Quote from: deisik on June 30, 2015, 11:23:04 AM

Quote from: RealBitcoin on June 30, 2015, 11:06:14 AM

2) There is such thing as downward volatility, i dont know the exact term, english is not my native language, but you calculate that just as the standard deviation, except you dont take the absolute value from the mean of both the above and below elements, instead you only count the items that are below the mean = price decreases. This indicator shows you the downward volatility, because the variance as such is an absolute value composed of 2 subsets of data.

I don't quite understand what you mean or how you calculate the value you speak about, but it won't be volatility, by any means. By definition, volatility means price deviation around some value, in both directions, that is, up and down. What you mean is most likely called trend and its range or strength...

Quote from: RealBitcoin on June 30, 2015, 11:06:14 AM

3) That was actually a joke, you cant short bitcoin, as in short in the financial sense. You can only buy & sell bitcoin, the "short" operation requires bitcoins to be printed out of thin air, or another collateral set aside by the exchange in form of swaps ( but thats just a workaround pseudo-shorting actually).
I know bitfinex does a good job with margin trading, but still you cannot short more bitcoins then they are on the exchange, whereas in the financial world with fiat money you can just grab a nice infiniate amount 0% interest fast loan and plummet a stock from 200$ to 1 cent in 15 minutes.

Actually, I'm not shorting Bitcoin in the sense of borrowing and selling it and then buying back at a lower price (or as luck would have it). I just started to sell my stash of bitcoins in small portions after the price had got above ~250$ (and buying back when the price rebounds)...

So far so good

1) This is the formula for my "downward volatility" , i dont know exactly the term for it, but if you calculate this, you will get that value, which will then show you the volatility of only the down movements, which should give you a risk understanding of bitcoin price crashes, because price increase doesnt matter, that is beneficial.

2) Well thats good for you, but if you want to short (which is much more simple @ bitfinex) you can short, and its simpler, because cashing out to dollar can be tricky with all the regulations and bank transfers, its just easier to put a short order when you think the price is going down, which i can already tell that it wont happen very soon.