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A form that an individual or organization must file with the SEC declaring the purchase of 5% or more of a publicly-traded company's voting stock. The Schedule 13D form must be filed within 10 days of such a transaction. When an investor buys a large amount of voting stock, it gives him/her a degree of control over the company's operations and may be a harbinger of a takeover attempt. Schedule 13D exists to promote transparency in the market and to comply with Rule 13D.
An SEC form required of anyone who acquires ownership of 5% or more of any publicly traded corporation's equity securities. The schedule must be filed with the SEC within ten business days of the date on which the 5% threshold has been reached.