Tether (USDT) pairs that do not exist on Bitfinex continue to rank high on CoinMarketCap
Mystery of Bitfinex USDT to USD Pair
According to Carylyne Chan, Global Marketing Lead at CoinMarketCap, the data is collected from Bitfinex's own API. In other words, Bitfinex's API is delivering data to external applications. Chan has submitted an API link for volume data points to CoinDesk (1*).
What the "volume" data point for a non-existent trading pair represents. Chan notes that CoinMarketCap is also confused by this fact;
“Based on this endpoint, like other sites, we are trying to display all pair data that the exchange provides through the API. As you asked, we are also contacting Bitfinex to clarify what this endpoint represents. However, there has been no response to our multiple inquiries.”
On the other hand, Bitfinex's Marketing Lead Kasper Rasmussen stated to CoinDesk via email;
“We do not directly provide a USDT to USD pair on Bitfinex. It is likely representing deposits and withdrawals or similar. USDT is only used as a transport layer on Bitfinex.”