So, after all, nothing happened? Or market just slow reacting?
Probably not. Market manipulation is harder than it sounds. CME limits what an entity/group/person can hold, which makes it almost unprofitable given the cost of manipulation.
On the other hand, this futures expiration dip is more of a fud than an actual event. Price fluctuates too much not because of actual manipulation, but because people expects and are afraid of that manipulation.
See, nothing happened. As Maveth says, CME on its own cannot really do much, so this was nothing much to do with futures in the first place. As people keep reminding anyway, none of the contracts actually involve Bitcoin. It is just a bunch of people betting on whether the price goes up or down.
As yes, the actual event does not cause price fluctuations, rather people react in anticipation of news, and events. They either panic and sell out of fear and uncertainty, or buy in the fear of missing out, this is the herd mentality famous in trading.
The way I see it is that the inflating price of BTC we witnessed towards the end of November and throughout December could have been big business/governments buying up lots of BTC. Then in order to manipulate the price downwards to ensure the Futures contracts executed successfully, many of these BTC are sold. This would explain the fact that $50bn falls off the market in less than 1 hour around a week ago...