Price Gaps: Four Types and What They Signal

Key Takeaways

• The four gap types are common (noise), breakaway (new trend), runaway (trend acceleration), and exhaustion (potential reversal).
• Runaway gaps often occur near the midpoint of a trend move, making them useful as a measuring tool for projecting the remaining distance.
• The belief that "all gaps fill" is only true for common gaps; breakaway and runaway gaps frequently go unfilled for months.
• Volume is the primary tool for classifying gaps in real time: exhaustion gaps often print the highest volume of the entire trend.

What It Is

On a daily chart, a gap appears when today's open is above yesterday's high (an up gap) or below yesterday's low (a down gap), leaving an untraded price zone between them. The classification system used today was formalized by Robert Edwards and John Magee in the 1948 book Technical Analysis of Stock Trends and has been refined by modern analysts like those at StockCharts.

The four canonical types are:

• Common gap. Everyday noise inside a trading range. Fills quickly, carries little signal.
• Breakaway gap. A gap that leaves a consolidation or breaks a major support or resistance level. Often marks the start of a new trend.
• Runaway gap (also called continuation or measuring gap). Occurs in the middle of an existing trend and signals acceleration.
• Exhaustion gap. Appears late in a trend, often on unusually heavy volume, and warns of a possible reversal.

The Intuition

Gaps exist because markets discretely re-open. Overnight news, earnings releases, or macro data can shift the equilibrium price by a meaningful amount while the exchange is closed. When trading resumes, price jumps to the new equilibrium without trading the zone in between.

What makes a gap interesting is not the jump itself but where it sits in the broader structure. A gap inside a quiet range tells you little. A gap that breaks a six-month base tells you the equilibrium has shifted materially. A gap in the middle of a roaring trend tells you the move has more fuel. A gap at the tail end of a months-long run, on climactic volume, tells you the last buyers are piling in just as the smart money exits.

The old saying "gaps always fill" is only partly true. Common gaps tend to fill within days. Breakaway and runaway gaps often do not fill for months or at all. Treating all gaps the same is the single biggest mistake in gap analysis.

How It Works

Context determines the gap type. Ask three questions.

Where is the gap located in the trend? A gap from a flat base is usually a breakaway. A gap mid-trend is usually a runaway. A gap after a long extended trend is suspect for exhaustion.

What did volume look like? Breakaway and runaway gaps tend to come with strong volume confirming the move. Exhaustion gaps often spike volume even higher, sometimes the highest reading of the trend, as the late crowd enters. Common gaps occur on unremarkable volume.

Does price follow through? Breakaway and runaway gaps hold their gains and extend over subsequent sessions. Exhaustion gaps stall within a few bars and start to fill. Watching the next three to five sessions often clarifies the classification.

Runaway gaps have a bonus property. They frequently occur near the midpoint of the total trend, which is why they are also called measuring gaps. If a trend began at $50 and runs to $70 before gapping to $75, projecting a similar distance beyond the gap often lands close to the eventual peak. This is a rule of thumb, not a guarantee.

Worked Example

Consider a stock that has consolidated between $40 and $45 for four months. Volume is flat. On a Tuesday the company reports strong earnings. The stock opens at $48, closes at $49, and volume is 4 times the 20 day average. That is a breakaway gap. The base is broken, volume confirms, and follow-through is likely. Historically, such gaps tend not to fill quickly.

Two months later the same stock has rallied to $62, with the 20 day SMA sloping steeply up. After consolidating for two days around $62, it gaps to $64 and closes at $65 on strong volume. That is a runaway gap inside the established trend. The measuring-gap rule of thumb, with the move starting at $45 and the gap near $63, projects continuation toward roughly $80.

Six weeks later the stock is near $82 after a near-vertical run. It gaps up to $85 at the open on the heaviest volume of the entire move, spikes to $87, then closes at $82, back inside the gap. That is a textbook exhaustion gap. The last buyers have been absorbed. Over the next two weeks the stock retreats to $74. The gap has filled, and the trend has likely turned.

Common Mistakes

1. Treating every gap as meaningful. Most intraday and daily gaps are common gaps inside ranges and fill within days. Acting on every gap as if it signals a new trend will produce many losing trades. Filter by location, volume, and pattern context before assigning weight.

2. Assuming gaps always fill. This is perhaps the most common myth. Breakaway gaps and runaway gaps often do not fill for many months or ever. Shorting a breakaway gap because "gaps always fill" is a reliable way to be stopped out as the new trend extends.

3. Misclassifying in real time. An exhaustion gap and a runaway gap can look identical for the first session or two. Both appear mid-to-late in a trend on heavy volume. The classification is only certain after you see the next three to five bars. Sizing positions as if you know for sure is a recipe for surprises. Use initial entries that assume you might be wrong, and let the follow-through confirm or deny.

Frequently Asked Questions

Q: What is a price gap in simple terms? A price gap is a zone on a chart where no trading occurred because the market opened at a price meaningfully different from the previous close, leaving an untraded area between the two bars.

Q: How do price gap types affect investment decisions? A breakaway gap above long-term resistance with heavy volume is an actionable long signal with a built-in stop below the gap. An exhaustion gap on the heaviest volume of a multi-month run is a warning to tighten stops or reduce exposure.

Q: What is a real-world example of the four gap types? A stock gaps up 8 percent on earnings from a flat base on four-times average volume, a breakaway gap. Two months later it gaps up 3 percent mid-rally on strong volume, a runaway gap. Near the peak it gaps up 5 percent on the highest volume ever, then closes back inside the gap, a textbook exhaustion gap.

Q: How can investors use price gap analysis practically? Classify the gap by its location in the trend and its volume before acting. A simple rule: never short a breakaway gap assuming it will fill quickly, breakaway and runaway gaps often remain open for months while the trend continues.

Q: How is a price gap different from a candlestick wick? A wick shows that price traded at an extreme intraday but returned before the close, so trading did occur there. A gap shows a zone where no transactions took place at all, the market simply skipped those prices between sessions.

Sources

1. StockCharts ChartSchool. "Gaps and Gap Analysis." https://chartschool.stockcharts.com/table-of-contents/chart-analysis/gaps-and-gap-analysis
2. Edwards, R. D. and Magee, J. (1948). Technical Analysis of Stock Trends. John Magee Inc. https://archive.org/details/technicalanalysi0000edwa
3. Gilliland, K. "Breakaway Gaps." Stocks & Commodities V. 29:1, via Fidelity. https://www.fidelity.com/bin-public/060_www_fidelity_com/documents/BreakawayGaps.pdf

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.