Stock screener — how to screen stocks effectively

What is a stock screener and how does it work?

A stock screener filters thousands of stocks by criteria you set: market cap, sector, PE ratio, revenue growth, debt levels, dividend yield, and dozens of other metrics. The output is a list of stocks matching your conditions — candidates for deeper research, not buy recommendations.

The screener's job is to narrow 7,000+ stocks to 10–20 worth researching. The research is your job.

Fundamental vs technical screening

Fundamental screening filters by business metrics: revenue growth, margins, debt levels, ROIC. This finds companies worth owning long-term.

Technical screening filters by price action: moving averages, volume, momentum. This finds timing opportunities for stocks you've already researched fundamentally.

The best approach uses both: fundamental screening to build the watchlist, technical screening to time the entry.

How to set screening conditions

Too few conditions → 500+ results (useless). Too many → 0 results (also useless). Start broad and narrow:

• Market cap > $1B (avoid micro-cap volatility)
• Revenue growth > 10% YoY (business is expanding)
• Debt/Equity < 1.5 (not overleveraged)
• Operating margin > 10% (profitable at the operating level)

Adjust thresholds based on your sector focus. A biotech company won't have positive earnings; a utility won't grow 20% annually.

From watchlist to real positions

The screener gives you candidates — not positions. After screening: (1) read the 10-K, (2) compute intrinsic value, (3) write thesis breaks, (4) check timing, (5) size the position. Each step is a separate decision.

How often should you run a screener?

Monthly for new ideas, quarterly for watchlist review. Daily screening leads to overtrading — the most common retail investing mistake.