Timing: The Honest Version

You've seen the chart: miss the 10 best days and your returns collapse. It's true, it's real data, and the way it's usually presented is quietly dishonest. Here's the version with the footnotes attached.

Last verified 2026-07-16

A statistic that only runs one direction

The 'miss the 10 best days' figure is real. What gets left out is that the best and worst days sit in the same volatile stretches, often days apart — several of the largest single-day gains in market history happened in the middle of crashes.

So you could run the identical analysis the other way and produce an equally dramatic chart: an investor who avoided the ten worst days would have done spectacularly. Nobody publishes that version, because it argues for timing rather than against it.

The honest conclusion from both charts together is narrower and more useful than either alone. Timing is unreliable in both directions. That's an argument for staying invested — not because markets only go up, but because the alternative requires being right twice, on exit and re-entry, and the evidence says people manage neither.

Lump sum usually wins, and DCA is still fine

Vanguard compared investing a lump sum immediately against spreading it over twelve months. Lump sum won roughly two-thirds of the time and by about 2.3 percentage points on average in US data.

The reason is unglamorous: markets rise more often than they fall, so money waiting on the sidelines misses more up-days than down-days. Dollar-cost averaging isn't a way to reduce risk so much as a way to take it later.

That said, the arithmetic isn't the whole decision. An investor who dollar-cost averages and stays invested beats one who lump-sums, panics in month three, and sells. If spreading it out is what makes you actually do it, the small expected cost is worth paying — and both options beat leaving the money in cash, which is the choice this comparison is usually used to avoid making.

When order starts to matter more than average

Everything above applies while you're contributing. Once you're withdrawing, a new risk appears that averages completely conceal.

Two retirees can earn identical average returns over thirty years and end in entirely different places, depending on when the bad years landed. Poor returns early, combined with withdrawals, force selling at depressed prices — and those shares are permanently gone from the recovery.

It reverses during accumulation, which is worth holding onto. An early crash while you're still buying is genuinely good for you: years of cheap purchases that participate in the eventual recovery. Same market, opposite effect, and the difference is only whether you're a net buyer or a net seller.