia Law. Kennedy v. Plan Administrator for DuPont Savings and Investment Plan
The one reliable way to redirect 401(k) benefits during a divorce is a Qualified Domestic Relations Order. A QDRO is a court order that directs the plan administrator to pay a specific portion of the account to a former spouse, child, or other dependent. It must identify both the participant and the alternate payee by name and address and specify either the dollar amount or percentage each person receives.5Internal 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, update the beneficiary form the day the divorce is final. The decree alone is not enough.
What a Surviving Spouse Can Do
Surviving spouses have the most flexible options of any beneficiary type.
- Roll the funds into your own IRA or 401(k). The money keeps growing tax-deferred, you do not have to take required minimum distributions until you reach your own RMD age (currently 73, rising to 75 in 2033), and you can name your own beneficiaries.2Office 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 under 59½ and need the money, because distributions from an inherited account are not subject to the 10% early withdrawal penalty regardless of your age.
- Take a lump sum. The full amount counts as ordinary income for the year, which can push you into a much higher tax bracket.
Surviving spouses are also eligible designated beneficiaries, which means they are exempt from the 10-year distribution deadline that applies to most other individual beneficiaries. A spouse who keeps the account inherited can stretch distributions over their own life expectancy.
The 10-Year Rule for Everyone Else
Before 2020, a non-spouse beneficiary could stretch withdrawals over their own life expectancy, sometimes across decades. The SECURE Act of 2019 ended that for most people. Non-spouse individual beneficiaries now must empty the inherited account by December 31 of the tenth year after the account owner’s death.2Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
Whether you also have to take annual distributions during that window depends on the original owner. The IRS finalized regulations in 2024 settling the question: if the owner had already started RMDs before dying, you must take annual distributions in years one through nine and drain the rest by the end of year ten.6Fidelity. Inherited 401(k) Rules If the owner died before reaching RMD age, you can time withdrawals however you want within 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 what you should have withdrawn, dropping to 10% if you correct the shortfall within two years.7Internal Revenue Service. Required Minimum Distributions (RMDs) A lump-sum distribution is always available, but the full balance hits as ordinary income in a single year. For a large account, spreading withdrawals across the full window usually produces a better tax outcome.
Who Escapes the 10-Year Rule
Certain beneficiaries, called eligible designated beneficiaries, can still stretch distributions over their life expectancy. The list is short:2Office 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, meaning a biological or legally adopted child. The exemption lasts only until the child turns 21, when the 10-year clock starts.
- A disabled individual, as defined in IRC Section 72(m)(7).
- A chronically ill individual, as defined in IRC Section 7702B(c)(2).
- Any individual not more than 10 years younger than the deceased, such as a sibling close in age.
Eligibility is tested on the date the account owner dies. Disability and chronic illness 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 must empty whatever remains within 10 years.
Trusts as Beneficiary
You can name a trust as your 401(k) beneficiary, typically to control how the money is spent, protect assets for a minor, or shelter funds for a beneficiary with a disability. The strategy works, but the trust must satisfy four conditions for its individual beneficiaries to be treated as the designated beneficiaries for distribution purposes (sometimes called a “look-through” or “see-through” trust):
- The trust is valid under state law.
- The trust is irrevocable or becomes irrevocable at the account owner’s death.
- The trust’s beneficiaries are identifiable from the trust document.
- A copy of the trust is delivered to the plan administrator by October 31 of the year after the account owner’s death.8Internal Revenue Service. IRS Private Letter Ruling 202035010
If the trust fails any of these tests, it is treated as having no designated beneficiary, which forces the five-year payout rule or the owner’s remaining life expectancy method depending on when the owner died. That accelerated timeline defeats the point of using a trust. Given the intersection of federal tax law, state trust law, and plan administration rules, this is work for an estate planning attorney.
How Inherited Distributions Are Taxed
Every dollar distributed from a traditional inherited 401(k) is taxed as ordinary income in the year the beneficiary receives it. No capital gains rate, 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.
Spreading withdrawals matters. A beneficiary under the 10-year rule who takes relatively even distributions can often stay in a lower bracket each year than someone who takes the balance all at once or waits until year ten.
Inherited Roth 401(k) accounts follow a different path. Because contributions were made with after-tax dollars, qualified distributions to beneficiaries are generally tax-free. The 10-year deadline still applies to non-spouse beneficiaries, but the timing pressure is far less punishing. Many beneficiaries drain Roth accounts last for exactly that reason.
One trap worth knowing: distributions paid directly from an inherited 401(k) may be subject to mandatory 20% federal income tax withholding. Rolling the inherited 401(k) into an inherited IRA first gives you more control over withholding.
Creditor Protection Depends on Where the Money Sits
Money inside an ERISA-covered 401(k) has strong creditor protection without a dollar limit, and that protection continues after the account owner’s death as long as the funds remain in the plan.
The protection can disappear once the beneficiary moves the money. The Supreme Court held in Clark v. Rameker that inherited IRAs are not “retirement funds” for bankruptcy purposes, meaning 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 money into their own IRA (not an inherited IRA) keeps the standard IRA bankruptcy exemption.
If creditors are a concern, leaving the funds in the 401(k) plan preserves the stronger ERISA protection. State laws on inherited IRA protection vary, and anyone facing creditor exposure should talk to an attorney who knows both federal and local rules.