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Premarket Gapper Scanner
Catch the small-caps gapping up — before the open
A low-float momentum gap scan: cheap stocks gapping up hard in the premarket or after-hours, ranked by premarket relative volume, with a flag for a news catalyst. Below is exactly how it works — every filter, every threshold, and the plain math behind each number. Nothing hidden.
The five pillars
Five pillars, four filters
A name makes the board when it clears four filters: gap, price, float and premarket volume. News is flagged on every row but not required, and relative volume ranks the board; it is not a filter on this scan (the Day Trading watch list applies a 0.25x soft floor). These are the default thresholds — the ones the free preview runs on.
Gapping up
The stock is up hard versus the session's reference close — premarket vs yesterday's close, after-hours vs today's close. That extended-hours move is the fuel a momentum play needs.
Filterpass if gap≥ 10%Low float
Few shares available to trade, so incoming demand moves the price faster. Low float is what turns a catalyst into a violent move.
Filterpass if float≤ 100M sharesReal premarket volume
At least 50k shares traded before the bell. Relative volume versus the stock's own average day ranks the board; it is not a filter on this scan.
Filterpass if premkt vol≥ 50kTradeable price
In the range where momentum runs happen and a normal account can take a real position — wide enough to include the optionable names, not just the sub-$20 tape.
Filterpass if price$1 – $100Has a catalyst
Each row shows whether there is a news headline from the last 24 hours — earnings, an offering, an FDA or contract event. It is shown, not required: a name without news can still make the board.
Flagshown if news≤ 24hMethod and credits
How ours differs
A 5-pillar low-float momentum gap scan of the kind popularized by day-trading educators such as Ross Cameron. This is our own independent implementation, not affiliated with or endorsed by Warrior Trading or Ross Cameron.
- Price runs $1 to $100 here; his published range is $1 to $20.
- Float is capped at 100M shares here; his material prefers a much smaller float than our 100M cap.
- Our relative volume is premarket volume divided by the 10-day average full-day volume. It is a ranking proxy, not his 5x-over-a-30-day-average measure. It ranks the board; it is not a filter on this scan (the Day Trading watch list applies a 0.25x soft floor).
- Each row shows whether there is a news catalyst, but news is not required for a name to appear on the board.
Read the original at warriortrading.com.
How every number is made
No black box — here's the math
Every column on the scanner is a plain, public calculation. We show them all. If we're this open about the free screener, you know the paid tools are built the same honest way.
Gap %
(session price − reference close)
÷ reference close × 100The true gap versus the session's reference close — yesterday's close for premarket, today's close for after-hours — not the open-to-open gap, so an extending runner reads correctly.
Relative volume (RVOL)
premarket volume
÷ 10-day average
FULL-day volumePremarket volume as a fraction of the stock's 10-day average full-day volume. A ranking proxy, not time-of-day adjusted, and not Warrior Trading's 5x measure. We compute this ourselves rather than using an off-the-shelf relative-volume field, because those are regular-session numbers and read as noise before the bell.
Float
shares available
to trade publiclyFree-float shares outstanding. Smaller float means each buy order moves the price more — the amplifier on any catalyst.
ATR (14)
14-period average
true rangeHow much the stock typically moves in a bar — a plain read on how volatile it is, straight off the daily chart.
RSI (14)
14-period relative
strength indexThe classic momentum oscillator (0–100). Context on whether the move is already stretched or just getting going.
Has news
any headline in the
last 24h (Benzinga)A real, sourced catalyst check on the exact ticker — so a mystery mover without a reason is easy to tell apart from a real story.
Run the top 10 free — no login, no key
The scanner is live as a free, keyless MCP endpoint. Point Claude Desktop, Cursor, or any MCP client at it and just ask “what's gapping?” — it auto-picks the live session and returns the top 10 on the default filters. Premarket 4:00–9:30am ET, after-hours 4:00–8:00pm ET.
{
"mcpServers": {
"tradermatrix-free": {
"type": "http",
"url": "https://api.tradermatrix.pro/api/mcp/free"
}
}
}On the Claude iOS / Android / web app? The mobile Connectors UI can't take a config file — add this URL instead (Settings → Connectors → Add custom connector), tap Connect free, and you're in. No key, no login:
https://api.tradermatrix.pro/api/mcp/free/connectGo further
A key unlocks the whole board
The free preview is the same engine, capped. A TraderMatrix API key opens it all up — and hands you the rest of the toolkit.
Tune every filter
Set your own float, price, gap %, and volume floors — dial the screen to your exact playbook instead of the defaults.
Up to 50 results
See the full ranked board, not just the top 10 preview.
More tools
Live options flow, GEX magnet levels, unusual activity, and wheel screeners — the same clean data behind one API key.
Start scanning your names
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