Can someone look over my code and see why I'm getting +2000% returns on Jan 31 2011? I was looking over the backtest results and saw the culprit was PXG, but the strange thing is my leverage is tracked and sticks right around 1. This is strange because on the 30th the algorithm had 393 shares of PXG, and then the next day the algorithm had 74804 shares. I'm still pretty new to python and quantopian, so any other advice/suggestions would be greatly appreciated!