What is earnings per share — and why it moves a share price?

Every time a company announces its results — whether that is HSBC, Tesco, or a FTSE 250 business you have picked for the Student Investor Challenge — three letters appear near the top of the headline: EPS. The share price often moves sharply within minutes of that number landing. Yet EPS is one of the most straightforward concepts in markets once you strip out the jargon. This guide explains what it is, how it is calculated, and — crucially — the buyback twist that catches many new investors off guard.

The one-sentence definition

Earnings per share (EPS) is a company’s net profit divided by the number of shares in existence. That is it. If a company made £10 million in profit and has 100 million shares outstanding, its EPS is 10p. Every share “earned” 10p of profit during that period.

The number is already expressed in pence or pounds (or cents and dollars in the US), which makes it immediately comparable across time periods and — with a little care — across companies.

Why you cannot just look at the share price

Imagine two companies. One has a share price of £500; the other trades at £5. Which is more profitable per share? You genuinely cannot tell from the price alone, because a share price reflects both underlying earnings and how many shares the company has issued. A business that split its shares 100 times would look cheaper without being any less valuable.

EPS fixes this. By dividing profit by the share count, it puts businesses of all sizes on the same footing. That is also why the price-to-earnings ratio uses EPS as its foundation: divide the share price by EPS and you get the P/E, the most widely used valuation shortcut in equity markets.

The EPS formula — keeping it simple

The formula is:

EPS = Net Profit ÷ Weighted Average Shares Outstanding

The “weighted average” part accounts for shares issued or bought back mid-year. If a company had 100 million shares for nine months and then issued 20 million more, you do not simply use 120 million — you weight the time periods to get a fairer denominator.

Let us walk through a concrete example with a fictional UK company, Clearbrook PLC:

• Net profit for the year: £24 million
• Weighted average shares outstanding: 300 million
• EPS: £24m ÷ 300m = 8p per share

Where do these numbers come from? Net profit comes from the income statement (sometimes called the profit and loss account); shares outstanding are disclosed in the balance sheet and the notes to the accounts. Both are published every time a company reports results. You do not have to hunt for them — the EPS line is nearly always printed at the top of any results announcement.

Basic EPS vs diluted EPS

You will almost always see two EPS figures in a results release, not one.

Basic EPS

Basic EPS uses the actual shares currently in issue — the ones you can see on the stock exchange today. It is the simpler number and the one most people picture when they say “EPS”.

Diluted EPS

Diluted EPS goes further. It adds in all potential shares that could come into existence: stock options granted to employees, warrants, and convertible bonds (loans that can be exchanged for shares). Because this inflates the denominator, diluted EPS is always lower than or equal to basic EPS — never higher.

Version	Denominator includes	Typical relationship
Basic EPS	Actual shares in issue	Higher number
Diluted EPS	Actual + potential shares (options, convertibles)	Lower, more conservative

Why does diluted EPS matter? Because options and convertibles represent a real future cost to existing shareholders — if they are exercised, each existing shareholder owns a slightly smaller slice of the same pie. Analysts and professional investors almost always use diluted EPS for comparisons because it is the more conservative, honest picture.

Practical tip: when you see an EPS headline in the press, glance at the small print to check which version is quoted. Many newspaper headlines use basic EPS; analysts’ models typically use diluted.

Why EPS goes up or down

EPS can change for two completely different reasons, and mixing them up is one of the most common mistakes new investors make.

Profit rises or falls

The obvious driver: if revenues grow or costs fall, net profit increases, and dividing a bigger number by the same share count gives you a higher EPS. This is the kind of EPS growth most people think of — the business is genuinely earning more money.

Share count changes — the buyback twist

Here is where it gets interesting. A company can increase its EPS without earning a single extra penny of profit by reducing the number of shares in issue. The most common way to do this is a share buyback: the company uses spare cash to repurchase its own shares on the open market and then cancels them.

