Tether has a history of manipulating the Bitcoin price and bringing an artificial pump and many a times Bitfinex has been criticized for the same. There are many reports backing this claim that Tether are strategically being printed during a downtrend to bring BTC back in uptrend. This does effect market for a short period and brings in an inorganic growth. But market always recovers from such an artificial pump.

This is the problem that keeps institutional investors away from crypto market. They can't enter in something which is highly manipulated. But as SEC is doing in some research, institutional money is expected to enter the market soon.