n5-minute test is suggested to filter out risky companies:
Auditor’s Opinion: Read the Auditor’s Opinion in the 10-K to make sure that it is a “going concern” and that the financial statements “present fairly, in all material respects, … in conformity with accounting principles generally accepted…”.
Lawsuits: Read footnotes for legal proceedings that can seriously harm the company. Stay away if you don’t understand the full impact of a lawsuit.
Unusual losses: Check how often the company reported unusual losses (e.g. bad debt, inventory write-downs, severance payments to laid-off workers, etc.) in the last several years.
Earnings restatements: Almost every major financial disaster was preceded by an earnings restatement. Make sure the company has not restated in the last several years.
Intangibles assets ratio: [(Goodwill + other intangibles) / Total assets] should be < 20%. Intangibles can be impaired and quickly disappear from the balance sheet. In credit crunch times, intangibles are hard to sell. Large intangibles are also a sign of management overpaying for acquisitions.
Debt-to-equity ratio: [(Sum of all interest-bearing debt including working capital lines of credit, short-term debt, long-term debt, and capital leases) / Shareholders’ equity] should be <= 75%.
Revenue growth: Look for revenue growth of >= 30% over the last 5 years (cumulative, not annual figure). Best revenue growth comes from increase in units sold, followed by price increases.
Stock-based compensation ratio: [Stock-based compensation / accrual profits] <= 15%. This measures how much of the profit goes to employees rather than shareholders.
Short ratio: [Number of shares short / Float] <= 15%. If more than 15%, understand why and determine if that is justified.