Gaps are one of the most misunderstood price phenomena in trading. To the untrained eye, they look chaotic—the market simply jumps from one price to another without trading in between. But to experienced traders, gaps represent high-probability setups with well-defined entry, exit, and risk-management points. This article explores what gaps are, why they form, the different types of gaps you'll encounter, and the specific trading strategies that generate consistent profits from gap price action.
What Are Gaps and Why Do They Form?
A gap occurs when price opens at a level significantly different from the previous close, creating a visual gap on your chart with no price action between the close and the new open. Gaps happen because price action occurs in between candles—overnight, during weekends, during news announcements, or when significant information reaches the market.
There are several reasons gaps form. Most commonly, overnight news or earnings announcements cause the next day's open to be dramatically different from the previous day's close. A company releases worse-than-expected earnings and the stock gaps down on open. A central bank announcement triggers currency gaps. Geopolitical events that happen whilst Western markets are closed cause Asian markets to open much higher or lower.
Gaps also form when market sentiment shifts sharply. Perhaps a company's guidance changes, or a sector suddenly falls out of favour, or positive economic data supports a currency. These shifts can be so dramatic that the market gaps rather than gradually moves. On forex charts, liquid instruments like EUR/USD gap less frequently, but gaps are common on less-liquid pairs and on stocks. On index futures, gaps happen regularly at the open.
Types of Gaps: Common, Breakaway, Runaway, and Exhaustion
Common Gaps (Area Gaps): These are minor gaps that occur regularly and often fill quickly. They happen in liquid markets without significant new information. For example, the price might close at £10.00 and open at £10.02 due to normal overnight order flow. These gaps typically fill within a few hours and rarely offer tradable opportunities. Common gaps are high-risk trades because they can disappear in minutes.
Breakaway Gaps: These occur when price breaks decisively out of a consolidation or range, often on elevated volume. A stock that's been ranging between £50 and £55 suddenly gaps up to £58 on heavy volume and breakout news. This is a significant gap that signals a trend is beginning. Breakaway gaps often do not fill—price continues in the direction of the gap. These are the gaps traders want to trade in the direction of the gap, not against it.
Runaway Gaps (Measuring Gaps): These occur in the middle of strong trends and represent the market's acceleration. You're in a clear uptrend, and suddenly price gaps up another 2% overnight. The gap reflects institutional buying pushing price higher during off-market hours. Runaway gaps often don't fill and represent the middle section of a larger move. These gaps should not be faded (traded against)—they're confirming the existing trend.
Exhaustion Gaps: These occur near the end of a strong move, often signalling that a trend is exhausted. Price has rallied hard, gaps up one more time on heavy volume, but then begins reversing. These gaps often fill quickly because they mark the final push before reversal. Exhaustion gaps can be excellent short opportunities—they signal the trend has gone too far too fast.
Gap Up vs. Gap Down: Directional Implications
The direction of the gap matters. A gap up generally signals bullish sentiment. The market is so excited about something that traders are willing to buy at higher prices immediately on open, not waiting for the previous day's close. This enthusiasm often continues throughout the day. Gap ups are bullish and frequently continue higher. If you're looking to fade (trade against) a gap, you should be particularly cautious with gap ups—the trend bias is against you.
Gap downs signal bearish sentiment and lower prices. Gap downs on high volume are particularly bearish and frequently continue lower throughout the day. If you want to short a gap, gap downs are far more likely to continue than gap ups.
The intensity of the gap matters too. A 0.5% gap is minor. A 2-3% gap is significant. A 5%+ gap is extreme. The larger the gap, the more important the news or order flow causing it. Extreme gaps are usually not faded—they're too powerful. You trade with them, not against them, until evidence suggests they're exhaustion gaps.
Gap Fill: Do Most Gaps Really Fill?
One common trading adage is "gaps always fill." This is partially true but dangerously oversimplified. Some gaps fill quickly. Others fill much later, if at all. The timing and likelihood of a fill depends on the gap type.
Common gaps almost always fill, often within hours. Breakaway gaps sometimes fill, but many don't—they represent the start of a new trend. Runaway gaps rarely fill immediately—they confirm an existing trend and price usually continues higher. Exhaustion gaps often fill but sometimes reverse so completely that price doesn't bother filling—it continues in the opposite direction.
