Inherited IRA 10-Year Rule Tax: Timing Penalty Index 2026

A middle-income heir (about $120,000 of other taxable income) who empties a $500,000 inherited traditional IRA in a single year, rather than spreading it evenly across the SECURE Act 10-year window, pays roughly 8.6% of the account, about $42,900, in extra federal income tax that a level-fill schedule would have kept (2026 United States federal single-filer brackets; Source: IRS Rev. Proc. 2025-32, 2026, and Q3 Advisors computation).

Q3 Advisors Research | Last updated July 2026 | Methodology and sources below

Executive summary

Key findings

• A non-eligible designated beneficiary must withdraw the entire inherited IRA by December 31 of the year containing the 10th anniversary of the owner’s death (Source: IRS Publication 590-B, 2025, United States).
• On a $500,000 inherited pre-tax IRA in 2026, a middle-income ($120,000) single heir who takes a one-year lump sum pays about $162,600 in federal tax (32.5% of the balance) versus about $119,600 under level withdrawals (23.9%), a timing penalty of about $42,900 (Q3 Advisors computation, United States federal, 2026).
• On a $1,000,000 account, the same middle-income heir’s timing penalty rises to about $105,500, or 10.5% of the balance (Q3 Advisors computation, United States federal, 2026).
• Dumping a $400,000 inherited IRA into one tax year lifts a $120,000-income single heir from the 22% marginal bracket into the 35% bracket, costing about $127,600 in federal tax versus about $95,600 under ten equal withdrawals, roughly $31,900 in extra tax (Q3 Advisors computation on 2026 United States federal brackets, 2026).
• A high-income ($300,000) single heir who level-fills a $500,000 inherited IRA saves only about $2,900 versus a year-10 lump sum, because both paths are taxed largely at 35% in 2026 (Q3 Advisors computation, United States federal, 2026).
• Relative to the pre-2020 stretch, the 10-year rule forces a first-year-equivalent annual distribution roughly 2.1 to 3.9 times larger, depending on the heir’s age at inheritance: 10.0% of the balance under the 10-year rule versus 2.6% (age 45) to 4.8% (age 65) under the pre-2022 Single Life Expectancy schedule (Q3 Advisors computation on IRS pre-2022 Single Life Expectancy divisors, United States, 2026).
• Under the pre-2020 stretch, a 50-year-old beneficiary used a pre-2022 Single Life Expectancy divisor of 34.2, spreading a pre-tax IRA across roughly 34 years; the 10-year rule compresses that same balance into a decade (Source: IRS Publication 590-B (2020), Appendix B, Table I, the pre-2022 Single Life Table in effect for deaths before 2020, United States).
• Inheriting at a $300,000 peak-earning income costs a heir about $91,500 more in federal tax on a $500,000 level 10-year payout than inheriting with $40,000 of retirement income (35.0% versus 16.7% effective, Q3 Advisors computation, United States federal, 2026).
• IRA distributions are statutorily excluded from net investment income, so an inherited-IRA withdrawal is not itself subject to the 3.8% Net Investment Income Tax, but it raises modified adjusted gross income and can newly expose a heir’s other investment income to the tax (Source: IRC Section 1411(c)(5) and Section 1411(b)).
• The five eligible-designated-beneficiary categories exempt from the 10-year rule are a surviving spouse, a minor child of the owner, a disabled individual, a chronically ill individual, and any individual not more than 10 years younger than the owner (Source: IRS Publication 590-B, 2025).
• When the owner died on or after the required beginning date, a non-eligible designated beneficiary must take annual distributions in years 1 through 9 and still empty the account by year 10 (Source: IRS final regulations T.D. 10001, IR-2024-190, July 2024; verify against 26 CFR 1.401(a)(9)-5 before republication).
• When the owner died before the required beginning date, no distribution is required in any year before the 10th, leaving the heir full discretion to level-fill or defer (Source: IRS Publication 590-B, 2025).
• The 2026 top single marginal rate of 37% begins at $640,600 of taxable income (Source: IRS Rev. Proc. 2025-32, 2026, United States federal), and the One Big Beautiful Bill Act of 2025 made the 10% to 37% rate structure permanent (Source: One Big Beautiful Bill Act, P.L. 119-21, 2025).

