Strongest Businesses by Quality Score (2026)

A stock can be cheap. It can have momentum. But if the underlying business is deteriorating, none of that matters. The Quality ranking isolates the question that should come first: is this a good business?

Two frameworks answer it. The Piotroski F-Score runs nine binary tests on the most recent financials — profitability, leverage, operating efficiency. Is net income positive? Is cash flow real (exceeding net income)? Is the debt burden shrinking? Each passed test earns a point out of 9. In Piotroski's paper, the high-score group (8–9 of 9) outperformed the low-score group (0–1 of 9).

The Buffett assessment looks across ten years instead, with tests from the Berkshire letters: ROE on average equity ≥ 15% in every year and ≥ 20% on average over 10 years (judged on at least 5); total debt ≤ 3 × owner earnings, and equity positive; and "moat signals in the numbers" — return on tangible capital ≥ 15% in at least 80% of the years, and gross (else operating) margin with a coefficient of variation ≤ 0.15 across the window. That is durability the filings can show; brand and competitive position are not in any filing, and the model does not score them.

How the two are blended depends on the sector profile. For a general company Buffett carries 65% of the Quality axis and Piotroski 35%. Companies in the bank, insurer, asset manager profiles are rated by Buffett alone, because Piotroski's signals assume a current ratio and a gross margin they do not report.

The companies at the top of this list pass the most of these tests on their latest filings: consistent cash, manageable debt, improving trends. They are not necessarily the cheapest or the fastest-rising, and the score describes the filings, not what the stock will do next: our backtest found no statistically significant excess return from the scores.