Consider Clearbrook PLC again. Suppose net profit stays flat at £24 million, but the company buys back 50 million shares during the year, reducing the count from 300 million to 250 million:

• Net profit: £24 million (unchanged)
• Shares outstanding: 250 million (down from 300 million)
• New EPS: £24m ÷ 250m = 9.6p (up from 8p)

EPS has risen 20% even though the business did not grow at all. This is why a rising EPS alone does not always mean the underlying company is becoming more profitable — you always need to check whether the share count changed.

The reverse is also true. Issuing new shares — through a rights issue, employee share schemes, or converting bonds — increases the denominator and dilutes EPS, spreading the same profit across more shares.

Adjusted (underlying) EPS — what the press release really means

Open almost any UK company’s results and you will find not two EPS figures, but three or four. Alongside basic and diluted EPS, companies routinely publish an “adjusted” or “underlying” EPS that strips out items they consider one-off or exceptional: restructuring charges when a factory closes, write-downs on an acquisition that turned out to be overpriced, or gains from selling a building.

The logic is that these items distort the picture of the ongoing business. The adjusted EPS is usually higher than the reported (statutory) figure, because the stripped-out items are typically costs rather than windfalls.

Neither number is dishonest — both appear in the same document. But the share price tends to react to whichever version the market uses as the benchmark, which is usually the adjusted figure. The statutory (GAAP) EPS is what has actually happened legally and financially; the adjusted EPS is management’s interpretation of what the recurring business earned.

Takeaway: always find both numbers. If adjusted EPS is much higher than statutory EPS, ask what was stripped out and whether it is genuinely one-off or a recurring cost dressed up as exceptional.

How to use EPS in the Student Investor Challenge

When a company you hold in the Challenge announces results, the EPS line is the first place to look. There are two comparisons that matter:

1. Analyst consensus expectations. Before results day, professional analysts publish their EPS forecasts. These are averaged into a “consensus estimate.” If the company beats it — an EPS beat — the share price typically rises. If it misses, the price often falls, sometimes sharply. You can read more about this mechanism in our explainer on why shares move on earnings.
2. Year-on-year comparison. Comparing EPS to the same period in the previous year shows whether the business is genuinely growing or shrinking. A company beating its numbers but reporting lower EPS than last year can still disappoint the market.

Over the course of a Challenge round, companies with a track record of steady, consistent EPS growth tend to be more resilient than those whose earnings swing wildly. This is not a guarantee — share prices are also driven by sentiment, interest rates, and sector dynamics — but it is a useful starting filter.

Finally, once you know a company’s EPS, you can calculate its P/E ratio yourself: divide the current share price by EPS. If a share trades at 400p and diluted EPS is 20p, the P/E is 20. That tells you the market is paying £20 for every £1 of annual earnings — useful context when deciding whether a share looks expensive or cheap.

The key numbers to remember

1. EPS = profit ÷ shares. The higher, the more profit per share the company is generating.
2. Diluted EPS is the conservative number. It includes all potential shares and is the version professionals prefer for comparisons.
3. EPS can move for two reasons: profit changes, or the share count changes. Always check both before drawing a conclusion.

Frequently asked questions

What does a higher EPS mean?

A higher EPS means the company is generating more profit per share. It does not automatically mean the share is cheap — you also need to check the share price relative to EPS, which is what the P/E ratio does.

What is the difference between basic and diluted EPS?

Basic EPS divides net profit by the actual shares currently in issue. Diluted EPS adds in potential shares from stock options and convertible bonds, giving a more conservative — and usually lower — figure. Analysts typically use diluted EPS for comparisons.

Can EPS go up even when profit stays the same?

Yes. If a company buys back some of its own shares, the total share count falls. Dividing the same profit by fewer shares produces a higher EPS. This is why rising EPS alone does not always mean the business is growing faster.

How do I use EPS during the Student Investor Challenge?

When a company in your portfolio releases results, find its EPS and compare it to: (a) what analysts expected, and (b) the same period last year. A surprise beat often lifts the share price; a miss tends to drag it. Tracking EPS growth helps you spot companies likely to hold value over the round.