price-earnings ratio
/ P-E /
Suppose a small shop earns 10,000 of profit a year, and someone offers to sell it to you for 150,000. You are paying 15 times its yearly earnings — a way of asking 'how many years of current profit am I paying for this?' The price-earnings ratio asks exactly this about a company's stock: how much the market charges for each dollar of the company's annual earnings.
The price-earnings ratio equals the market price per share divided by the earnings per share (EPS). If a stock trades at 60 and earned 4 per share last year, its P/E is 60 / 4 = 15 — investors are paying 15 for every 1 of yearly earnings. A high P/E means the market expects strong future growth (or the stock is simply expensive); a low P/E can mean modest growth expectations, a bargain, or hidden trouble. P/E is unusual among the ratios here because it blends a market figure (the share price, set by investors) with an accounting figure (earnings), so it reflects expectations, not just past performance.
The price-earnings ratio matters because it is the single most-quoted gauge of how cheap or dear a stock is, used everywhere from headlines to investment committees. It lets investors compare a stock against its own history, its rivals, or the whole market. The caveats run deep: earnings can be distorted by accounting choices and one-off items; a company with tiny or negative earnings produces a meaningless or undefined P/E; and a 'low' P/E is not automatically a bargain — the market may be pricing in real decline that the buyer ignores at their peril.
A fast-growing tech firm trades at a P/E of 40, while a mature utility trades at a P/E of 12. Investors are willing to pay much more per dollar of the tech firm's earnings because they expect those earnings to grow far faster — the P/E is pricing the future, not the present.
A high P/E prices in expected growth; a low one prices in caution.
A low P/E is not automatically cheap — the market may be correctly pricing in decline — and a firm with near-zero or negative earnings has a meaningless P/E.