They really are, big whales do manipulating the bitcoin price. Those groups are just doing the dumping and pumping the coins, so they are making a lot of profits consistently for having that advantage. One of them is the chinese group which have the half amount of bitcoin network.
Are you talking about Bitmain and Antpool,yes they have a huge amount of coins and so they could manipulate the market and juice the maximum profit out through trading but i am not sure how much they are manipulating other than they supported BU,nothing is true unless it is proved otherwise. Waiting to hear some positive news so that the price rises again.