NUA + Roth Conversion: Sequencing Strategy to Minimize Lifetime Tax

These two strategies are most powerful together — but only when sequenced correctly. The NUA distribution year can temporarily spike your income, making it the worst year for a Roth conversion. Done in the right order, the combination can save six figures in lifetime tax. Done wrong, it stacks two high-income events in the same year.

The fundamental tension

Roth conversions are cheapest in low-income years. You're deliberately paying tax today on pre-tax retirement money so that future growth is tax-free — the lower your rate today, the better the trade.

The NUA lump-sum distribution adds ordinary income equal to your cost basis in the year you take the distribution. For employees with a large cost basis, this can be a high-income year, potentially pushing you into the 24%, 32%, or even 35% bracket before any Roth conversion.

These two strategies don't conflict in principle — they conflict in timing. The key is identifying which years are cheap (low ordinary income) and which are expensive, then scheduling each strategy accordingly.

What NUA does to your income in the distribution year

When you take an NUA lump-sum distribution, the cost basis of your employer stock is taxed as ordinary income in that year.¹ The NUA appreciation itself is not taxed at distribution — it becomes long-term capital gain when you eventually sell the shares. But the cost basis hits immediately.

The takeaway: your appreciation ratio determines how much the NUA year penalizes Roth conversions. The higher the appreciation ratio, the smaller the basis, and the smaller the ordinary income spike.

The IRMAA trap: the hidden two-year delay

One of the most underappreciated consequences of a high-income NUA year is the IRMAA surcharge that arrives 26 months later.

IRMAA (Income-Related Monthly Adjustment Amount) is a Medicare Part B and Part D surcharge imposed on beneficiaries whose income exceeds certain thresholds. The catch: IRMAA is determined using your tax return from two years prior.² Your 2026 IRMAA is based on your 2024 income. So if you take your NUA distribution in 2026, the IRMAA hit arrives in 2028.

2026 IRMAA thresholds for Medicare Part B (based on 2024 income):²

Both spouses on Medicare pay the surcharge separately, so a $300K income year for a married couple adds $446.30 × 2 = $892.60 per month ($10,711 per year) to Medicare premiums for 12 months, two years after the NUA distribution. Planning around this threshold is as important as planning around the federal income tax bracket.

Three planning windows

Window 1: the pre-NUA year — often the best Roth opportunity

If you know you'll do NUA next year, the year before distribution is often your best Roth conversion window. You've retired (or are in the year of retirement with partial income), your salary income may be lower, and you haven't yet triggered the cost-basis spike.

What to do: model how much room remains below your target bracket ceiling — typically the top of the 22% or 24% bracket — and fill it with a Roth conversion. Converting $50K to $80K in the pre-NUA year at 22–24% can be dramatically cheaper than converting the same amount in the NUA year at 32–35%.

Window 2: the NUA year — depends on your appreciation ratio

Whether you can do a Roth conversion in the same year as your NUA distribution depends on how much the cost basis consumes your bracket headroom:

• High appreciation ratio (10:1+): Cost basis is small relative to position value. The ordinary income spike may be modest — under $100K for a $1M+ position. You may have bracket room for a modest Roth conversion, particularly if you retired mid-year and your salary income stopped.
• Moderate appreciation (4:1–8:1): The cost basis could push you into 24–32%. Roth conversion likely expensive this year — skip it or do a small amount to fill a lower bracket only.
• Low appreciation (2:1–3:1): The cost basis may consume most of the favorable bracket space. Avoid Roth conversion this year entirely.

Window 3: post-NUA years — the long Roth runway

After the NUA distribution year, your income structure changes substantially. You've moved the employer stock from the 401(k) into a taxable brokerage account. Income now flows from:

• Dividends on the employer stock (qualified, taxed at LTCG rates)
• Capital gains when you sell shares (long-term, at 0%/15%/20% rates)
• Social Security, if you've begun claiming (partially taxable based on combined income)
• Distributions from remaining pre-tax IRA/401(k) accounts (ordinary income, but now smaller since the stock is gone)

Long-term capital gains don't push you through the ordinary income brackets the way wages and IRA withdrawals do. A retiree with $80K of LTCG and $20K of SS income may have very little ordinary income — leaving a wide bracket opening for Roth conversions at 12% or 22%.³

RMD coordination: both strategies reduce future RMDs

Every pre-tax dollar removed from a 401(k) or IRA — whether by NUA distribution or Roth conversion — reduces your future Required Minimum Distribution (RMD) base. That's a compounding benefit: smaller RMDs mean less forced ordinary income at 73/75, lower Medicare costs, and potentially lower taxes on Social Security benefits.

The combination is particularly powerful: NUA removes the employer stock (often the largest asset) from the pre-tax account, and then annual Roth conversions in the post-NUA years systematically drain the remaining pre-tax balance over the years before RMDs begin. By the time RMDs are required, the pre-tax account may be small enough that the forced withdrawals no longer push you into high brackets or trigger IRMAA.

Note: Roth 401(k) and Roth TSP accounts are now also exempt from lifetime RMDs (SECURE 2.0, § 325, effective 2024⁴). If your plan has a Roth 401(k) option, contributing there (rather than converting after the fact) accumulates more years of RMD-free growth.

