May 28th, 2015, 10:20 am
I think you are missing something, although it could be that your use of "hedge" is different from what I have in mind. In a complete market, the relationship between different instrument prices are functional (it is usually possible to define the value of a security at a point in time as a function of a set of state variables) and measure independent. In that case, theoretically perfect hedges can be calculated and these will also be measure independent. If your market setting is incomplete, however, and you are implementing some kind of minimum variance hedge, then all sorts of things can be measure dependent, but then I would question the wisdom of engaging in measure changes to begin with.