Mechanism
Markets spend most time in normal conditions, but PnL is often decided in short violent bursts. If a single shock can erase months, your ‘edge’ is just leverage in disguise.
Process upgrade: turn this truth into a rule you can actually enforce. If the rule can’t be enforced, it will be broken under stress.
- Write the trigger condition in observable terms.
- Write the action in one sentence.
- Write the penalty for breaking it.
How it kills accounts
- You size for average volatility and average fills.
- A shock event widens spreads and increases slippage.
- Your stop fills late (or gaps), loss exceeds plan.
- Margin usage spikes, forcing liquidation at the worst moment.
How it kills accounts:
- The rule exists only in your head.
- Stress arrives and you improvise.
- Improvisation becomes inconsistency.
- Inconsistency becomes random results.
- Random results become a slow bleed.
Rule that survives
- Stress-test with ugly assumptions: 2–3× slippage, spread blowout, and stop skip.
- Size so the worst 5 minutes is survivable without decision-making.
- If your broker can change margin, assume they will when it hurts.
Rule that survives:
- Write the trigger in observable terms.
- Write the action in one sentence.
- Write the penalty for breaking it.
Example archetype
You hold into CPI because ‘my stop is set’. The stop is filled, but not where you thought. The day is decided before you can think.
Tell: if your rule isn’t enforceable, it’s a suggestion. Suggestions don’t survive stress.
Deep dive
Deep dive
Survival is a design constraint, not a personality trait. The account must survive the worst 5 minutes so the edge can express over the next 5,000.
Glossary: liquidity vacuum, margin close-out level.
Related: Exit liquidity matters more than entry.
Field checklist
- Write the rule in observable terms: if X, then Y.
- Remove choices under stress. Choices become rationalizations.
- Track the precursor: what state were you in before the mistake?
- Make deviations costly (size down, pause, review).
- Turn lessons into gates, not notes.