What Is EPS? Earnings Per Share Explained
Understand earnings per share, how it's calculated, the difference between GAAP and adjusted EPS, and why it matters for valuation.
Key Takeaways
- •EPS = Net Income ÷ Shares Outstanding
- •Trailing EPS uses last 12 months of actual earnings
- •Forward EPS uses analyst estimates for next 12 months
- •GAAP EPS follows accounting standards; adjusted EPS excludes one-time items
- •EPS growth is often more important than the absolute EPS value
Earnings Per Share (EPS) is one of the most important metrics in investing. It tells you how much profit a company earned on a per-share basis, and it's a key input in valuation ratios like the P/E ratio.
The Formula
EPS = Net Income ÷ Total Shares Outstanding
If Apple earned $100 billion in net income in the last 12 months and has 15 billion shares outstanding, its EPS is $100B ÷ 15B = $6.67.
This $6.67 represents the profit attributed to each share.
Trailing EPS vs. Forward EPS
Trailing EPS (TTM) uses the last 12 months of actual, reported earnings. It's backward-looking but certain.
Forward EPS uses analyst estimates of earnings for the next 12 months. It's forward-looking but based on assumptions.
Apple's trailing EPS might be $6.20 (actual), but analysts might estimate forward EPS of $6.80 if they expect earnings to grow. The P/E ratio can differ significantly depending on which version you use.
GAAP EPS vs. Adjusted EPS
GAAP EPS follows Generally Accepted Accounting Principles and includes all items: revenue, costs, taxes, and one-time charges like restructuring costs or losses from asset sales.
Adjusted EPS (also called "pro forma" or "operating" EPS) excludes one-time items. A company might report GAAP EPS of $3.50 but adjusted EPS of $4.20 because the gap includes a big one-time restructuring charge.
Both matter:
- GAAP EPS is what shareholders actually earned (legally and truly).
- Adjusted EPS shows what "normalized" earnings look like, filtering out noise.
Smart investors look at both. If adjusted EPS is much higher than GAAP EPS, ask why: What one-time costs is the company excluding? Are these truly one-time, or recurring?
Real Example
Imagine a software company reports:
- Revenue: $1 billion
- Operating expenses: $400 million
- Operating income: $600 million
- One-time restructuring charge: $200 million
- Taxes (at 25%): $100 million
- Net Income (GAAP): $300 million
- Adjusted Net Income (excluding restructuring): $500 million
- Shares outstanding: 100 million
GAAP EPS = $300M ÷ 100M = $3.00
Adjusted EPS = $500M ÷ 100M = $5.00
The restructuring is real and cost shareholders $200 million, but it might be a one-time event (e.g., closing factories, severance). Adjusted EPS of $5.00 represents the ongoing earning power without that charge. Both figures are true; they're just answering different questions.
Why EPS Matters for Valuation
The P/E ratio (Price-to-Earnings) is calculated as Stock Price ÷ EPS. If a stock is trading at $100 and has EPS of $5, its P/E is 20x.
The PEG ratio compares P/E to EPS growth rate. A stock with a P/E of 30x and EPS growing at 30% per year has a PEG of 1.0 (considered fair). The same stock with EPS growing at only 10% per year has a PEG of 3.0 (expensive).
Growing EPS is often more important than the absolute EPS level. A stock with $2 EPS growing at 50% per year might be a better buy than a stock with $5 EPS growing at 2% per year.
EPS Growth and Stock Performance
Over long periods (5–10 years), a company's stock price tends to follow its EPS growth. A company that doubles EPS usually sees its stock price roughly double over several years (assuming the P/E ratio stays constant).
However, in the short term (weeks to months), the stock price can diverge wildly from EPS. If the market expects 20% EPS growth and the company delivers only 15%, the stock can fall despite positive earnings growth. Conversely, a company that beats low expectations can see its stock spike.
How to Use EPS Comparisons
Do not compare EPS directly across stocks. Apple's $6.67 EPS and Microsoft's $4.80 EPS are not comparable—one stock is more expensive per share, but Microsoft might be the better value after adjusting for growth.
Compare P/E or PEG ratios instead:
- Apple at $250, EPS $6.20: P/E = 40x.
- Microsoft at $420, EPS $4.80: P/E = 87x.
- Even though MSFT has lower EPS, it's trading at a higher multiple (higher P/E).
Or compare EPS growth rates:
- If Apple's EPS is growing at 10% and Microsoft's at 15%, Microsoft's growth is faster.
Key Takeaways
- EPS = Net Income ÷ Shares Outstanding.
- Trailing EPS is historical; forward EPS is estimated.
- GAAP EPS is the official, legal figure; adjusted EPS filters one-time charges.
- P/E ratio (Price ÷ EPS) is used to value stocks.
- EPS growth often matters more than absolute EPS.
- Comparison: use P/E or PEG ratios, not absolute EPS numbers.
- High-growth companies justify high P/E multiples; low-growth companies warrant low multiples.
Frequently Asked Questions
What's the difference between GAAP and adjusted EPS?
GAAP EPS is the official figure following accounting standards. Adjusted EPS excludes one-time items (like a big restructuring charge) so you can see "normal" earnings. Both matter—look at both.
Can EPS go up while the stock goes down?
Yes. EPS could grow 10% but if the market expects 20% growth, the stock falls. EPS is one input; expectations and sentiment matter too.
How do I use EPS to compare stocks?
You don't compare EPS directly (a $50 EPS and a $2 EPS are not comparable). Instead, look at P/E ratio or EPS growth rate. A stock with 15% EPS growth is often better than one with 5% growth, all else equal.