The 4% Rule and Taxes: Safe Withdrawal Rates in Retirement

The 4% Rule and Taxes: Safe Withdrawal Rates in Retirement

Every widely cited “safe withdrawal rate,” from the 4% figure William P. Bengen published in 1994 to Morningstar’s 3.9% base case for 2026, is a gross-of-tax portfolio withdrawal rate. Bengen’s original 1994 study explicitly assumed a tax-free account, and the Trinity Study (1998) explicitly excluded taxes, fees, and Social Security (Source: Bengen 1994, Journal of Financial Planning; Cooley, Hubbard and Walz 1998, AAII Journal). The after-tax amount available from a stated withdrawal rate varies by account type and by tax bracket. None of the rates discussed here is a recommendation.

Table of Contents

By the numbers

  • 4% starting withdrawal rate identified by William P. Bengen; his precise worst-case “SAFEMAX” figure was approximately 4.15% (Source: Bengen 1994, Journal of Financial Planning; FPA reprint).
  • 33 years minimum portfolio longevity at a 4% initial rate across all historical start years Bengen tested, 50/50 stocks and intermediate-term Treasuries, US data from 1926 (Source: Bengen 1994, FPA reprint).
  • ~95% portfolio success rate at a 4% inflation-adjusted rate, 30-year horizon, on the original Trinity corporate-bond basis (Source: Cooley, Hubbard and Walz 1998; Wade Pfau reproduction, RetirementResearcher/Forbes 2015).
  • 3.9% base-case starting safe withdrawal rate in Morningstar’s “The State of Retirement Income: 2026,” up from 3.7% in 2025 (Source: Morningstar 2026, via FA-Mag, Keil Financial Partners, RetireGuide).
  • 0.91 correlation between the first 15 years of real returns and the eventual 30-year safe withdrawal rate (Source: Michael Kitces, kitces.com).
  • 10% to 37% range of 2025 federal ordinary-income tax rates applied to Traditional IRA and 401(k) withdrawals (Source: IRS, Rev. Proc. 2024-40).
  • 0%, 15%, 20% preferential 2025 long-term capital-gains rates that can apply to gains in taxable brokerage accounts (Source: IRS Topic No. 409).
  • Age 73 starting age for required minimum distributions under SECURE 2.0 (Source: IRS RMD FAQs).
Q3 Safe Withdrawal Rate Reference Series (1994-2026). A consolidated, sourced series of published base-case starting safe withdrawal rates: Bengen 4% (1994), Trinity 4% at approximately 95% success (1998), Bengen 4.5% (2006 book) and approximately 4.7% (later work and 2025 book), and Morningstar 3.3% (2021), 3.8% (2022), 4.0% (2023), 3.7% (2024), 3.7% (2025), and 3.9% (2026). Methodology: each entry is the highest first-year rate satisfying that author’s own survival criterion, reproduced only from figures verified against primary text or named secondary corroboration; all values are gross of taxes and fees.

Where the 4% rule came from: Bengen (1994)

The “4% rule” originates with William P. Bengen, CFP, a sole practitioner in El Cajon, California, in his article “Determining Withdrawal Rates Using Historical Data,” published in the Journal of Financial Planning in October 1994 (Source: Bengen 1994, verified against the Financial Planning Association’s 2004 “Best of 25 Years” reprint). Rather than run Monte Carlo simulations, Bengen used actual historical US market sequences drawn from Ibbotson Associates’ “Stocks, Bonds, Bills and Inflation: 1992 Yearbook.” His inputs over the period: US common stocks compounded at 10.3% per year, intermediate-term US Treasury notes at 5.1% per year, and inflation at roughly 3% per year (Source: Bengen 1994, FPA reprint, “The Averages”).

Bengen measured “portfolio longevity” for hypothetical retirees starting in each year from 1926 onward. Each retiree took a first-year withdrawal equal to a set percentage of the initial portfolio, then adjusted that dollar amount for inflation annually, with the portfolio rebalanced each year. His finding, in his own words: “Assuming a minimum requirement of 30 years of portfolio longevity, a first-year withdrawal of 4 percent … should be safe. In no past case has it caused a portfolio to be exhausted before 33 years, and in most cases it will lead to portfolio lives of 50 years or longer” (Source: Bengen 1994, FPA reprint, “Strategies and Applications”).

