Execution · 7 MIN READ
Stop-Loss Placement Starts With Invalidation
Define the event that proves a trade premise wrong before using the distance to calculate position size.Separate invalidation from discomfort
Price moving against a position does not automatically invalidate the setup. Define what must happen for the original reasoning to no longer hold: a structure break, failed breakout, time condition, or another testable event.
Place the stop or exit rule around that event, accounting for how the instrument trades. Then reduce size if the resulting distance risks too much.
Respect execution reality
A stop price is not always a guaranteed fill price. Gaps, fast moves, and limited liquidity can increase the realized loss. Treat slippage as part of risk planning for instruments and events where it is plausible.
Review changes honestly
If a stop is widened, moved, or overridden, record when and why. A management rule tested in advance differs from an improvised decision made to avoid accepting a loss.
Distinguish premise failure from normal movement
A breakout trade requires price to remain above a prior range after confirmation.
- Write the premise: acceptance above the range supports continuation.
- Define invalidation: a close back inside the range under the strategy's rules.
- Place the exit around that condition and calculate size from the resulting distance.
- If price briefly pulls back but the invalidation event does not occur, the original rule—not discomfort—governs the decision.
The stop expresses where the trade idea is wrong; position size expresses how much the account may lose if that happens.
Put the idea into your process
- Placing the stop at an arbitrary percentage with no link to the setup.
- Widening the stop because accepting the loss feels uncomfortable.
- Assuming a stop order guarantees the trigger price.
- Calling an improvised exit change active management after the fact.
- Write the invalidation event in a complete sentence.
- Identify whether it is price-, time-, or condition-based.
- Size the trade only after the stop logic is defined.
- Record every post-entry stop change with time and reason.
Prompts to use in your journal
- What exact event invalidates the premise?
- Was the stop changed after entry?
- Did realized loss differ from planned risk and why?
Real instruments may require contract, tick, pip, currency-conversion, tax, or venue-specific adjustments. TradeNarra does not provide investment advice, recommend trades, or promise outcomes.