there is not a single owner of bitcoin but to me every one who how much bitcoin he has, so he is the owner of such bitcoin and it is his property and he has the right to hold it or sell it or do shopping with it.
yes that is a fact there is not a single owner of bitcoin but every one who has bitcoin in his wallet is the owner of that bitcoin. some people says that Satoshi is the owner of bitcoin but i think he is just the developer of bitcoin and not the owner now.