What Is a Gap in Stocks? Gap-Ups and Gap-Downs Explained
A gap is when a stock opens at a noticeably different price than where it closed the day before — leaving a visible "gap" on the chart. Gaps are one of the clearest signals that something happened while the market was closed.
Why gaps happen
The stock market has set trading hours, but news never stops. Earnings reports, press releases and analyst notes often land after the close or before the open. By the time trading resumes, buyers and sellers have already re-priced the stock — so it opens higher or lower than yesterday's close instead of moving there gradually.
- Gap-up — the stock opens above the prior close, usually on good news or strong pre-market demand.
- Gap-down — the stock opens below the prior close, often on bad news, a disappointing earnings report, or a share offering.
The gap is not the same as the day's change
This trips up a lot of beginners. The gap measures the open versus the prior close. The day's change measures the current price versus the open (or prior close). A stock can gap up 30% and then fade to close up only 10% — or gap up and keep running. Watching whether a gap holds through the day is one of the most-watched setups in short-term trading (often called "gap and go" when it holds and continues).
Do gaps get "filled"?
Traders talk about a gap being "filled" when the price later trades back to the pre-gap level, closing the empty space on the chart. Some gaps fill quickly; many never do. It's a useful vocabulary word, not a rule — treating "gaps always fill" as a guarantee is a classic beginner mistake.
See it in the live market
Trader Club computes gaps every day from a full market scan. The biggest gap-ups and biggest gap-downs screeners show which small caps opened furthest from their prior close, with the gap and the day's change side by side so you can see whether the move held. To understand the news behind a big gap, see why stocks move and our daily news pages. Gaps often form in pre-market and after-hours trading.
Frequently asked
What is a gap in a stock?
A gap is when a stock opens at a meaningfully different price than its previous close, leaving an empty space on the chart. It usually reflects news or demand that built up while the market was closed.
What's the difference between a gap-up and a gap-down?
A gap-up is when a stock opens above the prior close (typically on positive news or strong demand). A gap-down is when it opens below the prior close (often on negative news, a weak earnings report, or a share offering).
Is the gap the same as the day's percentage change?
No. The gap measures the opening price versus the prior close. The day's change measures the current price versus the open or prior close. A stock can gap up big and then fade, so the two numbers can be very different.
Do gaps always get filled?
No. 'Filling the gap' means price later returns to the pre-gap level. Some gaps fill quickly and many never do — treating it as a guaranteed rule is a common mistake.
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