Fidelity Says the Average 401(k) Balance Hit $155,800. As Much as $34,000 of That Belongs to the IRS, and the Bill Grows Every Year It Sits Untouched

Fidelity Says the Average 401(k) Balance Hit $155,800. As Much as $34,000 of That Belongs to the IRS, and the Bill Grows Every Year It Sits Untouched

Your 401(k) statement shows a number that feels like yours, but a silent partner has a claim on a piece of it that grows larger every year you wait to settle up.

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Fidelity says the average 401(k) balance hit $155,800. If that number is yours, congratulations. Also: you owe a chunk of it to the IRS, and you have never been billed.

That is the quiet feature of a traditional 401(k). Every dollar in the account is pre-tax. Every dollar of gain is pre-tax. The tax gets paid on the way out, at whatever rate applies then, on whatever the balance has grown to by then. The bigger the balance, the bigger the deferred bill in absolute dollars.

What the Fidelity Number Actually Measures

Fidelity’s quarterly retirement analysis tracks tens of millions of accounts. The most recent report in this data set, Q4 2025, put the average 401(k) balance at $146,400, up 11% from Q4 2024, drawn from 26,200 corporate def...