BTC.sx

Btc.sx is the world's first Bitcoin derivative trading platform allowing users to trade both Long and Short on the price of Bitcoin. We allow positions to be opened with a single Bitcoin deposit and do not require a USD or cash deposit. In its first year, it has brokered over $50 million in trades and continues to be the market leader in its space. BTC.sx is backed by Seedcoin, the world's first seed-stage Bitcoin startup virtual incubator.