[colanderman]

You don't have to pay any tax on Bitcoins you own. You have to pay tax on the USD proceeds you make from their sale. This is no different from any other source of income in the US. Even bartering you have to pay taxes on: https://www.irs.gov/taxtopics/tc420

You can of course disagree with the concept of income tax, but Bitcoin is no special goose in that regard.

[lostboys67]

Depends if its treated as coinage or as a good - I don't pay CGT if I buy gold coins and sell it for a gain when it goes up in the UK for example