if I day trade QQQ/SPY/USO, is the profit/loss reported in schedule D or will it count as income due to partnership as the way ETF organized?
Securities ETFs are like trading stocks tax-wise. Commodities ETFs are also securities when it comes to a sale, but you may receive a K-1 at tax time with some income or loss to report. Then you need to adjust your cost basis too for the sale transaction. Learn more here Mar 23 11 - ETF tax and regulatory issues http://www.greencompany.com/blog/index.php?postid=109
In any business transactions, you should consider all the consequences before deciding up. Do not instantly approve it. You must study it first before making any move.