Schedule 13D
An form that must be filed with the SEC under Rule 13D when a person or group acquiring more than 5% of any class of a company's shares to disclose this information within 10 days of the transaction. Rule 13D requires the owner to also disclose any other person who has voting power or the power to sell the security.
Investopedia Commentary
Once the disclosure is made to the SEC, the company and the exchange(s) on which the company trades are notified of the new beneficial owner.
You can find most company's 13D filings in the SEC's EDGAR database.
Related Links
Policing The Securities Market: An Overview Of The SEC
Defining Illegal Insider Trading
See also: EDGAR, Exchange, Issuer, SEC, Securities Act of 1933
Also spelled: Schedule 13d
Schedule 13D