Stock Buybacks Are Doing the Work in Earnings

A company you own reports earnings. Profit is up 5%. Earnings per share is up 8%. The stock jumps, the headline says the company beat expectations, and nothing in the coverage explains where the extra three points came from.

They came from the denominator. Stock buybacks shrink the number of shares a company's profit is divided by, so earnings per share can rise faster than earnings do, or rise while actual profit is flat.

This is not fraud and it is not new. What is new is the scale: S&P 500 companies spent a record $1 trillion on buybacks in 2025, and announcements through the start of this year ran at the fastest pace ever recorded. Once you know how to spot the effect, you can read an earnings report far more accurately than the headline allows.

Start with the mechanism, because it is simpler than the coverage implies.

How Stock Buybacks Move Earnings Per Share

Earnings per share is a fraction. Net income on top, share count on the bottom. A company can raise it by increasing the top or by shrinking the bottom, and the headline number does not distinguish between the two.

When a company repurchases its own stock, those shares are retired or held in treasury and stop counting toward the total. The profit has not changed. The slices have just got bigger.

There is a genuine economic argument for it. A buyback returns cash to shareholders in a form that is often more tax-efficient than a dividend, because nobody pays tax until they choose to sell. Management also signals that it considers the stock undervalued, which carries some information.

What a buyback does not do is make the business better at anything. The cash that bought shares did not build a factory, hire engineers or pay down debt.

The Worked Example: Where Three Points Come From

Take a company earning $1 billion a year with exactly 1 billion shares outstanding. Earnings per share is $1.00.

Now run two scenarios across one year.

• Scenario one: buyback only. Profit stays at $1 billion. The company repurchases 3% of its shares, leaving 970 million. Earnings per share becomes $1.0309, a gain of 3.1%. The business performed identically.
• Scenario two: growth plus buyback. Profit rises 5% to $1.05 billion and the share count still falls 3% to 970 million. Earnings per share becomes $1.0825, a gain of 8.25%.

In scenario two, the headline says earnings per share grew 8.25%. The business grew 5%. The remaining 3.25 percentage points came from arithmetic.

That gap is the whole lesson. Neither number is false, but only one of them tells you whether the company sold more, charged more or ran leaner.

Scale the effect to the market and it stops being a rounding error. A $1 trillion annual repurchase programme across the index is a persistent tailwind under reported earnings per share, year after year, independent of how any business is actually doing.

The Thirty Second Check on Any Earnings Report

You do not need a data terminal for this. The number is printed on the face of the income statement in every quarterly filing.

Find the line labelled diluted weighted average shares outstanding. Compare it to the same quarter a year earlier. The percentage change is how much of the earnings per share move came from the share count rather than the business.

Three readings tell you three different stories:

• Share count falling faster than profit is growing. Most of the reported growth is mechanical. Treat the earnings per share figure with suspicion.
• Share count flat while profit grows. The growth is real operating performance.
• Share count rising despite announced buybacks. The repurchases are being used to offset stock issued to employees, so cash is leaving the company and shareholders are getting no reduction at all.

That third case is the one most worth catching. A company can announce a large buyback, spend the money, and still end the year with more shares outstanding than it started with.

Why the Scale Changed

Buybacks have been running at record levels, and the pace has been unusually front-loaded.

Bloomberg reported that S&P 500 companies announced $665 billion of repurchases in the four months through April, the most ever to start a year. The quarterly series is choppier than the annual total suggests: S&P Dow Jones Indices recorded $249.0 billion in the third quarter of 2025, a 6.2% gain after a 20.1% drop the quarter before.

Meanwhile analysts have been forecasting earnings growth of around 17% in each of the next two years, among the fastest back-to-back projections in years.

Put those together and the question becomes unavoidable. If a meaningful share of that 17% arrives through a falling denominator, the index is not growing as fast as the earnings per share series implies.

There is a concentration issue underneath it too. The largest companies do most of the repurchasing, which compounds a problem we covered in detail: your index fund is far less diversified than you think.

When a Buyback Is a Warning Sign

Repurchases are not automatically bad. Some of them are genuinely the best available use of cash. A few patterns should make you look harder.

Buybacks funded by borrowing. A company issuing debt to retire equity is increasing financial risk to improve a per-share statistic. That trade works until credit tightens, which is the same dynamic behind AI infrastructure spending shifting onto borrowed money.

Buybacks at the top of a price range. Management buying heavily after a long run is spending shareholder cash at the worst available price, whatever the stated reasoning.

Buybacks alongside falling revenue. If the top line is shrinking and earnings per share is growing, the company is managing the number rather than the business.

Buybacks that only cancel out dilution. Check gross repurchases against the net change in share count. If they match, the programme is employee compensation wearing a different label.

Frequently Asked Questions

What is a stock buyback?

A stock buyback, or share repurchase, is when a company uses its own cash to buy its shares on the open market. Those shares stop counting toward the total outstanding, so each remaining share represents a slightly larger claim on the company's profit.

Do buybacks make a stock go up?

They can, for two reasons: steady buying adds demand, and the higher reported earnings per share makes the stock look cheaper on a price to earnings basis. Neither effect reflects improved operating performance, so the move is not necessarily durable.

How do I tell how much of earnings growth came from buybacks?

Compare diluted weighted average shares outstanding to the same quarter a year earlier. If the share count fell 3% and earnings per share grew 8%, roughly 3 percentage points came from the repurchase and about 5 came from the business.

Are buybacks better than dividends?

They are more tax-efficient for many investors, because no tax is triggered until you sell, and they are easier for a company to pause without signalling distress. Dividends are more predictable and harder to quietly abandon, which some investors value more.

Why do companies buy back stock instead of investing?

Sometimes because there is nothing worth investing in at an acceptable return, which is a legitimate reason to return cash. Sometimes because executive pay is tied to earnings per share targets, which creates an incentive to shrink the denominator regardless.

How to Use This

Next time a company you hold reports, read the share count before you read the headline. It takes half a minute and it changes what the rest of the release means.

A record $1 trillion of annual repurchases sits underneath every index-level earnings figure now. Some of it is sensible capital return. Some of it is a growth story told through division.

The investors who get surprised are the ones who never checked which.

Disclaimer: This article is for informational purposes only and does not constitute financial advice. Always consult with a qualified financial advisor before making investment decisions. Past performance is not indicative of future results.