Direct answer
Gap risk is the risk of a sudden price jump that prevents an order from being executed at the level you assumed. Instead, trading resumes or updates at the next available quote (or execution opportunity), which can be higher or lower than expected. In forex, gap risk matters because price moves are not always continuous between consecutive quotes, especially during liquidity changes or market disruptions.
Mechanism or definition
A “gap” means there is a discontinuity: the next quoted/available price is not the same as what you expected based on the prior quote or on a stop/trigger level. Gap risk arises when there is a time period where your order cannot be executed at the desired price, and the market reopens or refreshes at a different level.
To keep the explanation independent from real-time claims, consider a simplified scenario with explicit assumptions:
- Assumption: your platform will execute a marketable order immediately when it is able to trade.
- Assumption: your reference price was the last available quote right before a disruption.
- Assumption: when liquidity returns, the first available price is meaningfully different.
If you place a protective stop based on an assumed continuous path, the stop’s intended price is no longer guaranteed to match your actual execution price. Instead, the order is filled at the next reachable price, which can worsen the realized result.
Evidence or example
Scenario (illustrative, not a guarantee of how any broker executes):
- You observe the last quote at a reference time.
- Trading conditions change such that the next available quote appears at a different price.
- Your order is triggered during the period when execution at the trigger price is not possible.
- When execution becomes possible, the order fills using the next available price.
Material consequence: even if your stop is “correct” in logic (it triggers), the economic protection can be weaker than expected because the fill happens after the gap. This is also why hedges can become less effective: if two legs do not reprice at the same time or at the same relative levels, the intended offset may not match the original assumption.
Limitations and risks
Gap risk is not a single measurable number you can reliably forecast. Key limitations and failure modes include:
- Uncertain gap size: you typically do not know how large the discontinuity will be before quotes arrive.
- Execution rules vary: order types (market, limit, stop) and platform behavior affect how an order maps to the first available execution.
- Data and timing mismatch: different timestamps (your chart time vs. your execution time vs. quote time) can make it hard to independently reconstruct what happened.
- Adverse direction is possible: a gap can move against your position, reducing the effectiveness of planned risk controls.
Verification or next question
To independently verify gap risk for a specific setup, focus on non-promotional, checkable items:
- Platform/execution documentation: find how market and stop orders are handled when liquidity is thin or trading resumes after interruption.
- Recorded executions vs. chart quotes: compare your order’s execution time and fill price to the nearest quoted prices around the discontinuity.
- Recreate assumptions: clearly state what you assumed about continuous pricing, immediate execution, and when your trigger became active.
Next question you can pursue: what exact order-handling rules apply to “stop” and “market” orders during low-liquidity or reopening periods in your execution environment?