Company Stock in Your 401(k): NUA Beats Diversifying?

The decision: diversify inside the plan, or NUA out first?

Marcus is 58, retiring from a Fortune 500 manufacturer in Columbus, Ohio. He files married filing jointly. His 401(k) holds $300,000 of company stock with a cost basis of $60,000 — meaning $240,000 of that balance is appreciation the plan never paid tax on. His advisor’s default suggestion: “Let’s rebalance out of the company stock inside the plan so you’re diversified, then roll it to an IRA when you leave.”

That advice would cost Marcus roughly $25,000–$40,000 in extra lifetime tax. Here is why: the moment he sells those specific shares inside the 401(k) — or rolls them to an IRA — he permanently forfeits Net Unrealized Appreciation (NUA) treatment under IRC §402(e)(4). Every future dollar from that money then comes out at ordinary income rates, up to 37%. The correct sequence is to distribute the shares in-kind first (NUA), pay ordinary tax on the $60,000 basis, lock the $240,000 appreciation into long-term capital gains treatment, and only THEN diversify — in a taxable brokerage account.

The diversification goal is right. The sequencing is what most people get backwards. Solve concentration risk after the NUA distribution, not inside the plan.

What NUA actually is, and why selling inside the plan kills it

Net Unrealized Appreciation is the difference between what your 401(k) paid for the employer stock (the cost basis) and what it’s worth at distribution. Under IRC §402(e)(4), when you take a lump-sum distribution of your qualified plan and receive the employer stock in-kind (the actual shares, not cash), the tax splits into two pieces:

• Cost basis — taxed as ordinary income in the year of distribution. On Marcus’s position, that’s $60,000.
• The NUA spread — the appreciation above basis, taxed at long-term capital gains rates when you eventually sell, no matter how long you held the shares. On Marcus’s position, that’s $240,000.

The catch — and this is the whole article — is that NUA only attaches to employer stock distributed in-kind. If you sell those shares inside the 401(k) and buy index funds to diversify, you’ve converted appreciated employer stock into ordinary plan dollars. The cost-basis/appreciation split is gone. There is no in-kind distribution to apply NUA to anymore. The same thing happens if you roll the shares into a traditional IRA: the entire value becomes ordinary-income IRA money, taxed at your §1 bracket on every withdrawal.

That’s why “diversify inside the plan” and “just roll it all to an IRA” are the two most expensive defaults in concentrated-stock planning. Both forfeit a six-figure tax break that you can only claim once, on the way out.

The math: NUA-out vs. diversify-inside-and-roll

Marcus has $300,000 of company stock, $60,000 basis, $240,000 NUA. He and his spouse expect roughly $190,000 of MFJ taxable income in retirement, which puts him in the 24% ordinary bracket ($206,701–$394,600 MFJ for 2026) and the 15% long-term capital gains bracket ($96,701–$600,050 MFJ). Their MAGI also clears the $250,000 MFJ NIIT threshold, so the 3.8% Net Investment Income Tax applies to the capital-gains portion.

The NUA route taxes the $240,000 appreciation at 18.8% (15% LTCG + 3.8% NIIT under IRC §1411) instead of 24%+ ordinary on the §1 brackets. That’s a $12,480 difference on the appreciation alone — and it grows every year the diversify-inside money would have compounded as ordinary-rate IRA dollars. The trade-off is paying the $14,400 ordinary tax on the basis up front in year one, which is why NUA favors a low basis position. At $60K basis on a $300K value (20%), the up-front cost is small relative to the locked-in capital-gains rate on $240K.

The break-even: when NUA stops winning

NUA is not automatically the answer. The lever is the basis-to-value ratio. You pay ordinary tax on the basis no matter what, so the more basis you have, the more ordinary tax you eat up front to access the capital-gains rate on a shrinking appreciation slice.

1. Basis under ~30% of value: NUA almost always wins. The appreciation slice is large and rides at 15–23.8% instead of ordinary rates. Marcus’s 20% basis is squarely here.
2. Basis 30–50% of value: the gray zone. Run the actual numbers using your ordinary bracket, your LTCG bracket, and whether NIIT applies. The shorter your time horizon before selling, the more NUA still helps.
3. Basis over ~50% of value: the rollover usually wins. You’d pay a big ordinary tax on the basis up front for a small capital-gains break on the appreciation — the deferral of a full IRA rollover beats it.

One more factor: your ordinary bracket in the distribution year. NUA forces the entire cost basis into one tax year as ordinary income. If retiring pushes you into a low bracket the year you separate (say 12% or 22%), the up-front basis tax is cheap and NUA looks even better. If you NUA in a high-earning year, you pay the basis tax at 32–37%. Time the lump-sum distribution for a low-income year when you can.

