[expatpat]

But, at some point currency profits may be taxed at exorbitant rates. So, a bank account overseas might be better for the long run.

Your profits will still be taxed by Obama if you stay legal. Even if you leave the US, assuming you are a US citizen.

[oblomov]

Yes, but if you don’t sell the other currency, a taxable event has not happened, and you won’t be taxed.