If crude went to 80 a barrel within a week or two you would see a big spike. But you won't see it hit the 400's because there is a drag associated with the product. Not sure about UWTI but if it trades CL futures the drag will usually be much more (as they rotate front month futures into back month futures there will be drag whenever there is contango which is normally) than if there are just management fees. But ye these products all have a drag that brings them down over time to the point where they eventually have to do a reverse split so holding them for long periods will net a loss vs the product they are holding.