The metric: what the 10-Year Rule Timing Penalty Index measures

The 10-Year Rule Timing Penalty Index measures the extra federal income tax a non-spouse, non-eligible-designated beneficiary pays by defaulting to the two most common withdrawal behaviors, a first-year lump sum or a year-10 “empty it all at once” distribution, instead of a tax-optimal level fill of one-tenth of the balance each year. It is expressed both as a dollar figure and as a percentage of the inherited balance, computed across four balance tiers crossed with two beneficiary income bands.

The index rests on one mechanical fact. Under a progressive bracket schedule, stacking a large pre-tax distribution into a single year pushes marginal dollars into higher brackets, while spreading the same balance across ten years keeps more dollars in lower brackets. The 2026 single brackets step from 22% at $50,400 of taxable income to 24% at $105,700, 32% at $201,775, 35% at $256,225, and 37% at $640,600 (Source: IRS Rev. Proc. 2025-32, 2026). A $500,000 lump lands a middle-income heir deep in the 32% band; ten $50,000 slices mostly stay in the 24% band.

The metric is deliberately narrow. It holds the heir a single filer, holds 2026 brackets constant, ignores account growth during the payout window, and excludes state income tax and second-order Medicare and Net Investment Income Tax effects. Those exclusions are conservative: account growth and state tax both widen the real penalty.

The data table: 10-Year Rule Timing Penalty Index (2026)

The table below is the citable asset. Every bracket cutoff and the $16,100 standard deduction are cited IRS 2026 inputs; the inherited balance, heir income, and heir age are analyst-chosen illustrative parameters, labeled as such. “Lump” is the entire balance distributed in one tax year; “Level” is one-tenth of the balance distributed in each of ten years; figures are incremental federal tax on the inherited dollars, on top of the heir’s other income, for a 2026 single filer (Source: IRS Rev. Proc. 2025-32, 2026; Q3 Advisors computation).

The pattern is clear. For a middle-income heir, the timing penalty grows steeply with balance because larger lumps climb through more brackets, peaking above 10% of a seven-figure account. For a high-income heir already anchored in the 35% bracket, timing is nearly neutral until the balance is large enough to reach into the 37% band above $640,600. The single most cited cell, a $500,000 account for a middle-income heir, loses about 8.6% of the balance, roughly $42,900, purely to withdrawal timing in 2026.

Breakdown by income band: why the peak-earner heir is the exposed persona

The 10-year window most often lands on adult children in their 40s and 50s, their highest-earning years, and that timing is the single largest determinant of the tax bill. The rule overlaps a full decade of a heir’s career, and each forced distribution stacks on top of already-high wages. Income band, not balance alone, sets the marginal rate at which the inherited dollars are taxed.

A $500,000 inherited IRA level-filled over ten years is taxed at an effective 35.0% for a $300,000-income single heir in 2026 (Q3 Advisors computation, 2026). The same account is taxed at an effective 16.7% for a heir with $40,000 of retirement income in 2026 (Q3 Advisors computation, 2026). That 18.3-point spread equals about $91,500 of United States federal tax on one $500,000 account (Q3 Advisors computation, 2026). A middle-income heir at $120,000 sits between them at an effective 23.9% (Q3 Advisors computation, United States federal, 2026).

The takeaway for the peak-earning heir is that the 10-year clock cannot be paused, but the marginal rate can be managed: distributions can be weighted toward any lower-income year within the window, such as a sabbatical, a gap between jobs, or the first year of retirement if it falls inside the decade. This is where the rule interacts with broader Roth conversion and income-smoothing planning.

Breakdown by balance and by heir age

Two illustrative parameters move the numbers most: the inherited balance and, for the stretch counterfactual, the heir’s age. Balance drives how far a lump climbs through the brackets. Age drives the length of the pre-2020 stretch and therefore the size of the structural compression the 10-year rule imposes.