The timeframe you're trading matters enormously. On daily charts, gaps sometimes take weeks to fill. On intraday charts, gaps fill much faster. A gap that looks intact on the daily chart might be getting filled at the intraday level. Your trading timeframe determines whether a gap-fill trade makes sense.
A critical insight: don't assume gaps will fill just because the textbook says they should. Instead, analyse each gap individually. What caused it? Is it a high-conviction breakaway or a minor overnight move? What's the volume context? Once you understand the gap's nature, you can decide whether trading the fill or trading with the gap makes more sense.
Trading the Gap Fill Strategy
The most common gap trading approach is fading the gap—entering a trade to profit from the gap filling. This works particularly well with common gaps and some exhaustion gaps. Here's the practical approach:
Setup: A gap has formed overnight. You've identified it's not a breakaway gap (price hasn't continued beyond the gap). You're betting price will return to fill the gap.
Entry: On the intraday timeframe, wait for the first pullback toward the gap. Don't enter immediately on open; that's when emotions and news flow are most extreme. Wait for a 30-60 minute pullback, then enter when price starts approaching the gap level. You're fading the initial gap move.
Stop Loss: Place your stop above (for gap-down fades) or below (for gap-up fades) the gap if it's a breakaway gap you don't want to hold through. Alternatively, place stops beyond the day's extreme if you're willing to hold through a strong trend. Gap fades often don't work because what caused the gap was strong enough to continue. Your stop needs to account for this.
Profit Target: Your target is the previous day's close—the gap-fill level. That's where most gap fades end. Some traders take profits at the 50% gap-fill level to avoid being caught if momentum reverses before full fill.
Best Gap Fills: Gap fills work best when: (1) The gap is small to moderate size (not an extreme gap that signals trend change). (2) The gap occurred without major news—just normal overnight order flow. (3) You're trading intraday—same-day gap fills are more reliable than waiting days for fills. (4) The market has no clear trend—gap fills work better in range-bound environments than in strong trends.
Trading Breakaway Gaps: Don't Fade These
Breakaway gaps are entirely different animals. These gaps occur when price breaks decisively out of a consolidation range or support/resistance level, usually on heavy volume. The gap signals a new trend is beginning. Fading a breakaway gap is fighting the momentum.
Setup: A stock has consolidated between £50 and £55 for weeks. Overnight, earnings are announced and it gaps up to £58. Volume is 5x normal. This is a breakaway gap—a new uptrend starting.
Entry: Don't short this gap hoping for a fill. Instead, buy pullbacks into the gap region if the uptrend is continuing. The breakaway gap becomes your area of support. If it pulls back toward £56-57, that's where you want to buy, not short.
Why breakaways work differently: Breakaway gaps occur when sentiment changes durably. Something fundamental has changed about the asset. The gap isn't noise to be faded—it's the market repricing the asset to a new, higher (or lower) equilibrium. Fighting this repricing is swimming upstream.
Identifying breakaway vs. exhaustion gaps: Volume is key. A breakaway gap comes on heavy volume—institutions are genuinely buying. An exhaustion gap comes on high volume but in the context of an already extreme move—it's the final push. Over time, you'll develop intuition. The "feel" of a breakaway gap is different from an exhaustion gap. A breakaway feels like institutions piling in; an exhaustion gap feels like retail panic.
Runaway Gaps: Confirming Trends, Not Reversals
Runaway gaps occur in the middle of strong trends. These gaps confirm the trend is powerful and continuing. They should be traded with the trend, not against it. When you see a runaway gap in an existing uptrend, it's not a signal to short—it's confirmation the uptrend remains intact and strong.
Runaway gaps are less suitable for mean-reversion traders who fade gaps. They're more useful for trend traders as confirmation that the trend is accelerating. If you're already long in an uptrend and see a runaway gap up, it's psychological reassurance that your trend trade is working and you should hold. If you're considering entering an uptrend and see a runaway gap, it confirms the trend is intact and strengthening.
Don't try to short runaway gaps. They're trend confirmations, not reversals. The market is accelerating in the trend direction. Your job is to trade with it.
Earnings Gaps: Special Considerations
Earnings gaps are among the most extreme gaps because earnings announcements can dramatically change a company's prospects. A stock might gap down 8-10% if earnings are terrible, or gap up 5-7% if they're exceptional. These gaps have unique characteristics:
Earnings gaps rarely fill immediately. The gap represents a repricing based on new fundamental information. Price doesn't rush back to the pre-earnings level—it often trends further in the gap direction as the market processes the earnings.
