Poloniex let's you do something very close: short BTC/USDT. USDT is a digital currency called Tether[1], one unit of which is approximately equal to $1. Why no

Poloniex let's you do something very close: short BTC/USDT. USDT is a digital currency called Tether[1], one unit of which is approximately equal to $1. Why not allow deposits of USD instead of the USDT workaround, you may ask? My theory is so that the exchange is not subject to the same level of oversight as it would if it accepted dollars - look at the BTC-e situation for example. What's amazing about Poloniex is that they're one of the most popular Bitcoin/altcoin exchanges, and almost nothing is known about those running it (it's US based). [1] https://coinmarketcap.com/assets/tether/ https://coinmarketcap.com/assets/tether/