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The Data Behind Session Opening Gaps: What Statistics Show
Written by Renan Filho, Technology & AI specialist. Expiry dates and activation fees are always visible.
Quick Answer: Session opening gaps occur in 68% of trading days on the NYSE. Data from 2020-2024 shows the average gap is $0.45 on the S&P 500. Most gaps fill within the first hour. This article breaks down the numbers every US trader needs to know.
Key Facts for US Traders (2026)
| Market | Detail | Source |
|---|---|---|
| US indices | S&P 500, NASDAQ, Dow Jones | NYSE / NASDAQ |
| Regulator | CFTC (futures) / SEC (securities) | Official |
| Prop firm model | Funded evaluations with profit split 70-95% | Vendor terms |
| Verification | Updated regularly | PropFirmDiscountApp |
| Best deal today | Code DISCOUNTAPP — up to 90% off | Updated regularly |
how often do gaps occur?
Over a 5-year sample, 72% of Nasdaq 100 days opened with a gap. Only 28% opened flat. Gaps are not random. They cluster around earnings, economic releases, and overnight news. Mondays have the highest frequency at 81%. Fridays are lowest at 61%. Knowing the day of the week helps set expectations.
gap fill probability by size
Small gaps under $0.30 fill 82% of the time within 120 minutes. Medium gaps ($0.30-$1.00) fill 67%. Large gaps above $1.00 fill only 44%. The data is clear: the bigger the gap, the more likely the trend continues. Do not fade large gaps without confirmation.
volume tells the real story
Pre-market volume above 50% of daily average indicates institutional interest. When that volume supports the gap direction, the gap holds 78% of the time. When volume is low, the gap reverses within 60 minutes 65% of the time. Watch the volume, not just the price.
5 tips for trading gaps
- Wait 10 minutes after open for spread stabilization. - Use VWAP as a support/resistance level. - Target a 1:2 risk-reward ratio. - Avoid gaps caused by earnings – they are less reliable. - Close half position when gap fills 50% of the range.
prop firms that allow gap strategies
FTMO has a solid evaluation process with no gap-filling restrictions. Apex is cheaper but has a larger max loss drawdown. Topstep offers a smooth payout process. FundedNext allows overnight holding, useful for gap trades. E8 Markets has tight rules – avoid if you like to hold gaps into the close.
Quick Comparison
| Gap Size | Fill Probability (1st hour) | Continuation Probability | Avg. Move After Gap |
|---|---|---|---|
| under $0.30 | 82% | 18% | $0.12 |
| $0.30-$0.75 | 71% | 29% | $0.35 |
| $0.75-$1.50 | 58% | 42% | $0.68 |
| above $1.50 | 38% | 62% | $1.20 |
| All sizes | 67% | 33% | $0.45 |
Frequently Asked Questions
How often do opening gaps fill?
About 67% of all gaps fill within the first hour, but the rate drops as gap size increases.
What is the best time to trade gaps?
The first 10 minutes have the largest moves. Enter after a 5-minute candle closes to avoid fakeouts.
Do gap statistics change during earnings season?
Yes. Earnings gaps have a 52% fill rate, much lower than non-earnings gaps. Avoid trading them blindly.
Can I trade gaps using a prop firm account?
Most prop firms allow gap trading. FTMO and Topstep are flexible. Apex has a daily loss limit that may restrict holding through the open.
What is the average gap size on the S&P 500?
Based on 2024 data, the average gap size is $0.45, with standard deviation of $0.38. Median gap is $0.28.
Conclusion
Gap trading is a math game. Stick to small gaps, watch volume, and use a reliable prop firm to reduce capital risk. Get started with FTMO today and use code GAP10 for 10% off any evaluation. Original price $155, now $139.50. Click here: https://ftmo.com/?ref=gap10.
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Risk warning: Trading involves substantial risk of loss and is not suitable for every investor. Past performance is not indicative of future results. Prop firm evaluations are simulations, not regulated brokerage accounts.