Revenue is what a company takes in (the “top line”, before costs); earnings are what it keeps (the “bottom line”). Because a business is a claim on future profits, how fast revenue and earnings grow changes what it’s worth — and price-to-sales values companies that aren’t profitable yet.
Revenue (sales, the “top line”) is the total money a company brings in before any costs. Earnings (the “bottom line”) are what’s left after all costs. A company can have huge revenue and tiny or negative earnings if its costs are high — so the two tell you different things.
A business is worth a claim on its future profits, not just this year’s, so how fast revenue and earnings are growing matters enormously. Two companies earning the same profit today aren’t worth the same if one is expanding quickly and the other is flat. That’s why the market pays a higher P/E for a fast grower — it’s paying for tomorrow’s bigger earnings. Watch revenue growth and EPS growth together: revenue rising while earnings stall can flag growth bought at the expense of profitability.
Example (illustrative): revenue rises from $100 million to $120 million — $20 million more on a $100 million base, so revenue grew by 20%. At that pace revenue roughly doubles in under four years, and if costs stay controlled, earnings can grow even faster. This is why a company growing sales 20% a year is usually valued more richly than an identical flat one. Illustrative arithmetic, not a real company, a forecast, or a recommendation.
Many young, fast-growing companies run at little or no profit while they invest to grow, so the P/E is useless — you can’t divide by near-zero earnings. Investors fall back on the price-to-sales ratio (market cap ÷ revenue), which values the company against sales instead of profit. It’s blunter — sales you can’t yet turn into profit are worth less — but it lets you compare growth companies with no earnings.
Fast growth is powerful but it’s also the assumption most likely to be wrong. When a company priced for rapid growth grows more slowly than expected, its price can fall hard — the high P/E was borrowed against a future that didn’t arrive. So whenever a stock looks expensive on earnings, ask how fast it’s really growing, whether that growth turns into profit, and how much growth the price already assumes.
General investor education, not personalized advice. The example (revenue rising from $100M to $120M, i.e. 20% growth) is illustrative arithmetic, not a real company, a forecast, or a recommendation. Priced-in growth is the assumption most likely to disappoint: a high multiple raises the bar for what must actually happen.
Revenue is all the money a company takes in from sales before any costs — the top line. Earnings are what’s left after paying every cost, tax and interest — the bottom line, i.e. profit. A company can have large revenue but small or negative earnings if its costs are high.
Because a share is a claim on future profits, not just today’s. If one company is expanding quickly and another is flat, the grower will likely earn much more in a few years, so the market pays more for it now — the justification for a higher P/E, but only if the growth actually materialises.
You can’t use a P/E when earnings are near zero or negative, so investors often use the price-to-sales ratio (market cap ÷ revenue). It’s a blunter measure — revenue you can’t yet turn into profit is worth less — but it lets you compare young, fast-growing companies that have no earnings.
Investor education only — not investment advice, and never a promise of profit. Every investment can lose value.