The Altman Z-Score is a formula that combines five financial ratios into a single number predicting how likely a company is to go bankrupt. Developed by NYU professor Edward Altman in 1968, it remains one of the most widely used tools for quickly gauging a company’s financial health. A score above 2.675 signals safety, while anything below 1.8 suggests serious trouble.
How the Formula Works
The Z-Score takes five ratios pulled from a company’s financial statements, multiplies each by a specific weight, and adds them together:
Z = 1.2A + 1.4B + 3.3C + 0.6D + 1.0E
- A (Working Capital / Total Assets): Measures how much short-term liquidity a company has relative to its size. A company that can’t cover its near-term bills is in trouble.
- B (Retained Earnings / Total Assets): Reflects how much profit a company has reinvested over its lifetime. Younger companies naturally score lower here, which the model accounts for since newer firms do fail more often.
- C (Earnings Before Interest and Tax / Total Assets): Captures core profitability, stripping out financing decisions and tax effects. This ratio carries the heaviest weight at 3.3, making it the single most influential variable in the score.
- D (Market Value of Equity / Total Liabilities): Compares what the stock market thinks the company is worth against what it owes. A shrinking market cap relative to debt is a red flag.
- E (Total Sales / Total Assets): Shows how efficiently a company uses its assets to generate revenue.
Each weight reflects how strongly that ratio correlated with bankruptcy in Altman’s original research. The profitability ratio (C) dominates because companies that can’t earn a return on their assets are fundamentally at risk, regardless of how the other numbers look.
Reading the Score: Three Zones
Once you calculate the Z-Score, it falls into one of three zones:
A score above 2.675 puts a company in the “safe zone,” meaning it shows no significant risk of bankruptcy based on its financials. Scores between 1.8 and 2.675 land in the “grey zone,” where financial distress is possible and the outlook is uncertain. A score below 1.8 places a company in the “distress zone,” where the probability of default is high.
The grey zone exists because financial health isn’t binary. A company scoring 2.0 might be recovering from a rough year or slowly deteriorating. Context matters here: a declining score over several quarters is more alarming than a single low reading after an unusual event.
What You Need to Calculate It
Everything you need comes from two standard financial documents. From the balance sheet, you’ll pull current assets, current liabilities (to get working capital), total assets, retained earnings, total liabilities, and the company’s market capitalization. From the income statement, you need earnings before interest and tax and total sales. All of these figures are available in a company’s public filings, and most financial websites like Yahoo Finance or Google Finance display them.
The one input that updates in real time is market value of equity (ratio D), since it depends on the current stock price multiplied by shares outstanding. This means a company’s Z-Score can shift day to day as its stock moves, even if nothing changes operationally.
How Accurate Is It?
Altman originally designed the model to predict bankruptcy within a two-year window. In subsequent testing, the Z-Score has shown roughly 75% accuracy in predicting bankruptcy and financial distress. That’s solid for a formula you can calculate on a napkin, but it also means one in four distressed companies gets misclassified.
The model works best as a screening tool rather than a definitive verdict. A low Z-Score tells you to dig deeper into a company’s finances. It doesn’t tell you the company will definitely fail.
Versions for Private and Non-Manufacturing Firms
The original formula was built using data from publicly traded manufacturing companies, which creates two problems. First, private companies don’t have a market capitalization, so ratio D can’t be calculated. Second, non-manufacturing companies (like service firms or tech companies) have very different asset structures, making ratio E less meaningful.
Altman addressed the first issue with the Z’-Score for private manufacturing companies. This version replaces market value of equity with book value of equity and adjusts the weights:
Z’ = 0.717A + 0.847B + 3.107C + 0.42D + 0.998E
For non-manufacturing firms, both public and private, Altman developed the Z”-Score, which drops the sales-to-assets ratio entirely to avoid penalizing companies with asset-light business models.
The Z-Score Plus Platform
Altman later partnered with Business Compass LLC to launch “Altman Z-Score Plus,” a digital platform available on mobile and desktop. It goes beyond the basic three-zone classification by assigning a 1-to-10-year probability of default, ranking a company’s bankruptcy likelihood against others in its industry, and providing a bond-rating equivalent that compares the score to what you’d expect from companies rated AAA through D.
The platform also covers non-U.S. companies, including those in emerging markets like China, making it useful for investors evaluating international stocks where financial transparency can be uneven.
Where the Z-Score Falls Short
The Z-Score relies entirely on accounting data, which means it’s only as good as the numbers a company reports. Companies that manipulate their financial statements can produce misleadingly healthy scores right up until they collapse.
The model also struggles with certain types of businesses. Financial companies like banks and insurance firms carry enormous liabilities by design, which distorts several of the ratios. Very young companies with minimal retained earnings will score poorly on ratio B regardless of their growth trajectory. And the original formula’s reliance on asset turnover (ratio E) can penalize capital-light businesses that generate huge revenue relative to a small asset base, or vice versa.
Perhaps the biggest limitation is that the Z-Score captures a snapshot. It tells you where a company stands today based on its most recent financials. It doesn’t account for pending lawsuits, management changes, new product launches, or shifts in market conditions. Tracking the score over time, quarter by quarter, gives a much more useful picture than any single calculation.