Updated August 2, 2026. Quick answer: when you remarry, your 401(k) beneficiary effectively resets. Federal law makes your current spouse the beneficiary of a workplace plan unless that spouse signs a waiver — and two things follow that almost nobody is told. A prenuptial agreement cannot do it, because the person signing is not yet a spouse. And a waiver your first spouse signed does not bind your second. Meanwhile your IRA runs on entirely different rules and will pay whoever is still named on the form.
None of this is anybody’s fault, and it is not a trap anyone set. It is a rule that protects spouses, working exactly as designed, in a situation the people affected were never told it applied to.
What the law actually does to a workplace plan
For a 401(k)-style plan the account is
“payable in full, on the death of the participant, to the participant’s surviving spouse (or, if there is no surviving spouse or the surviving spouse consents in the manner required under subsection (c)(2), to a designated beneficiary)”
29 U.S.C. 1055(b)(1)(C)
Read it carefully. The spouse is the beneficiary by operation of law. The form in the HR system is not what decides; it is only what decides once the spouse has consented otherwise. So a participant who married last year and named their children in 2009 has children on the form and a spouse entitled to the money.
The two sentences that make remarriage different
Both come from the same Treasury regulation, and between them they explain nearly every bad outcome in this area.
One. A prenup cannot waive it.
“Does consent contained in an antenuptial agreement or similar contract entered into prior to marriage satisfy the consent requirements …? No. An agreement entered into prior to marriage does not satisfy the applicable consent requirements, even if the agreement is executed within the applicable election period.”
26 CFR 1.401(a)-20, Q&A-28
This is the one that catches careful people. A couple marrying at 58, each with children, sits down with a lawyer and signs an agreement saying each keeps their own retirement accounts for their own children. It is a real agreement and it governs a great deal. It does not govern this, because the statute requires the consent of a spouse, and on the day the prenup was signed neither of them was one yet.
The fix is not complicated once you know: sign the consent again after the wedding. Same intention, valid this time.
Two. The last spouse’s consent does not carry over.
“If a participant’s spouse consents … is a subsequent spouse of the same participant bound by the consent? No. A consent … by one spouse is binding only with respect to the consenting spouse.”
26 CFR 1.401(a)-20, Q&A-29
So if your first marriage ended and your spouse had properly consented to your children being named, that consent ended with the marriage. Remarry, and the account reverts to the default with your new spouse as the person entitled to it — regardless of what the form still says.
What a valid waiver requires
The statute is specific, and the last requirement is where paperwork fails:
- the spouse consents in writing;
- the consent acknowledges the effect of the election — a signature on a form the spouse did not understand is exactly what this language exists to prevent;
- and the consent is witnessed by a plan representative or a notary public.
Not witnessed by a friend, and not simply mailed in. A consent missing the witness is not a weaker consent; it is not a consent.
Your IRA is a different animal entirely
IRAs are excluded by name from the part of ERISA that contains all of the above. The exclusion is explicit rather than accidental, which is why the asymmetry is so stark: a 401(k) protects your spouse automatically, and an IRA does not protect anybody. An IRA pays whoever is on the form.
| 401(k) and similar workplace plans | IRA | |
|---|---|---|
| Who gets it by default | Your current spouse, by law | Whoever the form names |
| Can you name someone else? | Only with your spouse’s witnessed consent | Yes, freely |
| Does remarriage change it? | Yes — it resets | No — which is its own hazard |
The second hazard is the mirror of the first: an IRA still naming a former spouse will generally pay the former spouse. That is a live problem on its own and the site covers it — why the form beats the divorce decree.
One caveat we will not overstate: in community-property states a spouse may have a state-law interest in an IRA regardless of the form. We did not verify any particular state’s rule for this page, so treat it as a question to ask locally rather than an answer to take from us.
Two more provisions worth knowing
A plan may impose a one-year marriage requirement. The statute permits a plan to withhold the survivor protection unless the couple “had been married throughout the 1-year period” ending at the annuity starting date or death. Plans differ, so this is a question for your plan document rather than a general answer.
A court order can override the default. Under a qualified domestic relations order a former spouse can be treated as the surviving spouse — and where that applies, the current spouse is not. If a divorce decree promised survivor benefits to a former spouse, that promise may already be attached to the account.
The audit, account by account
An hour, and it is the same hour whether you do it now or your family does it later under much worse conditions.
- Every workplace plan, current and old. Former employers hold more forgotten 401(k)s than anything else on this list. If you intend anyone other than your current spouse to receive them, get a fresh witnessed consent signed after the wedding date.
- Every IRA. These follow the form, so the form has to be right. Check contingent beneficiaries too — they are usually blank or badly out of date.
- Life insurance and annuities. Contract beneficiaries, not governed by your will.
- Bank and brokerage accounts with transfer-on-death instructions.
- The house. How it is titled will usually decide it before any document does.
- The will and any trust — last, because they control the least of what people assume. The designation controls, not the will.
If the goal is providing for both
Most people in a second marriage want the same two things: the new spouse secure, and the children not disinherited. Those are compatible, and the instruments that do it are well-established — a QTIP trust gives a spouse income for life with the remainder to your children, and the wider set of choices covers the rest. The state also has a view you cannot fully override: a surviving spouse can usually elect against the will.
The document that covers what the forms do not
None of this is fixed by a will: the 401(k) follows the beneficiary form and the plan’s spousal rules, exactly as the page explains. What a will does control is everything with no beneficiary form attached to it, and remarriage is usually the point at which that half goes out of date. LawDepot builds a state-specific last will and testament.
LawDepot pays us a commission if you buy through this link — it costs you nothing extra. We are not a law firm and this is not legal advice. Affiliate Disclosure.
Survivor requirements from 29 U.S.C. § 1055(a); the defined-contribution default from § 1055(b)(1)(C); consent mechanics from § 1055(c)(2)(A); the one-year rule from § 1055(f); the IRA exclusion from § 1051(b)(6); QDRO treatment from § 1056(d)(3)(F); the prenup and subsequent-spouse answers from 26 CFR § 1.401(a)-20, Q&A-28 and Q&A-29, read on both Cornell and the eCFR renderer. Read August 2026. Plan documents vary and this is general information, not legal advice.
If either spouse is not a US citizen, one default fails silently: there is no unlimited marital deduction for a non-citizen spouse — the statute denies it outright, and most plans are drafted assuming otherwise. Living abroad changes the benefits side too: Social Security usually follows you and Medicare never does.
Check whether any designation now names a minor, including as contingent — naming a child directly usually delivers a court process rather than money.