Stress-testing a retirement plan against a bad first decade
Take two retirements with identical average returns over thirty years. In one, the bad years come early; in the other, the same bad years come late. The first portfolio can run out while the second finishes with a surplus — same average, opposite outcomes. That gap is sequence-of-returns risk, and it is the single most important thing a retirement projection can hide from you.
Why withdrawals change everything
For an untouched lump sum, the order of returns doesn’t change the ending value at all — compounding is commutative when no money moves. Once cash flows enter, order starts to matter: with ongoing contributions, a late crash hits a bigger balance than an early one. But it is withdrawals that make sequence dangerous rather than merely relevant. Selling shares into a downturn converts a temporary loss into a permanent one — those shares are gone and can’t participate in the recovery. A bad first decade forces years of selling low; the identical decade arriving late hits a portfolio that already grew and is nearly done being needed.
The classic illustration: someone who retired into the 2008 financial crisis spent their first years withdrawing from a falling portfolio, while someone who retired in 2013 enjoyed a long expansion first. Same strategy, same spending rule — very different trajectories, purely from the start date.
What an average-return projection hides
A single deterministic line — “6% every year, forever” — has zero sequence risk by construction. Every year is average, so no year forces selling low. That’s why a straight-line projection is systematically the rosiest picture of a given plan, and why a plan that merely survives the straight line hasn’t yet been tested at all.
What a real stress test looks like
Three complementary methods, in increasing order of coverage:
- Shift the start year through history. Replay the plan as if retirement began in each historical year and look at the worst cohorts — the classic worst cases cluster around retirements that walked into deep bear markets or extended high-inflation stretches. This tests against sequences that actually happened, including the inflation that accompanied them.
- Run a Monte Carlo. Simulate thousands of return sequences and look at the distribution of outcomes, not one line. The output worth reading is more than the success percentage: when the failures happen, how deep the near-misses go, and what the spread of ending balances looks like. A 90% success rate whose failures all happen at 95 is a different plan from one whose failures start at 78.
- Test the response, not just the shock. The realistic question isn’t “what if I keep spending obliviously through a crash?” but “what happens if I cut spending when the plan calls for it?” Guardrail-style rules — trim withdrawals when the portfolio falls behind, raise them when it runs ahead — can be modeled directly, so the stress test shows the size and duration of the cuts a bad decade would demand. Knowing “the worst case asks for a 12% spending cut for four years” is actionable in a way a bare failure percentage is not.
Things worth modeling (not prescriptions)
Different households blunt sequence risk differently, and each mitigation has a cost that belongs in the model rather than in a slogan: keeping a cash buffer lowers expected growth; flexible spending trades certainty of lifestyle for durability; delaying Social Security buys more inflation-indexed floor at the price of larger early withdrawals; a part-time income bridge shrinks early-year selling. None is universally right. A good tool lets you model each and read the trade-off from the ledger instead of arguing about it in the abstract.
The takeaway
An average-return line doesn’t test sequence risk at all. The informative question is what the bad sequences do to a plan — and whether the plan has a designed response for when one arrives.
The RetireGolden planner runs deterministic, historical, and Monte Carlo projections over the same year-by-year ledger, with selectable guardrail spending rules and an adjustment outlook that summarizes the cuts a bad sequence would demand — depth, duration, and frequency, not just a success percentage. The return models and their assumptions are documented and tested against independent implementations.
RetireGolden guides are educational — not financial, tax, legal, or investment advice. Historical performance does not guarantee future results; simulations are models, not predictions. Decisions with real-world consequences deserve a qualified professional who knows your full situation.