@mint >also owned by the 'flare
You cannot own IPs.

You can get IPs assigned to a business, but there is no ownership.

You can assign whatever IP you want in a router and announce that via BGP, although in the past there was an agreement to only use assigned IPs.

Due to the amount of bad actors, there is RPKI now, which is typically configured to only assign the required keys to those who have the IPs assigned to them and therefore hijacking routes are rejected.