What does stepping out of the market actually cost?

Nobody sets out to time the market. What happens is that a decline gets frightening, cash feels sensible for a while, and the re-entry point never quite looks right. The problem is that the best days cluster inside the worst weeks — so the people who leave to avoid the falls almost always miss the rebounds too.

The investment

$
yrs
% p.a.
% s.d.
% p.a.

If you panic

% from peak
mo
Investors who sell in a panic typically wait for things to "feel safe again" — which is generally after the recovery has already happened.

If you think you can time it

%
Be generous with yourself. Professional forecasters do not reliably beat 50%.
×
Each round trip needs two correct calls: when to get out, and when to get back in.

Missing the best days

Same market, same period. The only difference is being in cash for a handful of the strongest days.

The panic seller

One simulated market path, with and without selling after a fall.

Stayed invested Sold after each fall

The odds of getting it right

Making sense of this one

Nobody decides to become a market timer. It happens by accident, one reasonable-sounding step at a time.

How it actually goes

The story is almost always the same. Markets fall. The news is alarming and the reasons sound solid. Moving to cash "until things settle down" feels prudent rather than dramatic. Then the market rebounds sharply while the news is still bad, the moment to return never looks right, and by the time it does you've missed the recovery you were trying to protect yourself from.

What makes this so unforgiving is a mathematical quirk: market returns aren't spread evenly across time. They're concentrated into a very small number of days — and those days cluster inside the worst weeks, when leaving feels most sensible.

An example: Gordon, 64

Gordon has $500,000 invested. In a sharp downturn he moves it all to cash, planning to return "when things stabilise". He's out for eleven months.

Over a 25-year investing life there are around 6,300 trading days. Missing just the ten best of them — four hundredths of one percent of the total — costs roughly a quarter of his final balance. Missing thirty costs over half.

The problem is that those ten days are unannounced, and they overwhelmingly land within days of the worst ones. Some of the largest single-day rises in market history happened in the middle of the 2008 crash. To catch them you had to be invested during the period that felt most unbearable.

Reading the odds section

This is the part worth sitting with. Every round trip needs two correct calls: when to get out, and when to get back in. Getting one right and one wrong is often worse than doing nothing.

At 60% accuracy per call — considerably better than professional forecasters manage — a single clean round trip has a 36% chance of working. Do it five times over a retirement and the odds of getting all ten calls right fall to well under 1%.

That's not a comment on anyone's judgement. It's what happens when you need to be right repeatedly, for decades, about something genuinely unpredictable.

What to take from it

The advice to stay invested isn't offered because sitting still is clever. It's offered because the alternative requires a run of correct predictions that almost nobody achieves.

If market falls genuinely worry you — and that's a perfectly reasonable thing to feel — the answer isn't better timing. It's a mix you can hold through a bad year, and enough cash that a downturn never forces your hand. The allocation calculator and the cash buffer calculator are the practical versions of that.

General information only — not financial advice. Daily returns here are simulated from the average and volatility you enter, not drawn from any actual market history; they are shown to illustrate the mathematical structure of the problem — that returns are concentrated in very few days — rather than to reproduce a specific period. Real markets cluster volatility and have fatter tails, both of which make the timing problem harder, not easier.