The Piotroski F-score runs nine accounting tests on profitability, leverage, liquidity and operating efficiency — designed to separate cheap-but-strong value stocks from cheap-but-dying ones. Scores run 0–9; 7+ indicates improving fundamentals. This heatmap colors US stocks by F-score, sized by market cap and grouped by sector.
Greener tiles pass more Piotroski checks, redder tiles fail more — the classic value-trap filter made visual.
7–9 is strong (most checks passed), 4–6 middling, 0–3 weak — Piotroski's original research showed low-score "cheap" stocks dramatically underperform high-score ones.
Nine binary signals: positive income, cash flow, rising ROA, earnings quality, falling leverage, rising liquidity, no dilution, rising gross margin, rising asset turnover.
As the second filter after a valuation screen — find cheap tiles on the P/E or P/B map, then verify they are green on F-score. Cheap + strong is the strategy; cheap + weak is the trap.
Heatmap data updates through the trading session. Fundamentals come from Finnhub and SEC filings; scores are simplified heuristics for screening — not investment advice.