Don't predict earnings gaps by trying to position ahead. Earnings announcements create liquidity crunches and wildly unpredictable moves. Many traders simply stay out of stocks in the 48 hours around earnings.
Fade earnings gaps only after confirmation. If a stock gaps down on earnings, wait 1-2 days. Is it recovering? Is there a bounce starting? Only then consider fading the gap. The first day is often too volatile to trade safely.
Use earnings gaps to identify trend reversals. Sometimes an earnings gap signals a major reversal. A hated stock beats expectations and gaps up 8%—this often signals the stock was oversold and a new uptrend is starting. Watch what happens next. If the gap holds and price continues higher, you've caught the start of a new trend. Don't fade it.
Weekend Gaps and Swing Trading
Swing traders who hold positions over weekends face weekend gaps. Markets close Friday afternoon and open Monday morning. Overnight, geopolitical events, economic data, or central bank actions can occur. The market opens Monday often significantly different from Friday's close.
Weekend gaps are particularly common in forex, where Asian markets trade over the Western weekend. A large move in Asian or Middle Eastern markets over the weekend often sets up a gap on Monday European open.
Risk Management for Weekend Gaps: If you hold positions into the weekend, be prepared for Monday gaps. Some traders scale back position sizes into Friday close to reduce weekend gap risk. Others accept the gap as the cost of swing trading. Some use wide stops that account for potential weekend gaps. Consider your risk tolerance.
Trading Weekend Gaps: If you're trading Monday opens, watch for weekend gaps carefully. They often represent significant moves and should be analysed like other gaps—identify whether they're breakaways, common gaps, or exhaustion moves. Often Monday gap-downs continue lower due to Asian weakness, and Monday gap-ups continue higher due to Asian strength.
UK and US Market Gap Differences
UK and US markets have different gap patterns worth understanding. The UK market opens at 8am GMT and closes at 4:30pm GMT. The US market opens at 2:30pm GMT and closes at 9pm GMT. Between UK close and US open, there's a 4.5-hour window when major US news and economic data can be released.
UK Overnight Gaps: FTSE 100 stocks sometimes gap on the open due to overnight US market moves or US economic data. If the US closed down hard, UK stocks might open lower. If positive US data releases overnight, UK stocks might open higher.
US Overnight Gaps: US markets often gap on the open due to overnight economic data, Fed announcements, or overseas developments. Pre-market and at-market volume is lower, so gaps can be more dramatic.
Afternoon Window Gaps: After the US market opens (2:30pm GMT), there's overlap between UK and US trading. Major moves happen here. By the time US close, gaps have often been clarified—you know whether an overnight gap is holding or filling.
Understanding these timing differences helps you understand when gaps are most likely and which ones are most reliable to trade.
Practical Gap Trading Examples
Example 1: Common Gap Fade (Intraday) HSBC closes Friday at 548p. Opens Monday at 552p on light volume (just normal weekend order flow). This is a small common gap. By 10am, the stock pulls back to 549p. You short here, targeting 548p. The gap fills within 3 hours and you take profits. This is textbook gap fade.
Example 2: Breakaway Gap (Do Not Fade) Unilever consolidates between £42 and £44 for a month. On Tuesday morning, strong earnings news breaks at 7am. The stock gaps up to £46.50 on massive volume. All the institutional positions buying. At 9am you're tempted to short this "overextended" gap. Don't. This is a breakaway. By next week, it's at £48. You would have lost badly shorting this gap. Instead, buy dips toward £45 as support.
Example 3: Earnings Gap Decision A tech stock gaps down 6% on disappointing guidance. Your instinct is to fade this gap—buy the dip. But by Wednesday morning, it's gapped another 2% lower. The gap didn't fill; instead it extended. By Friday, you'd have been stopped out with losses. The earnings gap signalled a new downtrend, not a bounce opportunity. You should have observed this and exited or gone short, not faded.
Gap trading is profitable when you respect the gap's nature. Common gaps and some exhaustion gaps can be faded. Breakaway gaps should be traded with, not against. Earnings gaps demand patience and observation before fading. Weekend gaps are opportunities for swing traders willing to accept gap risk. Master these distinctions and gaps become high-probability trading opportunities rather than random chaos.