This is just speculation, but I think NITE smells something brewing & wants all the shares they can get at 19.  MM's have a wall set up with 4 of them on the ask for about 3 mill shares showing & nite has 5k on the bid at 19. They are also 1st on the ask.  But he has bought over 1/2 mill showing a 5k bid.  Seems like he is trying to trick people into selling at 19 and taking all comers.  Does he know something is coming?

This is absolutely an opinion, so don't trade according to this lack of sleep, coffee induced rambling.

Mitch