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Price-to-Earnings Ratio

A valuation metric comparing a company's stock price to its earnings per share, indicating how much investors pay for each dollar of earnings.

Investment ManagementFinancial Reporting

FAQs

Does a low P/E always mean a stock is cheap?

No — low P/E may reflect poor growth prospects, earnings risk, cyclical earnings near a peak, poor management, or structural industry decline. 'Value traps' are stocks with persistently low P/E because the market correctly anticipates declining earnings. A high P/E for a company with strong growth and reinvestment opportunities may be more attractive than a low P/E with stagnant prospects.

What is the PEG ratio and why is it useful?

PEG = P/E ÷ Expected EPS Growth Rate (%). A PEG of 1.0x is considered fair value (paying one dollar of P/E for each percentage point of growth). Below 1.0x suggests undervaluation relative to growth; above 1.0x suggests premium pricing. PEG adjusts the P/E for growth, enabling comparison across companies with different growth rates. Limitations: growth rate estimates are uncertain; PEG works best for consistently growing businesses.

What is the Shiller CAPE ratio?

The Cyclically Adjusted Price-to-Earnings (CAPE) ratio, developed by Nobel laureate Robert Shiller, uses inflation-adjusted 10-year average earnings instead of trailing twelve months to smooth economic cyclicality. The historical average CAPE for the S&P 500 is approximately 17x; readings above 30x have historically preceded periods of below-average future returns. CAPE is a long-term market valuation indicator, not useful for timing short-term moves.

Related Terms

Enterprise Value

The total value of a company available to all capital providers — equity holders and debt holders — used as a basis for acquisition pricing and valuation multiples.

Discounted Cash Flow

A valuation method that estimates the present value of a company or investment by discounting projected future cash flows at an appropriate rate.

Return on Equity

A profitability ratio measuring how much net income a company generates per dollar of shareholders' equity.

Net Margin

The percentage of revenue remaining as net income after all expenses including interest, taxes, and non-operating items.

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The Price-to-Earnings (P/E) ratio is one of the most widely used stock valuation metrics, comparing the market price of a share to its earnings per share (EPS). It indicates how much investors are willing to pay for each dollar of the company's earnings — reflecting expected growth, earnings quality, and market sentiment.

P/E Ratio = Market Price Per Share ÷ Earnings Per Share (EPS)

Or equivalently: P/E = Market Capitalization ÷ Net Income

For a stock trading at $100/share with trailing twelve-month EPS of $5: P/E = $100 ÷ $5 = 20x, meaning investors pay $20 for every $1 of earnings.

Trailing P/E (TTM P/E) uses actual past earnings — concrete but backward-looking. Forward P/E uses next twelve months' consensus earnings estimates — more relevant for valuation but dependent on forecast accuracy. The S&P 500 historical average P/E is approximately 15–17x; as of 2024 it trades at roughly 20–25x, reflecting expectations of continued earnings growth and a lower discount rate environment than historical averages.

P/E ratios vary dramatically by industry and growth rate. High-growth technology companies trade at 30–100x P/E (market pays for future growth). Utilities trade at 15–20x (stable, predictable earnings). Banks at 8–12x (complex balance sheets, regulatory capital constraints). Value stocks often trade at 5–12x (slow growth or cyclical industries).

Limitations of P/E: it's meaningless for loss-making companies (negative EPS). Different accounting treatments affect EPS comparability. High P/E may reflect growth expectations, not overvaluation. Cyclical businesses show misleading P/E at earnings peaks (low P/E, seemingly cheap) and troughs (high P/E, seemingly expensive) — earnings normalize over the cycle.

Variants: PEG Ratio (P/E ÷ Earnings Growth Rate) adjusts for growth — a P/E of 30x with 30% growth has a PEG of 1.0x, considered fairly valued. Shiller CAPE (Cyclically Adjusted P/E) uses 10-year average earnings to smooth cyclicality.