Risk of Ruin: The Maths of Blowing Up an Account (and Why 10% Kills You)
Quick answer: risk of ruin does not depend on whether you are right. It depends on how much you risk per trade. At 10% per trade, 7 consecutive losses take half your account — and at a 45% win rate that streak appears, on average, once every 66 trades. At 1% you would need 69 losses in a row, which never happens. Size, not strategy, decides whether you survive.
Key takeaways
- Long losing streaks are normal; what makes them fatal is size.
- Each extra percentage point of risk shortens your margin dramatically.
- An account cut in half needs to double just to get back.
- Risk of ruin is controlled before you trade, not during the streak.
How many losses in a row take half your account
| Risk per trade | Consecutive losses to lose 50% | To lose 90% |
|---|---|---|
| 1% | 69 | 229 |
| 2% | 34 | 114 |
| 3% | 23 | 76 |
| 5% | 14 | 45 |
| 10% | 7 | 22 |
And how often that streak appears
At a 45% win rate — perfectly healthy if your winners are bigger than your losers — this is how often a streak of that length shows up on average:
| Risk | Streak needed | Appears once every | In practice |
|---|---|---|---|
| 10% | 7 | 66 trades | Three times a year |
| 5% | 14 | 4,300 trades | Once in several years |
| 3% | 23 | 930,000 trades | Practically never |
| 2% | 34 | 670 million | Never |
| 1% | 69 | Unimaginable | Never |
There is the jump that matters: between 5% and 10% there is no “twice the risk”. There is the difference between an improbable event and one that will happen to you this year.
Figures calculated for a system with a 45% win rate and independent outcomes. Your own win rate changes the numbers: a lower one makes long streaks considerably more frequent.
The recovery trap
Ruin does not arrive from the fall alone, but from what the fall then demands:
| If you lose | You need to gain |
|---|---|
| 25% | 33% |
| 50% | 100% |
| 75% | 300% |
| 90% | 900% |
An account down to 10% of what it was is not “almost gone”. It is gone in practical terms, because nobody multiplies what is left by ten.
The four rules that lower risk of ruin
- Fixed percentage risk. Between 0.5% and 1%. As the account falls, the money at risk falls with it.
- A daily limit. Two losses in a row and the day is over; this cuts the streak before it matters.
- A cap per correlated group. Three positions that move together are one position at triple size.
- Never raise risk in a drawdown. This is the single decision that turns a normal streak into a dead account.
Rule 2 is the most powerful and the cheapest. A daily limit turns a 7-loss streak into four separate bad days, and four bad days do not blow up an account. They just annoy you.
All four rules, the full capacity and frequency tables, the correlation multiplier and a printable survival audit are laid out in the free ebook The Risk of Ruin Handbook.
How to turn it into a system
Risk of ruin is controlled with parameters, not willpower. In Cortex Automation, risk per trade and schedule are fixed settings, so size does not creep up because the day is going badly; the Cortex Signal Kit delivers signals with a defined stop, which is the starting point of any sizing calculation. If you are already inside a streak, the free ebook The Drawdown Recovery Playbook covers the way out.
What exactly is risk of ruin?
The probability that your account falls below the point where you can no longer trade your plan.
Is risking 2% twice as dangerous as 1%?
Considerably more than twice. The relationship is not linear: each extra point sharply shortens the streak needed to sink you.
What if my system wins 70% of the time?
Streaks become less frequent but they still exist. And high win rates usually come with larger losers, which works against you.
Does this apply to funded accounts?
Yes, with even less margin: the program's loss limit arrives long before mathematical ruin does.
Can I recover an account down to 10%?
It would take a 900% gain. In practice, the sensible move is to start again with different rules.
Size decides, not the streak. Start with the free ebook The Risk of Ruin Handbook, then see Cortex Automation or try it with the Automation Test.
Disclaimer: educational content. Figures are illustrative and assume independent outcomes, which markets do not guarantee. Cortex Next is not a financial service and guarantees no results. Trading involves risk of loss.