The contrast that gives the rule its name is precise. Bengen wrote that “a 4.25-percent first-year withdrawal could exhaust a portfolio in as little as 28 years, were past conditions to repeat themselves” (Source: Bengen 1994, FPA reprint). That threshold near 4.15% to 4.25% is why the popular shorthand settled on 4%.

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The often-ignored allocation finding

Bengen did not recommend a rigid 50/50 portfolio. He tested five allocations (0%, 25%, 50%, 75%, and 100% stocks) against eight withdrawal rates (1% to 8%). He wrote: “I think it is appropriate to advise the client to accept a stock allocation as close to 75 percent as possible, and in no cases less than 50 percent. Stock allocations lower than 50 percent are counterproductive” (Source: Bengen 1994, FPA reprint). The 50% and 75% stock portfolios produced longevity within about a year of each other at most rates. Bengen’s recommended equity band was therefore 50% to 75%, not the 50/50 mix commonly attributed to him.

Bengen (1994): minimum historical portfolio longevity by withdrawal rate
Bengen (1994): minimum historical portfolio longevity by withdrawal rate. Source: Bengen 1994, Journal of Financial Planning (FPA reprint)

How the rate collapses as it rises

Bengen documented how quickly portfolio longevity falls as the withdrawal rate increases. A 3% initial withdrawal never produced portfolio longevity below 50 years, which he called the “absolutely safe” level, extending to roughly 3.5% (Source: Bengen 1994, FPA reprint, Figure 1(A) discussion). At 5%, clients retiring in the late 1960s or early 1970s might have had “only 20 years of funds.” At 6% with a 50/50 mix, a client expecting 30 years faced “31 scenario years when he would outlive his assets, and only 20 which would have been adequate,” a success rate under 40%. Rates of 7% and above he deemed impractical (Source: Bengen 1994, FPA reprint).

Withdrawal rate Bengen (1994), 50/50, historical minimum longevity Trinity (1998), 50/50, 30-yr, inflation-adjusted success
3.0% Never below 50 years (“absolutely safe”) Not separately reported here
4.0% Minimum 33 years (never exhausted under 33 years) ~95% (original corporate-bond basis)
4.25% Could exhaust in as little as 28 years Not separately reported here
5.0% Late-1960s/early-70s retirees: “only 20 years of funds” ~68%
6.0% 31 of 51 scenario years failed (under 40% adequate) ~43%
7%+ Deemed impractical Declines further

Sources: Bengen 1994 (FPA reprint); Trinity Study percentages via Wade Pfau, RetirementResearcher/Forbes 2015. The original 1998 per-allocation success percentages could not be read from the primary AAII PDF and are attributed to Pfau’s reproductions.

Trinity Study (1998): 30-year success rate by withdrawal rate, 50/50, inflation-adjusted
Trinity Study (1998): 30-year success rate by withdrawal rate, 50/50, inflation-adjusted. Source: Cooley, Hubbard and Walz 1998, via Wade Pfau (RetirementResearcher/Forbes 2015)

The Trinity Study (1998): a second, independent path to ~4%

Four years after Bengen, three finance professors at Trinity University in San Antonio, Texas, reached a similar conclusion by a different method. Philip L. Cooley, Carl M. Hubbard, and Daniel T. Walz published “Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable” in the AAII Journal (the journal of the American Association of Individual Investors), Vol. 10, No. 3, February 1998 (Source: Cooley, Hubbard and Walz 1998, AAII Journal). They used US historical returns from 1926 to 1995, applied monthly.

Their design tested payout periods of 15, 20, 25, and 30 years; five stock/bond allocations (100/0, 75/25, 50/50, 25/75, and 0/100); withdrawal rates from 3% to 12%; and both fixed-dollar and inflation-adjusted schedules. Their stock proxy was the S&P 500, and their bond proxy was long-term high-grade corporate bonds, which differs from Bengen’s use of intermediate-term Treasuries (Source: Cooley, Hubbard and Walz 1998; corroborated by Wade Pfau). Their innovation was the “portfolio success rate,” the percentage of historical windows in which the portfolio survived, rather than Bengen’s single worst-case minimum-longevity measure.

