Its just rumors about BANs , probably they will start regulate more whos buying and selling crypto . The market drop i guess is only because there is rumors/proofs that Tether made tether tokens of thin air and buy BTC with it to drive price up . You can read it here https://www.bloomberg.com/news/articles/2018-01-30/crypto-exchange-bitfinex-tether-said-to-get-subpoenaed-by-cftc