The $60,000 of After-Tax 401(k) Money a 63-Year-Old Will Roll Into His IRA Will Be Taxed Twice Unless He Files a Form Nobody Will Tell Him About

A 63-year-old retiring this fall has spent years putting extra money into his 401(k) after tax, above his regular pre-tax contributions. That amount now totals $60,000. His plan will mail a rollover packet, and his IRA custodian will gladly accept the money, but nobody in the chain is responsible for telling the IRS he already paid tax on those dollars. If the $60,000 lands in a traditional IRA and he never documents it, every withdrawal gets taxed as if it were pre-tax money. He pays income tax on the same dollars twice.

This is a common trap for disciplined savers who maxed out their plans. Rolling a 401(k) into an IRA normally lets participants avoid paying taxes on the accumulated balance, so people assume the after-tax portion is handled automatically. It is handled only if you handle it.

Why After-Tax Dollars Vanish in a Standard Rollover

After-tax 401(k) contributions are a separate bucket from Roth 401(k) money, and the contributions themselves have already been taxed, but any growth on them is still pre-tax. When everything flows into one traditional IRA, the custodian has no record of which dollars were taxed. The IRS assumes all of it is taxable unless you file Form 8606, which records your nondeductible basis.

The buckets are getting more complicated for workers his age. In 2026, employees 60 to 63 can make catch-up contributions of up to $11,250, and those who earned more than $150,000 in 2025 must direct catch-ups to a Roth 401(k). A late-career saver can easily hold pre-tax, Roth, and after-tax money in one plan.

Clean Separation Beats Decades of Basis Tracking

What matters most is whether that $60,000 stays mixed with pre-tax money or gets walled off permanently. Mixed basis in a traditional IRA triggers the pro-rata rule: each withdrawal is a blend, with only a proportional slice coming out tax-free. Suze Orman has warned that anyone with pre-tax IRA money who converts will “have to pay taxes when you convert according to a pro rata formula.”

That basis must be carried forward on Form 8606 for every year he takes a distribution. For someone born in 1963, required minimum distributions start at age 75 under SECURE 2.0, so the tracking could stretch across two or three decades. Records get lost, tax preparers change, and heirs rarely know the basis exists.

Path One: Send the $60,000 Straight to a Roth IRA

Most people in this position have strong reasons to consider this path. IRS guidance from 2014 lets a retiree split a single 401(k) distribution: after-tax contributions go directly to a Roth IRA, while pre-tax money and earnings go to a traditional IRA. The $60,000 moves tax-free, grows tax-free, and requires no basis tracking later.

Clark Howard gave a caller the same direction: “If it’s after-tax money, you could roll it into a Roth IRA. And that’s what I would do.”

Roth IRAs carry no lifetime RMDs for the original owner, so this money can sit untouched as a late-retirement reserve or a tax-free inheritance. One detail matters: Roth earnings are generally tax-free once you are at least 59½ and the funds have been in the account for at least five years. If he has no existing Roth IRA, opening one now starts that clock.

Path Two: Traditional IRA Plus Form 8606 Every Year

Rolling everything into a traditional IRA and filing Form 8606 does avoid double taxation. It is still the weaker choice. He gives up tax-free growth on $60,000, locks himself into pro-rata math on every withdrawal and future Roth conversion, and takes on a paperwork obligation. That obligation fails silently if missed. This path makes sense mainly when a plan refuses to process split distributions, which is worth confirming in writing before accepting.

Steps to Take Before the Rollover Check Is Cut

Start by reviewing your most recent 401(k) statement to locate the after-tax contribution total, listed separately from its earnings. Then request a direct rollover in writing that sends the after-tax contributions to a Roth IRA and everything else to a traditional IRA. After the rollover, check that Box 5 of your Form 1099-R reports the after-tax amount correctly.

Second, if you already rolled after-tax money into a traditional IRA in past years without filing Form 8606, file it now to establish your basis before withdrawals begin. The most costly mistake is accepting the plan’s default single-destination rollover.

If you have made nondeductible IRA contributions over several years and already taken distributions, a CPA reconstructing your basis can help recover tax you would otherwise pay twice.

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