At early business stages, revenue growth dominates because it signals product-market fit, market penetration, and the scalability of the business model. A company growing revenue 40% annually is building the revenue base from which future earnings will scale. At mature stages, earnings growth matters more — investors are now paying for demonstrated earnings power, not the promise of future profitability. The transition from a revenue-growth valuation framework to an earnings-growth framework is one of the most common inflection points where high-multiple stocks re-rate sharply lower.

Earnings growth without revenue growth is a red flag, not a feature. If a company grows EPS 15% but revenue grows only 3%, the gap is almost entirely from margin expansion, cost-cutting, or share buybacks — not genuine business expansion. Margin expansion and buybacks have finite limits; a business cannot cut its way to growth indefinitely. The highest-quality compounders grow revenue and earnings at similar rates, with earnings slightly faster as operating leverage kicks in at scale.

Organic growth — same-store sales growth, constant-currency revenue expansion, volume without price — reflects genuine product or service demand. Acquired growth adds revenue through M&A but carries integration risk, goodwill that must be amortized, and frequently destroys shareholder value at the deal level even when it grows the revenue line. The research on M&A returns is sobering: on average, acquirers underperform peers in the 3 years following large acquisitions. Revenue growth that requires continuous capital deployment for acquisitions is lower-quality than organic growth that compounds on its own.

Decomposing reported revenue growth into organic and inorganic components is essential for any company that pursues acquisitive growth. Look for constant-currency, organic, or ex-acquisition revenue disclosures in the MD&A section of quarterly filings. A company reporting 20% total revenue growth but only 4% organic growth is a very different investment from one reporting 18% organic growth. The former is buying growth at potentially high prices; the latter is compounding from within the existing business model.

The Rule of 40 is the SaaS industry's combined growth and profitability benchmark: revenue growth rate plus free cash flow margin (or operating margin) should equal or exceed 40. A company growing 30% with 15% FCF margin scores 45 — healthy. A company growing 60% at -10% FCF margin scores 50 — also healthy, but dependent on sustaining that growth rate. A company growing 10% at 5% FCF margin scores 15 — failing the test. The Rule of 40 normalizes the growth-vs-profitability tradeoff and provides a single benchmark for comparing SaaS businesses at different stages.

The sustainable growth rate — ROE multiplied by the retention ratio — provides the maximum rate at which a business can grow without external capital. A company with 25% ROE retaining 80% of earnings can sustainably grow at 20% annually. Companies that grow faster than their sustainable rate must continuously raise capital (debt or equity), diluting existing shareholders or increasing financial risk. Tracking sustainable growth relative to actual growth helps identify whether a company is building genuine compounding capacity or relying on financial engineering.