A frequently repeated claim holds that the Trinity Study found “100% success at 4% over 30 years.” The original study, on its corporate-bond basis, reported a success rate closer to 95%, not 100%, for a 4% inflation-adjusted withdrawal (Source: Wade Pfau reproduction, RetirementResearcher/Forbes 2015). The commonly quoted 100% figure comes from later Bengen-style recreations that use intermediate-term Treasuries. The authors’ summary conclusion was that “withdrawal rates of 3% to 4% … continue to produce high portfolio success rates for stock-dominated portfolios,” with success dropping sharply at higher rates (Source: Cooley, Hubbard and Walz 1998, via Pfau).

Sequence-of-returns risk: why the order of returns matters

Both origin studies point to the same underlying mechanism: the order in which returns arrive, not the long-run average, drives failure. Bengen identified the October 1968 cohort as his binding worst case, because early-retirement years combined a stock bear market with high inflation. He noted the 1973-74 recession was the more damaging event precisely because inflation followed it, whereas the 1929 crash was less damaging to withdrawal plans because deflation followed (Source: Bengen 1994, via robberger.com reproduction of paper quotes).

Michael Kitces has quantified when this “sequence risk window” bites. In his analysis, the correlation between the eventual 30-year safe withdrawal rate and the first year’s real return is only 0.213, a weak relationship. That correlation rises to roughly 0.79 to 0.81 over the first 10 years and reaches 0.91 over the first 15 years (Source: Michael Kitces, kitces.com). In plain terms, the real returns of the first 15 years of retirement effectively determine the safe rate, which is the empirical definition of sequence-of-returns risk.

Kitces: correlation of real returns to the 30-year safe withdrawal rate
Kitces: correlation of real returns to the 30-year safe withdrawal rate. Source: Michael Kitces, kitces.com

Morningstar’s forward-looking series (2021-2026)

Morningstar’s annual “The State of Retirement Income” reports take a different approach from Bengen and Trinity. Instead of historical sequences, Morningstar runs Monte Carlo simulations on forward-looking capital-market assumptions, reporting the highest starting rate with a 90% probability of success over a 30-year horizon, assuming fixed real withdrawals (Source: Morningstar, “The State of Retirement Income,” authors Amy C. Arnott, Christine Benz, and Jason Kephart).

The 2026 edition, published February 18, 2026, sets the base-case starting rate at 3.9%, up from 3.7% in 2025, assuming a roughly 30% to 50% equity allocation (Source: Morningstar 2026, corroborated by FA-Mag, Keil Financial Partners, RetireGuide, and Bogleheads). Morningstar states that higher-equity portfolios do not support the highest starting rates precisely because of the greater volatility and sequence-of-returns risk they carry. The firm also reports that flexible or guardrail strategies, such as foregoing inflation adjustments after down years, are modeled to support higher starting rates only when specific spending discipline is applied, such as foregoing inflation adjustments after down years, with reported figures up to approximately 5.7 percent; such strategies are conditional and are not universally applicable (Source: Morningstar 2026, via boldin and corroborating sources).

Report year Morningstar base-case starting SWR Assumptions
2021 (inaugural) 3.3% Balanced portfolio, 30-yr, 90% success
2022 3.8% Balanced portfolio, 30-yr, 90% success
2023 4.0% Balanced portfolio, 30-yr, 90% success
2024 3.7% Balanced portfolio, 30-yr, 90% success
2025 3.7% ~30-50% equity, 30-yr, 90% success
2026 3.9% ~30-50% equity, 30-yr, 90% success

Sources: Morningstar “The State of Retirement Income” editions, corroborated via PlanAdviser, 401kSpecialist, Keil Financial Partners, FA-Mag, RetireGuide, and boldin. Morningstar returns HTTP 403 to automated retrieval, so figures are confirmed through named secondary corroboration.

