The expiration of CBOE contract. We have seen many times that when the contract expires, there will be down or up moments in the market. But this moment was very big by breaking the support level of bitcoin $6000.
CBOE contract expiration could not led to this drastic change in the market, there might be some other reasons too.
Second is the twitter news from Craig Wright, who said they gonna bring the bitcoin to $1000 if the miners do not support BCH. This may not be the exact reason.
As we all know that on 12 December the Bakkt platform will be lunch. It might be the biggest platform for the institutional investor to enter in cryptocurrency. And Bakkt need a lots of Bitcoin before lunch and they need a huge amount of bitcoin.
The current market was was around $7000. They need to drop it down so they can accumulate the bitcoin.
Stay safe guys...