Here's a retirement planning fact that surprises most people:
Two retirees with the same starting balance, same withdrawal rate, and same average return over 20 years can end up with wildly different outcomes—one running out of money while the other dies with millions.
The difference? The order in which those returns happened.
This is called sequence of returns risk (or sequence risk), and it's one of the most important—and least understood—concepts in retirement planning.
When you're accumulating money (saving for retirement), volatility is annoying but not dangerous. Bad years early on hurt, but you have time to recover.
When you're decumulating money (spending in retirement), everything reverses. Bad years early on are devastating. You're selling shares at low prices to fund your spending, and those shares are gone forever—they can't participate in the recovery.
This asymmetry is sequence risk.
Let's compare two retirees:
Setup:
Retiree A: Bad Start
| Year | Return | End Balance |
|---|---|---|
| 1 | -20% | $750,000 |
| 2 | -10% | $625,000 |
| 3 | +5% | $606,250 |
| ... | (improving) | ... |
| 20 | $180,000 |
Retiree B: Good Start
| Year | Return | End Balance |
|---|---|---|
| 1 | +20% | $1,150,000 |
| 2 | +15% | $1,272,500 |
| 3 | +10% | $1,349,750 |
| ... | (declining) | ... |
| 20 | $2,400,000 |
Same average return. Same withdrawal rate. One has $180K left. One has $2.4 million.
When you withdraw money during a down market:
Early returns have an outsized impact because they affect a larger base of assets for a longer time.
| Year of Return | Impact on Final Wealth |
|---|---|
| Year 1 | Very High |
| Year 2-5 | High |
| Year 6-10 | Moderate |
| Year 11-15 | Lower |
| Year 16-20 | Lowest |
This is why the first 5-10 years of retirement are called the "danger zone."
Keep 1-3 years of expenses in cash or short-term bonds. During a market downturn, spend from the buffer instead of selling stocks at low prices.
Instead of fixed $50,000/year, use guardrails:
Any flexibility dramatically improves outcomes.
Some research suggests starting retirement with lower equity (40-50%), then increasing over time (to 60-70%). Protect when most vulnerable.
If you can delay Social Security until 70, you get:
This is why Monte Carlo simulation matters for retirement planning.
A fixed return calculator assumes 7% every year. It completely ignores sequence risk.
Monte Carlo runs hundreds or thousands of scenarios with different sequences:
The "success rate" (e.g., 85%) reflects how many of those sequences survived. A 15% failure rate means 15% of possible return sequences would bankrupt you.
This is exactly what sequence risk looks like in a model.
High Sequence Risk:
Lower Sequence Risk:
Sequence of returns risk means that the order of market returns matters as much as the average—especially in retirement.
Key takeaways:
Monte Carlo simulation is the only way to understand sequence risk. QuantCalc runs 1,000+ scenarios with different return sequences and shows you your true probability of success.
Try QuantCalc Free