Piotroski F-Score: A 9-Point Checklist for Financial Strength

A Simpler Idea Than It Looks

Joseph Piotroski's 2000 paper showed that inside the cheap-book-value group — the bottom value quintile — financial-strength filtering separated winners from dead money. His score is nine yes/no tests split across profitability, leverage/liquidity, and operating efficiency. Each pass gives one point; a score of 8 or 9 historically compounded double-digit alpha versus the bottom-quintile average. The uncomfortable insight: cheap stocks don't outperform on average; they outperform *only* in the sub-sample that has improving fundamentals. Without F-Score, value investing bleeds to the value traps.

What the F-Score Card Shows

The Piotroski F-Score card reports the current score (0–9) and walks through all nine tests individually, each marked pass or fail with the underlying calculation visible on hover. Profitability tests: positive net income, positive operating cash flow, ROA higher than prior year, CFO > net income. Leverage/liquidity tests: lower long-term debt ratio, higher current ratio, no new share issuance. Efficiency tests: higher gross margin, higher asset turnover. A trailing-16-quarter chart tracks the score over time so you can see whether quality is compounding or eroding.

Reading the Signal

Three interpretation rules produce most of the value. Score rising from 5→8 over several quarters is more actionable than a static high score; it indicates a company in the middle of an operational turnaround. Test concentration matters: an 8 missing only "no new share issuance" is materially better than an 8 missing "positive net income" — some failures are mechanical, others are diagnostic. Apply inside a valuation filter: F-Score is a quality screen, not a valuation tool; it's most useful on names already screening as statistically cheap via DCF, EV/Revenue, or FCF Yield.

Where It Fits

F-Score pairs with the Altman Z-Score (insolvency model — different failure mode) and Accruals Quality (earnings manipulation check). Taken together, the three form a practical solvency/quality/accrual screen that filters most value traps before they show up in the DCF.

Open the F-Score card → /app/stocks/AAPL/fundamentals