Gap Trading

Not all gaps are created equal. Understanding the type of gap determines whether to trade with the gap (continuation) or against it (fade/fill).

Common Gap: Occurs in range-bound or low-volume stocks with no specific catalyst. Often fills within 1-3 days because there is no underlying reason for the price displacement. These are the gaps that give rise to the "gaps always fill" saying.

Breakaway Gap: Occurs at the start of a new trend, often breaking out of a consolidation pattern or range. Accompanied by high volume and a fundamental catalyst. These gaps rarely fill quickly — they signal a genuine shift in supply and demand.

Continuation (Runaway) Gap: Occurs in the middle of a strong trend, reflecting accelerating momentum. Sometimes called a "measuring gap" because the gap's size can project the remaining move. If a stock trends from $50 to $60 and gaps to $65, the continuation suggests a target near $80 (double the initial move).

Exhaustion Gap: Occurs near the end of a trend, representing a final burst of momentum before reversal. Exhaustion gaps are followed by declining volume and a reversal within 1-3 sessions. They look identical to continuation gaps in real time, making them dangerous — the only reliable distinguishing factor is the volume pattern after the gap.

Island Reversal: A stock gaps up, trades in a range for a few days, then gaps down past the initial gap — creating an "island" of price action isolated by gaps on both sides. This is one of the strongest reversal patterns in technical analysis.

The "gap and go" is the most popular gap trading strategy for day traders. It trades in the direction of the gap, expecting momentum to continue.

Setup criteria:

• Gap of 3%+ (smaller gaps lack sufficient momentum)
• Pre-market volume at least 2x the average daily volume
• A clear catalyst: earnings beat, FDA approval, contract win, analyst upgrade
• Price holding above VWAP in pre-market (for gap ups)

Entry: Wait for the first pullback after the open. The initial spike at 9:30 AM often gets extended beyond fair value. Enter on the first 1-minute or 5-minute candle that makes a higher low after the opening push, confirming buyers are still in control.

Stop: Below the low of the first pullback or below the pre-market low. If the gap fails to hold its initial range after the open, the setup is invalidated.

Target: The prior day's high (for gap ups from inside a range), or use ATR-based targets. Many traders target 1x the gap size as a continuation move — a stock that gaps up $3 from $50 to $53 has a continuation target near $56.

Time filter: Gap and go setups work best in the first 30-60 minutes. After 10:30 AM, the initial momentum fades and the trade becomes a different (less favorable) setup.

The gap fill strategy bets that the stock will reverse and "fill" the gap — returning to the previous close.

When gap fills work:

• No catalyst (common gap) — the stock gapped on thin pre-market volume with no news
• Gap into resistance — the stock gapped up into a known resistance zone or moving average
• Declining pre-market momentum — the stock gapped up strongly at 7 AM but has been fading toward the open
• Extreme extension — ATR% on the gap is 2-3x the normal daily ATR, suggesting overextension

When gap fills fail (do not fade these):

• Earnings gaps with strong numbers and raised guidance
• Breakout gaps from multi-week consolidation patterns on high volume
• Sector-wide gaps (when the entire sector moves, it is not an individual stock phenomenon to fade)

Entry: Short the stock (or sell a long position) when it shows a clear reversal candle (shooting star, bearish engulfing) in the first 15-30 minutes. Alternatively, wait for the stock to break below VWAP, confirming the gap is failing.

Stop: Above the high of the day. If the stock makes a new high after you fade it, the gap fill thesis is wrong.

Target: The previous day's close (the "fill" level). Partial profits at 50% fill are common because not all gaps fill completely on the same day.

Finding the best gap trading candidates requires a systematic pre-market scan.

Scan criteria for gap and go:

• Gap up 3%+ from prior close
• Pre-market volume > 500,000 shares (or > 2x average daily volume)
• Price above $5 (to avoid penny stock noise)
• Relative volume (RVOL) > 3x
• News catalyst present

Scan criteria for gap fill:

• Gap up 2-5% from prior close
• No significant news catalyst
• Pre-market volume below average
• Stock at or near a resistance level (prior high, moving average, round number)

Timing: Most scanners update starting at 4:00 AM ET when pre-market opens, but the most useful scan runs between 8:00-9:15 AM ET when volume increases and patterns stabilize. Stocks that are gapping at 8:00 AM but have declining pre-market volume by 9:15 AM are better fade candidates.

Tools: Most brokers (IBKR, Tradier, Alpaca) offer built-in gap scanners. Third-party tools like Finviz, Trade Ideas, and Benzinga Pro provide real-time pre-market gap alerts with customizable filters.

Gap trades carry specific risks that require adapted risk management.

Slippage at the open: The market open (9:30 AM) is the most volatile moment of the day. Market orders placed at 9:30 can fill significantly worse than expected. Use limit orders or wait 30-60 seconds after the open for spreads to tighten.

Opening range stops: Instead of fixed dollar stops, many gap traders use the opening 5-minute range as their stop reference. If a gap-up stock makes a 5-minute low at $52, the stop goes below $52. This adapts the stop to the day's actual volatility.

Position sizing for gaps: Gaps create wider initial risk (the distance from entry to stop is often larger than typical day trades). Reduce position size accordingly — if a normal day trade risks $0.50 per share, a gap trade might risk $1.50 per share, requiring 1/3 the usual share count.

Avoid fading strong gaps: The most dangerous gap trade is shorting a stock that gaps up 10%+ on earnings with strong volume. Even if the stock looks overextended, the buying pressure from institutional re-pricing can sustain the move for days. If you must fade earnings gaps, wait until at least day 2-3 and use very small size.