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Stocks & Equities · definition

Price-to-Earnings (P/E) Ratio

The price-to-earnings ratio compares a company's share price with its earnings per share, describing how many dollars investors currently pay for one dollar of annual profit.

Written and reviewed by the Investing Value editorial teamLast reviewed 4 min read

The price-to-earnings ratio (P/E) is a valuation measure that divides a company's share price by its earnings per share (EPS). If a share trades at $50 and the company earned $2.50 per share over the past year, the P/E is 20: buyers are paying twenty dollars for each dollar of annual profit.

Key takeaways

  • P/E = share price ÷ earnings per share.
  • A trailing P/E uses the last twelve months of earnings; a forward P/E uses forecast earnings.
  • High P/E ratios often reflect expectations of strong profit growth; low ratios can reflect slow growth, higher perceived risk, or potential undervaluation.
  • The ratio is meaningless for companies with zero or negative earnings.

Reading the number

A P/E only acquires meaning in comparison, against the company's own history, against industry peers, or against the market average. Fast-growing software firms have routinely traded at far higher multiples than utilities, because buyers expect today's earnings to grow substantially. A low multiple is not automatically "cheap": it can signal that the market expects profits to stagnate or decline. Practitioners of value investing historically used low P/E ratios as one screen for potentially undervalued shares, while emphasising that the ratio alone proves nothing.

Variants

  • Trailing P/E, price divided by the past year's actual earnings. Factual but backward-looking.
  • Forward P/E, price divided by analysts' forecast earnings. Forward-looking but dependent on estimates.
  • CAPE / Shiller P/E, price divided by ten-year average inflation-adjusted earnings, used in academic work on long-run market valuation.

Limitations

Earnings are accounting figures shaped by depreciation choices, one-off items and buybacks, all of which can move EPS without changing the underlying business. The ratio also ignores debt, two companies with identical P/Es can carry very different obligations, which is one reason analysts read it alongside market capitalization and balance-sheet measures.

Frequently asked questions

What is a "normal" P/E ratio?

There is no universal normal. The long-run average for the U.S. market as a whole has hovered in the mid-to-high teens, but averages differ by era, industry and interest-rate environment.

What does it mean if a company has no P/E?

The company posted zero or negative earnings over the measurement period, making the division meaningless. Loss-making companies are evaluated with other measures.

Sources

This entry is for education only. Investing Value describes how financial concepts work; it does not provide investment, tax or legal advice, and nothing here is a recommendation to buy or sell any asset.

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