If an individual or a group obtain 5% of the shares of a publicly trading company by SEC they have to report within 10 days to the SEC on the form called 13D. The form will list the shareholders and the intent of the acquisition. If it is a hostile takeover, it should be stated.

I missed the purpose of the 13d in my first reading, so I thought I should share that paragraph with everybody.

If there are changes going forward, amendments are required. For example if the group acquires another 1% it is to be reported through an amendment. If the purpose changes another amendment needs to be filed.