For a middle-income heir, the timing penalty rises from 0.5% of a $100,000 account to 10.5% of a $1,000,000 account in 2026 (Q3 Advisors computation, United States federal, 2026). Under the pre-2022 Single Life Expectancy Table that governed deaths before 2020, a 45-year-old heir used a divisor of 38.8, a 50-year-old 34.2, a 55-year-old 29.6, a 60-year-old 25.2, and a 65-year-old 21.0 (Source: IRS Publication 590-B (2020), Appendix B, Table I, United States). The IRS updated these divisors upward effective January 1, 2022, so the current Table I (age 50 = 36.2) does not apply to a genuinely pre-2020 death. A younger heir had a longer stretch and, mechanically, a larger structural gap when that stretch was removed, though the effect is second-order to income band. The related annual-withdrawal mechanics are covered in the Q3 Advisors required minimum distributions 2026 guide.

What drives the numbers

Three forces set the tax outcome under the 10-year rule, in order of magnitude for the typical peak-earning heir. First and largest is the heir’s own income band, which fixes the marginal rate the inherited dollars stack onto. Second is withdrawal timing within the window, the behavior the Timing Penalty Index isolates. Third, and smallest under a constant-income assumption, is the structural loss of the multi-decade stretch itself.

The 2026 brackets make the timing effect concrete. The 22% band ends at $105,700 and the 24% band ends at $201,775 (Source: IRS Rev. Proc. 2025-32, 2026). A middle-income heir with $103,900 of taxable income after the $16,100 standard deduction sits at the very top of the 22% band, so even a $50,000 level slice pushes into 24%, while a $500,000 lump reaches into 32%. A high-income heir with $283,900 of taxable income is already in the 35% band, so timing barely moves the rate until a lump crosses $640,600 into 37%.

Account growth, excluded here, pushes in one direction only. A balance that keeps compounding inside the account during the payout window means larger required distributions later, widening the gap between a disciplined level fill and a deferred year-10 lump. The penalties in this report are therefore conservative floors, not ceilings.

Secondary triggers: NIIT and IRMAA

A large single-year distribution can reach beyond the income-tax brackets through two downstream channels. Both are second-order to the direct income tax and are modeled separately here.

Distributions from IRAs are statutorily excluded from net investment income, so the withdrawal itself is never subject to the 3.8% Net Investment Income Tax (Source: IRC Section 1411(c)(5)). The distribution does raise modified adjusted gross income, however, and can push a heir above the $200,000 single MAGI threshold, newly exposing their other investment income to the tax (Source: IRC Section 1411(b), threshold not inflation-indexed). Illustratively, a heir with $120,000 of wages and $15,000 of investment income sits below the threshold, but a $500,000 lump lifts MAGI to about $635,000, subjecting the $15,000 of investment income to the 3.8% tax, about $570 (Q3 Advisors computation, United States federal, 2026). A level fill that keeps MAGI under $200,000 in most years can avoid part of this.

A single-year spike also raises Medicare Part B and Part D premiums through the income-related monthly adjustment amount (IRMAA) two years later. The specific 2026 IRMAA MAGI tiers and premium surcharges were not verified against a CMS primary source in this analysis and are excluded from the dollar figures here; the direction of the effect, higher premiums after a large distribution, is established by the IRMAA statute. Q3 Advisors covers the mechanics in its Medicare IRMAA 2026 brackets analysis.

The excise-tax penalty for a missed distribution

When the owner died on or after the required beginning date, the 10-year rule layers annual required distributions onto years 1 through 9 (Source: IRS final regulations T.D. 10001, IR-2024-190, July 2024). Missing one of those required amounts carries a defined excise tax, not an open-ended liability.

The excise tax on a missed required distribution is 25% of the shortfall, reduced to 10% if the account holder takes the missed amount and files Form 5329 within the two-year correction window (Source: IRC Section 4974 as amended by the SECURE 2.0 Act of 2022; IRS Publication 590-B, 2025). The IRS also waived penalties for missed “specified” distributions in 2021 through 2024 while the final regulations were pending, with no make-up distributions required for those years (Source: IRS Notice 2022-53 for 2021 and 2022, IRS Notice 2023-54 for 2023, and IRS Notice 2024-35 for 2024).

