the form that overrides your will

the rule nobody tells you

You can write a perfect will. You can hire a lawyer, spell out exactly who gets what, sign it, notarize it, store it safely — and none of it will control what happens to your 401(k).

Beneficiary designations override your will. Always. Assets with a designation form — retirement accounts, life insurance, annuities, payable-on-death and transfer-on-death bank accounts — pass directly to whoever is named on that form. They never enter your estate, so your will never touches them.

Courts have been consistent about this: a beneficiary designation can't be overridden by will provisions or oral statements. If your will leaves your retirement accounts to your sister and the form still names a college roommate, the roommate inherits.

the case that proves it

In 2009 the US Supreme Court decided Kennedy v. Plan Administrator for DuPont Savings and Investment Plan, and the facts are worth sitting with.

William Kennedy named his wife as beneficiary of his retirement plan. They divorced. In the divorce, she expressly waived any interest in his plan. He never updated the form. He died. His estate — on behalf of his daughter — argued the waiver should control.

The Court ruled unanimously for the ex-wife. The plan administrator was obliged to follow the documents governing the plan, and the document said her name. The waiver didn't matter because the form was never changed.

why state law won't save you

A reasonable person assumes there's a backstop. Many states do have laws automatically revoking an ex-spouse's beneficiary status on divorce.

Those laws don't reach most workplace retirement plans. 401(k)s are governed by federal law — ERISA — and in Egelhoff v. Egelhoff (2001) the Supreme Court held that ERISA preempts state revocation-on-divorce statutes. The ex-spouse remained the beneficiary.

The practical translation is blunt: your divorce decree means nothing to your 401(k) administrator. They are legally required to pay the name on the form.

Can the family fight it afterward? Sometimes. Courts have allowed an estate to sue an ex-spouse to enforce a waiver after the money was paid — but that's expensive litigation with uncertain outcomes, years after the death, to recover money that's already been spent. Updating one form avoids all of it.

if you're married, there's a second rule

Federal law gives current spouses strong protection on workplace plans. Your spouse is generally the automatic beneficiary of your 401(k), and naming anyone else typically requires their notarized written consent.

Two consequences worth knowing. If you want your children, a parent, or a trust to receive the account instead, you'll need your spouse's signature — you can't do it quietly. And if you remarry without updating the form, a new spouse married less than a year may not be entitled to the account under ERISA, while the ex still listed might well be paid.

IRAs work differently — they follow state law, and in most states you can name anyone without spousal consent. Which means the rules governing two accounts sitting side by side in your life can be completely different.

the fifteen-minute fix

1. List every account with a beneficiary. 401(k)s from every job you've had, IRAs, life insurance (work and personal), annuities, HSAs, pensions, and any POD/TOD bank or brokerage accounts.
2. Log in and actually look. Don't rely on memory. Most people are genuinely surprised by at least one name — a parent listed at 22, an ex, or a blank field.
3. Name a primary and a contingent. The contingent inherits if the primary dies first. Naming only a primary is how accounts end up in probate anyway.
4. Use names and dates of birth, not relationships. "My spouse" is ambiguous years later; a name and a birthdate isn't.
5. Don't forget old employers. The 401(k) at the job you left in 2016 still has a form, and it still controls.
6. Set a recurring calendar reminder. Once a year, plus after any marriage, divorce, birth, or death.

the bottom line

This is the rare piece of financial admin with an enormous consequence and almost no effort: a login, a form, a name. No fee, no appointment, no expertise required.

It's also the one that most often goes wrong at the worst possible moment — discovered by grieving families who assumed the will covered it, and learn from a plan administrator that it never did.

Your next tiny step: open your current 401(k) right now and look at who's named. Just look. That single check is the whole article.