Altman Z-Score: The Bankruptcy Predictor That Still Works

A 1968 academic paper correctly flagged roughly 72% of corporate bankruptcies two years before they happened. That paper is the Altman Z-Score, and it still works on modern stocks like Ford (F) and Walgreens (WBA) in 2026.

What is the Altman Z-Score?

The Altman Z-Score is a composite financial-health score built by NYU professor Edward Altman in 1968. It takes five ratios from a company's balance sheet and income statement, weights them, and produces a single number that estimates the probability of bankruptcy within the next two years.

Altman's original study analyzed 66 manufacturing companies — 33 bankrupt and 33 still operating — and built the formula that best separated the two groups. In follow-up testing, the model correctly classified roughly 72% of bankruptcies two years ahead of the filing, and about 94% one year ahead.

For investors, the Z-Score is a fast triage tool. Before you dig into a stock's story, the Z-Score tells you whether the balance sheet can survive long enough for the thesis to play out.

How do you calculate the Altman Z-Score?

The classic formula for public U.S. manufacturers is:

Z = 1.2 × A + 1.4 × B + 3.3 × C + 0.6 × D + 1.0 × E

Where each letter is one of five ratios:

• A = Working Capital / Total Assets — short-term liquidity cushion
• B = Retained Earnings / Total Assets — long-term profitability buildup
• C = EBIT / Total Assets — operating efficiency
• D = Market Cap / Total Liabilities — market's confidence vs leverage
• E = Sales / Total Assets — asset turnover

The ratios come straight from the 10-K or any fundamentals dataset. The zones are: Z > roughly 2.99 is "safe", Z between approximately 1.81 and 2.99 is "grey zone" (distress risk), and Z below roughly 1.81 is "distressed".

There are two important variants. Z' (Z-prime) is for private manufacturers — it swaps book value for market cap in ratio D. Z'' (Z-double-prime) drops ratio E entirely and is designed for non-manufacturers and emerging-market companies.

Real stocks: where the Z-Score flags stress

Those numbers are approximate and fluctuate quarter-to-quarter — treat them as a starting point, not a final verdict. But the directional story is real. High-cash software names like Microsoft (MSFT) sit far inside the safe zone. Legacy pharmacy chains like Walgreens (WBA) have drifted well into the distressed zone alongside a collapsing stock price.

Compare two pairs:

• MSFT vs Oracle (ORCL): Both are software, but Oracle's debt-heavy balance sheet produces a meaningfully lower Z-Score despite comparable operating margins.
• COST vs Target (TGT): Both are big-box retailers, but Costco's membership cash generation lifts its Z-Score well above Target's.

How does the Z-Score complement the P/E ratio?

Totally differently — and that is the point. The P/E ratio answers "is this stock cheap or expensive?" The Z-Score answers "can this company survive?"

For a value stock trading at roughly 8x earnings, a low Z-Score means the cheap multiple reflects real bankruptcy risk, not a market misjudgment. For a growth stock at approximately 40x forward earnings, a safe Z-Score confirms the business can fund the growth without diluting shareholders.

Our guide on the P/E ratio covers what the earnings multiple does and does not tell you. Pair it with a Z-Score check and you are doing more due diligence than 90% of retail investors.

Common mistakes when using the Z-Score

• Applying it to financials or REITs: The Z-Score was calibrated on industrials. Banks, insurers, and REITs have totally different balance-sheet structures — skip them.
• Reading a single snapshot: A Z-Score of 2.5 could be improving (from 1.8 two years ago) or deteriorating (from 3.5). The trajectory matters more than the level.
• Ignoring off-balance-sheet items: Operating leases, contingent liabilities, and pension obligations can materially change the picture. Adjust for them.
• Using market cap in a crash: Ratio D uses market cap, which plummets in a bear market even if fundamentals are fine. The score will look worse than the business actually is.
• Treating it as a price target: The Z-Score is about solvency, not valuation. A "safe" company can still be overvalued.

Pro tips for advanced users

1. Look at the Z-Score trend across eight quarters, not one. Sudden drops are the real signal.
2. Cross-check with the Piotroski F-Score for profitability direction and the Beneish M-Score for earnings manipulation risk.
3. For non-manufacturers, use Z''. The formula is: Z'' = 6.56 × A + 3.26 × B + 6.72 × C + 1.05 × D, dropping ratio E. Thresholds shift accordingly.
4. Benchmark within a sector. A 2.2 Z-Score is alarming for a software company and average for a steel maker.
5. Combine with free cash flow yield. If a low Z-Score pairs with negative FCF, the distress signal is severe. If FCF is strongly positive, the score may be temporarily depressed by a capex cycle.

When the Altman Z-Score is the WRONG tool

• Financial companies: JPM, BAC, WFC, and insurers should be analyzed with tier-1 capital ratios, loan-loss provisions, and regulatory tests — not Z-Score.
• Asset-light platforms: Modern platform businesses can have low asset bases that distort ratios A, C, and E. A company like Shopify (SHOP) might score misleadingly low because it carries little "total assets" relative to its cash generation.
• Early-stage growth companies: Negative retained earnings in ratio B can push a high-potential company into the "distressed" zone even when capital markets will readily fund it.
• Commodity cyclicals at trough: Oil and gas E&Ps like DVN or EOG can score poorly at the cycle bottom and strongly at the top — without any real change in long-term solvency.

In all of these cases, a low Z-Score is a prompt to dig deeper, not a stop sign. Context is the difference between an experienced analyst and a retail investor following a checklist blindly.

How to put this into practice

Start simple. Pick five stocks you are considering, calculate the Z-Score for each using the most recent 10-K, and rank them. You will notice one or two you thought were safe land in the grey zone — and maybe one you avoided lands in the safe zone.

Our investment strategies guide covers how to layer solvency screens like Z-Score on top of a valuation framework. And if you want the full legendary-investor perspective, Benjamin Graham's margin-of-safety framework is essentially a qualitative version of exactly this kind of solvency test.

Ready to analyze these stocks yourself? Search any ticker on MainRatios to see valuations from 6 legendary investors - free.