TDPro

Premarket Gapper Scanner

Catch the small-caps gapping up — before the open

The classic low-float momentum screen: cheap stocks gapping up hard in the premarket or after-hours, on high relative volume, with a real news catalyst. Below is exactly how it works — every filter, every threshold, and the plain math behind each number. Nothing hidden.

Run it freeToday's watch listSee pricing

The five filters

Five things line up at once

A name only makes the board when all five are true at the same time. These are the scanner's 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.

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.

float≤ 100M shares

Real premarket volume

Enough shares actually changing hands before the bell for the move to be tradeable — and, measured against the stock's own average day, enough to be unusual.

premkt vol≥ 50k

Tradeable 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.

price$1 – $100

Has a catalyst

A real news headline in the last 24 hours — earnings, an offering, an FDA or contract event — the reason the stock is moving at all.

news≤ 24h

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 × 100

The 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 volume

What fraction of a normal entire day's volume has already traded before the open. 1.0× means a full day's worth is already done by 9:30 — 0.25× is already unusual. 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 publicly

Free-float shares outstanding. Smaller float means each buy order moves the price more — the amplifier on any catalyst.

ATR (14)

14-period average true range

How 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 index

The 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": { "traderdaddy-free": { "type": "http", "url": "https://api.traderdaddy.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.traderdaddy.pro/api/mcp/free/connect

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Go further

A key unlocks the whole board

The free preview is the same engine, capped. A TraderDaddy Pro 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.

26 more tools

Live options flow, GEX magnet levels, unusual activity, and wheel screeners — the same clean data behind one API key.

See all 24 tools & the API docs

Start scanning your names

Start free. Upgrade for tunable filters, the full board, live options flow, GEX, unusual activity, and more.

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