Gap (Price Gap)

Price gaps occur in U.S. equity markets primarily because trading halts overnight (and on weekends) while news, earnings releases, economic data, and global market developments continue to affect the supply and demand for securities. When the market reopens, the first trade of the new session may be far removed from where the prior session ended, creating a gap.

Technical analysts have historically classified gaps into several types. A common gap (also called a trading gap or area gap) is a small gap that occurs within a consolidation range, carries limited informational content in the technical framework, and tends to close — meaning price returns to fill the gap — relatively quickly. A breakaway gap occurs when price gaps out of a well-defined base or pattern, potentially signaling the beginning of a new trend move; these gaps are historically associated with elevated volume and may take much longer to fill, if at all. A runaway gap (also called a continuation or measuring gap) occurs midway through a strong trend, historically interpreted as confirming the trend's momentum. An exhaustion gap appears late in a mature trend, often near a top or bottom, and is characterized by high volume but quickly fading momentum — frequently followed by a gap fill as the trend reverses.

The concept of gap filling is well known in technical analysis: many gaps on equity charts are eventually retraced as price returns to the area where the gap occurred. Historical data on large-cap U.S. equities supports the observation that most gaps do eventually fill over varying time horizons, though the timing is unpredictable. Gaps in strongly trending stocks, particularly breakaway gaps, can remain unfilled for extended periods. Investors should avoid assuming that any specific gap will fill on a predictable schedule, as the gap-fill tendency is a statistical observation across many securities and conditions, not a rule governing individual securities.