Tax Bucket Strategy for Millionaires: The Three-Account Framework

Most $1M–$5M investors are over-concentrated in one tax bucket — usually traditional (pre-tax) accounts they've been maxing for decades. When RMDs start at 73 or 75, those accounts turn into a tax bill you can't avoid. The fix is systematic: build all three buckets now while you still have choices.

The three tax buckets

Every dollar you've saved lives in one of three tax environments:

Why all three buckets matter at $1M–$5M

A single bucket creates a single point of tax failure. A saver who spent 30 years maximizing a traditional 401(k) has built a large, growing, mandatory-distribution liability: Required Minimum Distributions starting at age 73 (born 1951–1959) or 75 (born 1960+) will force withdrawals regardless of whether you need the money — and stack on top of Social Security, investment income, and any other income to push your effective rate higher each year.

Having money in all three buckets lets you dial your taxable income precisely in retirement:

• In low-income years, pull from traditional first — you're filling the lower brackets cheaply.
• In high-income years, pull from Roth — zero taxable addition, no IRMAA impact, no SS taxation trigger.
• Taxable accounts provide flexibility: long-term gains taxed at preferential rates, and unrealized gains can be passed to heirs with a step-up in basis under IRC §1014.⁵

Target bucket ratios by life stage

These are guidelines, not rules. The right balance depends on your income, tax bracket, state of residence, estate goals, and expected spending in retirement. A fee-only advisor models your specific household trajectory.

Bucket Balance Analyzer — 2026

Enter your current balances to see your bucket distribution, projected RMD exposure, and top recommended actions.

Roth conversion: the primary rebalancing lever

Unlike contributions (capped at $7,500–$8,600/year for IRAs in 2026), Roth conversions have no annual limit. You can move any amount from traditional to Roth in a given year — you'll owe ordinary income tax on the conversion, but the converted funds then grow and withdraw tax-free forever.

The optimal conversion strategy targets "filling the bracket": calculate how much income you can add before crossing into the next higher bracket, and convert that amount each year. In a typical pre-retirement scenario with MFJ income of $250,000, that might be $153,400 of headroom before hitting the 32% bracket — room to convert a meaningful amount annually at the 24% rate.

Withdrawal sequencing in retirement

Once all three buckets exist, retirement withdrawal order controls your tax bill each year:

1. Required Minimum Distributions first — these are mandatory from traditional accounts once you hit RMD age. They set your taxable income floor.
2. Fill lower brackets with traditional withdrawals — if your RMDs don't reach the top of the 22% bracket, additional traditional withdrawals at that rate are worth taking to avoid pushing income into the 32–37% range later.
3. Use taxable for large pulls — long-term gains in taxable are taxed at 0%/15%/20% (stacked on top of ordinary income), usually lower than traditional withdrawal rates for most retirees.
4. Roth for spikes — whenever a large expense (medical, travel, home repair) would push income into a higher bracket or IRMAA tier, pull from Roth instead. Zero tax, zero MAGI impact.

Common mistakes at $1M–$5M

• All traditional, no Roth: Three decades of 401(k) maximization without any Roth conversion creates a ticking RMD bomb. Many investors realize this at 65 when the conversion window is narrowing fast.
• Converting too much at once: A $500,000 single-year Roth conversion is taxable income in the year of conversion. At 37% + 3.8% NIIT it can cost $200,000+ in one year. Spreading over 10 years at 24% costs half as much in total tax.
• Ignoring IRMAA in conversion planning: The first IRMAA tier ($109,000 single / $218,000 MFJ in 2026) adds $594–$1,188/yr per person. The jump from Tier 1 to Tier 2 at $137,000 / $274,000 adds another $594/yr. Stay just below thresholds when possible.
• Forgetting the step-up in basis: Assets in your taxable account get a step-up to fair market value at death (IRC §1014). For highly appreciated positions you intend to leave to heirs, selling those inside a Roth conversion can be less efficient than holding them taxable and letting step-up eliminate the embedded gain.
• Backdoor Roth pro-rata trap: If you hold pre-tax IRA funds when doing a backdoor Roth, the IRS applies the pro-rata rule — a portion of every conversion is taxable based on your total IRA balance. Clear pre-tax IRA funds into your 401(k) first if your plan allows it.

Sources

1. IRS Topic 409 — Capital Gains and Losses. Long-term capital gains rates 0%/15%/20% based on taxable income; 2026 thresholds per IRS Rev. Proc. 2025-67.
2. IRS Publication 590-B — Distributions from IRAs. Ordinary income tax treatment of traditional IRA distributions; Uniform Lifetime Table for RMD calculations.
3. IRS — Roth IRAs. Tax-free qualified distributions after 5-year holding period and age 59½; contribution limits and income phase-outs.
4. SECURE 2.0 Act of 2022, §325. Eliminates lifetime RMDs from Roth 401(k) and Roth 403(b) accounts effective January 1, 2024.
5. IRC §1014 — Basis of Property Acquired from a Decedent. Step-up in basis to fair market value at date of death; unchanged by OBBBA P.L. 119-21.
6. CMS — 2026 Medicare Part B and D Premiums and Deductibles. IRMAA thresholds: Tier 1 begins $109,000 (single) / $218,000 (MFJ); 2026 values.

Tax values verified against 2026 sources: IRS Rev. Proc. 2025-32 (brackets), IRS Rev. Proc. 2025-67 (LTCG, contribution limits), CMS 2026 fact sheet (IRMAA). SECURE 2.0 RMD ages per §107 of Pub. L. 117-328.