The maths of losing: why a 50% loss needs a 100% gain
Avoiding catastrophic loss matters more than capturing every gain, because the maths is not symmetric.
Down 50%, then up 50%, leaves you down 25%. This asymmetry is not a curiosity. It is the mathematical reason that avoiding disaster matters more than capturing every opportunity, and it governs how much you should ever risk on one idea.
The arithmetic of holes
To recover from a loss you must gain a larger percentage than you lost, because you are now gaining on a smaller base. The deeper the hole, the more brutally this bites.
Look at the shape of that curve. Small losses are recoverable and roughly symmetric. Past about 50% the curve turns vertical, and you are no longer investing, you are hoping. There is no clever position sizing that fixes a 90% drawdown.
Survival first
Rule number one: never lose all your money. There is no rule number two, because if you break rule one there is no game left to play.
This is why professionals obsess over position sizing while amateurs obsess over entry points. The size of your bet determines whether a bad outcome is a lesson or an ending. The entry point determines almost nothing by comparison.
- Cap single-position risk. If one holding can take more than 20 to 25% of your portfolio with it, you are one bad quarter from a hole that takes years to climb out of.
- Refuse leverage on volatile assets. Leverage converts a survivable drawdown into a terminal one. See the leverage article for exactly where that line sits.
- Keep cash. Not to time the market, but so that a forced sale is never the reason you realise a loss.
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Avoiding catastrophic loss matters more than capturing every gain, because the maths is not symmetric.
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