Well there's some fresh FUD for you, someone started selling USDT to USD at exact same time someone shorted BTC to USDT
I wonder how much is underwater
They record the number ofmargined longs and shorts, measured in BTCs.
Example: on 2018-04-22 BTCUSDLONGS closed at 28341.8851 and BTCUSDSHORTS closed at 24171.6528. This tells us that the value of margined longs held at Bitfinex was worth 28341.8851 Bitcoins. You might infer bullish sentiment at that moment because BTCUSDLONGS exceeded BTCUSDSHORTS. But note that the information says nothing about how many traders were involved nor how many longs and shorts. Theoretically, the entire BTCUSDLONGS position (28341.8851 BTC) could be held by just one margin trader, and total longs (ie margined longs + unmargined longs) could be any reasonable number you might imagine.
The same conclusions apply to BTCUSDSHORTS.
When both BTCUSDSHORTS and BTCUSDLONGS are displayed in the same window / pane they provide a crude indicator of market sentiment and historic popularity of margin trading in the BTC spot-market on Bitfinex exchange.
Currently it appears that no other exchange provides similar information, but fortunately Bitfinex is a big exchange so the information becomes a reasonable sample / proxy for the BTC market as a whole.
In this case ticker BTCUSDLONGS is divided by BTCUSDSHORTS, leading to ticker "BTCUSDLONGS/BTCUSDSHORTS"
Type that in and press Enter