Stock Insights Academy · Model comparison
Piotroski F-Score vs. Altman Z-Score: What Each Measures
These scores are often grouped together, but they answer different questions. Piotroski evaluates whether financial fundamentals are improving and internally consistent; Altman estimates corporate distress risk from weighted accounting ratios.
Awards nine binary signals across profitability, leverage/liquidity and operating efficiency.
Best suited to
- Fundamental quality screening
- Value-stock research
- Comparing year-over-year direction
Main limitation: Binary signals discard magnitude and can oversimplify borderline changes.
Combines five weighted ratios to classify financial distress risk.
Best suited to
- Credit and solvency screening
- Asset-heavy non-financial companies
- Identifying balance-sheet warning signs
Main limitation: Original thresholds fit public manufacturers better than banks, startups or many service businesses.
Key differences
| Criterion | Piotroski F-Score | Altman Z-Score | Decision insight |
|---|---|---|---|
| Primary question | Are fundamentals improving? | How elevated is distress risk? | Quality momentum and default risk are related but not identical. |
| Output | Integer from 0 to 9 | Continuous weighted score | Do not compare the raw numbers directly. |
| Time dimension | Uses current and prior-year changes | Mostly current balance-sheet relationships | F-Score emphasizes direction; Z-Score emphasizes condition. |
| Best use | Screen then investigate | Risk flag then investigate | Neither score replaces financial-statement analysis. |
Improving operations with a still-weak balance sheet
A cyclical manufacturer may earn a high F-Score as profitability and cash generation recover from a trough.
The same company can retain a weak Z-Score because accumulated losses and leverage still leave little balance-sheet protection.
Together, the scores describe a recovery with meaningful residual solvency risk—more useful than forcing one score to answer both questions.
Practical verdict
Which approach should you use?
Use Piotroski to assess the direction and quality of fundamentals. Use Altman to flag balance-sheet distress. When both are applicable, the combination is stronger because improvement does not necessarily mean safety, and safety does not necessarily mean improving economics.
Related calculators and guides
Frequently asked questions
Is a high F-Score the same as a high Z-Score?
No. A high F-Score indicates more positive fundamental signals, while a high Z-Score generally indicates lower modeled distress risk.
Can a company score well on one and poorly on the other?
Yes. Improving profit and cash flow can lift F-Score before leverage and retained earnings recover enough to improve Z-Score.
Do these scores work for banks?
Not reliably. Financial institutions have structurally different leverage, liquidity and balance-sheet economics.
Are the scores buy signals?
No. They are screening and diagnostic tools. Valuation, business quality, accounting context and forward-looking risks still matter.