Two retirees with identical portfolios and identical average returns over 30 years can have wildly different outcomes. The timing of losses is what kills retirement plans.
Here's a thought experiment that illuminates one of retirement's most dangerous hidden risks. Imagine two people, both retiring with $500,000, both withdrawing 4% ($20,000) per year adjusted for inflation. Both achieve the same average annual return of 7.3% over their 30-year retirement. But one retires in 1966. The other retires in 1982. The first runs dry at age 85. The second leaves over $1 million to their heirs.
The Devastating Mathematics
Research extending Bengen and Kitces' work found that roughly 77% of a portfolio's final retirement outcome can be explained by the average return of just the first 10 years. In fact, no historical U.S. retirement cohort with a first-decade average real return above 3.9% has ever failed at a 4% withdrawal rate. Early losses force you to sell more shares at depressed prices to fund withdrawals — shares that are never there to recover when markets rebound.
Kitces.com, sequence of return riskDuring the accumulation phase, sequence risk doesn't matter much — you're buying more shares when markets are low (dollar-cost averaging works in your favor). But in retirement, you're a seller. When markets drop 40% and you must sell shares to cover expenses, you crystallize losses permanently. Those sold shares can't recover when markets rebound.
| Scenario | Year 1-5 Returns | Year 26-30 Returns | Portfolio at Year 30 |
|---|---|---|---|
| Good Sequence | +12% avg | +3% avg | $987,000 |
| Bad Sequence | -8% avg | +18% avg | $12,000 |
| Flat Sequence | +7.3% avg | +7.3% avg | $456,000 |
The 1966 retiree faced the worst sequence in U.S. history: a decade of poor stock returns combined with high inflation (stagflation), which inflated expenses faster than assets could recover. The 1982 retiree caught the start of one of the greatest bull markets in history — both experienced similar long-run averages but had radically different retirements.
The Research-Backed Finding
According to research by Michael Kitces and Wade Pfau, the "rising equity glidepath" — starting retirement with a higher bond allocation (often 20-40% equities) and gradually shifting to more equities (60-80%) over the retirement horizon — counterintuitively outperformed static allocations in 2 of the 3 historical periods they tested. This is the opposite of what most advisors recommend.
Pfau & Kitces, FPA JournalStandard historical backtesting averages out the good and bad sequences. Monte Carlo simulation explicitly models thousands of possible sequence scenarios, including tail risks that may not appear in the historical record. A 90%+ success rate in Monte Carlo means your plan survives 9,000+ out of 10,000 randomly drawn market scenarios — including many worse than anything in recorded history.
Apply the strategies in this article to your specific situation. FuturePath models your portfolio with 1,000 Monte Carlo simulations across 50-state tax rules.