How to actually execute the NUA-then-diversify sequence

The order of operations is unforgiving. Miss a step and you blow the lump-sum requirement, which voids NUA for the whole distribution.

1. Confirm a triggering event. NUA requires a lump-sum distribution following separation from service, reaching age 59½, death, or disability. Retiring at 58 after separation qualifies for Marcus.
2. Empty the entire plan in one tax year. A lump-sum distribution under IRC §402(e)(4)(D) means the full balance of all like plans comes out within a single calendar year. You can split where it goes — but the timing is one year.
3. Take the employer shares in-kind to a taxable brokerage account. The actual stock certificates/shares transfer; do NOT let the custodian sell and send cash, and do NOT route the shares through an IRA.
4. Roll the rest of the plan (non-employer assets) to a traditional IRA in the same distribution. That portion keeps tax deferral; only the employer stock gets NUA treatment.
5. Pay ordinary tax on the cost basis with the year-one return (your custodian reports it on Form 1099-R, with the NUA amount in box 6).
6. Now diversify. In the taxable account, sell company shares to dial down concentration. The locked-in NUA spread keeps its long-term capital-gains character even if you sell the next day — you only owe additional LTCG on gains above the distribution-date price.

Cherry-pick your lots. The IRS lets you elect NUA on the highest-appreciation (lowest-basis) shares and roll the rest to the IRA. If your 401(k) bought company stock over 20 years at wildly different prices, NUA the cheap early lots and roll the expensive recent lots — that minimizes the ordinary tax on basis while maximizing the capital-gains-rate appreciation.

What most people miss: the “just diversify, it’s safer” trap

The single most common mistake is treating concentration risk and tax sequencing as the same decision. They aren’t. Here’s the myth and the correction:

There’s also a subtle RMD angle. Once you roll non-employer assets to a traditional IRA, that money is subject to required minimum distributions starting at age 73 (born 1951–1959) or 75 (born 1960 or later) under SECURE 2.0 §107. The NUA shares in your taxable account are not subject to RMDs — they can sit, be sold on your schedule, and be tax-loss-harvested against. Pulling the appreciated stock out via NUA shrinks the IRA balance that will later be force-distributed as ordinary income, which can also blunt IRMAA Medicare surcharges driven by RMD-inflated MAGI.

The under-59½ bonus most people don’t know

If you separate from service in the year you turn 55 or later, the cost-basis portion of a NUA distribution can avoid the 10% early-withdrawal penalty under the “rule of 55” (IRC §72(t)(2)(A)(v)). And the NUA spread itself is never subject to the 10% early-distribution penalty — it’s capital gain, not an early plan withdrawal. For someone retiring early with low-basis company stock, NUA can deliver penalty-free access to a six-figure position at capital-gains rates while a same-aged peer who rolled to an IRA is locked out until 59½ or stuck with 72(t) substantially-equal-payment rules.

State tax: where NUA wins by even more

Most states tax capital gains as ordinary income (no preferential state rate), so the federal LTCG advantage doesn’t always carry to the state line. But the relative comparison still favors NUA, because the alternative — IRA withdrawals — is also taxed as ordinary income at the state level, plus the IRA money keeps generating taxable distributions for decades.

• No-income-tax states (FL, TX, TN, NV, WA, WY, SD, AK, NH): the entire NUA position — basis and spread — faces zero state tax. Retiring to one of these before the distribution year maximizes the break.
• High-tax states (CA 13.3%, NY 10.9%, NJ 10.75%): both NUA and the rollover get hit at the state level, but pulling the appreciation out at federal LTCG rates and selling on your own timeline still beats decades of state-taxed ordinary IRA withdrawals.
• Washington’s 7% long-term capital gains tax applies only to gains over $250,000 — relevant if a large post-distribution sale stacks on top of the NUA spread in one year. Spread the diversification sales across calendar years to stay under the threshold.

The decision lever

Pull on one number: your basis-to-value ratio. At Marcus’s 20% basis ($60K on $300K), NUA-out-then-diversify saves roughly $12,000–$25,000 versus diversifying inside the plan or rolling to an IRA — and the gap widens every year the alternative would have compounded as ordinary-rate IRA dollars. Below 30% basis, NUA almost always wins; above 50%, the rollover usually does. Time the lump-sum distribution for a low-income year, take the lowest-basis lots in-kind, roll the rest to an IRA, and solve your concentration risk in the taxable account — where you still control the timing of every gain. The one thing you cannot undo is selling those shares inside the plan first. Sequence before you diversify.