Price does not always move through levels. Sometimes it simply skips them. No trade happened there. No candle formed there. The market stepped over that price as though it never existed, and your stop-loss went with it.
It is Sunday evening, 5:02 PM New York time. The forex market is reopening after the weekend. A trader holding a long position on EUR/USD from Friday's close set their stop-loss at 1.0820, two pips below a clean support level, the textbook placement. Friday's close was 1.0865. The market reopens at 1.0791. Not because price moved through 1.0820 while no one was watching. There simply was no 1.0820 during those two days. The market skipped it. The stop-loss was triggered at 1.0791, twenty-nine pips below where it was placed, and the broker's fill notice arrives at a price the trader never agreed to pay. This is a liquidity gap. Not a glitch. Not an anomaly. A structural feature of a market that appears continuous but is not.
A liquidity gap, sometimes called a price gap, is the space between one price and the next where no transaction occurred. On a chart it appears as a literal gap, a candle that opens far above or below the previous candle's close, with empty space between them. In that space, the order book was either absent or so thin that a single order moved price across the entire range in one step. Nobody bought or sold at any price in that gap. It simply ceased to exist as a tradable location for the duration of the gap's formation.
Weekend gap The most predictable and the most ignored
Forex closes Friday at 5 PM New York time and reopens Sunday around 5 PM. Geopolitical events, central bank statements, or economic data released during those 48 hours reprice the market overnight. Traders holding positions into the weekend carry full gap risk. Stops placed during the week cannot protect them from a Monday open far away from their level.
News gap The spike that skips the middle. Extreme data surprises or unexpected central bank interventions can produce intraday gaps. When market makers withdraw their quotes simultaneously, a single order can move price through ten, twenty, or fifty pips with nothing in between. The Swiss franc surge in January 2015 was, mechanically, a cascade of gaps inside gaps.
Session gap The dead hours trap
Between the New York close and the Asian open, roughly 5 PM to 7 PM New York time, interbank depth thins to a fraction of its peak levels. A modestly sized order during this window can move price through multiple pips with no intermediate fills. Traders with tight stops in open positions are disproportionately exposed here.
Flash gap Market structure failure, full stop
Rare but devastating. Multiple liquidity providers withdraw simultaneously due to technical failure or correlated risk management decisions. Price moves hundreds of pips in seconds with almost no two-way market. The British pound flash crash in October 2016, a six percent move in two minutes during thin Asian trading, remains one of the clearest examples.
The mechanics of a gap are simpler than they appear. Every price on a forex chart requires a buyer and a seller to agree at that level. When liquidity thins, the distance between the nearest willing buyer and seller widens. If a large enough order arrives, it exhausts all available sellers at one price, then all sellers at the next, then the next, jumping across levels that had no orders sitting at them. Each skipped level is a gap. The size of the gap is a direct measure of how few orders existed in that price range at that moment.
Order book depth varies dramatically across the trading day. During the London and New York overlap, liquidity is deepest. During the Asian session, it thins. Around the New York close and into the weekend, gap risk is at its highest. GBP/USD, October 7, 2016, 7:09 AM Sydney time. Asian session, minimal liquidity. An algorithm placed a large sell order into a near-empty order book. Sterling fell from 1.2600 to 1.1378 in under two minutes. Traders with stop-losses at 1.2550, 1.2500, 1.2400, any level in that range, were filled, if they were filled at all, somewhere near the bottom. Some accounts were pushed into negative equity. The market recovered most of the move within minutes. The fills did not. "A stop-loss is a guaranteed exit at your specified price when the market is liquid. In a gap, it becomes a best-efforts order executed at whatever price the market offers next, which may be far from what you placed."
What gaps reveal about forex market structure
The forex market is not continuous. It is a series of overlapping sessions with real liquidity vacuums between them. The idea of 24-hour trading hides the fact that depth varies dramatically across time.
Stop-loss orders do not guarantee exit price. They guarantee an attempt to exit. In normal conditions, that attempt is filled near the intended level. In a gap, it is filled at the next available price, wherever that may be.
Gaps tend to fill. Price often returns to the gap area within hours or days as the market stabilises. The unfilled space becomes a zone where orders were skipped and often revisited.
Leverage amplifies gap damage. A trader using high leverage with tight stops can experience losses far beyond intended risk in a single gap event.
Risk Holding leveraged positions over the weekend with tight stops near obvious levels is one of the highest-risk behaviours in retail forex. For two days, your stop does not function in any meaningful way.
Tactic Reduce position size before weekends if holding is necessary. Alternatively, place stops at levels that reflect real structural breaks rather than obvious nearby points.
Truth Gap-fill strategies exist, but they require patience. The fill often happens gradually. Entering immediately after a gap forms, expecting continuation, is where most losses occur. Waiting for signs of stabilisation before trading the fill direction is the more grounded approach.
A gap on a chart is not a mystery. It is the market admitting that it had no price to offer between two levels at a specific moment. Every gap is a visible record of missing liquidity. Understanding them does not remove the risk. It makes the risk visible, and that is where disciplined trading actually begins.
