This is a good question and I am sure that the currency traders have a better answer for us than stock traders. But there is another side and that is the IRS. There is a fair amount of speculation on how the IRS views profit and loss. As that becomes clearer then I think that will be the same way you will view it because who wants to keep two sets of books. Most of what I have seen so far is the worst outcome of putting every exchange valued in equivalent dollars at the time regardless of whether $ are used in the transaction or not.