> This is not gain at all. At least in theory: You own some tons of gold at the start of the process, you have the same tons of gold at the end of the process.

I see a lot of comments like this but I just can't get my head around what you are trying to prove (or disprove).

Every definition of gain (or loss for that matter) implies that the same amount of _something_ is now worth more (or less) than when you bought it.

Following you logic, if I buy a share of MSFT at $10, sell it for $100, there is no gain because I still have 1 share of MSFT?