100% of all #Bitcoin is in self-custody.
Discussion
I see what you did there.
Possession is 9/10ths of the law, it's true.
It's just you either control the keys or someone else does.
Are you saying there is no Bitcoin left on the exchanges?
You are right, if your the exchange has your keys, they own it. But people should be able to trust exchanges when they are protected by the law. At least during the transaction process, after that, they should move it to their own wallet.