Its full of systems that short stocks/etfs but in C2 you dont use any kind of Stock Borrow Fee to calculate performance, that give very bad image of the reality.
Right now: IB-Stock Borrow Fee for DUST 14,5% and NUGT 2%
A system like this: https://collective2.com/details/104155140 short all year similar instruments like that.
Then you show a very different performance than the real one, if you will calculate this fee the performance is the half of the one you show in the results of C2.
I’ve found this big discrepancy after analysis some of the systems I follow and dont see real performance close to the hipotetically performance in C2.
This fee is much bigger in some cases than open/close fees but are you not counting properly