EPS (Earnings Per Share) and Diluted EPS
The headline that a company earned about $740 million matters less than 'how much did the one share I own earn for me?' That number is exactly what EPS shows.
EPS is 'the profit one share earned'
EPS (Earnings Per Share) is a company's net profit divided by its number of shares. From a single shareholder's point of view, it shows 'how much did my one share earn?'
Basic EPS = (net profit attributable to common shares) ÷ weighted average shares outstanding
The key here is the 'weighted average share count.' When a company issues more shares through a paid-in capital increase mid-year, or buys back and cancels its own shares, the share count changes. You use a value that averages those changes over the period. Just using the year-end share count would create distortion.
EPS is the raw material for the P/E ratio (P/E = share price ÷ EPS), so it's a foundational building block of valuation.
Diluted EPS: accounting for shares that haven't been issued yet
Let's take it one step further. A company has things that aren't shares right now but 'could turn into shares later.' Employee stock options and convertible bonds (CBs) are examples.
If all of these convert into shares, the share count grows, and the profit per share gets watered down (diluted). Diluted EPS is calculated by assuming this worst case.
Diluted EPS = adjusted net profit ÷ (basic shares + potential shares)
Because the denominator gets bigger, diluted EPS is always less than or equal to basic EPS. It never gets larger.
If the gap between basic EPS and diluted EPS is large, it means the company has many potential shares like stock options and convertible bonds. That's a signal that your ownership value could be diluted later, so it's safer to also look at the more conservative diluted EPS.
Things to watch out for when reading EPS
EPS is useful, but it has a few traps.
First, EPS is affected by the 'share count.' When a company buys back and cancels its own shares, EPS rises even with unchanged profit, because the share count (denominator) shrinks. Conversely, EPS gets diluted when shares increase through a capital raise. So when you see 'EPS went up,' you need to look at the cause—did it rise because profit grew, or because the share count fell?
Second, EPS is based on accounting profit, so it can be swayed by one-off items (such as gains on asset sales). That's why it's better to look at the trend over several years rather than a single quarter, and to check it alongside actual cash generation (cash flow).
EPS is a foundational building block of valuation, but rather than judging a company by this one number, it's important to make a habit of viewing it as a set along with revenue, cash flow, and debt.
よくある質問
Q. If EPS goes up, is that always a good thing?
It's generally positive, but you need to look at 'why it went up.' It's good if profit actually grew, but EPS could also have risen because the company bought back shares and shrank the share count (the denominator). Neither is bad for shareholders, but they're different in nature, so confirm the cause.
Q. Should I look at basic EPS or diluted EPS?
To judge conservatively, I recommend looking at diluted EPS. It's the 'more sober' number that accounts for potential shares. Especially for growth companies with many stock options and convertible bonds, the gap between the two can be large, so the diluted basis is more realistic.
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