Historical PE Methodology: TTM vs Annualized Quarterly EPS
Historical PE ratios depend on how you define earnings at each measurement point. Two common approaches are trailing twelve months (TTM) earnings and annualizing the most recent quarterly EPS.
- Different earnings definitions can produce meaningfully different historical PE series.
- TTM smooths quarter-to-quarter noise but lags turning points.
- Annualized quarterly EPS is responsive but can overreact to one unusual quarter.
- Keep the same method when comparing across time or peers.
Two common methods for the “E” in PE
TTM method: use the sum of the past four quarters of EPS at each measurement point.
Annualized quarterly method: take the most recent quarter’s EPS and annualize it (multiply by 4) to estimate a run-rate.
Tradeoffs: responsiveness vs stability
- TTM: more stable, but slower to reflect turning points.
- Annualized quarter: faster, but can be distorted by seasonality or one-time items.
When each method is most useful
- Use TTM when you want stable comparability.
- Use annualized quarterly when the business is changing quickly and you want a run-rate read.
- For cyclicals, consider additional normalization before concluding a stock is “cheap.”
How this fits with HistoricalPERatio.com pages
Company pages often show multiple PE calculations around earnings dates, helping you compare how valuation looks under different earnings definitions.
Related pages on HistoricalPERatio.com
FAQ
Why can TTM and annualized-quarter PE disagree?
Because they measure different earnings windows: one smooths over a year, the other extrapolates the most recent quarter.
Is annualizing quarterly EPS always valid?
It’s a useful approximation, but seasonality and one-time items can make it misleading.
Which method should I use for fast growers?
Annualized quarterly can be helpful, but cross-check with TTM to avoid overreacting to one quarter.
What about negative earnings?
Both methods can become not meaningful. Focus on the earnings trajectory and path to profitability.
How do I compare a company to its own past?
Choose one method and stick with it across the history for apples-to-apples context.
What should I do after seeing a high historical PE?
Ask whether growth, margins, or risk profile changed—and compare to peers using the same method.