--- title: "What Is a Share Buyback, and Why Do Companies Do It?" description: "A share buyback is one of the biggest sources of demand in the stock market: S&P 500 companies spent roughly $942bn repurchasing their own shares in 2024. Here is how buybacks work, why boards favor them, and why critics push back." category: "Markets" category_url: https://boursel.com/category/markets author: "Kenji Nakamura" published: 2026-07-04T19:37:11.000Z updated: 2026-07-04T19:37:11.000Z canonical: https://boursel.com/article/what-is-a-share-buyback-and-why-do-companies-do-it tags: ["buybacks", "shareholder-returns", "dividends", "corporate-finance", "explainer"] --- # What Is a Share Buyback, and Why Do Companies Do It? A share buyback is one of the biggest sources of demand in the stock market: S&P 500 companies spent roughly $942bn repurchasing their own shares in 2024. Here is how buybacks work, why boards favor them, and why critics push back. When a company generates more cash than it needs, it has a handful of ways to hand the surplus back to owners. One of the most common, and most debated, is the share buyback. Alongside dividends, buybacks have become a defining feature of modern markets: S&P 500 companies spent about $942bn repurchasing their own stock in 2024, [according to S&P Dow Jones Indices](https://www.spglobal.com/spdji/en/corporate-news/article/sp-500-q3-2025-buybacks-post-modest-62-gain-to-249-0-billion-after-declining-20-1-amidst-uncertainty-in-q2/). Here is what that actually means. ## What a buyback is A buyback, also called a share repurchase, is simply a company using its own cash to buy its shares back from investors in the market. Those shares are then either cancelled or held in reserve. The business itself does not change, but the number of shares it is divided into shrinks. That is the key mechanism. If a company is a pie cut into a fixed number of slices, a buyback removes some slices and hands the cash to the holders who sold. Everyone who keeps their shares is left owning a slightly bigger piece of the same company. ## How companies do it Most buybacks happen through open-market purchases: the board authorizes a program of a certain size, and the company buys shares gradually on the exchange over months, at whatever the market price happens to be. A program is an authorization, not a promise; companies can slow, pause or stop. A less common route is the tender offer, where a company offers to buy a set number of shares directly from holders at a fixed price, usually above the current market price, by a deadline. It is faster and more expensive, and tends to be read as a stronger signal that management thinks the stock is cheap. ## Why boards like them Companies give several reasons for choosing buybacks: - **Returning spare cash.** When a firm has more money than it has attractive projects to invest in, a buyback returns it to shareholders instead of letting it sit idle. - **Offsetting dilution.** Firms issue new shares to pay staff in stock. Buying shares back cancels out that increase, keeping the share count from creeping up. - **Lifting earnings per share.** Profit divided by fewer shares produces a higher figure per share, even when total profit is unchanged. That is arithmetic, not growth, but it can flatter closely watched metrics. - **Signaling.** Buying its own stock can be a way for management to say it considers the shares undervalued. ## Why critics push back The core objection is that buybacks can favor the short term. Money spent retiring shares is money not spent on research, wages or new capacity, and the boost to the share price and to per-share earnings is immediate and visible. Executive pay sharpens the concern. Because many bosses are rewarded on per-share measures, a buyback that lifts earnings per share can also lift their bonuses, even without any improvement in the underlying business. An analysis published by the Harvard Law School Forum on Corporate Governance found that a large share of big companies use per-share metrics in incentive plans and often do not adjust them for the effect of buybacks, [the Forum reported](https://corpgov.law.harvard.edu/2023/07/16/share-buybacks-and-executive-compensation-assessing-key-criticisms/). Critics also question buybacks funded by borrowing, or run while a company underinvests. ## Buybacks versus dividends, and the tax angle Both buybacks and dividends return cash, but they differ in an important way. A dividend pays every shareholder in cash now, and is generally taxable in the year it is received. A buyback delivers its value through a higher share price and is taxed only when the investor chooses to sell, which lets the gain be deferred. That flexibility, companies can adjust buybacks year to year without the backlash a dividend cut invites, is part of why they have grown so popular. Policymakers have started to lean against them at the margin. Under the Inflation Reduction Act, the United States introduced a 1% excise tax on corporate stock repurchases, applying to buybacks made after December 31, 2022, [according to the Congressional Research Service](https://www.congress.gov/crs-product/R47397). The levy is small, and whether it meaningfully changes corporate behavior is still debated, but it marks a shift toward treating buybacks and dividends more alike. ## Sources - [S&P 500 Buybacks (Q3 2025 release)](https://www.spglobal.com/spdji/en/corporate-news/article/sp-500-q3-2025-buybacks-post-modest-62-gain-to-249-0-billion-after-declining-20-1-amidst-uncertainty-in-q2/) - [The 1% Excise Tax on Stock Repurchases (Buybacks)](https://www.congress.gov/crs-product/R47397) - [Share Buybacks and Executive Compensation: Assessing Key Criticisms](https://corpgov.law.harvard.edu/2023/07/16/share-buybacks-and-executive-compensation-assessing-key-criticisms/)