The Average Inherited 401(k) Is $267,900. The 10-Year Rule Will Cost You Thousands in Taxes.

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The SECURE Act rewrote how inherited retirement accounts work, and the consequences are now landing on a generation of heirs. For most non-spouse beneficiaries who inherited a 401(k) on or after January 1, 2020, the entire account must be emptied by the end of the tenth year after the original owner’s death. The IRS finalized the rules in 2024, and starting in 2025, beneficiaries of accounts whose owners were already taking required minimum distributions must also take annual RMDs. This article walks through how the rule works, what it does to a typical inherited balance, and where the tax math gets uncomfortable.

The Rule in Plain Terms

Before the SECURE Act, a non-spouse beneficiary could stretch distributions from an inherited 401(k) or IRA across their own life expectancy, often for decades. That option is gone for most heirs. The 10-year rule replaces it. The account must be at zero by December 31 of the tenth year following the year of death. There is no annual schedule mandated by the statute itself, but the IRS confirmed that if the original owner has already reached their required beginning date, the beneficiary must take annual RMDs in years 1 through 9 and take the remainder in year 10.

Five categories of beneficiaries are exempt and can still stretch: surviving spouses, minor children of the decedent (until age 21), disabled or chronically ill individuals, and beneficiaries less than 10 years younger than the original owner. Everyone else, including adult children, siblings, and most grandchildren, is on the 10-year clock.

What the Math Looks Like on a Typical Account

The average Baby Boomer 401(k) balance is 260,300 dollars, according to a recent 2026 retirement analysis. That is the kind of account adult children are now inheriting. Spread evenly over 10 years, that works out to roughly $26,030 per year of additional taxable income on top of whatever the beneficiary already earns. Distributions from a traditional inherited 401(k) are taxed as ordinary income. A beneficiary in their peak earning years, already in the 24% or 32% federal bracket, can lose a meaningful share of the inheritance to taxes simply by accepting the default schedule.

Distributions from a traditional inherited 401(k) are taxed as ordinary income. A beneficiary in their peak earning years, already in the 24% or 32% federal bracket, can lose a meaningful share of the inheritance to taxes simply by accepting the default schedule. The squeeze gets tighter for heirs of larger accounts. Fidelity counted 654,000 401(k) millionaires in Q3 2025. A million-dollar inherited balance distributed over a decade adds $100,000 a year of taxable income, which can push a middle-income heir into a higher bracket for the entire 10-year window.

Spouse Rules Are Different

A surviving spouse has three options that no other beneficiary has. They can roll the account into their own IRA or 401(k) and treat it as their own. They can remain a beneficiary of the inherited account, in which case required minimum distributions will be based on the age of your deceased spouse. Or they can disclaim the account and let it pass to contingent beneficiaries. The choice usually comes down to age. A younger spouse who needs access without penalty often stays a beneficiary. An older spouse who wants to delay RMDs often rolls it over.

Where the 10-Year Rule Pinches Hardest

The rule was written to raise federal tax revenue, and it does that by compressing tax-deferred growth that used to span generations. Three situations cause the most damage:

1. Heirs in their 40s and 50s who inherit during peak earning years and have no room to absorb extra income.
2. Accounts inherited from a parent who was already taking RMDs, which now require annual distributions in addition to the year-10 cleanout.
3. Large traditional balances inherited alongside other taxable income, where a 10-year drawdown pushes the beneficiary into the top marginal bracket.

What Beneficiaries Can Actually Do

Three moves change the outcome materially:

1. Model the tax cost before touching the account. A beneficiary can choose any distribution pattern over the 10-year period, subject to annual RMDs where required. Front-loading distributions in low-income years (e.g., a sabbatical, early retirement, or a gap between jobs) usually beats a flat schedule.
2. Consider a Roth conversion strategy for the original owner while they are still alive. Converting traditional balances to Roth before death means the heir inherits a Roth account, which is also subject to the 10-year rule but is distributed tax-free.
3. Check the plan documents. Some 401(k) plans force a faster payout than the IRS rule requires. Rolling the inherited 401(k) into an inherited IRA preserves the full 10-year window and gives the beneficiary control over timing.

The 10-year rule changes who keeps the savings. For heirs of the average Boomer 401(k), the difference between a planned drawdown and a default one can run into tens of thousands of dollars.

The post The Average Inherited 401(k) Is $267,900. The 10-Year Rule Will Cost You Thousands in Taxes. appeared first on 24/7 Wall St..