The document that decides who inherits your 401(k), IRA, or life insurance is usually not your will. It is a one-page beneficiary form you may have filled out years ago, and in most cases it controls no matter what your will says. For newly married women, and especially for women remarrying with children from an earlier relationship, that single form is where the most expensive mistakes in merging finances tend to happen. This checklist is written for women who have recently married or remarried, or who are planning a wedding this fall. It is general education; your estate-planning attorney and plan administrators have the final word on your accounts.
Why the Form Beats the Will
Retirement accounts, life insurance, annuities, and accounts with payable-on-death or transfer-on-death designations pass by contract, directly to the named beneficiary, outside probate. Your will governs only what is left in your probate estate.
The U.S. Supreme Court has enforced this rule repeatedly for employer plans covered by the Employee Retirement Income Security Act (ERISA). In Kennedy v. Plan Administrator for DuPont Savings and Investment Plan (2009), the Court unanimously held that a plan administrator properly paid a deceased employee’s savings plan balance to his former wife, because she was still the named beneficiary, even though she had waived her interest in the divorce decree. In Egelhoff v. Egelhoff (2001), the Court held that ERISA overrides state laws that automatically revoke an ex-spouse’s designation after divorce. In Hillman v. Maretta (2013), it reached a similar result for federal employee life insurance.
The practical lesson: a will, a divorce decree, a verbal promise, or what everyone “knows” you wanted will generally not redirect an account with a valid beneficiary form on file.
The Mistakes That Show Up After a Wedding
An ex-spouse, parent, or sibling is still named. Many women name a parent or sibling on their first 401(k) and never revisit it. After marriage, that designation stays in force until you change it.
No one is named, or the named person has died. The account then follows the plan’s default rules, which may send it to your estate. That can mean probate delays and, for retirement accounts, a less favorable distribution timeline for heirs.
Minor children are named directly. A minor cannot take control of an inheritance. Naming a child under 18 can force a court-supervised guardianship of the money. A trust or a custodial account under your state’s Uniform Transfers to Minors Act is usually the better structure, and it is worth setting up with an attorney.
Remarried women assume the will protects their children. It does not, for accounts with beneficiary forms. If you want children from a prior relationship to inherit your 401(k), the designation itself has to say so.
The 401(k) Spousal Rule Most People Miss
For most employer plans covered by ERISA, including 401(k)s, federal law makes your spouse the automatic beneficiary once you are married, unless your spouse signs a written waiver, witnessed by a notary or a plan representative, consenting to someone else. Defined benefit pensions go further, generally requiring a joint-and-survivor annuity for married participants unless the spouse consents in writing to a different payout.
Two consequences:
- A prenuptial agreement generally does not waive these rights. Under Treasury regulations, a waiver signed before the marriage is not valid spousal consent. If you and your new spouse agreed in a prenup that each of you would leave your 401(k) to your own children, your spouse typically needs to sign the plan’s own consent form after the wedding.
- An improper waiver can be thrown out. If the consent was not properly witnessed, the surviving spouse can still be entitled to the account.
IRAs work differently. Federal law does not require spousal consent to name a non-spouse beneficiary on an IRA. In community property states, however, a spouse may have a legal interest in IRA contributions made during the marriage, and some custodians require spousal consent there.
A Merging-Finances Checklist
Work through this list together, account by account.
- Inventory every account with a beneficiary designation: current and old 401(k)s and 403(b)s, IRAs, HSAs, pensions, annuities, employer group life insurance, individual life insurance policies, and bank or brokerage accounts with payable-on-death or transfer-on-death instructions.
- Request a written copy of the beneficiary on file from each administrator. Do not rely on memory or an old statement.
- Name primary and contingent beneficiaries. The contingent covers the case where your spouse dies first or at the same time.
- Decide what goes where, deliberately. Spouses get distribution options no other beneficiary has, including rolling an inherited IRA into their own. Most non-spouse beneficiaries must empty an inherited retirement account within 10 years under the SECURE Act. That difference can matter as much as who inherits.
- For blended families, coordinate the forms with the plan. Some couples name the spouse on the 401(k) and children on life insurance or an IRA. Others use a trust. Whatever the plan, the forms and the will should match.
- Retitle joint assets on purpose. Joint tenancy with right of survivorship passes to the surviving owner automatically. Keeping some accounts separate is a legitimate choice, especially for property brought into a second marriage.
- Update your will and powers of attorney after the wedding. Some states partially revoke or modify a will made before marriage, so do not assume an older will still works as written.
- Review again after every life event: a birth, a death, a divorce, a job change, or a rollover. A rollover to a new IRA usually requires a new beneficiary form.
Name Changes and the Tax-Filing Choice
Change your name with Social Security first. The IRS matches the name and Social Security number on your return against SSA records, and a mismatch can delay processing of a joint return. Update SSA, then your employer, then your accounts.
Your filing status depends on December 31. Per IRS Publication 501, if you are married on the last day of the year, you are considered married for the entire year. A couple marrying in November or December 2026 chooses between married filing jointly and married filing separately for the full 2026 tax year. Joint filing usually produces the lower combined tax. Separate filing can make sense when one spouse has large medical expenses, is on an income-driven student loan repayment plan, or has tax debts the other spouse does not want to share liability for.
Update withholding. Two earners who both switch their Form W-4 to “married” without using the multiple-jobs step can end up underwithheld. Use the IRS withholding estimator after the wedding.
If either of you buys Marketplace health insurance, report the marriage within 30 days. Premium tax credits are based on household income, and combining incomes can change eligibility.
Sit down with your spouse and the account list in step 1, pull every beneficiary form on file, and fix anything that no longer matches what you both intend. Then schedule a meeting with an estate-planning attorney to align the will, any trust, and the forms so they tell the same story.
