Sequence-of-Returns Risk, Explained Without the Jargon

While you are contributing, a crash is a discount. Once you are withdrawing, the same crash is a permanent loss of shares you had to sell to eat. That asymmetry has a name, and it is the single most under-appreciated risk in retirement planning.

The demonstration

Take two investors, each starting with £1,000,000 and withdrawing £40,000 a year, adjusted for inflation. Give them exactly the same set of annual returns — just in opposite order.

Investor A: -15%, -10%,  +8%,  +8%,  +8% ...
Investor B:  +8%,  +8%,  +8%, -10%, -15% ...

Identical average. Identical set of years.
A sells shares into two down years at the start;
B sells into two up years and meets the losses
with a much larger base.

The arithmetic is unforgiving: a withdrawal taken during a drawdown removes a larger proportion of the portfolio, so there is less capital left to participate in the recovery. The loss compounds against you.

Why it does not apply while you are saving

The same mechanism runs in reverse during accumulation. Regular contributions into a falling market buy more units — the poor early years are an advantage, provided you keep contributing. This is why the standard advice ("stay invested") is genuinely right for a saver and genuinely incomplete for a retiree.

The riskiest window in a financial life is roughly the five years either side of the moment you stop earning.

The usual mitigations

• A cash buffer. Two to three years of spending in short-duration assets, so a bad year does not force equity sales.
• Flexible spending. The ability to cut discretionary spending by 10–15% in a bad year does more mathematical work than most asset allocation changes.
• A rising equity glide path. Counter-intuitively, some research suggests starting retirement more conservative and increasing equity exposure over time reduces failure rates, precisely because it protects the vulnerable early window.
• Any income at all. Part-time work in the first years covers a disproportionate share of sequence risk.

None of these increases expected return. They all reduce the variance of outcomes in the window where variance hurts most, which is a different and more valuable thing.

Educational content, not financial advice.