Once any person or group of persons (affiliates and collaborators constitute a group) acquires 5% they have to make a public filing of their ownership interest with the SEC. And other rules kick in if they are acquiring for the purpose or having the effect of changing or influencing the control of the issuer of the securities.
Any legal analysis I post may not be relied upon by anyone for any purpose. If you want legal advice you can rely on, hire a lawyer. Federal District Courthouse, Newark