There is no loss, money just go from one bank account to another and Bitcoins from one adress to another.
The amount of money in banks stay the same.

But I'm asking you that because a friend ask me who is loosing the profit we make?

That was a very easy question to answer, who ever sold YOU the coins is the one who lost out on the profit that you gained.

Sometimes it s so easy u don't even think about it.