Not all gaps are tradeable. A gap that fills within 30 minutes is a different animal from a gap that becomes a continuation signal. The key is identifying which type of gap you are dealing with before 9:30 AM — and having a rule for each scenario so you are never guessing.
The Four Types of Gaps on Nifty
Gaps occur when Nifty opens significantly above or below the previous day's close. On NSE, this happens due to overnight global moves, domestic news, or pre-market order imbalances. Not all gaps behave the same way. There are four types:
- Common Gap (Fill gap): Small gap (0.2–0.4%) with no significant news catalyst. These fill (price returns to PDC) 70–80% of the time within the first 60–90 minutes. Do not trade in the gap direction — trade the fill.
- Breakaway Gap: Large gap (0.8%+) above a key resistance or below a key support level, on high volume, driven by a major catalyst (earnings, RBI policy, FII flow). These rarely fill on the same day. Trade in the gap direction after the first 15-minute candle confirms.
- Runaway Gap (Continuation Gap): Gap in the direction of an established trend, mid-trend, with above-average volume. Confirms the trend is strong. Add to existing positions or initiate in the gap direction.
- Exhaustion Gap: Large gap at the end of a long trend, on high volume, after a multi-week move. This often marks the end of the trend — not a continuation. Trade carefully; wait for price action confirmation before acting.
Treating every gap-up as a bullish signal and buying the open. A gap-up in a downtrend, or a small common gap in a ranging market, is more likely to fill than to continue. Retail traders who buy every gap-up are consistently stopped out as professional traders fade the gap and sell into the retail buying. Always identify the gap type first.
The Gap Fill Decision Framework
Before 9:15 AM, answer these three questions to classify your gap:
- Gap size: Less than 0.4% = common gap (likely fills). 0.4–0.8% = watch first candle. More than 0.8% = potential breakaway or runaway gap.
- News catalyst: Is there a specific, significant reason for the gap? RBI policy, quarterly results, major global event? Yes = breakaway potential. No obvious catalyst = fill probability increases.
- Gap vs key level: Does the gap open above PDH or below PDL? Gap above PDH = bullish breakout potential. Gap below PDL = bearish breakout potential. Gap inside yesterday's range = fill probability high.
Gap Up Playbook
When Nifty opens higher than yesterday's close, here is your decision tree:
- Gap up above PDH (0.5%+ gap): Wait for first 15-min candle. If it closes above PDH — genuine breakout, buy above first candle high. If it closes back below PDH — bull trap / gap fill developing. Trade the fill short to PDC or PDL.
- Gap up inside yesterday's range (small gap): High fill probability. Watch price action. If the first 15-min candle is bearish and closes near its low — short toward PDC. If buyers defend and close near the high — stay flat or look for long setups at PDH.
- Gap up after multiple strong up days: Exhaustion warning. Do not buy the gap. Wait for a reversal signal — shooting star, evening star, or bearish engulfing on the 15-min chart — then trade the fill aggressively.
Gap Down Playbook
- Gap down below PDL (0.5%+ gap): Wait for first 15-min candle. If it closes below PDL — genuine breakdown, sell below first candle low. If it closes back above PDL — bear trap / gap fill developing. Buy above the recovery candle for the fill to PDC or PDH.
- Gap down inside yesterday's range (small gap): High fill probability. If first candle is bullish — buy toward PDC. If sellers hold and close near low — look for short setups at PDL.
- Gap down after strong earnings / global selloff: Potential breakaway gap. Do not fade (buy) these gaps immediately. Let price stabilize for 30 minutes. If Bank Nifty and Sensex are also gapping down — the move is broad and likely to continue.
For any gap on Nifty, your entry direction is determined by the close of the first 15-minute candle — not the open. A gap-up that closes the first 15-min candle in the upper half of the candle range = bullish continuation. A gap-up that closes the first 15-min candle in the lower half = gap fill developing. This single rule handles 80% of gap scenarios correctly.
Using Gift Nifty to Predict the Gap
Gift Nifty (formerly SGX Nifty) trades from 6:30 AM IST and gives you an early indication of where Nifty will open. Check it at 8:45 AM for the most accurate pre-market read:
- Gift Nifty premium vs spot: Calculate the expected open: Nifty Spot close + (Gift Nifty - previous Gift Nifty close). If Gift Nifty is 150 points above yesterday's close, expect approximately a 150-point gap-up.
- Gift Nifty trending vs static: If Gift Nifty is moving — still trending up or down at 8:45 AM — the gap direction may still be forming. Check again at 9:00 AM for a final read.
- US Dow Futures: Check simultaneously. If Dow Futures are positive AND Gift Nifty is positive, the bullish gap has broad support. If they diverge, treat the gap with more caution.
Nifty Gap Statistics to Know
- Gaps less than 0.3% fill within the same session approximately 75% of the time.
- Gaps greater than 0.8% continue in the gap direction (no fill) approximately 60% of the time on the same session.
- Monday gaps are the most likely to fill — weekend news is already priced in by 10:00 AM as institutional traders return to their positions.
- Gaps on Budget Day, RBI policy day, and quarterly results days for major index constituents are the most likely to be breakaway gaps — trade in the gap direction with strong confirmation.
- Gaps that leave a price vacuum (no trading range overlap with previous day) are the strongest gaps — they indicate genuine institutional urgency and rarely fill on the same day.
Setup: Nifty closes at 24,300 on Monday. No major news. Gift Nifty at 9:00 AM: 24,150 — gap down of 150 points (0.62%). No significant domestic or global news catalyst. PDL: 24,180. The gap is inside the previous day's range (below PDC but above PDL).
Classification: Small-medium gap, no catalyst, inside range. Gap fill probability: high.
9:15 AM: Nifty opens at 24,155. First 15-min candle: Low 24,110, High 24,195, Close 24,180 — closes near the HIGH of the candle. Bullish first candle = gap fill signal.
Entry: Buy at 24,185 (above first candle high). Stop: 24,100 (below first candle low). Risk: 85 points.
Target: 24,300 (PDC / gap fill). Reward: 115 points. R:R: 1:1.35.
Result: Gap fills by 10:30 AM. Nifty reaches 24,295. Exit at 24,290. Clean fill trade in 75 minutes.
For the next 10 trading days, log every gap: size, direction, catalyst (yes/no), gap vs PDH/PDL, and whether it filled or continued. After 10 days your own data will confirm the patterns. Read next: India VIX: What It Is and How It Changes Your Trading Strategy.