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Pre-market Routine

How to Scan for Setup Candidates Before Market Open

Pomegra Learn

How to Scan for Setup Candidates Using a Stock Scanner Setup?

Effective pre-market scanning begins the moment you sit down at your desk before the open bell rings. You're not looking for trades yet—you're building a watchlist of candidates that fit your specific strategy. A stock scanner setup filters thousands of symbols down to a manageable list of high-probability candidates based on volume, price action, liquidity, and volatility. Without a systematic scanner setup, you'll either miss opportunities or chase random stocks based on emotion rather than rules.

Quick definition: A scanner is an automated tool that applies multiple filters (volume thresholds, price ranges, technical patterns) to identify securities matching your pre-defined criteria. A well-tuned stock scanner setup runs overnight or in the early morning to populate your watchlist before market open.

Key takeaways​

  • A scanner setup must prioritize liquidity filters to avoid illiquid stocks with wide spreads and slippage risk.
  • Volume-based filters eliminate low-volume noise and focus on stocks with institutional activity.
  • Tailor your scanner setup to your strategy: momentum, gaps, reversals, or breakouts require different thresholds.
  • Run your scanner 30–60 minutes before market open to capture pre-market movers and overnight gaps.
  • Review your scanner results in context—watchlist stocks still need manual confirmation before you trade.

Building a Liquidity-First Scanner Setup​

Liquidity is the foundation of any scanner setup. A stock trading 50,000 shares per day in a wide bid-ask spread is worthless to an active trader. You need stocks that move enough volume to allow you to enter and exit without moving the market yourself. Start your stock scanner setup by filtering for average daily volume (ADV) of at least 500,000 to 1,000,000 shares over the past 20 trading days. For smaller accounts, drop that threshold to 300,000 shares, but never go below.

Next, apply a price range filter. Stocks priced between $5 and $500 tend to attract different types of traders and have different liquidity profiles. Many active traders focus on the $10–$200 range because it balances liquidity, volatility, and regulatory requirements (PDT rules). Your stock scanner setup should include a price-range filter that matches your account size and trading rules.

Finally, add a bid-ask spread filter. Stocks with spreads wider than 1–2 cents at the open are problematic—they eat into your profit margins and slow your exits. Your scanner setup should filter for tight spreads during extended hours, which signals institutional interest and pre-market liquidity.

Volume and Volatility Thresholds in Scanner Setup​

Volume alone doesn't tell you everything. You need to understand recent volume trends within your stock scanner setup. A stock that averaged 2 million shares over the past three months but only traded 300,000 yesterday is a potential alert—something changed. Build a scanner setup that flags sudden volume spikes (2–3x normal ADV) because those often precede big moves.

Volatility filters complete the picture. Average True Range (ATR) over the past 20 days tells you the typical daily range. If a stock's ATR is 50 cents and the stock gapped 3 dollars overnight, that's a setup candidate worth monitoring. Your scanner setup should calculate ATR and alert you to candidates where overnight movement exceeded 150–200% of the typical daily range. These are the stocks with the most energy at the open.

Tailoring Your Scanner Setup to Your Strategy​

Your stock scanner setup must match your trading edge. A gap-trader scans for overnight price gaps >3–5% relative to the previous close. A momentum trader scans for stocks up >5–10% on heavy volume. A mean-reversion trader scans for stocks down >5–8%, looking for bounces off overnight panic.

Define your scanner setup criteria before you build the scanner. Write down: minimum ADV, price range, gap thresholds, volume multipliers, and any technical filters (moving average proximity, support/resistance levels). This discipline prevents you from tweaking the scanner every morning based on your emotional mood. A static, rule-based stock scanner setup is reproducible and lets you track what actually works for your strategy.

Decision tree​

Pre-market Scanner Setup in Action​

Let's walk through a real scanner setup scenario. You set your filters: ADV >1M, price $20–$300, bid-ask <2 cents, volume >2x ADV, and gap >3%. Your scanner runs at 6:30 AM and returns 12 candidates. You now have 90 minutes before the open to analyze each candidate manually. You check level-2 order flow, news, sector trends, and peer strength (more on those in later sections). Of the 12 candidates, 5 pass your manual confirmation, and those 5 become your A-list watchlist for the day.

Without the stock scanner setup, you would have scanned 3,000+ stocks manually or relied on curated watchlists from other traders (which you shouldn't do—your setup is unique to your account and psychology).

Common mistakes​

  • Filters too tight: If your scanner setup returns zero or one candidate daily, your thresholds are too restrictive. Loosen volume or gap filters slightly and let manual review handle edge cases.
  • Ignoring data quality: Your scanner setup is only as good as the data feeding it. Verify that your data source is real-time and accurate; stale or wrong data will populate your watchlist with false candidates.
  • Over-relying on automation: A scanner setup is a tool to narrow the universe, not a trading signal. Every candidate still requires manual confirmation of price action, liquidity, and catalyst.
  • Forgetting to backtest: Test your stock scanner setup on historical data to confirm it would have surfaced actual good trades. If it captures 50 trades per day with a 35% win rate, you've built a useful setup.
  • Changing filters mid-week: Resist the urge to tweak your scanner setup after a losing trade. Rule-based discipline means sticking with the same filters for at least a month before adjusting.

FAQ​

How often should I run my stock scanner setup?​

Once before market open (30–60 minutes prior) is the standard. Some traders run a second scan 15 minutes before the open to catch final pre-market moves. Running more frequently generates decision fatigue without adding signal.

Can I use a free scanner for my setup?​

Most free scanners lack advanced filters like ATR or custom indicators. Paid platforms (Thinkorswim, TradingView, Finviz Elite) offer more flexibility. Start with whatever tools you have access to and upgrade as your edge becomes clearer.

Should my scanner setup include technical indicators like moving averages?​

Yes, but use them as secondary filters, not primary. A stock above its 20-day and 50-day moving averages has directional bias, which can enhance a scanner setup—but liquidity and volume are the foundation.

What's the difference between a scanner and a watchlist?​

A scanner is an automated tool that applies filters. A watchlist is the output—the list of candidates it generates. Many traders confuse the two. Your scanner setup generates your watchlist; your watchlist doesn't trade itself.

How many candidates should my scanner setup produce daily?​

Aim for 5–15 candidates per day. Fewer than 5 and your filters may be too tight. More than 20 and you'll lack time to manually review each one before the open. Quality over quantity.

Can I combine multiple scanner setups?​

Absolutely. Run one setup for gaps, another for momentum, another for reversals. Then cross-reference the results to find candidates that appear on multiple scans—those are your highest-conviction setups.

Summary​

A well-designed stock scanner setup is your daily gateway to opportunity. By filtering for liquidity (ADV, spreads), volume (spikes, momentum), and volatility (overnight gaps, ATR), you transform thousands of possible trades into a manageable watchlist of high-probability candidates. Your scanner setup must align with your strategy, run before market open, and output candidates that you then confirm manually. The stock scanner setup is not a buy signal—it's a question generator that forces you to ask: "Why is this stock on my list, and what do I see in the order flow and news to support a trade?"

Next​

Pre-market Gappers and Movers