Picture two people retiring on the same day, with the same capital, invested in the same global index fund. Over the next twenty-five years, the market delivers the exact same sequence of annual returns to both of them — some years at 20%, others at -15%, most somewhere between 5% and 10% — just in a different order for each. The average annualized return, calculated over the full period, is identical for both. And yet one of them ends those twenty-five years with twice the money of the other, or even runs out of capital early while the other lives comfortably. The only difference between the two is the order in which those returns arrived. This is sequence of returns risk, one of the least intuitive and most consequential concepts in retirement planning, and one of the least explained outside technical circles.
What sequence of returns risk actually is
Sequence of returns risk describes the fact that, once you start withdrawing money from a portfolio on a regular basis, the order in which market gains and losses occur affects the final outcome as much as, or more than, the average return over the period. This doesn’t happen while you’re only accumulating capital without withdrawing anything: in that phase, the order of returns is irrelevant to the final result, because your capital doesn’t change for reasons unrelated to the market itself. But the moment you start taking money out — to live off your portfolio during retirement, for instance — everything changes.
The reason is purely mechanical, nothing mysterious about it. When you withdraw a fixed amount (or a fixed percentage) from a portfolio that just dropped 20%, you’re selling a larger proportion of your holdings to raise that same amount of cash. That leaves you with fewer shares left to benefit from the subsequent recovery. If, instead, that same 20% drop happens in a year when you don’t need to withdraw anything — because you’re still accumulating, or because you have another source of income that year — the hit gets diluted: your capital recovers over time without you having been forced to sell at the worst possible moment.
Why the average doesn’t tell the whole story
The long-term average annualized return is the number that dominates almost every conversation about investing, and for good reason: during the accumulation phase, it’s practically all that matters. But during the withdrawal phase, that same figure can hide brutal differences in real-world outcomes.
A numerical example makes this clear. Suppose a €500,000 portfolio from which you withdraw €20,000 a year (an initial 4%, adjusted afterward for inflation). In Scenario A, the portfolio suffers a 30% drop in the very first year of retirement and then recovers with solid returns for the rest of the period. In Scenario B, the exact same returns occur but in reverse order: the good years come first, and the 30% drop happens at the end. The average return of both scenarios is mathematically identical. But in Scenario A, the initial drop forces you to sell a disproportionate share of the portfolio while prices are depressed, and that capital never gets a chance to recover because it has already left the system. In Scenario B, the capital had years to grow before the drop arrived, and by the time it hits, the portfolio is much larger and can absorb the blow without jeopardizing future withdrawals. The result: Scenario A can exhaust the capital a full decade earlier than Scenario B, despite starting from the exact same average return.
This is why two retirees who left the workforce five years apart, with similar portfolios and similar spending strategies, can end up with radically different wealth and peace of mind. It isn’t luck in some vague sense — it’s a mathematical consequence of exactly where in the market cycle each of them happened to start withdrawing.
The critical window: the years around retirement
Sequence risk isn’t spread evenly across an entire retirement. It concentrates heavily in the first five to ten years after active income stops, precisely because at that point the capital is still large (years of accumulated withdrawals haven’t yet shrunk it) and any percentage decline translates into a substantial absolute loss, compounded by the need to keep selling shares to cover living expenses.
Research on this phenomenon — most notably William Bengen’s original work behind the 4% rule, and the later Trinity Study refinements — points to a consistent pattern: if the first years of retirement coincide with a prolonged bear market, the probability of running out of money early rises sharply, even if the rest of the period delivers above-average returns. It’s the reason people who retired right before 2008 had a substantially harder experience, at the same nominal withdrawal rate, than those who retired five years later.
This has a direct practical implication: the exact date of your retirement — something that appears to depend solely on your personal decision — interacts with a factor entirely outside your control, namely the state of the market at that precise moment. Two people identical in every respect except the year they retire can end up with completely different financial fates.
During accumulation, the risk flips
It’s worth clarifying a point that often causes confusion: during the accumulation phase — while you’re contributing money regularly to your portfolio without withdrawing anything — sequence risk doesn’t disappear, but it works in reverse and in a far more benign way. If the market drops early in your investing life, it actually works in your favor: you’re buying shares cheaply with your future contributions, and when the market recovers, that bargain-priced capital appreciates strongly. This is the mechanism behind dollar-cost averaging: early downturns, far from being a problem, are an opportunity to accumulate more units for the same amount of money.
The problem appears exactly when the cash flow reverses — when you go from putting money in to taking it out. That inflection point — usually retirement, though it can also be a large home purchase funded from invested capital, or any substantial and sustained withdrawal — is the moment when sequence risk starts working against you if the market happens to fall right then.
Strategies to reduce the impact
There’s no way to eliminate sequence risk entirely, because market behavior in the years surrounding your retirement can’t be predicted or controlled. But there are well-established strategies for reducing its impact:
Reduce the withdrawal rate in down years. A flexible withdrawal strategy — cutting spending in a year when the portfolio has fallen, instead of sticking to a fixed inflation-adjusted figure — substantially reduces the probability of running out of capital. This requires some ability to adjust your standard of living, which isn’t available to everyone, but where it is, it’s one of the most effective levers available.
Keep a cash or short-term fixed-income buffer. Holding one to three years of expenses in cash or low-risk assets lets you avoid selling equity shares exactly when their price is depressed. You draw from that buffer during bad years and replenish it with the gains from good years.
Gradually reduce portfolio risk as retirement approaches (the so-called glide path), rather than keeping the same stock-bond allocation for your entire life. A somewhat more conservative portfolio in the years immediately before and after leaving work reduces exposure during the most dangerous window, at the cost of giving up some potential return.
Diversify your income sources in retirement, so you don’t depend entirely on your investment portfolio. A public pension, rental income, or partial part-time work income all reduce the amount you need to withdraw from market assets during bad years.
Consider a more conservative initial withdrawal rate than the classic 4%, especially if you retire amid elevated market valuations or low interest rates, since both factors have historically preceded periods of higher adverse sequence risk.
In practice
Sequence of returns risk isn’t a reason to avoid equities, nor to indefinitely postpone retirement out of fear of a bad market moment. It’s better understood as an argument for building a withdrawal plan with room to maneuver: a spending rate that can flex, a cash buffer that avoids forced selling at the worst possible time, and an asset allocation that becomes somewhat more conservative during the most vulnerable window. The market’s long-term average return remains the single most important variable for building wealth. But once you start living off that wealth, the order in which returns arrive stops being a statistical footnote and becomes the variable that decides whether your money lasts twenty years or thirty-five.
