I have more than 1M of this stock :( and accumulated it not at this price but in the way you described.
The answer is: in the current volume there a lot of shares circulating between same people (no finger points!). So it is not about accumulation it is about everaging investment buy using the market situation and NOT decapitation.
Of course it is IMHO, but I am the person made some days 30% of the day volume on BMK.