Manipulation is nothing new in Market. There may have little manipulation in Crypto too. But I dont think not in any form of Cartel. This is just mare speculation. Its pretty tough to manipulate a market that is based on decentralization.
any market can be manipulated. The financial market it's self is pretty decentralized (even more then bitcoin). If you think of it over 50% of the BTC mining market is in china and is controlled by 4 organizations. What financial market in the world is more at the whim of so few people? Can you imagine the potential for inside trading here? And what's worse is that because of the de-regulation and pseudo-anonimity of bitcoin this is neither illegal, nor easy to prove. You wanted total freedom with your money? You have it. No rules other then jungle rules. Survival of the fittest.