Premarket stock scanner setup: build the list before you build the trigger.

1. Separate premarket filters from regular-session filters

Do not copy an intraday scan and simply run it earlier. Extended-hours liquidity is different, and some indicators depend on regular-session calculations. Trade Ideas specifically documents that its Relative Volume filter does not calculate in premarket.

2. Start with observable premarket conditions

A practical premarket screen can focus on price, gap or percentage change, premarket volume/activity, and liquidity constraints. These are inputs for creating a candidate list; they are not a recommendation to trade every stock that qualifies.

3. Add context before the open

For each candidate, identify why it is active, whether liquidity is usable, nearby reference levels, and whether the stock fits the strategy you are prepared to trade. This is where news and chart context can matter more than adding another scanner filter.

4. Design the opening handoff

At the bell, the job changes from list-building to event monitoring. An opening-range alert, high-of-day event, or another defined trigger can take over from the static premarket list. The goal is to monitor fewer names more precisely.

5. Save separate configurations

Maintain distinct premarket and regular-session scans rather than toggling many settings each day. That reduces configuration mistakes and makes paper-testing results easier to interpret.

A practical premarket review checklist

Before keeping a symbol on the opening watchlist, verify four things: the extended-hours move is large enough to matter to your strategy; premarket activity is sufficient to make the move interpretable; you know the obvious reference levels you will monitor after the open; and the symbol still fits your liquidity and price constraints. Then write down the event that would make you look again after 9:30. If you cannot name that event, the ticker is only interesting—not yet operationally useful.

This checklist also makes the next day easier: you can review whether the scanner selected the right type of candidates independently from whether any individual trade worked.