Why would you do that?
Bitcoin was / is a pretty cool technological innovation. But the main use-case seems to be buying illegal things or laundering money, and vast majority of transactions are just speculators.
Also, the fact that it is difficult to short is further evidence of a bubble.
1) Actual legitimate Bitcoin payments are increasing and real.
https://blog.bitpay.com/bitpay-growth-2017/
2) Even if this whole thing does collapse, never short something like Bitcoin unless you have unlimited cash to support such a short. Even if you're right, can you continue to sustain your short if the peak is $100,000 a coin before the collapse? (And the new bottom is $10,000, still higher than right now)
If the price goes there, can you afford the short?
>* Traders will devise a suitable risk management plan prior to initiating a short position. Unlike the media driven nonsense about a large activist shorting a bull market permanently, many traders can and do make leveraged long and short trades all the time, with the intention of exiting at a loss if the trade doesn’t go immediately (for some definition of immediately) in their favor. *
In my experience working at prop firm that was trading (speculating) on futures, this is the case. We would enter leveraged short/long positions based on some kind of signals with some kind of risk framework for all assets in the portfolio.
Also a smart shorter will always put in a stop loss price, but stop losses can slide because cryptocurrencies move fast.
I’ve been watching bitcoin since sub-$1 prices. A further 10x increase at some point is not so crazy.
If you want to make money, buy BTC. You might win and you might lose, but your odds are far better than if you try to short something that has made a 1000% gain in the last 12 months.
I'm not saying there are no good uses for bitcoin, of course. For example, if someone used bitcoin to import prescription drugs from Canada to the U.S, that's great. But it doesn't justify a $100B+ market cap, and as it stands, the hard part of doing that is importing the drugs, not exporting the money.
Similarly, just because Tor is useful mostly to criminals and a few human-rights advocates or privacy enthusiasts, I don't expect the Tor Browser to ever gain a major market share.