My last trade of the year 2009 went horribly wrong and I'm still stuck. I haven't closed my position. Before that trade, I'd had a small net profit, but with that trade which is still open, I have a net loss as of December 31, 2009. Most of the trades I've made are short sales, so they are treated as income. From a tax point of view, do I have a net profit or loss? Do I need to pay taxes even though I'm far underwater? Thanks!