Why an Ex-Spouse Can Still Claim Your 401(k)-Even After Divorce and Remarriage

ERISA beneficiary forms can override a new spouse, a will, and a divorce decree

TL;DR: Your 401(k) does not follow your heart, your divorce decree, or your will. It follows the last beneficiary form filed with the plan.

That is the hard lesson investors keep learning too late. ERISA overrides wills, trusts, and divorce decrees, and the Supreme Court has reinforced that rule in cases involving plan benefits distributed according to the beneficiary designation. After remarriage, the problem can get worse because people often assume their new spouse is automatically protected. Often, that is not how an ERISA plan works.

Why this matters now

The exposure is not theoretical. More than 1.8 million Americans divorced in 2023, and many households in the peak retirement-savings years still have real money at stake: people aged 45 to 54 have an average of $188,643 in retirement savings. A stale beneficiary designation can redirect a six-figure inheritance to the wrong person.

The mistake is also deceptively simple. A participant can retain the retirement assets in the divorce, update their will, remarry, and still lose the 401(k) battle if they do not complete the plan's own beneficiary paperwork. Courts have upheld that result, ruling that the ex was entitled to receive the entirety of the account when the plan's designation was never properly changed.

Why 401(k)s need their own paperwork after divorce

This is mainly a paperwork problem, not a mystery of motive.

The plan relies on forms, not fairness

An ERISA 401(k) is administered based on the documents on file with the plan, not on what the participant intended, what a divorce judge ordered, or what seems fair after the fact. The controlling rule is that the plan should distribute the benefits as directed in the beneficiary designation, and the Supreme Court has said administrators may rely on the plan terms and beneficiary designation forms even after divorce.

That creates a blind spot. In a divorce, assets get divided, titles get updated, and estate documents get revised. But the 401(k) needs its own paperwork. If that step is skipped, the account can still go to the ex-spouse. In one recent case, the participant had been in the plan for more than 30 years, and his ex-wife remained listed as beneficiary after the divorce settlement gave her only part of the account. The court still held that the ex was entitled to receive the entirety of the account.

Why reasonable people still get this wrong

People often confuse intent with completion. The participant may:

• tell someone, "Get my ex removed"
• send a fax or email asking for "any necessary paperwork"
• update other estate documents
• assume the plan will honor the obvious intent

That is exactly where it fails. In the recent 7th Circuit case, the participant asked his secretary to fax a request to remove his ex-wife and to process "any necessary paperwork." The designation was not changed because the update must be made in accordance with the plan's requirements. Under ERISA, an incomplete or improperly executed change is not enough, and the attempted change will fail.

The compliance trap

Even fairness arguments do not always fix the problem. In these cases, the key question is whether the plan's own change-of-beneficiary process was properly completed. If it was not, the live designation generally controls.

TL;DR: Divorce can split the marriage, but it does not automatically update the beneficiary form. If the plan's required steps were not completed, intent can lose to documentation.

What to do before remarriage compounds the problem

After a divorce, the account remains exposed until the plan receives a properly executed change, because the update must be made in accordance with the plan's requirements.

Action checklist

• Log in and read the live designation. ERISA plans are controlled by the plan terms and beneficiary designation forms, and administrators are expected to distribute the benefits as directed in the beneficiary designation.
• Use the plan's current process. Do not rely on faxes, emails, or informal requests unless the plan says they count.
• Name contingent beneficiaries. If the primary beneficiary cannot take the inheritance, a missing contingent can push the account toward the estate or trigger default treatment under the plan.

When the risk may be lower

Remarriage alone does not redirect a 401(k) if the ex-spouse is still the named beneficiary. If a Qualified Domestic Relations Order (QDRO) was properly executed and processed by the plan, the immediate exposure may already be resolved. If not, the stale designation can still control.

Review beneficiaries after major life events, especially after divorce and before remarriage. Once the plan pays out under the last live designation, the window to redirect those funds is gone.