Morningstar base-case starting safe withdrawal rate, 2021-2026
Morningstar base-case starting safe withdrawal rate, 2021-2026. Source: Morningstar The State of Retirement Income editions, via FA-Mag, Keil, PlanAdviser, 401kSpecialist

The full reference table: published rates, 1994-2026

Year Author / Study Starting SWR Portfolio Method / criterion
1994 Bengen, Journal of Financial Planning 4% (SAFEMAX ~4.15%) 50/50 (recommends 50-75% equity) Historical; worst-case minimum longevity
1994 Bengen, “absolutely safe” floor 3% to 3.5% 50/50 Historical; never below 50-yr longevity
1998 Cooley, Hubbard and Walz (Trinity) 4% at ~95% success 50/50 Historical; portfolio success rate
2006 Bengen, “Conserving Client Portfolios” 4.5% Diversified (+ ~30% small-cap) Historical SAFEMAX, added asset classes
~2021 Bengen, “Universal SAFEMAX” ~4.7% 50/50 Valuation-conditioned historical
2021 Morningstar (inaugural) 3.3% Balanced Forward Monte Carlo; 90% success
2022 Morningstar 3.8% Balanced Forward Monte Carlo; 90% success
2023 Morningstar 4.0% Balanced Forward Monte Carlo; 90% success
2024 Morningstar 3.7% Balanced Forward Monte Carlo; 90% success
2025 Morningstar 3.7% ~30-50% equity Forward Monte Carlo; 90% success
2026 Morningstar (Arnott, Benz, Kephart) 3.9% (up to ~5.7% flexible) ~30-50% equity Forward Monte Carlo; 90% success
2025 Bengen, “A Richer Retirement” 4.7% More diversified Historical SAFEMAX, broader diversification

Tier note: Bengen 1994 and Trinity 1998 rates are primary/reprint. The exact Trinity percentages and all Bengen post-1994 revisions and all Morningstar figures are secondary corroboration.

Published starting safe withdrawal rates: historical vs forward-looking
Published starting safe withdrawal rates: historical vs forward-looking. Source: Bengen 1994/2006/2025; Trinity 1998; Morningstar 2021-2026

The tax layer every published rate leaves out

A key framing point for a US retiree is that none of the rates above is an after-tax spending figure. Bengen’s 1994 work explicitly assumed a tax-free account. The Trinity authors explicitly excluded taxes, fees, transaction costs, and Social Security. Morningstar likewise excludes taxes and non-portfolio income (Source: Bengen 1994; Cooley, Hubbard and Walz 1998; Morningstar 2026). A stated rate of 3.9% or 4% is a gross portfolio withdrawal. What lands in the retiree’s checking account depends on the account the money comes from.

Pre-tax accounts (Traditional IRA and 401(k))

The IRS states that “distributions from traditional IRAs that you include in income are taxed as ordinary income,” with no capital-gains treatment (Source: IRS Publication 590-B, 2025). The 2025 federal ordinary-income brackets run 10%, 12%, 22%, 24%, 32%, 35%, and 37% (Source: IRS, Rev. Proc. 2024-40). Beginning at age 73, required minimum distributions are forced under SECURE 2.0, raising taxable income whether or not the money is spent; the excise penalty for a missed RMD was reduced to 25%, or 10% if corrected timely (Source: IRS RMD FAQs). Retirees planning around these forced distributions may want to review our overview of required minimum distributions for 2026.

Roth accounts

A qualified Roth IRA distribution is entirely tax-free, covering both contributions and earnings, and is therefore 100% spendable. A qualified distribution requires the 5-year rule (at least five tax years since the first Roth contribution) plus a qualifying event such as reaching age 59 and a half, disability, death, or a first-home purchase up to a $10,000 lifetime limit (Source: IRS Publication 590-B, 2025). Roth IRAs also carry no required minimum distributions during the original owner’s lifetime, which gives the retiree control over the timing and size of taxable income (Source: IRS Publication 590-B, 2025).

Taxable brokerage accounts

In a taxable account, only the gain is taxed on a sale, not the return of basis, and long-term gains (assets held more than one year) qualify for preferential rates of 0%, 15%, or 20% (Source: IRS Topic No. 409). Because a large share of a taxable-account withdrawal is often a return of basis, and because long-term rates sit below ordinary rates, taxable accounts frequently yield a higher spendable fraction per dollar than pre-tax accounts. Higher earners may also owe the 3.8% Net Investment Income Tax on the lesser of net investment income or the amount by which modified adjusted gross income exceeds the threshold ($200,000 single, $250,000 married filing jointly for 2025) (Source: IRS Topic No. 559). Our note on the Net Investment Income Tax for 2026 covers this in more detail.

