Schedule 13D

Last updated: September 29, 2025

Quick definition

Schedule 13D is an SEC filing that individuals or groups must submit when they acquire more than 5% ownership in a publicly traded company's voting stock. The filing reveals who the buyer is, why they bought the shares, and what they plan to do with their ownership stake—making it especially important for activist hedge funds.

Schedule 13D is one of the most critical reporting requirements that hedge funds face when making large equity investments. This is particularly true for funds that pursue activist strategiesInvestment approaches where funds buy significant stakes in companies to push for operational, financial, or strategic changes through direct engagement with management or proxy contests., where they buy significant stakes in companies to push for changes. The filing acts as an early warning system that alerts companies and their shareholders when someone accumulates a substantial ownership position.

The Securities and Exchange Commission (SEC) recently updated these rules in 2023-2024. The changes shortened the time investors have to file these reports, ensuring that the market gets information about major ownership changes more quickly.

Under Section 13(d) of the Securities Exchange Act of 1934, anyone who acquires more than 5% of a company's voting stock must file Schedule 13D within five business days. This applies to any class of voting equity securitiesShares or other equity instruments that provide holders with voting rights in corporate governance matters. that are registered under Section 12 of the Exchange Act. The filing must include detailed information about the buyer's plans or proposals for influencing control of the company.

The SEC shortened this deadline from the previous ten-day requirement as part of its effort to modernize disclosure rules for today's fast-moving markets. This change means that investors and funds must act quickly once they cross the 5% threshold.

Schedule 13D requires extensive disclosure across several key areas. First, filers must identify themselves and provide background information about who they are. They must also explain where the money came from to buy the shares and how much they spent on the acquisition.

Most importantly, the filing must describe the purpose behind the purchase. This includes any plans the buyer has for the company, whether they intend to seek control, or if they plan to propose changes to management or business operations. The filer must also report exactly how many shares they own and disclose any contracts or arrangements they have with other parties regarding the company's securities.

The rules also cover derivative securitiesFinancial instruments whose value is derived from underlying assets, including options, futures, swaps, and forwards.—financial instruments whose value is tied to the company's stock price, including cash-settled derivativesFinancial instruments settled in cash rather than physical delivery of the underlying asset, whose value depends on the performance of stocks, bonds, commodities, or other assets.. This comprehensive disclosure helps inform the market about significant ownership changes and potential battles for corporate controlThe power to direct the management and policies of a corporation through ownership of voting shares or other governance mechanisms..

Once someone files an initial Schedule 13D, they must update it whenever material facts change. Under current SEC rules, this means filing an amendment within two business days of any significant development. An increase or decrease in ownership of 1% or more automatically counts as material and triggers the amendment requirement.

Other material changes that require amendments include shifts in investment strategy, changes in how the investment was funded, or modifications to the buyer's plans for the company. This ongoing disclosure requirement ensures that the market stays informed about evolving situations.

Activist hedge fund managers must pay particularly close attention to Schedule 13D requirements because their investment strategies typically involve taking large positions in companies specifically to drive change. For these funds, the filing serves a dual purpose: it fulfills a legal requirement while also serving as a strategic announcement that signals their intentions to company management and the broader market.

The accelerated filing deadlines that took effect in 2024 create additional pressure for activist funds. They must now maintain sophisticated compliance systems that can meet the tight reporting deadlines while still allowing them to execute their investment strategies effectively. This means having processes in place to track ownership levels, monitor crossing the 5% threshold, and prepare comprehensive filings quickly when required.

DISCLAIMER: THIS PAGE OFFERS GENERAL EDUCATIONAL INFORMATION ABOUT FINANCIAL AND LEGAL TERMS. IT IS NOT INTENDED TO PROVIDE PROFESSIONAL ADVICE AND IS PRESENTED "AS IS" WITHOUT ANY WARRANTIES. THE CONTENT HAS BEEN SIMPLIFIED FOR CLARITY AND MAY BE INACCURATE, INCOMPLETE, OR OUTDATED. ALWAYS SEEK GUIDANCE FROM QUALIFIED PROFESSIONALS BEFORE MAKING ANY DECISIONS. DATABENTO IS NOT RESPONSIBLE FOR ANY HARM OR LOSSES RESULTING FROM THE USE OF THIS INFORMATION.

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