如何做空比特币

    你敢对赌比特币泡沫终将破裂吗？

    当然。但这将是一笔代价高昂的交易。而如果最终泡沫破裂，即使投资者能从中获益，利润也不会太高。

    对赌的传统方式是“做空”。要想进行卖空交易，就必须先借入你要对赌的股票或债券或其他任何东西。而借入比特币几乎是不可能的。据称香港一家公司正在测试提供比特币做空交易，但笔者并未找到太多这方面的信息。

    投资者可以购买衍生工具合约，等到比特币价格下跌时，合约价值就会上涨。目前，有许多机构推出了比特币期权和期货产品。

    其中一家机构是莫斯科的比特币交易所ICBIT。

    比特币股权交易所MPEx也推出了比特币期权。这家交易所为以比特币交易股份的公司提供股权交易服务，目前共有四家这样的公司。

    布鲁克林交易处理商BitInstant正计划在明年年初成立一家比特币期权交易所。

    这些机构均要求开立账户后才能进行交易，而且都不接受美元。所以，你首先必须从其他地方购买比特币，然后将其转入ICBIT或MPEx的账户后才能开始交易。而购买比特币本身就有很大难度。

    在MPEx开设账户要收费30个比特币，按照周三的收市价格，这相当于33,000美元。

    好消息是，ICBIT可以免费提供账户，但要收取交易佣金。而要想查看合约价格，投资者必须启动账户，并存入最低0.1个比特币。（比特币可以分割到小数购买。）

    我决定从经纪公司Coinbr展开调查。这家公司允许投资者在MPEx上交易期权，无需在MPEx开立账户。不过，如果要开始交易，仍需在Coinbr的账户中存入至少0.1个比特币。好在MPEx允许任何人查看合约价格，所以在开始操作之前，你能比较清楚地了解情况。

    首先：既然投资者计划做空比特币，自然要买入看跌期权。所谓看跌期权是指允许投资者以预定价格卖出投资品的衍生工具合约。如果该投资品的实际价格下跌至预定价格或执行价格以下，则投资者能够获利。

    投资者也可以卖出看涨期权（以预定价格购买的权利），但这种操作的风险更高，而且需要抵押。因此，笔者还是坚持看跌期权。

    Can you bet on the likely eventual bitcoin crash?

    You bet. But it's an expensive trade. And even if you're right, you won't walk away with much, if anything.

    The traditional way you bet against something is to "short it." But in order to do a short sale you have to borrow a share of stock or bond or whatever you are looking to bet against. And borrowing bitcoins is nearly impossible. There is a company based in Hong Kong in testing phase that seems to offer bitcoin shorting, but I couldn't find out much about it.

    What you can buy is a derivative contract that will rise in value when bitcoins fall in price. There are a number of places that sell options and futures on bitcoins.

    One place -- ICBIT, a bitcoin exchange -- is run by a guy in Moscow.

    MPEx, a stock exchange for companies with shares traded in bitcoins -- there are four of them -- also lists bitcoin options.

    BitInstant, a Brooklyn-based payment processor, is planning on launching a bitcoin futures exchange early next year.

    All of these places require that you open an account to start trading, and none of them take dollars. So you have to buy some bitcoins elsewhere, which in itself is no easy task, and transfer them to your ICBIT or MPEx account before you can get started.

    MPEx charges 30 bitcoins to open an account, which at Wednesday's closing price was $33,000.

    I heard good things about ICBIT, which offered accounts for free but charges a commission when you trade. But to see the prices of the contracts, you had to get your account up and running and deposit a minimum of 0.1 bitcoins. (You can buy bitcoins in fractions.)

    I decided to check out Coinbr, a brokerage firm that allows you to trade options on MPEx without opening an account there. You still have to deposit 0.1 bitcoin in a Coinbr account to get started. But MPEx allows anyone to see the prices of its contracts, so you know what you are getting into before you start.

    Here we go: If you are betting against bitcoins, what you want to do is buy a put option, which is a derivative contract that allows you to sell something at a set price. If the actual price of the thing falls below the set price, or strike price, you make money.

    You could also sell a call option, the right to buy at a set price, but that is riskier and requires collateral. So I stuck to looking at put contracts.