A stock buyback, or share repurchase, is when a company uses its own cash to buy its shares back from the market. It is one of the two main ways a company returns money to shareholders, the other being dividends, and it has become the bigger of the two for large US firms. Done well it rewards owners; done to flatter a number it can mislead them. Here is how it works and what to watch.

What a buyback does

When a company buys back shares, those shares are usually retired, which shrinks the total number outstanding. Because earnings are then divided among fewer shares, earnings per share rises even if total profit is flat. That mechanical lift is the single most important thing to understand: a buyback can raise EPS without the underlying business earning a cent more.

A simple illustration shows the effect. Suppose a company earns $100 million and has 100 million shares, so EPS is $1.00. If it buys back 10 million shares, the same $100 million is now split across 90 million shares, lifting EPS to about $1.11, an 11 percent rise with profit unchanged. Nothing about the business improved; the slices just got bigger because there are fewer of them. For how EPS sits inside a results statement, see how to read a company earnings report.

A buyback also returns cash to the shareholders who sell, and it signals that management thinks the shares are worth owning, or at least that it has cash it would rather return than reinvest. Unlike a dividend, a buyback is flexible: a company can start, pause or stop it, which is why firms often favor buybacks when profits are uncertain.

The numbers are large

US buybacks run into the hundreds of billions of dollars a quarter. According to S&P Dow Jones Indices data, S&P 500 companies spent a record $293.5 billion on share repurchases in the first quarter of 2025, up 23.9 percent from a year earlier. Apple alone spent $26.2 billion that quarter, the most of any single company and among the largest quarterly buybacks in S&P 500 history. In its November 2, 2026 results Apple said it returned $28 billion to shareholders in the September quarter through dividends and buybacks combined.

Those sums show why buybacks matter to the market as a whole: they are a major source of demand for shares and a large share of the cash that leaves corporate balance sheets each year.

The case for, and against

The case for buybacks is straightforward. If a company has more cash than it has good investments to make, returning it to shareholders is better than letting it sit idle or spending it badly. Buybacks are tax-efficient relative to dividends for many investors, because they do not trigger an immediate taxable payment; a shareholder who does not sell simply owns a slightly larger slice of the company. For how a sale is taxed when you do sell, see how capital gains are taxed in the US.

The case against is about motive and timing. A buyback that lifts EPS can make a management team's pay targets easier to hit without improving the business, because executive bonuses are often tied to per-share earnings. Companies also have a poor record of timing, often buying heavily when shares are expensive and cash is plentiful, then stopping in downturns when shares are cheap, the opposite of what a bargain-hunter would do. And cash spent on buybacks is cash not spent on research, wages or paying down debt, a trade-off critics say can leave a company weaker when conditions turn. A buyback funded by borrowing is the version worth the most scrutiny, since it swaps a permanent debt for a one-time lift to earnings per share.

The 1% excise tax

Policymakers took notice. The Inflation Reduction Act, signed on August 16, 2022, created a 1 percent excise tax on the value of corporate stock repurchases by publicly traded US companies, under Section 4501 of the tax code, and it applies to buybacks made after December 31, 2022. The Treasury and the IRS finalized the rules in late 2025, narrowing the tax's reach, for example exempting certain debt-like preferred stock redemptions, and dropping a contested rule that would have caught some repurchases of foreign stock. At 1 percent the tax is small next to the sums involved: on Apple's $26.2 billion of first-quarter 2025 buybacks it would be roughly $262 million, a rounding error against the company's profit. But it is a real cost that did not exist before 2023 and a signal of political scrutiny, and proposals to raise the rate have circulated since.

What to watch, not what to chase

The useful questions about a buyback are concrete. Is EPS growth coming from real profit or just from a shrinking share count? Is the company buying back stock while also raising debt to do it? And is it repurchasing shares at prices that look expensive on measures like the price-to-earnings ratio? A buyback is neither good nor bad on its own; it depends on the price paid and the cash given up. The same program can be a smart use of surplus cash at one company and a way to mask stagnant profits at another. Whether a company's buyback makes its shares more attractive is a judgment that rests on those details and your own goals, not on the headline size of the program.