Gross margin (revenue minus cost of goods sold, divided by revenue) measures the economics of production and delivery — how much is left after the direct cost of making or delivering the product or service. It is a structural signal: high gross margins indicate pricing power, scale advantages, or low marginal cost of additional revenue (as in software). Operating margin subtracts operating expenses (SG&A, R&D, depreciation) from gross profit — it measures business efficiency after all recurring operating costs. Net margin is the bottom line after interest expense and taxes, reflecting the full cost of the capital structure.

The hierarchy of diagnostic value: gross margin tells you about competitive positioning and business model quality; operating margin tells you about management execution and cost discipline; net margin tells you about financing choices and tax management. Gross margin is the hardest to manipulate and the most structurally revealing. A company with 20% gross margin cannot operate a 25% operating margin business — the ceiling is set at the gross level. A company with 70% gross margins has enormous potential operating leverage as it scales fixed operating costs across a growing revenue base.

Software has near-zero marginal cost of reproduction — once code is written, delivering it to an additional customer costs almost nothing in incremental hosting, support, and infrastructure. This economic reality produces structurally high gross margins: 70-80% is standard for pure SaaS, 75%+ is a benchmark for enterprise software with minimal services revenue. When a company claiming to be a software business reports gross margins below 60%, it typically signals significant professional services, hardware, or other lower-margin revenue components diluting the software margins.

High gross margins are the foundation of operating leverage — the ability to grow operating income faster than revenue as the business scales. A software company with 75% gross margins that doubles revenue while keeping absolute R&D and S&M costs flat would see operating income scale dramatically. This is the SaaS profitability inflection story investors pay high multiples for. The path from 'burn cash to grow revenue' to 'generate high-margin free cash flow' runs directly through maintaining or expanding gross margins as scale grows.

A company with 15% operating margin that was 25% three years ago is in structural decline regardless of how respectable the absolute level appears. Declining gross margins signal pricing pressure (competitors forcing price concessions) or cost creep (input costs rising faster than pricing). Declining operating margins with stable gross margins signal cost structure problems — hiring ahead of revenue, inefficient go-to-market spending, or R&D that is not converting to revenue. Expanding operating margins in a growing business is one of the rarest and most valuable combinations in equity markets.

The EBITDA margin (earnings before interest, taxes, depreciation, and amortization, divided by revenue) is preferred over net margin for capital-intensive businesses because it removes the depreciation charge — a non-cash expense whose magnitude often bears little relationship to true maintenance capital requirements. For an asset-light software business, EBITDA margin closely tracks FCF margin. For a capital-intensive industrial, EBITDA margin substantially overstates cash generation because high maintenance capex is excluded. FCF margin (free cash flow divided by revenue) is ultimately the most honest long-run profitability signal.