Due to some but considerable negative effects happened in last period such as , Government restrictions against Bitcoin, Banning, Criminal activities using Bitcoin, Panic token holders and other false rumors that made ridicules accusations against Bitcoin
Although we are facing such problems for a long long time where bitcoin managed to survive and I am hopeful that it will even survive in more critical condition, but in current time I think that the reason for the decrease of bitcoin price is because of some bad news that are wondering in the market.