What “1-in-100” Market Losses Mean for Pension Investors

Most investment risk tools are technically correct and practically useless: a “1-in-100” loss sounds like a once-a-century event, but for anyone who stays invested long enough it is a once-or-twice-in-a-lifetime experience.

This note reframes pension risk in terms of drawdowns, the falls investors actually see on their statements, and offers a simple rule of thumb for matching portfolio volatility to the loss you can live through without changing strategy.

Key findings

• At roughly 15% annual volatility, which many “balanced” pensions run at, normal bad periods often mean 25–30% drawdowns, serious stress 30–40%, and full crises can push losses beyond 40%.
• In the real world, 20% losses cause anxiety and second-guessing, 25% losses trigger strategy changes, and 30%+ losses cause panic or capitulation.
• A practical rule of thumb: maximum tolerable drawdown ≈ 2.5x portfolio volatility, so a 25% drawdown tolerance implies around 10% volatility.
• Many default pensions quietly run at 14–18% volatility, implying drawdowns of 30–45%.
• If a 30% temporary loss would cause you to change strategy, your pension risk is too high.

What the paper covers

1. What investors actually experience
2. Reframing risk in drawdown terms
3. Why this matters for pensions
4. The pension-safe volatility rule
5. The line that actually matters