Quote from monty21:
Probably just outperform the market relative to the amount of risk they take. That's why on a $100,000,000 account I can only see arbitrage strategies used.
You can't just day trade a $50,000,000 account the same way you can a $5,000,000 one. Guys that trade with less than $1,000,000 can return 300%.
So it has to do with total profit, rather than %. Consistent profitability is also better than speculating, taking great risks, and outperforming a more conservative guy.... the consistent trader will win in the long-run.
Read fooled by randomness... traders sometimes don't understand the role of chance in a short-term time frame. (If you happen to be long more times than short in a bull market, does that make you a good trader? Is it skill or just probability?)