Many people believe a will is the master document that decides who gets everything they own. For a large share of the typical household's wealth, it is not. Retirement accounts, life insurance, and accounts with a named beneficiary generally pass by the form on file with the institution, not by what the will says.

That gap catches families off guard, and it can send a large account to an ex-spouse, a long-deceased parent, or a single child when the will says "equally to my children." This guide explains what a will actually controls, which assets bypass it, and how the two documents interact, with a worked example that shows how an otherwise sensible plan can split in the wrong proportions.

This is general education, not legal advice. Probate rules, will formalities, and transfer-on-death options vary by state, so consider talking with an estate-planning attorney about your own situation.

What a will does (and does not) do

A will is a legal document that takes effect at death and typically does four things:

• Names an executor to settle your affairs.

• Directs who receives probate assets, meaning property held in your name alone with no beneficiary or survivor attached.

• Names a guardian for minor children.

• Can make specific gifts, such as a car or heirloom, to named people.

It does not control assets that pass by contract, by title, or by beneficiary form. Those go straight to the person named, usually without court involvement. The Internal Revenue Service describes the principle for retirement accounts: the owner designates the beneficiary under the procedures the plan sets up, and some plans require specific beneficiaries, such as a spouse.

If you die without a valid will, state "intestacy" law decides who receives your probate assets, which may differ from what you would have chosen.

Which assets follow the will and which do not

The practical message: for many households, the retirement accounts and life insurance policies are among the largest assets, and a will does not reach them. Trusts are a related tool covered in a separate article.

What happens when the two documents conflict

The beneficiary form generally wins. The clearest example comes from the U.S. Supreme Court. In Kennedy v. Plan Administrator for DuPont Savings and Investment Plan (2009), a man divorced and his ex-wife waived her rights to his retirement plan in the divorce decree, but he never changed the beneficiary form. The Court held that the plan administrator had to follow the plan documents and pay the named beneficiary, the ex-wife, even though a court order had waived her interest. The decision applies to plans covered by the federal ERISA law, such as employer 401(k) plans; IRAs and insurance policies follow their own contracts and state law, and some states automatically cancel an ex-spouse's designation after divorce, though you should not count on that.

Two related points often missed:

• Employer plans may require your spouse. Under many plans, a spouse must be the beneficiary unless he or she waives that right in writing, so naming someone else without that waiver may not hold up.

• Silence has consequences. If your named beneficiary has died and no contingent beneficiary exists, the account may fall back to your estate, where it goes through probate under your will or intestacy.

Worked example: a plan that splits the wrong way

Meet Daniel, a hypothetical single parent with two adult children, Ana and Ben. His will says: "Everything goes equally to Ana and Ben." All numbers are illustrative and were verified with a script.

Daniel's assets at death: $1,330,000 total

Step 1: Probate assets follow the will. Home + bank + brokerage = $510,000, split equally: $255,000 each.

Step 2: Everything else follows the forms.

• 401(k): $420,000 goes to the ex-spouse

• IRA: $150,000 goes to Ana

• Life insurance: $250,000 goes to Ben

Step 3: Totals

Daniel intended $665,000 for each child. Instead, the ex-spouse receives nearly a third of his wealth and Ben receives $100,000 more than Ana. None of it required anyone to break the law; each institution simply followed the paperwork.

The fix takes an afternoon. Update the 401(k) to name both children equally and set the IRA and insurance forms to 50/50 as well. Then each child receives exactly $665,000 of the $1,330,000.

One more wrinkle: the 401(k) and IRA are pre-tax accounts, so withdrawing them creates income tax for the beneficiary, while the house and brokerage account are not taxed the same way. A truly equal split may require thinking about after-tax value, not just face value. At a hypothetical 24% tax rate, $420,000 in a 401(k) is worth roughly $319,200 after tax.

Why the beneficiary choice also affects taxes

The IRS rules for inherited retirement accounts differ by who inherits. A surviving spouse has the most flexibility. Most other individual beneficiaries who are not "eligible designated beneficiaries" must generally empty the account within 10 years of the owner's death, while an estate or other non-person beneficiary can face an even shorter payout window. Naming the estate as beneficiary by default, or leaving the field blank, can therefore cost your heirs flexibility. Payout rules are covered in a separate article on required minimum distributions.

What most guides get wrong

Most advice stops at "update your will." The bigger risk is the opposite: a perfectly updated will can still be overridden by an outdated form. A will is revised after major life events; beneficiary forms often sit untouched for decades because they live on separate websites, stapled to separate employers. A divorce decree, a remarriage, or a new will does not rewrite them. Treat the beneficiary forms as part of the estate plan, not an afterthought.

A practical checklist

• List every account that has a beneficiary: retirement plans, IRAs, life insurance, annuities, HSAs, and POD/TOD accounts.

• Name primary and contingent beneficiaries on each.

• Use full legal names and percentages rather than vague labels like "my kids."

• Check minors: a child generally cannot receive assets directly; a custodian or trust may be needed.

• Review after every life event: marriage, divorce, birth, death, and large changes in assets.

• Make sure your will, forms, and account titles tell the same story.

• Mind the size: the federal estate tax applies only to estates above $15,000,000 per person in 2026, so it affects very few families, though some states tax smaller estates.

Frequently Asked Questions

1. Does my will override my beneficiary form? No. For assets with a valid beneficiary designation, the form generally controls, regardless of the will.

2. Do I still need a will if I have beneficiaries on everything? Usually yes. A will covers assets without a beneficiary, names guardians for minor children, and names an executor.

3. What if my beneficiary dies before me? If you named a contingent beneficiary, the account usually goes there. If not, it may fall to your estate and probate.

4. Can a divorce decree change my 401(k) beneficiary? Not by itself in an employer plan governed by ERISA, as the Kennedy case illustrates. Update the form.

5. Is the federal estate tax a concern for most people? Not usually. The 2026 federal basic exclusion amount is $15,000,000 per person, and state taxes vary.

Key Takeaways

• A will controls only probate assets; retirement accounts, life insurance, and POD/TOD accounts follow their beneficiary forms.

• When the two conflict, the beneficiary designation generally wins, as the Supreme Court's Kennedy decision shows for ERISA plans.

• In the worked example, an outdated form sent about 32% of the estate to an ex-spouse and left the children unequal.

• Name contingent beneficiaries and review forms after each life event.

• Pre-tax accounts and cash are not equal dollars once taxes are considered.

• The 2026 federal estate tax exclusion is $15,000,000 per person.

Sources

• Internal Revenue Service, Retirement topics: Beneficiary

• Internal Revenue Service, What's new: Estate and gift tax

• Internal Revenue Service, IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill

• U.S. Supreme Court, Kennedy v. Plan Administrator for DuPont Savings and Investment Plan, 555 U.S. 285 (2009)

This article is for general educational purposes only and does not constitute financial, investment, tax, or legal advice.

Last updated: October 2026