What Is the Altman Z-Score and How Do You Use It to Spot Bankruptcy Risk?

Every value investor eventually confronts the same uncomfortable question: is this cheap stock genuinely undervalued, or is it cheap because the business is quietly heading toward insolvency? The Altman Z-Score, developed by NYU professor Edward Altman in 1968, gives you a structured, numbers-based way to start answering that question across any publicly traded market.

The Five Ratios the Z-Score Combines

The formula weights five accounting ratios, each measuring a different dimension of financial health:

1. Working capital to total assets. Measures short-term liquidity. A company burning through working capital relative to its asset base is losing its buffer against unexpected shocks.
2. Retained earnings to total assets. Reflects accumulated profitability over the life of the business. Young or persistently loss-making firms score poorly here by design.
3. EBIT to total assets. Strips out financing and tax effects to show how productively the asset base generates operating profit.
4. Market value of equity to book value of total liabilities. This is the only market-based input. It captures how much the market thinks the equity cushion exceeds the debt load.
5. Revenue to total assets. Gauges how efficiently management turns assets into sales, a useful proxy for competitive effectiveness.

Altman weighted these ratios through a statistical technique called discriminant analysis, calibrated on a sample of US manufacturers. The weights are fixed constants, not something you adjust.

How to Read the Score

These thresholds were derived from the original US manufacturing sample. They are widely cited benchmarks, not guarantees.

The Variants That Actually Matter for Our Four Markets

Altman himself recognised that the original model was too narrow. He produced two important variants:

• Z'-Score (private companies). Replaces the market-value-of-equity input with book value of equity, since private firms have no quoted share price.
• Z''-Score (non-manufacturers and emerging markets). Drops the revenue-to-assets ratio entirely, because asset-turnover norms vary so widely across service industries and frontier markets that including it distorts the score.

That last point matters directly for our four markets.

United States (NYSE / NASDAQ)

The original Z-Score was built on US industrial companies, so it fits domestic manufacturers and capital-goods businesses most cleanly. It is a reasonable first screen for an industrial conglomerate or an automotive supplier, but analysts routinely switch to the Z''-Score for US retailers, software firms, or any company whose asset base is primarily intangible.

United Kingdom (LSE)

The UK market is heavily weighted toward financials, mining and energy, and consumer staples exporters. Banks and insurers are explicitly excluded from the Altman model (Altman carved them out himself because their balance sheet structures are fundamentally different). For a British miner or an oil major, the Z''-Score is more appropriate than the original. A value desk screening LSE small-caps in cyclical industries will often flag grey-zone scores that simply reflect low asset turnover in a downturn rather than genuine insolvency risk.

Canada (TSX)

The TSX is dominated by energy producers, base-metals miners, and financials. The same bank and insurer exclusion applies. For the energy and mining names that make up the TSX's backbone, commodity-price cycles regularly drag Z-Scores into the grey zone at trough prices, even for companies with investment-grade debt and ample reserve bases. A value desk here learns quickly that a low Z-Score on a TSX oil producer in a commodity trough is a very different signal from a low Z-Score on a TSX retailer with shrinking same-store sales.

Nigeria (NGX)

The NGX is concentrated in banking, consumer goods, cement, and telecoms. Because the original Z-Score excludes banks, and because Nigerian consumer and industrial firms often carry significant naira-denominated debt alongside foreign-currency revenues or costs, the Z''-Score is almost always the right variant to reach for. Currency devaluation can swing the book-value-of-equity input sharply within a single reporting period, so a value desk studying NGX names must read Z-Score changes alongside the naira trend rather than treating the score as a standalone verdict.

How a Value Desk Actually Uses the Z-Score

The Z-Score is a screening tool, not a verdict. Here is the practical workflow:

1. Use it to eliminate, not to select. A company in the distress zone gets a much harder look before it reaches any valuation work. A business heading toward insolvency has no intrinsic value worth modelling.
2. Pair it with a margin-of-safety framework. Even a company in the safe zone can be a bad investment if you overpay. The Z-Score guards against the left tail (bankruptcy), while your margin of safety guards against paying too much for a survivor.
3. Watch the direction, not just the level. A score that has moved from 1.5 to 2.3 over three years is telling a different story than one that has slipped from 3.1 to 1.9. Trend analysis often reveals more than the snapshot.
4. Check the sector and the variant. Confirm you are using the right version of the formula for the industry and market. Applying the original manufacturing model to an NGX commercial bank produces a meaningless number.
5. Cross-reference with cash-flow statements. Accounting ratios can be massaged; free cash flow is harder to fake. A distress-zone Z-Score accompanied by consistently positive free cash flow deserves more nuance than one paired with cash outflows.
6. Factor in the economic cycle. Capital-intensive sectors on the TSX and NGX move in and out of grey zones with commodity or currency cycles. Assess whether distress is structural (the business model is broken) or cyclical (the industry is at a trough).

What the Z-Score Cannot Do

• It does not account for off-balance-sheet obligations, which have sunk companies that looked fine on paper.
• It does not capture qualitative factors: management quality, regulatory risk, or the presence of a dominant competitor.
• It was not designed for financial institutions. Using it on a bank or insurer on any of our four markets will produce a result that is not meaningful.
• It is backward-looking. The ratios are drawn from historical financial statements, and a sudden shock (a currency crisis, a commodity collapse, a fraud revelation) will not appear in the score until the next set of accounts is filed.
• Emerging-market accounting standards and disclosure depth vary. An NGX company's filed accounts may not carry the same auditing depth as a NYSE counterpart, so the inputs themselves carry additional uncertainty.

A Concrete Illustration

Consider a hypothetical TSX-listed junior miner in a commodity trough. Its Z-Score might sit at 1.6, well inside the distress zone, because low commodity prices have crushed EBIT and the market has marked down its equity. A mechanical reading says: avoid. But a value desk asks: does the company have unencumbered reserves, a low-cost asset, and the balance sheet to survive two more years of low prices? If yes, the Z-Score is flagging cyclical stress, not structural failure, and the margin of safety calculation becomes the more important question. Contrast that with a consumer-goods company on the NGX whose score has drifted down steadily over five years while leverage has risen and margins have compressed. That is a very different signal, one the Z-Score is capturing accurately.

The Bottom Line

The Altman Z-Score is one of the most durable quantitative tools in a value investor's kit precisely because it forces you to look at solvency before you look at price. Cheap stocks stay cheap, or become worthless, when the underlying business cannot survive. Across the NYSE, LSE, TSX, and NGX, the right variant of the formula, applied with an understanding of the sector and the economic cycle, gives you a fast, systematic way to separate genuine deep-value candidates from value traps on the road to insolvency. Use it as a filter at the front of your research process, not as a substitute for the full work that follows.

This guide is produced for educational purposes only and does not constitute personalized financial or investment advice. Always conduct your own due diligence or consult a qualified financial adviser before making any investment decision.

AlphaTeak scores any stock across eight pillars, estimates fair value, and keeps an honest, public track record. Analysis and education, not advice.

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