ConceptReviewed
P/E (Price-to-Earnings Ratio)
Name variants
- English
- P/E (Price-to-Earnings Ratio)
- Kanji
- 株価収益率
Quality / Updated / COI
- Quality
- Reviewed
- Updated
- Source
- Citations & Trust
- COI
- none
TL;DR
The P/E ratio shows how much investors pay per unit of earnings.
Definition
The Price-to-Earnings (P/E) ratio is share price divided by earnings per share, reflecting market expectations about growth and profitability.Because it embeds market expectations, P/E must be evaluated with growth and risk assumptions.
Decision impact
- It links market expectations to earnings, improving valuation decisions.
- Trend tracking shows how expectations shift over time.
- Peer comparison helps form over/undervaluation hypotheses.
Key takeaways
- Confirm the EPS definition and time period used.
- Adjust for one-time earnings effects to read sustainability.
- Interpret alongside growth and margin indicators.
- Account for capital structure and accounting differences.
- Make valuation assumptions explicit before decisions.
Misconceptions
- A low P/E is not always a bargain without quality checks.
- Growth assumptions can make P/E misleading if wrong.
- It should not be used as the only decision metric.
Worked example
Example: Compare a company's P/E to peers to assess whether growth expectations are high or low.Compute P/E using adjusted EPS and show growth and risk assumptions alongside it.Avoid simplistic comparisons across very different industries.Use multi-year averages if earnings are volatile.
Citations & Trust
- Principles of Finance (OpenStax)