Quote from logic_man:
I once read an essay on money management and position-sizing that said almost any return was possible, provided the trader is willing to put up with the resulting volatility of the equity curve. I keep a running tab of what my strategy would generate if I were using Kelly betting sizes. It's way more than 4%/day, but it also would have led to some 90%+ drawdowns from equity peaks. So, if you can obtain the leverage and don't mind the equity curve volatility, any positive expectancy strategy can generate 4% daily returns. Ultimately, you'd run into liquidity issues, of course, because no market, not even the ES, is large enough to keep compounding at that rate for more than a short time, relatively speaking.