The Great Wealth Transfer context

The 10-year rule sits directly in the path of one of the largest intergenerational asset shifts on record, which sharpens why a canonical timing metric matters. Cerulli Associates projects $124 trillion in United States wealth will transfer through 2048, of which about $105 trillion flows to heirs and about $18 trillion to charity (Source: Cerulli Associates, 2024, United States households). Published estimates of the transfer’s total size vary with the methodology and time horizon used, so no single figure is definitive; this analysis relies only on the Cerulli projection above and asserts no competing dollar total.

A material but unquantified share of that transfer sits in tax-deferred IRAs and 401(k) balances now governed by the 10-year rule for non-spouse heirs. A verified average inherited-IRA balance per heir was not available from a primary source (Cerulli, ICI, EBRI, or the Federal Reserve Survey of Consumer Finances) in this analysis, so no per-heir dollar average is asserted here. What the mechanics establish is that the larger the tax-deferred balance and the higher the heir’s income, the more the timing of withdrawals inside the 10-year window determines the federal tax collected.

Original synthesis

1. The 10-Year Rule Timing Penalty Index

Logic and formula: for each cell, timing penalty equals the incremental federal tax of a one-year lump sum minus the incremental tax of a level fill, where lump tax equals Tax(TI0 + B) minus Tax(TI0), and level tax equals ten times [Tax(TI0 + B/10) minus Tax(TI0)]. TI0 is the heir’s other income minus the $16,100 standard deduction, B is the inherited balance, and Tax() applies the 2026 single bracket schedule. Inputs: 2026 single brackets and standard deduction (Source: IRS Rev. Proc. 2025-32, 2026). Result: the penalty ranges from 0.0% to 10.5% of the balance, headlined by 8.6% (about $42,900) on a $500,000 account for a middle-income heir. Limitations: single filer, constant 2026 brackets, no account growth, no state tax, and the two default behaviors are illustrative of common practice rather than an observed adoption rate, which was not verified to a primary source.

2. The SECURE Act Distribution Compression Ratio

Logic and formula: how much larger the forced annual distribution is under the 10-year rule than under the pre-2020 life-expectancy stretch, which is the mechanical driver of any bracket compression. The 10-year rule requires a first-year-equivalent slice of one-tenth of the balance, 10.0%. The pre-2020 stretch required a first-year slice of one divided by the beneficiary’s pre-2022 Single Life Expectancy divisor. The compression ratio equals the divisor divided by 10. Inputs: pre-2022 Single Life Expectancy divisors for deaths before 2020 (Source: IRS Publication 590-B (2020), Appendix B, Table I, United States): age 45 = 38.8, age 50 = 34.2, age 55 = 29.6, age 60 = 25.2, age 65 = 21.0. Result, reproducible from those divisors: the pre-2020 first-year slice ranges from 2.6% (age 45) to 4.8% (age 65) of the balance, versus 10.0% under the 10-year rule, so the rule forces a slice roughly 3.9 times larger at age 45, 3.4 times at age 50, 3.0 times at age 55, 2.5 times at age 60, and 2.1 times at age 65. Larger slices are what push more dollars across the 2026 United States federal bracket lines shown in the Timing Penalty Index above. Limitations and honest scope: translating this mechanical compression into a single multi-decade after-tax effective-rate premium would require assumptions about the heir’s income and the federal bracket schedule across 20 to 40 future years and about account growth, none of which can be fixed to a primary source; this analysis therefore publishes only the reproducible distribution-size ratio and asserts no specific multi-decade effective-rate premium. The current post-2022 Single Life Table (age 50 = 36.2) is not used here because it does not apply to a death occurring before 2020.

3. Peak-earning-year exposure ratio

Logic: the 10-year rule overlaps a full decade of a heir’s working life. Comparing the effective tax on an identical $500,000 level payout at a $300,000 peak income versus a $40,000 retirement income isolates the cost of timing the inheritance into peak years. Inputs: 2026 single brackets and standard deduction (Source: IRS Rev. Proc. 2025-32, 2026). Result: 35.0% versus 16.7% effective, a gap of about $91,500 on one account, meaning inheriting at peak income roughly doubles the federal tax on the same balance versus inheriting in low-income retirement. Limitations: illustrative income levels, single filer, constant brackets, no state tax.

