3.69% – 10.64% Across 123 historical 60/40 cohorts, the highest withdrawal rate that lasted a full 30 years ranged from 3.69% (the 1966 start year) to 10.64%, with a median of 6.15%. A constant 4% inflation-adjusted withdrawal survived in 95.9% of cohorts. These are historical results, not a forecast.
The question
The 4% rule is a single number, but retirement outcomes are not. The year you retire locks in the exact sequence of returns and inflation you live through, and that sequence — not just the long-run average — decides whether a plan lasts. So we asked the empirical question directly: across every retirement start year in the historical record, what was the highest inflation-adjusted withdrawal rate that a 30-year retirement could actually have sustained?
The data
Every figure on this page is computed from Robert J. Shiller, "Irrational Exuberance" long-horizon dataset (ie_data.xls, Data sheet), retrieved 2026-07-21 from econ.yale.edu and committed to our repository as a frozen annual snapshot so the study reproduces offline. From it we take, for each January: the S&P Composite total return (price plus reinvested dividends), the CPI level (to convert everything to real, inflation-adjusted terms), and the 10-year Treasury (GS10) yield. Bond total returns are a documented construction from those yields — see Methodology — not an actual bond-fund series.
Result 1: the highest safe withdrawal rate, cohort by cohort
Most cohorts could have sustained far more than 4%; the median was 6.15%. But a cluster of start years in the mid-to-late 1960s sits well below the rest. The single hardest was 1966, whose portfolio could support only 3.69% for 30 years. The ten most demanding cohorts:
| Retirement start year | Max 30-yr rate (60/40) | Lasted at 4.0% | at 4.5% | at 5.0% |
|---|---|---|---|---|
| 1966 | 3.69% | no | no | no |
| 1965 | 3.79% | no | no | no |
| 1968 | 3.92% | no | no | no |
| 1969 | 3.93% | no | no | no |
| 1967 | 3.99% | no | no | no |
| 1964 | 4.06% | yes | no | no |
| 1973 | 4.20% | yes | no | no |
| 1906 | 4.20% | yes | no | no |
| 1962 | 4.25% | yes | no | no |
| 1972 | 4.37% | yes | no | no |
Result 2: survival by withdrawal rate and allocation
Raising the withdrawal rate steadily lowers the share of cohorts that lasted the full 30 years. A higher equity weight raised both the median and the survival share, at the cost of a wider spread:
| Allocation | Worst cohort | Worst max rate | Median max rate | Best max rate | Lasted at 4% | at 4.5% | at 5% |
|---|---|---|---|---|---|---|---|
| 60/40 (headline) | 1966 | 3.69% | 6.15% | 10.64% | 96% | 89% | 75% |
| 50/50 | 1966 | 3.63% | 5.93% | 10.34% | 95% | 84% | 70% |
| 80/20 | 1966 | 3.77% | 6.59% | 11.23% | 97% | 92% | 80% |
What it implies for retirees
- 4% was conservative in most of history, but not all of it. It lasted in 95.9% of cohorts — the shortfalls clustered in a single difficult era, not scattered randomly.
- Sequence, not average, is the risk. The worst cohorts were defined by weak real returns and high inflation in the FIRST decade of retirement.
- Allocation shifts the whole distribution. More equity lifted the median and the survival share here, but the safe rate is really about surviving the worst sequence, not the average one.
Test a withdrawal plan against these histories
Run your own allocation, horizon, and spending against both the historical record and forward-looking return models in the full planner — and see where your plan lands relative to these cohorts.
Open the planner →Methodology
Source. Robert J. Shiller, "Irrational Exuberance" long-horizon dataset (ie_data.xls, Data sheet), retrieved 2026-07-21 from
http://www.econ.yale.edu/~shiller/data/ie_data.xls, frozen as the committed annual snapshot
research/data/shiller-annual-2026-07.csv. The snapshot is January-anchored: for each year we take
the S&P Composite total return from that January to the next (dividends reinvested monthly), the January CPI
level, and the January GS10 yield.
Cohorts. For every retirement start year with a full 30-year window in the snapshot (1871–1993, 123 cohorts), we walk a rebalanced portfolio and take a constant inflation-adjusted withdrawal at the start of each year. All returns are real: each year's nominal return is divided by that year's realized CPI inflation. A cohort "survives" a given rate if the balance is never driven negative across the 30 annual withdrawals; the maximum sustainable rate is found by bisection to two decimal places.
Bond returns are a construction, not a fund. The snapshot stores GS10 yields. We build an annual 10-year Treasury total return using the standard constant-maturity par-bond approximation: hold a par bond with coupon equal to the starting yield, revalue its nine remaining years at next year's yield, and add the coupon — the standard approach in the withdrawal-rate literature. This is a documented construction from yields and is not presented as actual bond-fund performance.
These are historical outcomes, not forecasts. The study describes what portfolios started in each past year would have experienced. It makes no claim about future returns; for a forward-looking view see the capital-market-expectations stress test. See our methodology for assumptions shared across QuantCalc research.
Reproducibility
Full per-cohort results are published as open data under a CC0 public-domain dedication: results.csv and summary.json. The computation is deterministic and reproduces from the committed snapshot with no network access. Source: Robert J. Shiller, "Irrational Exuberance" long-horizon dataset (ie_data.xls, Data sheet) (econ.yale.edu, retrieved 2026-07-21).
Changelog
- v2026.1 — initial release (2026-07-21). 123 cohorts (1871–1993), 60/40 headline plus 50/50 and 80/20, from the 2026-07-21 Shiller snapshot.
FAQ
What is a retirement cohort, and why analyze by start year?
A cohort is everyone who retires in the same year and therefore lives through the same sequence of market returns and inflation. Because the ORDER of returns matters as much as the average, two retirees with identical long-run averages can have very different outcomes depending on when they started. Rolling the same 30-year rule across every historical start year is the classic way to see that spread.
Which cohort was the hardest, and why?
In this data the 1966 start year was the most demanding for a 60/40 portfolio: its highest sustainable withdrawal rate was only 3.69%. Retirees who started in the mid-to-late 1960s met a long stretch of high inflation and weak real stock returns early in retirement — the sequence-of-returns pattern that does the most damage, because withdrawals compound against a portfolio that has not yet grown.
Did the 4% rule hold up historically?
For a 60/40 portfolio, a constant 4% inflation-adjusted withdrawal lasted the full 30 years in 95.9% of the 123 cohorts. It fell short in the remaining 4.1% — a small set clustered around the mid-1960s start years. The median cohort could have withdrawn far more: about 6.15% a year.
How is this different from the forward-looking 4% study?
This page is history: what actually happened to portfolios started in each year since 1871. Our companion study, the forward-looking capital-market-expectations stress test, instead asks whether 4% survives six published forecasts of FUTURE returns. History tells you the range that has already occurred; the forecast study tells you what today's return expectations imply. They answer different questions and are best read together.
Can I test my own numbers?
Yes. The full planner lets you run your own allocation, horizon, and spending against both historical and forward-looking return models, so you can see where your plan sits relative to these cohorts.
Published 2026-07-21 by QuantCalc Research. Educational research, not financial advice. Related: the 4% rule vs. forward-looking forecasts · dynamic vs. static withdrawal strategies.