This chart represents a historical price record of $BTC sitting in exchanges carrying the omni-based cryptocurrency Tether, $USDT. Displayed here, on the left is the rapid price fluctuations currently experienced by tether, and on the right Bitfinex's premium on Bitcoin compared to the price of Bitcoin on '$USD on-ramp' exchanges such as Bitstamp- which do not carry $USDT-$BTC pairings.