Crypto trading, or cryptocurrency trading, is simply the exchange of cryptocurrencies. Like in Forex, you can also buy and sell a cryptocurrency for another, like Bitcoin or altcoin for USD and Euro. This is one way of getting involved in the world of cryptocurrencies without having to mine it.
The Big Bit Trading works through financial institutions and operates on several levels. Trades between foreign exchange dealers can be very large, involving hundreds of millions of dollars. Because of the sovereignty issue when involving two currencies, Big Bit Trading has little (if any) supervisory entity regulating its actions.