I bought some oil 3x bull etf for fun in early december 2015, it was around $6 while oil future was around $40. Now is around 3 months later, oil future is back to around $37.5 but the etf price is only around $2.5 which is not even half of $6. I know there are factors like contango and etf management fee but this is just 3 months time period. If anyone can show some explaination or math would be very helpful. Luckily I just bid very small amount of money.