Analyzing a stock before buying comes down to five checks you can run from free SEC filings: describe the business in one sentence, test whether revenue repeats, weigh debt against cash flow, judge whether competitors can copy the advantage, and compare the price against the company's own history. The primary source for all five is Form 10-K, the annual report every US-listed company must file with the Securities and Exchange Commission, available free on EDGAR. NewsJay publishes information and education, not investment advice, and nothing here is a recommendation to buy or sell any security.
Why start with the 10-K instead of the share price?
The annual report anchors everything because it is the company speaking for itself, under legal liability for material misstatements. The share price tells you what the crowd paid yesterday; the 10-K tells you what you would actually own. Reading it first also immunizes the analyst against narrative drift: a stock that sounds exciting in a headline often reads far less interesting in Item 1, where the company must describe its real operations, customers, and risks in plain sequence.
Step 1: Can you explain the business in one sentence?
If the business cannot be summarized — who pays whom, for what, and why — the analysis stops there. Complexity is not disqualifying; banks and insurers are intricate by nature. But an analyst who cannot say whether the money comes from product sales, subscriptions, advertising, or financing cannot later tell whether results improved for a durable reason or a cosmetic one. Write the sentence down before reading further, then check it against the revenue segments the company reports.
Step 2: Does the revenue repeat?
Revenue quality separates money that arrived from money that will arrive again. In the 10-K's segment disclosures and management discussion, look for the share of revenue under subscription, contract, or repeat-purchase patterns versus one-time sales, and track three years of the trend. A software firm with 85% recurring revenue and a retailer with flat store traffic both book revenue, but the first has a floor under next year and the second does not. Growth bought through acquisitions deserves the same skepticism: the organic revenue line, when disclosed, is the honest one.
Step 3: How much debt sits against the business?
Debt converts ordinary downturns into existential ones. The working screens are simple: total debt against EBITDA, where many credit analysts treat more than roughly 3x as elevated, and the current ratio, where a figure below 1 means current liabilities exceed current assets. Then read the maturities schedule in the debt footnote — five quiet years can hide a wall of refinancing in year six. Compare interest coverage, operating income against interest expense, across at least three years to see whether the cushion is widening or thinning.
Step 4: Can a competitor copy the advantage?
A durable advantage appears as pricing power or stubbornly low costs: customers stay because switching is painful, the network grows more useful with size, a brand supports premium prices, or scale makes rivals' unit economics uncompetitive. The test is in the margins — a company holding high margins for a decade against determined competition has something structural, while a company whose margins swing with input prices is competing on effort. Item 1A, the risk factors section, is usefully read here: management's own list of what could end the advantage is often more candid than any outside commentary.
Step 5: Is the price reasonable against history?
Valuation is the last step precisely because it only means something after the business is understood. Compare the price-to-earnings ratio and enterprise value to EBITDA against the company's own five- and ten-year ranges and against direct competitors, not against the whole market — a supermarket chain and a software firm carry structurally different multiples. A shrinking share count from buybacks and honest, funded growth can justify a fuller price; a multiple supported only by a story cannot. No valuation measure is a verdict, and none is a price target.
What does the finished checklist look like?
The table below compresses the five steps into the questions worth answering before any purchase.
| Check | Primary source | Warning sign |
|---|---|---|
| Business model | 10-K Item 1 | Cannot be explained in one sentence |
| Revenue quality | Segment note, MD&A | Dependence on one-time or related-party sales |
| Debt load | Balance sheet, debt note | Debt above roughly 3x EBITDA; refinancing walls |
| Competitive position | Item 1A, margin history | High margins with no cost or switching moat |
| Valuation | Filing data, peer set | Multiple far above own history without change in business |
How long should this take?
A first pass on an unfamiliar company runs several focused hours: the 10-K read, the segment arithmetic, and the peer comparison. The second company in an industry takes half that, because the industry vocabulary is already loaded. Experienced analysts keep notes on every company they pass on, because the file written today is the comparison case the next opportunity needs.
How does the checklist change for banks and insurers?
Financial companies hide in plain sight inside standard frameworks: revenue quality means deposit franchise and spread income rather than recurring subscriptions, and the moat often lives in cost of funding. The working adjustments: replace debt-to-EBITDA with regulatory capital ratios, where common equity tier 1 above roughly 10% reads comfortable for large banks; watch net interest margin through rate cycles rather than one year; and read the allowance for credit losses as the earnings regulator it is. The five questions stand; the sources that answer them move to the same filings' specialized schedules.
FAQ
Do I need paid data services to do this?
No. EDGAR provides every filing free, and company investor-relations pages supply presentations and transcripts. Paid platforms add convenience and historical ratios, but the primary documents needed for these five checks are public. Cost never has to gate the analysis.
What if the company is not US-listed?
Most large foreign issuers trading in the US file Form 20-F annual reports with the same discipline. For listings abroad, the local regulator's equivalent filing serves, though accounting standards differ. The five checks stay the same; the source changes.
How often should the analysis be refreshed?
Re-run the checklist at each annual report and after any major acquisition or leadership change. Quarterly filings update the numbers, but the durable questions — moat, debt trajectory, revenue quality — move at annual speed. Reviewing more often mostly adds noise.
Does this checklist work for ETFs?
Not directly. Funds are analyzed on holdings, costs, tracking, and tax behavior rather than business quality. The single-stock checklist applies to the companies inside a fund, not to the fund wrapper itself.
For more context, read How to Use a Stock Screener Without Fooling Yourself.
For more context, read how to read a balance sheet.
For more context, read Price-to-Earnings Ratio Explained for Stock Buyers.