Deductions that shelter part of a withdrawal

For 2025, following the One Big Beautiful Bill Act (P.L. 119-21, signed July 4, 2025), the standard deduction is $15,750 for single filers and $31,500 for married filing jointly (Source: IRS newsroom, OBBBA provisions). For tax years 2025 through 2028, individuals age 65 and older may claim an additional $6,000 deduction per eligible person, available whether they itemize or take the standard deduction, phasing out above $75,000 of MAGI (single) or $150,000 (joint) (Source: IRS newsroom, OBBBA). These deductions shelter part of an ordinary-income withdrawal, raising the spendable fraction of pre-tax withdrawals. See our summary of the senior and standard deduction for 2026.

The figures below are arithmetic illustrations under stated assumptions. They are not projections, not a safe-withdrawal-rate recommendation, and do not account for your circumstances. All rates cited are attributed to their original authors. Consult a qualified professional before making decisions.

Worked examples: gross rate versus account type

Consider a hypothetical retiree with a $1,000,000 portfolio applying published gross rates (arithmetic under stated assumptions, not a recommendation of any withdrawal rate). These are arithmetic illustrations of the gross dollar figures only, not projections of any outcome.

Published rate Gross first-year withdrawal on $1,000,000 Account-type note (factual)
Morningstar 2025 (3.7%) $37,000 From a Roth qualified distribution, the full $37,000 is spendable (0% tax). From a Traditional IRA, ordinary-income tax applies (Source: IRS Pub 590-B).
Morningstar 2026 (3.9%) $39,000 Taxable-account gains taxed at 0/15/20%; return of basis is untaxed (Source: IRS Topic 409).
Bengen 1994 (4.0%) $40,000 Bengen assumed a tax-free account; a Traditional IRA version is reduced by ordinary-income tax (Source: Bengen 1994; IRS).
Bengen later work (4.7%) $47,000 Standard and senior deductions shelter part of a pre-tax withdrawal (Source: IRS/OBBBA).

Illustrative arithmetic on a hypothetical balance. Actual tax depends on total income, filing status, and bracket. Not a projection.

The interaction between withdrawals and other tax rules can compound the effect. Larger ordinary-income withdrawals can raise the taxable share of Social Security benefits and can push a household into higher Medicare premium tiers. Readers may find our related material useful: taxation of Social Security benefits for 2026 and Medicare IRMAA 2026 brackets and premiums.

2025 tax treatment by account type (illustrative rate ranges)
2025 tax treatment by account type (illustrative rate ranges). Source: IRS Publication 590-B (2025); IRS Topic No. 409; IRS Rev. Proc. 2024-40

2025 deductions that shelter ordinary-income withdrawals (MFJ)
2025 deductions that shelter ordinary-income withdrawals (MFJ). Source: IRS newsroom, One Big Beautiful Bill Act provisions (2025)

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Frequently asked questions

What is the 4% rule?

The 4% rule refers to William P. Bengen’s 1994 finding that a first-year withdrawal of about 4% of a portfolio, adjusted for inflation each year afterward, survived at least 33 years in every historical US start-year case he tested using a 50/50 stock and intermediate-term Treasury portfolio (Source: Bengen 1994, Journal of Financial Planning, FPA reprint).

Who created the 4% rule?

William P. Bengen, CFP, a financial planner in El Cajon, California, in “Determining Withdrawal Rates Using Historical Data,” Journal of Financial Planning, October 1994 (Source: Bengen 1994, FPA reprint).

What was Bengen’s precise figure?

Bengen’s precise worst-case sustainable rate, which he later termed SAFEMAX, was approximately 4.15%, widely rounded to 4%. He noted a 4.25% rate could exhaust a portfolio in as little as 28 years under repeat historical conditions (Source: Bengen 1994, FPA reprint).

What is the Trinity Study?

A 1998 study by Trinity University professors Philip L. Cooley, Carl M. Hubbard, and Daniel T. Walz, published in the AAII Journal, that measured “portfolio success rates” across withdrawal rates, allocations, and horizons using US data from 1926 to 1995 (Source: Cooley, Hubbard and Walz 1998, AAII Journal).

Did the Trinity Study find 100% success at 4%?

