Volume Spike
A trading day with well-above-average volume — often the first sign that something has changed before price fully reflects it.
What it means
Volume is simply how many shares (or coins) changed hands on a given day. A volume spike is a day where that number is well above the symbol's own recent average — a sign that unusually many market participants were active, whether from news, an institutional order, or a broader shift in sentiment. Because volume often moves before price fully catches up, a spike is commonly watched as an early signal worth a closer look, independent of which direction price itself moved that day.
How MarketWall calculates it
MarketWall compares each day's volume to the trailing 20-session average, and only counts it as a spike above roughly 1.5x that average, on a symbol with enough genuine daily liquidity that the ratio is meaningful (very thin names are excluded, since a small absolute change looks huge in percentage terms). A spike's score decays over the following days, since a spike from a week ago isn't a fresh signal anymore. See the Data Sources & Methodology page for the full signal list.
How it's typically used
A volume spike on its own is directionally neutral — it says "unusual activity happened here," not which way it points. It's typically read alongside price action and other signals: a volume spike combined with a Bollinger breakout or a support reject is generally read as stronger confirmation than either alone, since it suggests real participation behind the move rather than a thin, easily-reversed one.
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FAQ
How much above average counts as a "spike"?
MarketWall's threshold is roughly 1.5x the trailing 20-session average volume.
Does a volume spike fade over time?
Yes — MarketWall decays a spike's score day by day, since a big-volume day from a week ago is no longer a fresh, actionable signal.
See more signals in the interactive walkthrough, read the full Data Sources & Methodology page, or explore it live on a real chart — AAPL or BTC.