According to CNBC, federal prosecutors had launched a criminal probe into the cryptocurrencies earlier this year based on suspicions that their price was being manipulated. I think it might be the main reason behind the price of bitcoin dropping to around $4000, but I also wonder whether it could be that authorities are afraid that Bitcoin and other cryptocurrencies are taking over the financial system since they're now so popular.
Manipulated? who's done it? How can you be sure about that? I think the main reason the price dropping so deep is because people started to sell their coins. moreover, sellers are actually are a bit more rather than buyer. It affects to the price of course. When Bank are afraid of bitcoin, I think people already know why.