How Sequence-of-Returns Risk Can Derail a Retirement Plan

Same Returns, Completely Different Outcomes

Two retirees each start with $1,000,000 and withdraw $50,000 per year. Over 20 years, both portfolios experience exactly the same set of annual returns — +10%, -15%, +20%, +8%, and so on — but in opposite order: one retiree experiences the best years first, the other experiences the worst years first. Despite identical average returns, their outcomes diverge dramatically. The retiree who experienced early losses runs out of money years before the other, whose portfolio continues growing long after.

This is sequence-of-returns risk: the mathematical reality that the timing of investment returns matters as much as the average return when withdrawals are occurring. It is the single most underestimated risk in retirement planning — invisible during accumulation but potentially catastrophic during distribution.

The Math Behind the Risk

During accumulation, sequence of returns is irrelevant. An investor who contributes regularly experiences dollar-cost averaging that actually benefits from early losses (buying more shares at lower prices). The math reverses completely during distribution.

When withdrawals fund living expenses during a bear market, two harmful things happen simultaneously. First, more shares must be sold at depressed prices to raise the same dollar amount, permanently removing those shares from the portfolio. Second, the remaining portfolio is smaller precisely when it needs a large base to recover from the loss. This combination — selling into weakness while reducing the recovery base — is the mechanical engine of sequence risk.

Historical Evidence: Retirement Classes of 1966 and 1982

The 1966 U.S. retirement cohort illustrates sequence risk at its worst. A retiree who retired in January 1966 with $1,000,000 and withdrew 4% annually inflation-adjusted faced the stock market decline of 1966–1970, the oil crisis recession of 1973–1974, and the prolonged stagflation of 1977–1982 in their first 16 retirement years. The S&P 500 delivered a cumulative real (inflation-adjusted) return of approximately -37% over the decade ending in 1974. Many 1966 retirees following conventional withdrawal strategies ran out of money in their late 70s.

Contrast the 1982 retirement cohort. Retiring into the beginning of an 18-year bull market, these retirees saw their portfolios grow faster than their withdrawals. Many accumulated significantly more wealth in real terms by their 90s than they started with at 65. Same strategy. Same initial asset allocation. Vastly different outcomes due to the order of returns they happened to experience.

• A retiree using a 4% withdrawal rate from 1966 had a 40% historical probability of depleting a balanced portfolio within 25 years
• A 1982 retiree using the same 4% rate would have seen their $1M portfolio grow to over $2.5M by 2007
• The difference was not strategy or discipline — it was the sequence of market returns experienced

The Fragile Decade: First 10 Years of Retirement

Research by financial planner Michael Kitces and Wade Pfau identifies the first 10 years of retirement as the critical vulnerability window. A severe market downturn in years 1–10 of retirement is approximately three times more damaging to long-term portfolio survival than the same downturn in years 15–20.

The reason is asymmetric: recovering from a 50% loss requires a 100% gain, and when the portfolio is small and the investor is still withdrawing, that recovery becomes extremely difficult. A $1,000,000 portfolio that drops to $500,000 in year three while still distributing $50,000 annually needs to grow to $1,500,000 just to return to the original path — a 200% return from a depleted base.

• Research shows that portfolio survival probability drops significantly when a 30%+ loss occurs in the first five years of retirement
• The same loss occurring after year 15, when portfolio health is more established, shows much smaller impact on survival probability
• This fragility window is why the years immediately preceding and following retirement require distinct risk management

Strategies to Manage Sequence Risk

Sequence risk cannot be eliminated, but several strategies reduce its impact. Each involves a different approach to the core challenge of avoiding forced selling during market downturns.

The bucket strategy divides the retirement portfolio into segments by time horizon. Bucket 1 holds 1–2 years of expenses in cash, generating no market return but providing withdrawals without selling equities during downturns. Bucket 2 holds bonds or stable assets for years 3–7. Bucket 3 holds equities for long-term growth. During a market decline, withdrawals come from Bucket 1 while Bucket 3 recovers. Once markets stabilize, Bucket 3 gains replenish Bucket 1 and 2.

The Safe Withdrawal Rate Debate

William Bengen's 1994 paper introduced the 4% rule — the finding that a 50/50 stock/bond portfolio could sustain inflation-adjusted 4% withdrawals for 30 years based on all historical data from 1926 onward. The 4% rule implicitly accounts for sequence risk by using the worst historical sequences in its analysis.

Subsequent research by Pfau and others suggests that current low-interest-rate environments and high equity valuations may reduce safe withdrawal rates to 3–3.5%. The debate is unresolved, but the core insight — that sequence risk means retirees should plan more conservatively than average market returns suggest — is not.

This article is for informational purposes only and does not constitute financial advice.