Don't you have to MAKE a profit first for it to be taxable?
Seriously though, BTC seems to have found a floor around $6400, however the lack of transparency and the conflicted interests of some of the mining hardware manufacturers who are also big holders means you can never be sure where the floor really is.
I think I read somewhere that the total market value of either Bitcoin or it might have been all the virtual currencies is about $220bn, that's about 1/5 of the amount bet on the Asian gambling markets in a 'normal' week.....in other words far too easy to move the whole market if you assume that maybe 20-40% of the total market value is liquid.