Those 1-month FX contests are a joke. Anyone can trade with really high leverage and occasionally make 400% in a given month. There's a reason you never see the same people winning those contests month after month, though. Mr. 400% becomes Mr. Margin Call the following month. There's also a reason you rarely see 6- or 12-month contests. (I think FXStreet may run a longer-term contest, but I'm not sure.)
Leverage is a factor: - With an account value of 100k a FX Retail trader can scalp 5-10 millions and profit from the intraday market volatility. - HF manage several millions and can't scalp billions to replicate the same kind of performance: they have to scale in and out in longer time frame or to be much less leveraged. And investors would run away with the drawdowns showed by Duka's "trader's of the month"
No. You should not be asking this type of question. They are the outcome of selection bias. In layman terms, luck.
...and actually being paid 2/20 for it...in some cases 3/50 (SAC Capital). ay, ay, ay... I think, I have to change this landscape a bit and charge 4/60 for REAL PERFORMANCE