You need incredible amounts of liquidity to move the market. Usually this would be a huge mistake, as moving against the market will surely fail. Remember the 30k bear whale on Stamp? He tried to hold the market down and failed miserably. Smart whales move with the market, not against it.
Moving with the market actually means riding on the bodies of the majority.
A market mover will be one that is forced in a net position through the counter-party.
His net position will decide the outcome of his next move.