Originally Posted by HarryT
How is it "not true"? Unless you sell your shares, your "loss" is purely a theoretical one, as is your "gain" if the price goes up.
At first you have exchanged real money against shares. So you have 'lost' the money in the first place (at least at that point).
The value of the share is determined by the amount of money you get at that time. That means you loose or win monetary value (not money) every second.
Anyway, if it's better for your psychological state you can tell yourself that you didn't loose money.