This is an interesting development in Cryptocurrencyland. Tether is a USD peg using an ERC20 token (Ethereum) that has existed quite successfully for about 3 years, despite hard evidence that the 2B+ in USD that backs the currency is actually there. Willy-nilly USDT printing has been implicated in the crypto bubble of winter 2017.
Over the last several days, tether (USDT) has been sliding. Bitfinex (the exchange/company that controls Tether) has been pulling USDT out of circulation (-$250M yesterday), but as of yet, USDT has not recovered its peg.
Of interest, BTC, ETH and others have been trading at a premium on Bitfinex, possibly because traders are dumping USDT for crypto to get off of the exchange. This would be similar to the BTC bubble in 2013 created by an inability to get USD off of MtGox.