How a Roth conversion before death changes the math

Because the tax outcome hinges on the marginal rate of whoever ultimately pays, the identity of that payer can be shifted before death. If an owner converts a traditional IRA to a Roth during life, the owner pays income tax at the owner’s marginal rate, and the heir later takes distributions from the inherited Roth free of income tax, though the 10-year emptying requirement still applies (Source: IRS Publication 590-B, 2025). The comparison is therefore owner’s conversion rate versus heir’s peak-earning distribution rate.

Illustratively, if an owner in a lower bracket converts a balance that a heir would otherwise empty at a 35.0% peak-earning effective rate on a $500,000 account, the conversion moves the tax to the lower-rate payer and removes the 10-year bracket-compression risk entirely for the heir. If the owner’s rate is higher than the heir’s expected rate, leaving the traditional IRA can be more efficient. This is a rate-arbitrage decision, not a universal rule, and Q3 Advisors models the crossover in its how much to convert to Roth and Roth conversion break-even analyses. State residency changes the answer again, as covered in Roth conversion and state taxes.

Figures

Source quality ranking

Tier 1 (primary, government and statutory): IRS Publication 590-B (2025), including Appendix B, Table I, for the 10-year rule, eligible-designated-beneficiary definition, and before-required-beginning-date rule; IRS Publication 590-B (2020), Appendix B, Table I, for the pre-2022 Single Life Expectancy divisors that govern deaths before 2020. IRS Rev. Proc. 2025-32 for 2026 single brackets and the standard deduction. One Big Beautiful Bill Act, P.L. 119-21 (2025), for the permanence of the 10% to 37% rate structure. IRS final regulations T.D. 10001 / IR-2024-190 (July 2024) for the after-required-beginning-date annual-distribution mechanic, and IRS Notices 2022-53, 2023-54, and 2024-35 for the missed-distribution penalty relief spanning 2021 to 2024. IRC Sections 1411 and 4974 for the NIIT exclusion, MAGI threshold, and missed-distribution excise tax.

Tier 2 (credible market research and professional analysis, corroboration only): Tax Foundation “2026 Tax Brackets,” citing Rev. Proc. 2025-32; Kiplinger on the 2026 age-65 additional deduction; Grant Thornton and Kitces.com analyses of T.D. 10001; Cerulli Associates for the Great Wealth Transfer projection.

Tier 3 (reputable journalism and explanatory, background only): Wolters Kluwer, Ascensus, Aprio, Voya, and Groom Law Group summaries of the final regulations. No competing Great Wealth Transfer dollar estimate is relied upon; only the Cerulli projection is cited.

Excluded and why: the 2026 Medicare Part B premium and IRMAA tiers (not verified to a CMS primary source this session); any specific average inherited-IRA balance per heir (no ICI, EBRI, or Federal Reserve SCF figure gathered); the exact Federal Register text of T.D. 10001 (mechanic confirmed via IRS newsroom, primary regulatory text not opened); and all aggregator, calculator, and SEO content pages, which are non-authoritative.

Most quotable statistics

Data limitations

• The model ignores account growth during the payout window; a balance that keeps compounding widens the 10-year-versus-stretch gap, so the penalties here are conservative floors (2026).
• All figures assume 2026 single-filer brackets held constant; married-filing-jointly brackets, with a 37% threshold of $768,700, change the answer materially (Source: IRS Rev. Proc. 2025-32, 2026).
• State income tax is excluded; residents of high-tax states face larger total penalties.
• The Medicare IRMAA and NIIT MAGI effects are second-order and are excluded from the direct income-tax figures.
• Inherited balance, heir income, and heir age are illustrative analyst assumptions, not empirical averages, because no primary-source distribution of inherited-IRA balances was gathered this session.
• The share of non-spouse beneficiaries actually subject to the 10-year rule, versus the eligible-designated-beneficiary exceptions, is defined by statute but not quantified here, because no primary-source population breakdown was verified.

