A stock buyback is a company's use of its own cash to repurchase its own outstanding shares, which shrinks the share count and mechanically raises earnings per share without any change in underlying profit. Buybacks by publicly traded U.S. companies now carry a 1% federal excise tax on repurchases made after December 31, 2022, under final regulations the Internal Revenue Service issued in 2025.
For a long-term investor, buybacks matter less as a headline number and more as one of two main ways a company can return cash to shareholders, the other being dividends. Understanding the mechanics, the disclosure rules, and the tax now attached to repurchases helps separate a company genuinely returning capital from one merely offsetting new share issuance.
What is a stock buyback?
A stock buyback, also called a share repurchase, is a corporate transaction in which a company spends cash to buy shares of its own stock, typically retiring them or holding them as treasury shares. The immediate effect is fewer shares outstanding. Because per-share metrics like earnings per share and dividends per share are calculated by dividing a fixed pool of profit or cash by the share count, a smaller share count raises those figures even if total company profit is unchanged.
How do companies actually buy back shares?
Open-market purchases made through a broker are the dominant method, accounting for roughly 95% of buyback activity, according to a mechanics explainer published by The Motley Fool. Companies using this method are generally limited to buying no more than 25% of a stock's average daily trading volume, a restriction meant to prevent the purchases from severely distorting supply and demand for the shares.
Three less common methods also exist, per the same source:
- Fixed-price tender offers, where a company invites shareholders to voluntarily sell a set number of shares at a specified price.
- Dutch auctions, where investors submit offers within a price range and the company buys at the lowest price needed to reach its target share count.
- Private negotiations, used for large, concentrated holdings, and less commonly, agreements involving put options tied to a future share-price trigger.
Why does a buyback increase earnings per share?
The effect is arithmetic, not operational. In a hypothetical illustration used by The Motley Fool to explain the concept, a company earning $5 million in annual profit with 1 million shares outstanding reports $5.00 in earnings per share. If that company repurchases 50,000 shares, the same $5 million in profit is now divided across 950,000 shares, producing $5.26 in earnings per share — a roughly 5% increase with no change in the company's actual profitability. This is a hypothetical illustration only; it assumes profit stays constant and no new shares are issued elsewhere, an assumption that does not always hold at real companies that also grant employee stock compensation.
What must companies disclose about their buybacks?
The Securities and Exchange Commission adopted amendments in May 2023 requiring public companies to disclose daily repurchase activity — the number of shares bought and the average price paid — along with the rationale for the buyback and the criteria used to determine its size, according to the SEC's own press release announcing the rule. The amendments also added checkboxes flagging officer and director trades made during a repurchase announcement period. For most companies, the requirement began with the first periodic filing covering a full fiscal quarter starting on or after October 1, 2023. Then-SEC Chair Gary Gensler said the changes were meant to “increase the transparency and integrity” of buyback programs and narrow the information gap between issuers and investors, per the same release.
What is the federal buyback tax, and does it change the math?
Since the start of 2023, publicly traded U.S. corporations have owed a 1% excise tax on the fair market value of stock they repurchase, a levy created under the Inflation Reduction Act. The IRS finalized detailed regulations for the tax in late 2025, effective November 24, 2025, which apply the tax to “covered corporations” — domestic companies whose stock trades on an established securities market — while excluding repurchases tied to certain reorganizations, take-private deals, and retirement-plan contributions, and exempting companies whose annual repurchases fall under $1 million, according to the Internal Revenue Bulletin publishing the final rules.
The tax is a real, if modest, drag on the earnings benefit buybacks produce. S&P Dow Jones Indices, which tracks buyback spending across the S&P 500, reported that the excise tax reduced aggregate S&P 500 GAAP earnings by 0.50% for full-year 2024, based on that year's repurchase volume.
How large are buybacks right now, and does that matter for a portfolio?
S&P 500 companies spent a record $942.5 billion on buybacks in 2024, up 18.5% from $795.2 billion in 2023, according to S&P Dow Jones Indices. Fourth-quarter 2024 spending alone reached $243.2 billion, up 7.4% from the prior quarter. “After declining in 2023, companies have increased their buyback expenditure and set an annual record in 2024,” said Howard Silverblatt, senior index analyst at S&P Dow Jones Indices, in the firm's report on the data. These are historical figures for 2023 and 2024 only and are not a forecast of future buyback activity or stock performance.
For a long-term investor, a rising industry-wide buyback total is not, by itself, a signal to buy or avoid any stock, and this article does not recommend any action on individual securities. The more useful question at the level of a single company is whether its buybacks are shrinking the share count investors actually hold, or largely offsetting new shares issued through employee stock compensation — a distinction visible in a company's reported diluted share count over several years, not in the buyback dollar figure alone. Comparing buyback spending, dividend payments, and free cash flow over time, rather than reacting to a single quarter's headline, is consistent with the long-horizon approach this publication takes to capital-return decisions generally.
This article is for information and education only. It is not personalized investment advice, and it does not recommend buying, holding, or selling any security.
For a related stocks perspective, read How S&P 500 Index Additions and Deletions Actually Work.
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