Since a portion of the Fund’s assets are invested in short positions in bitcoin futures contracts, the Fund will likely decline in value when the price of bitcoin futures contracts goes up (unless such losses are offset by gains in the value of the Fund’s positions in other investments), a result that is the opposite from the results of taking long positions in bitcoin futures contracts.
Bitcoin is pseudonymous rather than anonymous in that the cryptocurrency within a wallet is not tied to people, but rather to one or more specific keys (or "addresses"). Thereby, bitcoin owners are not identifiable, but all transactions are publicly available in the blockchain. Still, cryptocurrency exchanges are often required by law to collect the personal information of their users.
This means simply that you put down 1 bitcoin and you can trade 20 on OKCoin, or 100 bitcoin on BitMEX. The multiple refers to the initial margin you need to open the nominal position value. You simply set the margin aside as collateral, and if the position goes against you, the collateral will be used to exit your position into a liquidation, or margin call.
In this guide we don't want to deal with social loss risk, so use the FCA-regulated, London-based bitcoin derivatives exchange CryptoFacilities. They offer contracts with 2% margin requirement (50x leverage) as well as a 15% margin requirement (6.5x leverage). They are 100% bitcoin based, but they don't accept US customers. Sign up here to get started: