what is schedule 13d 
schedule 13d is a form that must be filed with the u s securities and exchange commission sec when a person or group acquires more than 5 of a voting class of a company s equity shares schedule 13d must be filed within 10 days of the filer reaching a 5 stake schedule 13d is also known as a beneficial ownership report understanding schedule 13dinvestors may decide to buy a large number of shares in a publicly held company for a variety of reasons for example they could be activist investors attempting a hostile takeover institutional investors who believe the stock is undervalued or a dissident shareholder contemplating a proxy contest with the goal of replacing management 