Recommended dataset fields

A downloadable version of the 10-Year Rule Timing Penalty Index would contain: heir filing status; heir other taxable income; inherited pre-tax balance; heir age at inheritance; owner death relative to required beginning date (before or on/after); Single Life Expectancy divisor; year-by-year distribution under lump, level, and stretch paths; incremental federal tax per path; effective tax rate per path; timing penalty in dollars and as a percent of balance; SECURE Act distribution compression ratio (10-year slice versus pre-2020 stretch first-year slice); flag for MAGI crossing the $200,000 NIIT threshold; and the tax-year bracket schedule applied.

Suggested headlines

• Mistiming an Inherited IRA Costs Middle-Income Heirs 8.6% of a $500,000 Account, 2026 Analysis Finds
• The 10-Year Rule Timing Penalty: How Heirs Lose Up to $105,000 on a Seven-Figure Inherited IRA
• Inheriting at Peak Income Doubles the Federal Tax on a $500,000 IRA, Q3 Advisors Finds
• Why a $400,000 Inherited IRA in One Year Jumps a Middle-Income Heir Three Tax Brackets
• The SECURE Act Compression Ratio: The 10-Year Rule Forces Annual Distributions Roughly 2 to 4 Times Larger Than the Pre-2020 Stretch

Frequently asked questions

How much extra federal tax does a non-spouse heir pay by taking a lump sum instead of spreading it across the 10-year window?

On a $500,000 inherited traditional IRA, a middle-income single heir (about $120,000 of other income) pays roughly $42,900 more, 8.6% of the account, by taking a one-year lump sum versus ten equal withdrawals in 2026 (Q3 Advisors computation on IRS Rev. Proc. 2025-32 United States federal brackets, 2026). The penalty falls to about $494 on a $100,000 account and rises to about $105,500 on a $1,000,000 account.

What percent of the inherited IRA is lost to timing on a $250,000, $500,000, and $1,000,000 account?

For a middle-income single heir in 2026, the timing penalty is about 6.2% of a $250,000 account, 8.6% of a $500,000 account, and 10.5% of a $1,000,000 account (Q3 Advisors computation, United States federal, 2026). For a high-income heir already in the 35% bracket, the same figures are near 0.0%, 0.6%, and 1.3%, because most dollars face one rate regardless of schedule.

How much larger is the annual distribution under the 10-year rule than under the pre-2020 stretch?

The 10-year rule forces a first-year-equivalent annual distribution of 10.0% of the balance, versus 2.6% to 4.8% under the pre-2022 Single Life Expectancy schedule that governed deaths before 2020, depending on the heir’s age at inheritance (Source: IRS Publication 590-B (2020), Appendix B, Table I, United States). That is a slice roughly 3.9 times larger at age 45, 3.4 times at age 50, and 2.1 times at age 65 (Q3 Advisors computation, United States federal, 2026). Those larger slices are the mechanical reason more dollars cross bracket lines; the exact added effective tax depends on the heir’s income and is not reducible to a single multi-decade figure.

How much does a $400,000 inherited IRA in one year cost a $120,000-income heir versus level withdrawals?

A $400,000 lump lifts a $120,000-income single heir from the 22% marginal bracket into the 35% bracket in 2026 (Source: IRS Rev. Proc. 2025-32, 2026). The one-year distribution incurs about $127,600 in federal tax versus about $95,600 under ten $40,000 withdrawals, a difference of roughly $31,900 (Q3 Advisors computation, United States federal, 2026).

What percent of non-spouse beneficiaries are subject to the 10-year rule versus the exceptions?

The 10-year rule applies to every designated beneficiary who is not one of five eligible-designated-beneficiary categories: a surviving spouse, a minor child of the owner, a disabled individual, a chronically ill individual, or anyone not more than 10 years younger than the owner (Source: IRS Publication 590-B, 2025). A precise population share was not available from a primary source, so no percentage is asserted; in practice the captured group is typically adult children and grandchildren.

How large is the penalty for missing a required distribution, and how is it reduced?

Missing a required annual distribution under the 10-year rule triggers an excise tax of 25% of the shortfall, reduced to 10% if the account holder withdraws the missed amount and files Form 5329 within the two-year correction window (Source: IRC Section 4974 as amended by the SECURE 2.0 Act of 2022; IRS Publication 590-B, 2025). The IRS separately waived penalties for missed specified distributions in 2021 through 2024 (Source: IRS Notice 2022-53 for 2021 and 2022, IRS Notice 2023-54 for 2023, and IRS Notice 2024-35 for 2024).

