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Net Unrealized Appreciation (NUA): The 401(k) Tax Break Most People Never Use

By Bob Lobclaw · July 13, 2026

This one only applies to a specific situation: you’re leaving a job (retiring, changing employers, or otherwise separating from service) and your 401(k) holds employer stock that has appreciated significantly since it was purchased. If that’s you, Net Unrealized Appreciation — NUA — is a rule worth knowing about before you roll everything into an IRA on autopilot, because the default move can cost you a meaningfully larger tax bill than necessary.

The basic idea

Normally, rolling a 401(k) into an IRA preserves tax deferral, but every dollar you eventually withdraw — contributions and all the growth — is taxed as ordinary income. NUA offers a different path for the employer-stock portion specifically: instead of rolling that stock over, you take it as an in-kind lump-sum distribution into a regular taxable brokerage account. At that moment, you owe ordinary income tax only on the stock’s cost basis — what the plan actually paid for the shares — not on its current market value.

The difference between market value and cost basis at distribution is the “net unrealized appreciation.” It isn’t taxed at all when you take the distribution. When you eventually sell the shares, that appreciation is taxed at long-term capital gains rates — regardless of how long you’ve actually held the stock since distribution, which is the special part of this rule. Any additional appreciation after the distribution date is taxed normally, as short- or long-term capital gains depending on how long you hold it from that point forward.

A simplified example

Say your 401(k) holds employer stock now worth $200,000, with an original cost basis of $40,000 — $160,000 of net unrealized appreciation.

  • Roll it all to an IRA: no tax today, but the full $200,000 is eventually taxed as ordinary income whenever it’s withdrawn.
  • Elect NUA instead: pay ordinary income tax now on the $40,000 basis only, and the stock moves to a taxable brokerage account. The $160,000 NUA is taxed at long-term capital gains rates whenever you sell — well below ordinary rates for most filers.

The bigger the gap between cost basis and current value, the more this favors NUA. A stock that’s barely appreciated has little to gain from the strategy; deeply appreciated stock from years of payroll contributions is exactly the case NUA was built for.

The rules you have to follow exactly

  • It has to be a genuine lump-sum distribution — the entire balance of every plan you hold with that employer, distributed within a single calendar year.
  • It has to follow a triggering event: separation from service, reaching age 59½, total disability, or death.
  • The stock has to move in-kind — as actual shares — into a taxable brokerage account. Selling it inside the plan first, or rolling any portion of it into an IRA, can break the election for that distribution.
  • The basis is reported as taxable income for the distribution year on Form 1099-R; the NUA amount is also reported, but isn’t taxed until sold.

Miss any of these and you can lose the NUA treatment entirely for that distribution, which is why this is not a do-it-yourself-at-tax-time decision — it has to be elected correctly with the plan administrator at the moment of distribution, and it can’t be undone afterward.

When it tends to make sense

  • The embedded gain is large relative to the cost basis.
  • You’re comfortable holding a concentrated single-stock position outside a retirement account, at least until you choose to diversify (which itself triggers the capital gains tax on whatever you sell).
  • You expect to be in a meaningfully higher ordinary-income bracket than the long-term capital gains rate you’d otherwise pay.
  • You’d rather this money not count toward future Required Minimum Distributions — because it leaves the retirement-account wrapper entirely at distribution, NUA stock in a taxable brokerage account isn’t subject to RMDs at all.

When it doesn’t

You give up further tax-deferred growth on that portion of the balance. The ordinary income tax on the cost basis is due in the distribution year regardless of whether you’ve sold any stock yet, which can be a real cash-flow crunch — and a large one-time income spike can push you into a higher bracket or, closer to Medicare age, trigger an IRMAA surcharge two years later. And if you’re under 59½ without another exception available (such as the Rule of 55, which requires separating from service in or after the year you turn 55), the basis portion can still be subject to the 10% early-withdrawal penalty, which erodes the advantage.

The bottom line

NUA is narrow — it only matters if you’re separating from an employer whose stock makes up a meaningful, highly appreciated slice of your 401(k) — but when it applies, the tax difference between an ordinary rollover and an NUA election can be substantial. It’s also a one-shot, hard-to-reverse decision, so it’s worth running the numbers with a CPA or tax advisor before you initiate any distribution or rollover, not after. For the other side of the pre-tax-vs-taxable tradeoff, see the Roth vs. 401(k) comparison.

Educational content, not personalized financial or tax advice — see the disclaimer.