The original study, on its corporate-bond basis, reported a success rate near 95%, not 100%, for a 4% inflation-adjusted withdrawal over 30 years. The 100% figure comes from later recreations using intermediate-term Treasuries (Source: Wade Pfau reproduction, RetirementResearcher/Forbes 2015).

How do Bengen and Trinity differ?

Bengen used intermediate-term Treasuries and measured the single worst-case minimum longevity (SAFEMAX). Trinity used long-term corporate bonds and measured the percentage of historical windows that survived (success rate) (Source: Bengen 1994; Cooley, Hubbard and Walz 1998).

What allocation did Bengen recommend?

An equity allocation of 50% to 75%, as close to 75% as the client could accept, and in no case below 50% (Source: Bengen 1994, FPA reprint).

What is Morningstar’s current safe withdrawal rate?

Morningstar’s “The State of Retirement Income: 2026,” published February 18, 2026, sets the base-case starting rate at 3.9%, up from 3.7% in 2025, assuming roughly 30% to 50% equities, a 30-year horizon, and 90% success probability (Source: Morningstar 2026, via FA-Mag, Keil Financial Partners, RetireGuide).

Why is Morningstar’s rate lower than Bengen’s?

Morningstar uses forward-looking return forecasts rather than historical returns, and it factors in current equity valuations, which produces a lower base case than Bengen’s historically derived figures (Source: Morningstar 2026; Bengen 1994).

Has Bengen changed his own number?

Yes. Adding diversification raised his figure to 4.5% in his 2006 book, and later work and his 2025 book “A Richer Retirement” cite approximately 4.7% with a more diversified portfolio (Source: FPA Journal review November 2023; Advisor Perspectives; CNBC 2025).

Are these rates before or after tax?

Before tax. Bengen assumed a tax-free account, and both Trinity and Morningstar exclude taxes. Every published rate is a gross portfolio figure (Source: Bengen 1994; Cooley, Hubbard and Walz 1998; Morningstar 2026).

How are Traditional IRA and 401(k) withdrawals taxed?

As ordinary income, at the 2025 federal rates of 10% to 37%, with no capital-gains treatment (Source: IRS Publication 590-B, 2025; IRS, Rev. Proc. 2024-40).

How are Roth withdrawals taxed?

A qualified Roth distribution is entirely tax-free and 100% spendable, provided the 5-year rule and a qualifying event are met (Source: IRS Publication 590-B, 2025).

How are taxable brokerage withdrawals taxed?

Only the gain is taxed, and long-term gains qualify for preferential rates of 0%, 15%, or 20%; the return of basis is not taxed (Source: IRS Topic No. 409).

What is the Net Investment Income Tax?

An additional 3.8% tax on the lesser of net investment income or the amount MAGI exceeds $200,000 (single) or $250,000 (married filing jointly) for 2025 (Source: IRS Topic No. 559).

When do required minimum distributions begin?

At age 73 under SECURE 2.0, rising to 75 for those turning 73 after December 31, 2032. RMDs are taxable ordinary income (Source: IRS RMD FAQs).

Do Roth IRAs have required minimum distributions?

Not during the original owner’s lifetime. RMD rules apply to beneficiaries after death (Source: IRS Publication 590-B, 2025).

What is the 2025 standard deduction?

$15,750 for single filers and $31,500 for married filing jointly, following the One Big Beautiful Bill Act (Source: IRS newsroom, OBBBA).

What is the senior deduction?

For tax years 2025 through 2028, an additional $6,000 deduction per eligible person age 65 and older, phasing out above $75,000 MAGI (single) or $150,000 (joint), available whether itemizing or taking the standard deduction (Source: IRS newsroom, OBBBA).

What is sequence-of-returns risk?

The risk that poor returns early in retirement, combined with ongoing withdrawals, deplete a portfolio before later good returns can help. Bengen identified early down markets plus inflation (the 1968 and 1973-74 cohorts) as his binding constraint (Source: Bengen 1994; Kitces, kitces.com).

How much do early returns matter?

By Kitces’s analysis, the correlation between the first 15 years of real returns and the eventual 30-year safe rate is 0.91, versus only 0.213 for the first year alone (Source: Michael Kitces, kitces.com).

Can flexible strategies support a higher rate?

