i think there is an opportunity to make anywhere from 0 to 50% in one single day and one single trade. its upto the person, his strategy, and the market in his favour. believe me i made 40% in one single trade on january 7th 2009. so far i never had such big profit or loss. but i gtta admit i am a newbie and i was paper trading that time.lolz.
but the thing we need to watch is the strategy, i always use full leverages.
i have lost upto 15% of my capital intraday, but again all on paper.
i do dis every day same strategy and full leverages, and end of the month it gives me a result of anywhere from 50- 200% no kidding
cheers!!!