How much of the Great Wealth Transfer passes through accounts subject to the 10-year rule?

Cerulli Associates projects $124 trillion in United States wealth will transfer through 2048, with about $105 trillion going to heirs (Source: Cerulli Associates, 2024, United States households). Other published estimates differ with the methodology and time horizon used, so no single competing total is asserted here. The tax-deferred share governed by the 10-year rule is large but was not quantified to a primary source in this analysis.

How much does inheriting during peak earning years add to the tax bill?

The 10-year rule overlaps a full decade of a heir’s career, most often in the 40s and 50s. A $500,000 level 10-year payout is taxed at an effective 35.0% for a $300,000-income single heir versus 16.7% for a heir with $40,000 of retirement income in 2026, a difference of about $91,500 on one account (Q3 Advisors computation, United States federal, 2026).

How much can the 3.8% NIIT add to a large single-year distribution?

The distribution itself is excluded from net investment income and is never directly subject to the 3.8% Net Investment Income Tax (Source: IRC Section 1411(c)(5)). But it raises MAGI: a heir with $120,000 of wages and $15,000 of investment income, pushed by a $500,000 lump to about $635,000 of MAGI, newly owes 3.8% on the $15,000, about $570 (Q3 Advisors computation, United States federal, 2026). A level fill can keep MAGI under the $200,000 single threshold in most years.

How much does a level withdrawal save a high-income heir versus a year-10 lump on a $500,000 IRA?

A high-income single heir (about $300,000 of other income) saves about $2,900 by level-filling a $500,000 inherited IRA rather than taking a year-10 lump sum in 2026 (Q3 Advisors computation, United States federal, 2026). The saving is small because both paths are taxed largely at the 35% rate; the level strategy matters far more for middle-income heirs, where it saves about $42,900 on the same account.

Sources

IRS, Publication 590-B (2025), “Distributions from Individual Retirement Arrangements (IRAs),” including Appendix B, Table I (Single Life Expectancy), irs.gov/publications/p590b and irs.gov/pub/irs-pdf/p590b.pdf. 10-year rule text, eligible-designated-beneficiary definition, before-required-beginning-date rule, stretch divisors, and Form 5329 excise tax.
IRS, Rev. Proc. 2025-32, “Tax year 2026 inflation adjustments,” irs.gov/newsroom. 2026 single brackets and $16,100 standard deduction, $2,050 age-65 additional deduction.
IRS, Final Regulations T.D. 10001; IR-2024-190 (July 18, 2024); and IRS Notices 2022-53, 2023-54, and 2024-35. Annual required distributions in years 1 through 9 when the owner died on or after the required beginning date; penalty relief for missed distributions in 2021 and 2022 (Notice 2022-53), 2023 (Notice 2023-54), and 2024 (Notice 2024-35). Verify against 26 CFR 1.401(a)(9)-5 before republication.
Internal Revenue Code Section 1411(c)(5) and Section 1411(b). Statutory exclusion of IRA distributions from net investment income and the $200,000 single MAGI threshold (not inflation-indexed).
Internal Revenue Code Section 4974, as amended by the SECURE 2.0 Act of 2022. 25% excise tax on missed required distributions, reduced to 10% on timely correction.
Cerulli Associates (2024), “Cerulli Anticipates $124 Trillion in Wealth Will Transfer Through 2048,” press release dated December 5, 2024, cerulli.com. Great Wealth Transfer projection, United States households.
One Big Beautiful Bill Act, P.L. 119-21 (2025). Permanence of the 10% to 37% federal individual rate structure.
IRS, Publication 590-B (2020), Appendix B, Table I (Single Life Expectancy). Pre-2022 stretch divisors in effect for deaths before 2020, used for the compression-ratio counterfactual.
Corroborating (Tier 2): Tax Foundation, “2026 Tax Brackets and Federal Income Tax Rates”; Kiplinger, “Extra Standard Deduction for 65 and Older”; Grant Thornton and Kitces.com analyses of T.D. 10001.