Morningstar reports that flexible or guardrail strategies can support starting rates up to approximately 5.7% in its 2026 edition by managing sequence-of-returns risk (Source: Morningstar 2026, via boldin and corroborating sources).

Do these studies apply outside the US?

No. All figures use US historical or US forecast market data and are not validated for other markets (Source: Bengen 1994; Cooley, Hubbard and Walz 1998; Morningstar 2026).

Sources

Bengen, William P., “Determining Withdrawal Rates Using Historical Data,” Journal of Financial Planning, October 1994 (FPA 2004 reprint): https://www.financialplanningassociation.org/sites/default/files/2021-04/MAR04%20Determining%20Withdrawal%20Rates%20Using%20Historical%20Data.pdf .
Cooley, Hubbard and Walz, “Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable,” AAII Journal, February 1998 (catalog): https://en.wikipedia.org/wiki/Trinity_study .
Wade Pfau, “Safe Withdrawal Rates for Retirement and the Trinity Study,” RetirementResearcher and Forbes 2015: https://retirementresearcher.com/safe-withdrawal-rates-for-retirement-and-the-trinity-study/ ; https://www.forbes.com/sites/wadepfau/2015/06/10/safe-withdrawal-rates-for-retirement-and-the-trinity-study/ .
FPA Journal, “Revisiting William Bengen’s SAFEMAX Portfolio Withdrawal Rate,” November 2023: https://www.financialplanningassociation.org/learning/publications/journal/NOV23-revisiting-william-bengens-safemax-portfolio-withdrawal-rate-OPEN .
4% rule overview: https://en.wikipedia.org/wiki/4%25_rule .
Michael Kitces, “Understanding Sequence Of Return Risk & Safe Withdrawal Rates,” kitces.com: https://www.kitces.com/blog/understanding-sequence-of-return-risk-safe-withdrawal-rates-bear-market-crashes-and-bad-decades/ .
Morningstar, “The State of Retirement Income”: https://www.morningstar.com/business/insights/research/the-state-of-retirement-income ; 2026 corroboration: https://www.fa-mag.com/news/morningstar-safe-retirement-withdrawal-rate-for-2026-is-3-9-85940.html ; https://keilfp.com/blogpodcast/morningstar-safe-withdrawal-rate/ ; https://www.retireguide.com/news/morningstar-unveils-latest-retirement-income-report/ .
IRS Publication 590-B (2025): https://www.irs.gov/publications/p590b .
IRS federal income tax rates and brackets (Rev. Proc. 2024-40): https://www.irs.gov/filing/federal-income-tax-rates-and-brackets .
IRS Topic No. 409, Capital gains and losses: https://www.irs.gov/taxtopics/tc409 .
IRS Topic No. 559 and Net Investment Income Tax: https://www.irs.gov/taxtopics/tc559 ; https://www.irs.gov/individuals/net-investment-income-tax .
IRS RMD FAQs: https://www.irs.gov/retirement-plans/retirement-plan-and-ira-required-minimum-distributions-faqs .
IRS newsroom, One Big Beautiful Bill Act provisions: https://www.irs.gov/newsroom/one-big-beautiful-bill-provisions-individuals-and-workers ; https://www.irs.gov/newsroom/one-big-beautiful-bill-act-tax-deductions-for-working-americans-and-seniors .

About the author

Craig Wear, CFP(R), is the founder of Q3 Advisors, a registered investment adviser focused on retirement tax planning. This briefing was prepared and reviewed by the Q3 Advisors team using primary sources, including the original Bengen (1994) and Trinity (1998) research, Morningstar’s published reports, and IRS publications, with named secondary corroboration where primary documents were not machine-readable.

Disclaimer

This material is provided by Q3 Advisors, a registered investment adviser, for informational and educational purposes only. It is not investment, legal, or tax advice, nor a recommendation or solicitation to buy or sell any security or to adopt any strategy. Information is believed to be from reliable sources as of the dates cited, but its accuracy is not guaranteed and figures are subject to change. Past performance does not guarantee future results, and the value of investments can go down as well as up. Registration with the SEC or a state does not imply a certain level of skill or training. See Q3 Advisors’ Form ADV Part 2A for information on services, fees, and conflicts of interest. Readers should consult their own qualified tax, legal, or financial advisor before making any decisions.

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