Futures Gaps: Fill or Extend? A Checklist and a Test Plan Instead of Folk Statistics

The rule that gaps always fill gets repeated until it sounds like a law, and traders who take it literally fade a big overnight move at the open and watch it keep going. Gaps fill sometimes and extend other times. The useful question is how to sort the two before the open, and how to find out whether your sorting is any good, because the fill percentages quoted online come without data you can inspect.

Define the Gap Before You Measure It

A gap here means the difference between the prior regular-session close and the regular-session open at 9:30 AM ET. Futures trade overnight, so there's no literal hole in the chart, and the number depends on which prior price you choose. Pick one reference, such as the last regular-hours print or settlement your platform's session template gives you, and write it down. Keep the same one every day, or your sample means nothing.

Size matters in relation to normal volatility. Compare the gap to the recent daily ATR instead of using point buckets someone else chose. A gap of 5 points means something different when ATR is 40 than when it's 90.

The Four Questions

Before the open I run through four questions. They organize the decision. They are not a validated scoring model, and I'd treat any score as a note, not a probability.

1. Is there an obvious catalyst? A policy decision, a data surprise, or earnings from a heavy index component can justify a repricing. A gap with no identifiable reason may be more likely to retrace, though that's an idea to test.
2. How did the overnight move trade? Look at overnight volume on the move. A move on heavy volume is a different thing from one on thin trading.
3. What's the regime? Is the gap in the direction of the prevailing daily trend or against it?
4. How big is it versus ATR? Small relative to ATR is ordinary noise. Large relative to ATR is unusual and may lead to continuation, or may be a sharp overreaction. Both happen.

If most answers lean toward fill, I plan a fill approach. If most lean toward extension, I plan to trade with the gap. If it's mixed, I'd rather wait for the opening range and decide from price action.

Trading a Fill

• Don't enter at the open. Give the first 15 minutes to show whether price is actually moving toward the fill.
• Enter on the first failed counter-move in the fill direction, for example a failed bounce after a gap up begins to retrace.
• The target is the prior-session reference close.
• The stop sits beyond the opening print. If price returns to and holds beyond the open, the idea is wrong.

Hypothetical ES example: prior close 5000.00, open 5012.00, a 12-point gap up. Price drops, bounces, and the bounce fails. Short at 5009.00 with a stop at 5013.50, which is 4.5 points or $225 per ES contract ($22.50 on MES). The fill target is 5000.00, 9 points or $450, so 2R on paper. A partial exit at the halfway point of the gap, 5006.00, would bank 3 points ($150). Costs and slippage reduce all of this.

Partial fills are common enough that I plan for them. Taking half off near the midpoint and trailing the rest is a way to avoid needing the full fill.

Trading an Extension

When the checklist leans toward continuation, trade with the gap. Wait for the opening range to form, say 9:30 to 10:00 AM ET, then enter on a close beyond the opening range high (gap up) or low (gap down). The stop goes on the other side of the range, and the target is the next reference level or a measured move equal to the gap. The hard part is psychological. After a large drop, everything in you says it's overdone, and you need the plan written before the open to resist that.

Collect Your Own Gap Statistics

1. Fix your gap definition and keep it.
2. For every session, log gap direction and size, the ATR ratio, whether there was a catalyst, and the four answers.
3. Record outcomes: filled by the close, filled in the first hour, partial, or extended. Include every session, not only the memorable ones.
4. Look at outcomes by checklist answer once you have a sample large enough to mean something. A handful of sessions or thirty trades doesn't prove an edge, and different market regimes can flip results.
5. Trade the plan in SIM only to check mechanics. SIM fills don't reproduce live queue position or slippage.

Use a data source with real history for this and don't fill missing sessions with guesses.

Where KPL Fits

Gap analysis can be done before the open, but the KPL map can't. KPL levels are fixed reference prices anchored to the regular-session opening print, the standard ES and NQ map has four levels, and they don't move intraday. The map is only complete once the open prints. After that, you can see where the gap's fill target and your plan sit relative to those levels. The KPL trading overview explains how the levels work. The Intro tier is $97 per month after a 7-day trial and includes the course, daily ES and NQ KPL levels, and community access. You can start it from the Intro trial page.