transferring bitcoin among friends and taxes I gave my friend btc (ie sent it to their address) to trade together with their btc last week. I'm suddenly worried about taxes (in the US). If right now, they give me back exactly as much btc as I gave them, are there tax ramifications? Can I sell the btc after > a year and pay the 15% capital gains tax or whatever, or is there some short-term hold complication, and do I have to pay more?
They will most likely see any BTC credit in your account as "income" and you are taxable for it, unless you can prove it otherwise. This is a matter of when the IRS will start cracking down on these exchanges and request them to provide a 1099 for every user. I do not do trading via fiat because of this. The end-game is to acquire more Bitcoins, not fiat. 

When its time to sell your Bitcoin for fiat, you won't have to because everyone will be willing to take it. -- See this: http://imgur.com/gE8hDnY