When kids fight over toys, they're not only trying to gain play-time with it. Anyone with kids will tell you it is really about ownership, or more accurately - entitlement. If you do not have kids, think about your siblings when you were young, or your friends from an early age.
Now, hardly anyone thinks about what is the best or optimal use of data. Most people are concerned with how the data can best serve their objectives. This is rightfully so. You are rewarded if you achieve certain goals and the data is there to server you. But never make the mistake - you do not, EVER, own valuable data!!
Let me explain. Most people would agree that data is meaningless without context. A context is only valuable if it relates to some sort of communication need, which usually relates one entity to another. Hence data has no value without information and information has no value without communication. So you can own data, but it is meaningless and worthless to the rest of the word unless it exist in the context of some sort of communication - which means you do not have exclusive rights to it.
The uncertainty principle states that you cannot have absolute confidence in the value of certain pairs of properties. In the world of data you cannot have absolute ownership and utilization. If you declare an absolute set of stakeholders as the owners of the data, you are limiting the opportunity for the data to be used to its fullest extent (you are likely to inhibit access from some of its rightful users). On the other hand, if you allow the data to be used by all its rightful (some unknown) users, you cannot conclude absolute ownership as you are uncertain of the full set of stakeholders in the data value chain.
You can have "my" data. It is invaluable. But know this: It is not my data and you can only have it if we agree to cap its value and only if our joint entitlement helps me achieve my goals.