Whales and institutional investors is the main factor that make the price in high fluctuacion. Without them, the market with sideaway in long time without any high fluctuacion. Usually before pump the market, whales will doing first accumulation that difficult to detect it. After they did accumulation, and then ready to pump. They did it to make profit and to shake the market to trigger others investor come in to market.
Whales are indeed one of the reasons why the cryptocurrency market is being manipulated. They want to make a profit by controlling the market and making people panic about the state of the market that has been controlled by the whales. Pump and dump will happen according to their plan. Many FUDs are spread to make the market price crash and buy them cheap and then make good news to take profits. Very simple, but market manipulation like the whales must be detected so as not to get caught up in the game.