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Financial ratios distill accounting information into dimensionless measures for comparability across firms and time. Profitability ratios (ROE, ROA, margins), leverage ratios (debt/equity, interest coverage), efficiency ratios (asset turnover, receivables days), and valuation ratios (P/E, Price/Book) reveal financial health and cheapness. Ratio analysis is most powerful when tracking changes over time and comparing to peers and benchmarks.
Build a financial ratio spreadsheet for a peer group of companies, calculate historical trends, and correlate ratios to stock returns.
Raw accounting numbers — $4 billion in net income, $80 billion in assets — tell you little on their own. Is $4 billion impressive? It depends on how much capital was deployed to generate it and how the figure compares to competitors. Financial ratios convert these absolute numbers into dimensionless measures that are comparable across firms of different sizes and across time. Building on the valuation fundamentals you already know, ratios are the working toolkit of equity analysts, credit officers, and corporate strategists.
The ratio landscape organizes naturally into four families. Profitability ratios measure how efficiently the firm converts resources into earnings. Return on Equity (ROE = net income / equity) tells shareholders how much profit was generated per dollar they own. Return on Assets (ROA = net income / total assets) abstracts from financing to measure operational efficiency. Net margin (net income / revenue) tells you what fraction of each revenue dollar survives as profit. These ratios are meaningless in isolation; a 12% ROE is outstanding in regulated utilities but mediocre in software. Comparison to peers and to the firm's own history is essential.
Leverage ratios measure financial risk — how much of the firm's assets are financed by debt rather than equity. Debt-to-equity (total debt / equity) and interest coverage (EBIT / interest expense) reveal whether the firm can service its obligations. High leverage amplifies both returns and risk: a firm with 50% debt/capital magnifies equity returns in good times and magnifies losses in downturns. Credit analysts focus heavily on interest coverage because a ratio below 1.5x signals the firm may struggle to meet interest payments. Efficiency ratios measure how productively the firm uses its assets — asset turnover (revenue / assets) measures sales generated per dollar of assets, while receivables days (accounts receivable / daily sales) measures how quickly customers pay.
Valuation ratios link market prices to fundamentals, connecting accounting statements to the stock valuation models you know. Price-to-Earnings (P/E) tells you how many dollars investors pay per dollar of current earnings — high P/E implies expectations of future growth. Price-to-Book compares market value to accounting book value; P/B above 1 means the market believes the firm earns above its cost of capital. These multiples are the foundation of comparable company analysis: you value a private firm or assess whether a public firm is cheap by computing the median P/E of peers and applying it to the target's earnings. The power of ratio analysis is that it reduces a complex financial statement to a handful of numbers that reveal, when read together, whether a business is profitable, efficient, financially safe, and reasonably priced.