Unlike a majority of the newcomer cryptocurrencies of 2017, Tether has maintained an almost constant price of $1. This currency is designed to be backed by an underlying Fiat currency, unlike the other cryptocurrencies. This means that 1 USD is backed by 1 Tether (written 1 USDT). It is a widely integrated digital-to-fiat alternative currency. You can use, sell or buy Tethers on Shapeshift, GoCoin, Bitfinex and other exchanges.
The constant price of Tether can partly be attributed to the fact that it is backed by actual Fiat currencies. The price change to be observed on this altcoin reflects a lot of what is happening to the real world currencies. However, the market capitalization of this altcoin is simply astronomical. At the start of January 2017, the market capitalization was $9.951 million. It has grown steadily over the months to reach a current high of $853.9 million. The current price of the altcoin is $1.02. It remains to be seen how the stepping in of CME derivative exchange into the crypto market will influence the prices.