Definition
What is a premarket scanner?
A premarket scanner evaluates supported market activity before the U.S. regular session opens. It can focus on gap percentage, current price, premarket volume, relative participation, float, market cap, exchange, catalyst status, and distance from premarket levels.
Who it is for
Built for active traders who verify the evidence.
TraderBase is for active traders who prepare a focused watchlist before the open and want early-session data labeled with its session, source time, and connection state.
How it works
From changing data to a focused review.
- 1Limit evaluation to the premarket session and identify the display timezone.
- 2Filter by supported gap, price, premarket volume, dollar volume, float, market cap, and catalyst fields.
- 3Inspect premarket high and low, spread, prints, chart structure, filings, and offering context.
- 4At the open, rerank or remove candidates as regular-session liquidity and structure replace the premarket state.
Capabilities
The information connected to this workflow.
Session-aware prices
Keep premarket calculations separate from regular-session fields and reference prices.
Gap and mover workflows
Combine supported price movement with absolute volume and liquidity boundaries.
Premarket levels
Carry the current high, low, and prior-close context into the opening plan.
Catalyst review
Inspect available news, SEC filings, offerings, earnings, and market-status evidence with timestamps.
TraderBase approach
What makes TraderBase different?
TraderBase treats a premarket list as provisional. It shows delayed or disconnected states, does not turn thin early liquidity into a live guarantee, and lets regular-session evidence change the ranking.
Common questions
Premarket scanner FAQ
What does a premarket scanner show?
It can show supported stocks meeting early-session price, gap, volume, float, market-cap, liquidity, and catalyst conditions. Exact fields depend on the provider and account configuration.
Why can premarket rankings change at the open?
Regular-session participation, spreads, volume, and price discovery can differ sharply from premarket conditions. A responsible workflow reevaluates the list rather than preserving an outdated rank.
Are premarket prices always easy to trade?
No. Extended-hours liquidity can be thin, spreads can be wide, and broker order rules vary. A displayed price is not a guaranteed executable price.