如何做空比特幣

????你敢對賭比特幣泡沫終將破裂嗎？

????當然。但這將是一筆代價高昂的交易。而如果最終泡沫破裂，即使投資者能從中獲益，利潤也不會太高。

????對賭的傳統方式是“做空”。要想進行賣空交易，就必須先借入你要對賭的股票或債券或其他任何東西。而借入比特幣幾乎是不可能的。據稱香港一家公司正在測試提供比特幣做空交易，但筆者并未找到太多這方面的信息。

????投資者可以購買衍生工具合約，等到比特幣價格下跌時，合約價值就會上漲。目前，有許多機構推出了比特幣期權和期貨產品。

????其中一家機構是莫斯科的比特幣交易所ICBIT。

????比特幣股權交易所MPEx也推出了比特幣期權。這家交易所為以比特幣交易股份的公司提供股權交易服務，目前共有四家這樣的公司。

????布魯克林交易處理商BitInstant正計劃在明年年初成立一家比特幣期權交易所。

????這些機構均要求開立賬戶后才能進行交易，而且都不接受美元。所以，你首先必須從其他地方購買比特幣，然后將其轉入ICBIT或MPEx的賬戶后才能開始交易。而購買比特幣本身就有很大難度。

????在MPEx開設賬戶要收費30個比特幣，按照周三的收市價格，這相當于33,000美元。

????好消息是，ICBIT可以免費提供賬戶，但要收取交易傭金。而要想查看合約價格，投資者必須啟動賬戶，并存入最低0.1個比特幣。（比特幣可以分割到小數購買。）

????我決定從經紀公司Coinbr展開調查。這家公司允許投資者在MPEx上交易期權，無需在MPEx開立賬戶。不過，如果要開始交易，仍需在Coinbr的賬戶中存入至少0.1個比特幣。好在MPEx允許任何人查看合約價格，所以在開始操作之前，你能比較清楚地了解情況。

????首先：既然投資者計劃做空比特幣，自然要買入看跌期權。所謂看跌期權是指允許投資者以預定價格賣出投資品的衍生工具合約。如果該投資品的實際價格下跌至預定價格或執行價格以下，則投資者能夠獲利。

????投資者也可以賣出看漲期權（以預定價格購買的權利），但這種操作的風險更高，而且需要抵押。因此，筆者還是堅持看跌期權。

????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.