Net unrealized appreciation, or NUA, is a rule that lets you move employer stock out of a 401(k) and pay long-term capital gains tax on the growth instead of ordinary income tax. Most people never hear about it because it only applies at the exact moment they leave a job or retire, and most plan administrators will not bring it up unless you ask. It can save six figures in tax on a large stock position. It can also backfire badly if you trigger it at the wrong time or with the wrong amount of stock.
The strategy sits at the intersection of two things people rarely think about together: how 401(k) distributions get taxed, and how company stock accumulates inside a retirement account over a career. If you worked somewhere that matched in stock, or let you buy company shares inside your 401(k), NUA is worth understanding before you roll that account into an IRA on autopilot.
Here is the mechanic. When you take a lump-sum distribution from a 401(k) that holds employer stock, you can choose to move that stock into a regular taxable brokerage account instead of rolling it into an IRA. You pay ordinary income tax immediately, but only on the stock's original cost basis, meaning what the plan actually paid for it over the years, not what it is worth today.
The difference between that cost basis and the current market value is the net unrealized appreciation. That gain sits untaxed until you sell the shares, and when you do sell, it gets taxed at long-term capital gains rates no matter how long you personally have held the shares after the distribution. This is the part people miss: the holding period requirement gets waived entirely for the NUA portion.
Everything else in the 401(k), the cash, the mutual funds, the bond funds, rolls into an IRA as normal. Only the employer stock gets pulled out this way. NUA is not an all-or-nothing choice for the whole account. It is a carve-out for one asset inside it.
Say you have $400,000 in employer stock inside your 401(k), and the plan originally paid $60,000 for those shares over the years through match and payroll contributions. The cost basis is $60,000. The unrealized appreciation is $340,000.
Roll the whole thing into an IRA and you defer tax now, but every dollar you eventually withdraw gets taxed as ordinary income, at rates that can run as high as 37% federally depending on your bracket in retirement. Use NUA instead, and you pay ordinary income tax on just the $60,000 basis now. The $340,000 gain gets taxed later, when you sell, at capital gains rates, which top out at 20% federally for most people plus the 3.8% net investment income tax if it applies.
That gap between 37% and 20% on $340,000 is not small. It is the entire reason this rule exists as a planning tool rather than a footnote in the tax code. Financial advisors who actually run these numbers for clients will tell you: for a large, low-basis stock position, NUA usually wins by a wide margin over a straight IRA rollover.
The tax bill on the basis amount still has to get paid the year of the distribution, and it has to get paid out of pocket or from other funds, not from the stock itself, since selling shares to cover it would undercut the whole point. That upfront cash requirement is the main reason people shy away from NUA even when the math favors it.
NUA is not available to everyone with a 401(k). It requires a specific trigger event: separation from service, reaching age 59½, disability, or death. You cannot do this while still actively employed and simply holding shares in the plan. The distribution also has to be a lump-sum distribution, meaning the entire vested balance of the plan comes out within a single calendar year, not spread across multiple years.
That lump-sum requirement trips up more people than any other part of the rule. If you took a partial distribution last year and plan to take the rest this year, you may have already disqualified yourself. All qualified plans of the same type held with that employer, not just the 401(k) specifically, generally need to be distributed together within the same tax year for the election to hold up.
Company stock also has to have appreciated meaningfully for NUA to matter. If your cost basis is close to current value, there is no gain to shelter, and you should just roll the account into an IRA like normal. NUA is a tool for people who have accumulated significant, low-basis employer stock over a long tenure, not a general 401(k) strategy.
People blow this up in a few predictable ways. The most common: rolling part of the plan into an IRA before doing the NUA distribution on the stock. Once any part of the balance has been rolled over, the lump-sum requirement is broken and NUA is off the table for that plan, permanently, for that distribution event.
Another common mistake is taking a distribution too early or too late relative to the triggering event, misunderstanding the calendar-year rule. The clock resets with each new triggering event, but you do not get to cherry-pick timing across years once you have started taking distributions from the plan.
