A gap is a discontinuity under a defined chart or session comparison. An opening gap compares a session's opening price with a prior close. A gap between entire candle ranges is a different definition, so state which you are measuring.

Opening Prints and Pre-Market Prices Differ

Extended-hours transactions can inform expectations, but the last pre-market price does not mechanically set the official opening print. Venue opening procedures and eligible orders determine that process. Check the relevant exchange trading information.

A chart excluding extended hours can show an opening gap despite trades occurring between the two prices outside the displayed session. Splits, dividend adjustments, missing data and futures rolls can also affect apparent discontinuities.

Pattern Labels Often Use Hindsight

“Common” is used for a routine gap, “breakaway” for one beyond a prior area, “continuation” for one within a move and “exhaustion” for one near its eventual end. If the label depends on later continuation or reversal, it was not known at the opening trade.

A gap fill means a return to the reference price under your definition. It is not guaranteed, and an eventual fill years later does not validate a short-term strategy with limited money and time.

Measure the Gap Before Interpreting It

From a $50 reference close to a $52 open, the percentage gap is 4%. Record the session, symbol, data source and adjustment method. A percentage alone does not tell you whether it is meaningful for that instrument.

Volume and a known announcement can be additional observations. Neither establishes that a large gap cannot fill soon or that a small gap is merely noise.

Keep Fade and Continuation Rules Separate

A fade trades toward the reference; a continuation rule trades away from it. Each needs a trigger, order, loss plan and exit horizon. A fixed 15–30-minute wait does not guarantee the direction is clear.

Use actual executable prices in the review, account for short-sale conditions where relevant, and include failed trades. Our gap-strategy guide develops this distinction without assigning a universal gap-fill probability.

Risk Disclaimer: Trading involves substantial risk of loss. Past performance is not indicative of future results. See our full risk disclaimer.