What Is the Altman Z-Score?
The Altman Z-Score is a bankruptcy prediction model that distills a company's financial health into a single number. Edward Altman built it in 1968 by applying statistical analysis to a sample of manufacturers that had failed and a matched group that had survived, identifying which ratios best separated the two populations. In his original research the model correctly classified the large majority of bankruptcies a year before they occurred.
The score sorts companies into zones. A Z-Score above 2.99 places a firm in the safe zone, where bankruptcy risk is considered low. Scores between 1.81 and 2.99 fall into a grey zone where the model is inconclusive, while anything below 1.81 signals meaningful distress risk over the following two years.
The Formula
For publicly traded manufacturers, Z = 1.2A + 1.4B + 3.3C + 0.6D + 1.0E. The inputs are A = working capital / total assets, B = retained earnings / total assets, C = EBIT / total assets, D = market value of equity / total liabilities, and E = sales / total assets. Profitability carries the heaviest weight — the 3.3 coefficient on EBIT-to-assets makes operating earnings the most influential input.
Altman later published adapted versions: the Z'-Score for private companies substitutes book value of equity for market value, and the Z''-Score for non-manufacturers and emerging-market firms drops the asset turnover term because it varies too much across industries. Using the wrong variant is a common analytical mistake, since the original coefficients were calibrated on mid-century manufacturers.
How Analysts Use It
Credit analysts and distressed investors use the Z-Score as a fast screen rather than a final verdict. A score that deteriorates over several quarters flags a company for deeper work, such as reading its covenant package or modeling its liquidity runway. Lenders and rating analysts also reference it when monitoring portfolios, because it condenses a full financial statement review into one comparable number.
The model has real limitations: it relies on backward-looking accounting figures and works poorly for banks and other financial companies, whose balance sheets look nothing like a manufacturer's. Even so, a score below 1.81 remains a widely watched warning sign, and interviewers at distressed and restructuring shops expect candidates to know the zone cutoffs and the intuition behind each ratio.