People also underestimate the tax bill on the basis. If your cost basis is $150,000 instead of $60,000, that is $150,000 of ordinary income landing in one tax year, on top of whatever else you earned that year. It can push you into a much higher bracket, trigger the 3.8% surtax, and even affect Medicare premium surcharges two years later if you are near retirement age. Nobody should do NUA without running a full projection first, ideally with a tax professional who has actually handled one of these before, not just read about it.
The honest answer to when NUA beats a rollover depends on three inputs: the size of the unrealized gain, your current tax bracket, and your expected tax bracket in retirement.
| Factor | Favors NUA | Favors IRA Rollover |
|---|---|---|
| Ratio of gain to basis | High (gain is most of the value) | Low (basis is most of the value) |
| Current tax bracket | Lower, easier to absorb the basis tax hit | Higher, basis tax hit is expensive now |
| Expected retirement bracket | Similar or higher than today | Much lower than today |
| Plans to hold stock long-term | Yes, benefits from cap gains treatment | Plans to diversify out immediately anyway |
| Need for immediate cash to pay basis tax | Have it available outside the plan | Would need to sell shares to cover it |
If you expect to be in a much lower tax bracket in retirement than you are now, the deferred-taxation advantage of a rollover can actually beat NUA, since ordinary income tax on withdrawals at a low future rate might land below even the capital gains rate paid today. This is the scenario advisors skip past too quickly. NUA is powerful, but it is not automatically correct just because it exists.
Estate planning changes the calculus too. Stock held in a taxable account under NUA does not get the same step-up in basis treatment on the appreciation portion at death that other assets do, since the NUA amount retains its character. That is a detail worth a real conversation with an estate attorney if the position is large enough to matter for heirs.
The single biggest mistake is doing nothing and rolling everything into an IRA out of habit, because that is what the plan administrator defaults to and what most rollover paperwork nudges you toward. Once that rollover happens, the NUA election is gone. There is no undo.
The second biggest mistake is doing NUA on a small position where the tax savings do not justify the complexity and the upfront cash outlay. NUA shines on large, low-basis positions, not on a modest stock holding worth $20,000. Run the numbers before committing to anything.
The third mistake is treating the concentrated stock position like it is risk-free after the distribution. Getting favorable tax treatment on employer stock does not mean you should keep holding a huge, undiversified position in one company. Plenty of people who nailed the tax move still got hurt when the stock dropped 40% two years later because they never sold. Tax efficiency and diversification are separate decisions, and NUA only solves the first one.
Net unrealized appreciation is the growth in value of employer stock held inside a 401(k), measured from what the plan originally paid for the shares to their current market value. When you distribute that stock correctly under IRS rules, this growth gets taxed at long-term capital gains rates instead of ordinary income rates. It only applies to employer stock, not to other assets inside the plan.
You need to take a lump-sum distribution of the entire vested plan balance within one calendar year to qualify, but the stock itself goes into a taxable brokerage account rather than an IRA. Everything else in the plan, like cash or mutual funds, can still roll into an IRA as part of that same lump-sum distribution. Splitting the distribution across multiple years disqualifies the NUA election entirely.
The cost basis is what the 401(k) plan actually paid to acquire the employer shares over time, not the current market price. This figure comes from plan records, and the plan administrator is required to report it on the distribution paperwork. You owe ordinary income tax on this basis amount in the year of distribution, regardless of when you eventually sell the stock.
No. NUA requires a qualifying triggering event: separation from service, reaching age 59½, disability, or death. You cannot elect NUA treatment on employer stock while still actively employed and simply holding the shares in the plan. The lump-sum distribution has to follow one of these specific events.
No. NUA generally wins when the unrealized gain is large relative to the cost basis and your current tax bracket can absorb the upfront tax on that basis. If you expect a much lower tax bracket in retirement, deferring everything through an IRA rollover can sometimes beat NUA on an after-tax basis. The decision depends on running actual numbers, not a blanket rule.