Celtics: the early selling seen today (you mention WDCO as playing the leading role), to exert downward pressure on the share price, was initially effective, and could have been intended to neutralize the consequences of the excellent PR. Since then the buys have prevailed over the sells, and quite a few investors have taken that "opportunity to get cheaper stock". When 'buying low' comes as a windfall opportunity flat in the face of great announcements, it's a good move to step in and 'seize the moment'.