Are you serious? Do you think someone is going to send out the Bat Signal to notify “friend or foe”? To answer your original question: yes and yes…..as it is with 1, or 50 or 100, or 10,000 share transactions everyday the stock trades.
Foe. These are big block 'Dark Pool' trades. They're not known to the public until after execution which can sometimes take all day. Usually in small stocks like AMRN, this is released to the delayed consolidated tape after hours so as not to upset normal trading which could prevent the seller from executing at desired price if their activity were known to the public.
News 
Market Data 
Discover 
