[broiler]

I would say that 40% sounds steep in terms of the tax rate for that win. Of course, I say that without knowing what your income tax situation is. My initial thought is always in the 25-33% range.

Your tournament win is gambling income, just like any other poker winnings that you have for the rest of the year. The only thing that I would add is that with a $10k win, your Party account has more than $10k in it and now you have a foreign account that must be reported. No tax is due for reporting the foreign account, but there are penalties for not reporting and getting caught.