another possibility on todays tradinghave seen this before several times in the healthcare sector , mostly on US exchanges (usually when some big money hedge fund or BP or both are combined) employs "fade" strategies meant to wear out retail (lots of 100 share lots hitting the bid, and 4 out of 5 days in the red))...and during this when some good news comes out from the target company they simply "sell the pop" (actually very easy for them to do) .... this works very well on retail because it frustrates them and adds to the "fade" strategy often already being used..... causing many retail to throw in the towel with frustration...