Worked example: coordinating NUA + Roth across a 10-year window

Elena, 61, is retiring in Q4 2026 from a large manufacturing company where she worked 30 years. Her 401(k) holds:

• $1.2M employer stock — cost basis $80K (15:1 appreciation ratio)
• $600K non-employer-stock funds (pre-tax)

She is married (MFJ), husband is 63 and not working. They have modest Social Security expected at 67. No pension.

Year 0 (2026, final year of employment): Elena retires in October. Partial salary year — roughly $120K combined ordinary income including salary. She does a $40K Roth conversion of non-company-stock funds, filling to $160K total (within the MFJ 22% bracket top⁵). NUA distribution not taken this year — she and her advisor plan for 2027.

Year 1 (2027, NUA year): Elena takes the lump-sum distribution. The $80K cost basis hits ordinary income. Combined with modest other income (dividends, interest), MAGI is approximately $95K. Modest — stays under the 2027 IRMAA lookback threshold for 2029. She does a small $20K Roth conversion to fill to approximately the 22% bracket top. Total 2027 MAGI: ~$115K.

Year 2–3 (2028–2029): No IRMAA surcharge (2027 MAGI was below the single-pair threshold). Elena is living off dividends and periodic stock sales — all LTCG. Ordinary income low: ~$30K (distributions from non-company-stock 401(k) + SS not yet claimed). She converts $60K/year to Roth at effective 12–22% rate. By end of 2029, she's converted ~$120K of the $600K pre-tax balance.

Years 4–7 (2030–2033): She begins Social Security at 67. Combined income rises but remains manageable. Continues $50K/year Roth conversions. By 73, her pre-tax balance is under $250K — RMDs are small enough not to cause bracket or IRMAA problems.

Result vs. rollover-only path: In the rollover path, Elena rolls the full $1.8M to IRA. By 73, RMDs on a $1.8M account (plus growth) force $90K+ of taxable withdrawals annually, pushing her into the 24% bracket, triggering IRMAA, and increasing the taxability of Social Security. The NUA + sequenced Roth path avoids this by systematically removing pre-tax assets early, at low rates, before RMDs begin.

Five sequencing mistakes that cost six figures

1. Doing a large Roth conversion in the same year as NUA. Both events add ordinary income — stacking them in Year 1 can push you into the 32–35% bracket on the Roth conversion, eliminating most of the conversion's value. The NUA year is usually not the time for aggressive Roth conversions unless your cost basis is very small.
2. Ignoring the IRMAA lag. The NUA distribution year's income determines IRMAA two years later. A single year of spiked MAGI can cost $10,000+ in Medicare surcharges — real money that doesn't appear anywhere on a typical NUA analysis. Model IRMAA explicitly.
3. Waiting until RMDs start to begin Roth conversions. RMD age is 73 (born 1951–1959) or 75 (born 1960+) under SECURE 2.0.⁴ The 10–15 years between retirement and RMD start is often the cheapest Roth conversion window of your life. Don't squander it.
4. Treating the two strategies as separate decisions. NUA analysis and Roth conversion analysis are often done in different meetings, by different advisors, in different years. The combined impact of sequencing requires modeling them together across a 10–15 year horizon. Advisors who specialize in NUA are most likely to run this integrated model.
5. Forgetting state taxes. Some states tax Roth conversions at ordinary income rates regardless of how low your federal rate is. California, New Jersey, and others have no bracket preference — a 22% federal conversion could cost 30%+ all-in. A NUA specialist who knows your state's rules will factor this into the sequencing recommendation.

Sources

1. IRC § 402(e)(4) — Net Unrealized Appreciation rules; cost basis taxed as ordinary income at distribution, NUA excluded from gross income, becomes LTCG on later sale. See also IRS Publication 575.
2. SSA POMS HI 01101.020 — 2026 IRMAA Sliding Scale Tables, published 12/02/2025. 2026 IRMAA based on 2024 MAGI. Part B base premium $202.90; surcharges $81.20–$487.00/month. Values verified against Kiplinger Medicare Premiums 2026 guide.
3. Tax Foundation: 2026 Federal Tax Brackets and Rates. 2026 LTCG 0% threshold: $49,450 single / $98,900 MFJ taxable income; 15% rate above that threshold. Ordinary income brackets: 37% above $640,600 single / $768,600 MFJ. Standard deduction $16,100 single / $32,200 MFJ.
4. SECURE 2.0 Act of 2022 (P.L. 117-328): § 107 raises RMD age to 73 (born 1951–1959) / 75 (born 1960+); § 325 eliminates Roth 401(k) and Roth TSP lifetime RMDs effective 2024.
5. IRS Rev. Proc. 2025-67 — 2026 Tax Inflation Adjustments (including OBBBA amendments). 2026 ordinary income bracket thresholds and standard deductions.

NUA is a one-shot, irreversible election. Roth conversion is permanent. Tax values verified against 2026 IRS guidance and SSA IRMAA tables. Integrated multi-year analysis — not single-year snapshots — is essential for these decisions. Specialist review strongly recommended.