Equity screening and valuation: how to filter 19,000 symbols without blind spots

Stock screening is the starting point of the investment discovery process.

With over 19,000 public equities traded across US markets, finding compelling investment opportunities requires quantitative filters that separate high-quality compounders from value traps.

However, standard equity screeners suffer from severe design flaws:

• Rigid dropdown menus that force analysts to conform to arbitrary vendor categories.
• Hidden survivorship bias that excludes delisted or bankrupt companies from historical screens.
• Opaque filtering logic where the analyst cannot verify the exact screening parameters applied.

This guide outlines best practices for institutional equity screening and universe discovery.

3 Fatal Traps in Stock Screening

1. Natural Language Screening with Explicit Criteria

Modern equity screening allows analysts to describe an investment thesis in plain English:

• Example Query: "US industrial companies with market cap over $2B, ROIC above 15%, debt-to-equity below 0.8, and insider buying in the last 6 months."
• The Transparency Rule: The screener must convert the natural language query into explicit, editable numerical filters across its 161 metric categories, ensuring the analyst retains full control over the universe boundaries.

2. Controlling for Survivorship Bias

When backtesting a quantitative screening strategy:

• If a screener only includes companies that are active today, it retroactively ignores all businesses that failed, went bankrupt, or were liquidated during past downturns.
• Massari provides an explicit Survivorship Toggle, allowing analysts to include or exclude delisted historical entities at will.

3. The 4-Filter Quality Compounder Screen

A proven baseline screen for identifying durable fundamental businesses:

1. High Return on Capital: Trailing 5-year average ROIC $> 15\%$.
2. Gross Margin Stability: Gross Margin standard deviation $< 3\%$ across economic cycles.
3. Cash Conversion: Free Cash Flow to Net Income $> 90\%$.
4. Conservative Leverage: Net Debt to EBITDA $< 2.0 ext{x}$.

Massari allows analysts to convert any custom screen into an active watchlist, a simulated portfolio, or a live API query in a single click.

The Bottom Line: Moving from Discovery to Diligence

Quantitative screening is only the first step in the investment process. A screen identifies candidates; rigorous due diligence proves the thesis.

Once you filter the market down to high-conviction ideas, Massari allows you to seamlessly transition from screening into Click-to-Source financial statement auditing, earnings transcript analysis, and live Excel valuation models without switching tools.

Explore our natural language screener across 19,000+ symbols and turn quantitative filters into defensible investment theses.